boiling water reactor simulations, models, and

The Pennsylvania State University

The Graduate School

Department of Mechanical and Nuclear Engineering

BOILING WATER REACTOR SIMULATIONS, MODELS, AND

BENCHMARKING USING THE THERMAL HYDRAULICS SUB-CHANNEL

CODE CTF

A Thesis in

Nuclear Engineering

by

Christopher Gosdin

©2015 Christopher Gosdin

Submitted in Partial Fulfillment

of the Requirements

for the Degree of

Master of Science

December 2015

ii

The thesis of Christopher Gosdin was reviewed and approved* by the following:

Maria Avramova

Associate Professor of Nuclear Engineering

Thesis Advisor

Kostadin Ivanov

Professor of Nuclear Engineering

Arthur Motta

Chair of Nuclear Engineering

Professor of Nuclear Engineering and Materials Science and Engineering

*Signatures are on file in the Graduate School

iii

ABSTRACT

CTF, the version of the thermal-hydraulic sub-channel code COBRA-TF being

jointly developed and maintained by Pennsylvania State University (PSU) and Oak Ridge

National Laboratory (ORNL) for applications in the U.S. Department of Energy (DOE)

supported Consortium for Advanced Simulation of Light Water Reactors (CASL) project,

uses a two-fluid, three-field representation of two-phase flow, which makes the code

capable of modeling two-phase flow in Boiling Water Reactors (BWR) during nominal

operating conditions.

The sub-channel code CTF is used for Pressurized Water Reactors (PWR) for best-

estimate evaluations of the nuclear reactor safety margins; however, due to its capabilities,

CTF is powerful and valuable computational tool for modeling BWRs. CTF has been

subjected to a strict verification procedure, by addressing the mathematical accuracy of the

numerical solutions on multiple stages. The code was then validated using numerous of

experimental databases, including the U.S. Nuclear Regulatory Commission (NRC) /

Nuclear Energy Agency of the Organization for Economic Co-operation and Development

(NEA-OECD) Boiling Water Reactor Full Bundle Tests (BFBT) Benchmark. The BFBT

benchmark contains a large amount of test cases representative of BWRs steady-state and

off-nominal operating conditions, which makes it one of the most widely used benchmark

for validating BWR modeling tools. Two of the main experimental tests involve critical

power tests and void distribution tests. Specific experimental cases were chosen and

simulated using CTF. Statistical studies were carried out on the void distribution cases to

evaluate the code modeling uncertainties.

iv

This thesis also focuses on application of CTF to mini- and whole-core BWR

calculations on a pin-cell resolved level; as well as on demonstrating that CTF can properly

model bypass flow in BWR cores. To increase the confidence in the CTF’s BWR modeling

capabilities, extensive simulations have been performed using the international NEA-

OECD / US NNRC Oskarshamn-2 benchmark, including modeling of a single and 2x2

assemblies on a pin-by-pin level, and a full core model on an assembly level. Each model

is varied, with an increasing amount of detail. The results demonstrate that CTF is capable

of modeling basic and complex BWR core configurations and operating conditions. Using

the three Oskarshamn-2 simulations, CTF’s capabilities of modeling BWRs was further

verified.

.

v

Table of Contents

List of Figures ........................................................................................................................... vii

List of Tables ............................................................................................................................. xii

List of Abbreviations.............................................................................................................. xiii

List of Publications ..................................................................................................................xiv

Acknowledgments ..................................................................................................................... xv

Chapter 1: Introduction ............................................................................................................ 1 1.1 Impetus ............................................................................................................................................. 4 1.2 Thesis Structure .............................................................................................................................. 5

Chapter 2: Literature Review .................................................................................................. 7 2.1 Verification of CTF ........................................................................................................................ 7 2.2 Validation of CTF using Small Scale Tests .............................................................................. 9

2.2.1 CTF Test of GE Nine-Rod Bundle Experiment .......................................................................... 9 2.1.2 CTF Test of PELCO’s Sixteen-Rod Test Section Experiment ............................................ 16

2.3 Benchmarks: Introduction and Previous Validation Work ...................................... 22 2.3.1 Void Distribution and Uncertainty ............................................................................................ 22 2.3.2 Critical Heat Flux and Dry-Out Location Analysis ................................................................. 31 2.3 Oskarshamn-2 1999 BWR Stability Event Benchmark ............................................................. 38

Chapter 3: CTF Application to BWR Modeling and Simulations ............................... 39 3.1 CTF Models .................................................................................................................................. 39

3.1.1 Single Assembly on a Pin-Cell Resolved Level ....................................................................... 41 3.1.2 2x2 Array Assemblies on Pin-cell Resolved Level ................................................................. 43 3.1.3 Full Core on Assembly-Cell Resolved Level ............................................................................ 44

3.2 Results ............................................................................................................................................ 45 3.1.1 Single Assembly ................................................................................................................................. 46 3.2.3 2x2 Assembly ...................................................................................................................................... 48 3.2.3 Overall Comparisons between Models 1 and 2 ........................................................................ 50 3.2.4 Full Core ............................................................................................................................................... 53

3.3 Observations ................................................................................................................................. 59

Chapter 4: CTF Validation of BFBT .................................................................................. 61 4.1 Void Distribution ........................................................................................................................ 61

4.1.1 CTF Model ........................................................................................................................................... 62 4.1.2 Results ................................................................................................................................................... 70 4.1.3 Sensitivity Analysis ........................................................................................................................... 77

4.2 Critical Power .............................................................................................................................. 83 4.2.1 CTF Model ........................................................................................................................................... 83 4.2.2 Results ................................................................................................................................................... 86

Chapter 5: Conclusions and Future Work ........................................................................ 93 5.1 Conclusions ................................................................................................................................... 93 5.2 Future Work ................................................................................................................................. 96

Works Cited .............................................................................................................................. 98

vi

Appendix A: Sample CTF Input Deck for BFBT BWR FA ........................................ 100

Appendix B: Void Distribution Sensitivity Plots ............................................................ 119

vii

List of Figures

Figure 1: Sample PWR design [2] ...................................................................................... 1 Figure 2: Sample BWR design [2] ...................................................................................... 2 Figure 3: Comparison of Bundle Average Mass Fluxes in two-phase tests [9] ................ 11 Figure 4: Comparison of Bundle Average Quality in Two-Phase Tests [9] ..................... 11 Figure 5: Comparison of Corner Sub-channel Mass Fluxes in Two-Phase Tests [9] ....... 12

Figure 6: Comparison of Corner Sub-channel Quality in Two-Phase Tests [9] ............... 12 Figure 7: Comparison of Side Sub-channel Mass Fluxes in Two-Phase Tests [9] ........... 13 Figure 8: Comparison of Side Sub-channel Quality in Two-Phase Tests [9] ................... 13 Figure 9: Comparison of Center Sub-channel Mass Fluxes in Two-Phase Tests [9] ....... 14

Figure 10: Comparison of Center Sub-channel Quality in Two-Phase Tests [9] ............. 14 Figure 11: Comparison of Sub-channel Mass Fluxes in Two-Phase, Non-Uniform Heated

Tests [9] .................................................................................................................... 15 Figure 12: Comparison of Sub-channel Qualities in Two-Phase, Non-Uniform Heated

Tests [9] .................................................................................................................... 15 Figure 13: Comparison of Bundle Average Velocity [9] .................................................. 17 Figure 14: Comparison of Bundle Average Quality [9] ................................................... 18

Figure 15: Comparison of Corner Sub-channel Velocity [9]............................................ 18 Figure 16: Comparison of Corner Sub-channel Quality [9] ............................................. 19 Figure 17: Comparison of Side Sub-channel Velocity [9]............................................... 19

Figure 18: Comparison of Side Sub-channel Quality [9] ................................................. 20 Figure 19: Comparison of Internal Sub-channel Velocity [9] .......................................... 20

Figure 20: Comparison of Internal Sub-sub-channel Quality [9] ..................................... 21

Figure 21: Comparison of Center Sub-channel Velocity [9] ............................................ 21

Figure 22: Comparison of Center Sub-channel Quality [9] .............................................. 22 Figure 23: Two Phase Pressure Drop [17] ........................................................................ 25

Figure 24: Predicted vs. Measured Sub-channel and Bundle Average Void Fractions [17]

................................................................................................................................... 25 Figure 25: Predicted vs. Measured Bundle Average Void Fraction during Pump Trip

Transient [17] ............................................................................................................ 26 Figure 26: Predicted vs. Measured Bundle Average Void Fraction during Turbine Trip

[17] ............................................................................................................................ 26 Figure 27: BWR Bundle Radial Power Distribution [19] ................................................. 27 Figure 28: BWR Bundle Axial Power Distribution [19] .................................................. 28 Figure 29: CTF Model [19]............................................................................................... 29

Figure 30: Comparison of Single-phase and Two-phase Pressure Drops [20] ................. 33 Figure 31: Predicted versus Measured Critical Power for Experiment Assembly Using 3

Different Turbulent Mixing Models ......................................................................... 36

Figure 32: Predicted over Measured Critical Power versus Flow Rate ............................ 37 Figure 33: Predicted over Measured Critical Power versus Pressure ............................... 37 Figure 34: Predicted over Measured Critical Power versus Subcooling .......................... 37 Figure 35: Oskarshamn-2 Power Oscillations [23] ........................................................... 38 Figure 36: Single BWR assembly pattern ......................................................................... 42 Figure 37: Varying models of complexity for single BWR assembly .............................. 42

viii

Figure 38: Varying models of complexity for 2x2 BWR array ........................................ 43 Figure 39: Possible modeling schemes for CTF ............................................................... 44 Figure 40: Full core assembly types [21] .......................................................................... 45 Figure 41: Pressure over the axial position for single BWR assembly ............................. 46

Figure 42: Vapor Void Fraction over axial position for single BWR assembly ............... 48 Figure 43: Pressure over axial position for 2x2 BWR array ............................................. 49 Figure 44: Vapor void fraction over axial position for 2x2 BWR array ........................... 50 Figure 45: Pressure over axial pressure for single and 2x2 BWR assembly .................... 51 Figure 46: Vapor void fraction over axial pressure for single and 2x2 BWR assembly .. 52

Figure 47: Pressure over axial position for bundle and bypass regions ............................ 52 Figure 48: Pressure over axial position for type 4 assemblies .......................................... 55 Figure 49: Pressure over axial position for type 2 and 3 assemblies ................................ 55 Figure 50: Pressure over axial position for type 1 assemblies .......................................... 56

Figure 51: Vapor void fraction over axial position for type 4 assemblies ........................ 58 Figure 52: Vapor void fraction over axial position for type 2 and 3 assemblies .............. 58

Figure 53: Vapor void fraction over axial position for type 4 assemblies ........................ 59 Figure 54: Description of BFBT assembly types 0-1, 0-2, and 0-3 [18] .......................... 64

Figure 55: Description of BFBT assembly types 1,2, and 3 [18] ..................................... 65 Figure 56: Description of BFBT assembly type 4 [18]..................................................... 66 Figure 57: Void measurement locations and techniques used in BFBT facility [18] ....... 68

Figure 58: Channel map for assembly types 4, C2A, C2B, and C3 with area and wetted

perimeter ................................................................................................................... 68

Figure 59: Channel map for assembly types 0-1, 0-2, and 0-3 with area and wetted

perimeter ................................................................................................................... 69 Figure 60: Channel Map of loss coefficient for spacer grids calculated by Shiralkar and

Radcliffe [13] ............................................................................................................ 69

Figure 61: BFBT spacer grid design [18] ........................................................................ 70 Figure 62: Comparison of measured and predicted bundle-averaged exit void [25] ........ 72 Figure 63: CTF-predicted and measured bundle-averaged thermal equilibrium quality

[25] ............................................................................................................................ 73 Figure 64: CTF void predictions vs experimental measurement of sub-channels for all

BFBT test cases......................................................................................................... 73 Figure 65: Average void measurements for specific channel categories in experiment [25]

................................................................................................................................... 74 Figure 66: CTF void predictions vs experimental measurement of all corner sub-channels

for all BFBT test cases .............................................................................................. 75 Figure 67: CTF void predictions vs experimental measurement of all side sub-channels

for all BFBT test cases .............................................................................................. 76

Figure 68: CTF void predictions vs experimental measurement of all normal inner sub-

channels for all BFBT test cases ............................................................................... 76

Figure 69: CTF void predictions vs experimental measurement of all sub-channels

touching unheated conductors for all BFBT test cases ............................................. 77 Figure 70: Mass flow rate sensitivity test ......................................................................... 79 Figure 71: Power sensitivity test ....................................................................................... 80 Figure 72: Pressure sensitivity test ................................................................................... 80 Figure 73: Enthalpy sensitivity test................................................................................... 81

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Figure 74: Equilibrium distribution weighting factor sensitivity test ............................... 81 Figure 75: Turbulent mixing coefficient sensitivity test ................................................... 82 Figure 76: THETA sensitivity test .................................................................................... 82 Figure 77: Radial power profile for assembly type C2A [18] .......................................... 84

Figure 78: Axial power profile for assembly type C2A [18] ............................................ 85 Figure 79: Thermocouple locations for critical power experiments using assembly C2A

[18] ............................................................................................................................ 86 Figure 80: Experimental DNB location (green) compared to CTF simulation DNB

location ...................................................................................................................... 90

Figure 81: Temperature map of all rods in Test Case SA510800 at height 3.521m......... 90 Figure 82: Temperature map of all rods in Test Case SA510800 at height 3.009m......... 91 Figure 83: Temperature map of all rods in Test Case SA510800 at height 2.497m......... 91 Figure 84: Difference in temperature between the critical power case and the steady state

case before at height 3.521m .................................................................................... 91 Figure 85: Difference in temperature between the critical power case and the steady state

case before at height 3.009m .................................................................................... 92 Figure 86: Difference in temperature between the critical power case and the steady state

case before at height 2.497m .................................................................................... 92 Figure 87: CASL toolkit VERA for LWR reactor core simulations [14] ......................... 93 Figure 88: Equilibrium distribution weighting factor sensitivity Test Case 0011-58 .... 119

Figure 89: Power sensitivity Test Case 0011-58 ............................................................ 119 Figure 90: Turbulent mixing coefficient sensitivity Test Case 0011-58 ........................ 119

Figure 91: Mass flow rate sensitivity Test Case 0011-58 ............................................... 120 Figure 92: Enthalpy sensitivity Test Case 0011-58 ........................................................ 120 Figure 93: Pressure sensitivity Test Case 0011-58 ......................................................... 120

Figure 94: THETA sensitivity Test Case 0011-58 ......................................................... 121

Figure 95: Equilibrium distribution weighting factor sensitivity Test Case 0011-61 .... 121 Figure 96: Power sensitivity Test Case 0011-61 ............................................................ 121 Figure 97: Turbulent mixing coefficient sensitivity Test Case 0011-61 ........................ 122

Figure 98: Mass flow rate sensitivity Test Case 0011-61 ............................................... 122 Figure 99: Enthalpy sensitivity Test Case 0011-61 ........................................................ 122

Figure 100: Pressure sensitivity Test Case 0011-61 ....................................................... 123 Figure 101: THETA sensitivity Test Case 0011-61 ....................................................... 123

Figure 102: Equilibrium distribution weighting factor sensitivity Test Case 0021-16 .. 123 Figure 103: Power sensitivity Test Case 0021-16 .......................................................... 124 Figure 104: Turbulent mixing coefficient sensitivity Test Case 0021-16 ...................... 124 Figure 105: Mass flow rate sensitivity Test Case 0021-16 ............................................. 124 Figure 106: Enthalpy sensitivity Test Case 0021-16 ...................................................... 125


Figure 109: Equilibrium distribution weighting factor sensitivity Test Case 0021-18 .. 126 Figure 110: Power sensitivity Test Case 0021-18 .......................................................... 126 Figure 111: Turbulent mixing coefficient sensitivity Test Case 0021-18 ...................... 126 Figure 112: Mass flow rate sensitivity Test Case 0021-18 ............................................. 127 Figure 113: Enthalpy sensitivity Test Case 0021-18 ...................................................... 127 Figure 114: Pressure sensitivity Test Case 0021-18 ....................................................... 127

x

Figure 115: THETA sensitivity Test Case 0021-18 ....................................................... 128 Figure 116: Equilibrium distribution weighting factor sensitivity Test Case 0021-21 .. 128 Figure 117: Power sensitivity Test Case 0021-21 .......................................................... 128 Figure 118: Turbulent mixing coefficient sensitivity Test Case 0021-21 ...................... 129

Figure 119: Mass flow rate sensitivity Test Case 0021-21 ............................................. 129 Figure 120: Enthalpy sensitivity Test Case 0021-21 ...................................................... 129 Figure 121: Pressure sensitivity Test Case 0021-21 ....................................................... 130 Figure 122: THETA sensitivity Test Case 0021-21 ....................................................... 130 Figure 123: Equilibrium distribution weighting factor sensitivity Test Case 0031-16 .. 130

Figure 124: Power sensitivity Test Case 0031-16 .......................................................... 131 Figure 125: Turbulent mixing coefficient sensitivity Test Case 0031-16 ...................... 131 Figure 126: Mass flow rate sensitivity Test Case 0031-16 ............................................. 131 Figure 127: Enthalpy sensitivity Test Case 0031-16 ...................................................... 132


Figure 130: Equilibrium distribution weighting factor sensitivity Test Case 0031-18 .. 133 Figure 131: Power sensitivity Test Case 0031-18 .......................................................... 133

Figure 132: Turbulent mixing coefficient sensitivity Test Case 0031-18 ...................... 133 Figure 133: Mass flow rate sensitivity Test Case 0031-18 ............................................. 134 Figure 134: Enthalpy sensitivity Test Case 0031-18 ...................................................... 134


Figure 137: Equilibrium distribution weighting factor sensitivity Test Case 0031-21 .. 135 Figure 138: Power sensitivity Test Case 0031-21 .......................................................... 135 Figure 139: Turbulent mixing coefficient sensitivity Test Case 0031-21 ...................... 136

Figure 140: Mass flow rate sensitivity Test Case 0031-21 ............................................. 136

Figure 141: Enthalpy sensitivity Test Case 0031-21 ...................................................... 136 Figure 142: Pressure sensitivity Test Case 0031-21 ....................................................... 137 Figure 143: THETA sensitivity Test Case 0031-21 ....................................................... 137

Figure 144: Equilibrium distribution weighting factor sensitivity Test Case 4101-53 .. 137 Figure 145: Power sensitivity Test Case 4101-53 .......................................................... 138

Figure 146: Turbulent mixing coefficient sensitivity Test Case 4101-53 ...................... 138 Figure 147: Mass flow rate sensitivity Test Case 4101-53 ............................................. 138

Figure 148: Enthalpy sensitivity Test Case 4101-53 ...................................................... 139 Figure 149: Pressure sensitivity Test Case 4101-53 ....................................................... 139 Figure 150: THETA sensitivity Test Case 4101-53 ....................................................... 139 Figure 151: Equilibrium distribution weighting factor sensitivity Test Case 4101-55 .. 140 Figure 152: Power sensitivity Test Case 4101-55 .......................................................... 140

Figure 153: Turbulent mixing coefficient sensitivity Test Case 4101-55 ...................... 140 Figure 154: Mass flow rate sensitivity Test Case 4101-55 ............................................. 141

Figure 155: Enthalpy sensitivity Test Case 4101-55 ...................................................... 141 Figure 156: Pressure sensitivity Test Case 4101-55 ....................................................... 141 Figure 157: THETA sensitivity Test Case 4101-55 ....................................................... 142 Figure 158: Equilibrium distribution weighting factor sensitivity Test Case 4101-58 .. 142 Figure 159: Power sensitivity Test Case 4101-58 .......................................................... 142 Figure 160: Turbulent mixing coefficient sensitivity Test Case 4101-58 ...................... 143

xi

Figure 161: Mass flow rate sensitivity Test Case 4101-58 ............................................. 143 Figure 162: Enthalpy sensitivity Test Case 4101-58 ...................................................... 143 Figure 163: Pressure sensitivity Test Case 4101-58 ....................................................... 144 Figure 164: THETA sensitivity Test Case 4101-58 ....................................................... 144

Figure 165: Equilibrium distribution weighting factor sensitivity Test Case 4101-61 .. 144 Figure 166: Power sensitivity Test Case 4101-61 .......................................................... 145 Figure 167: Turbulent mixing coefficient sensitivity Test Case 4101-61 ...................... 145 Figure 168: Mass flow rate sensitivity Test Case 4101-61 ............................................. 145 Figure 169: Enthalpy sensitivity Test Case 4101-61 ...................................................... 146


xii

List of Tables

Table 1: GE Nine-Rod Bundle Test Conditions [9].......................................................... 10

Table 2: PELCO-S Sixteen-Rod Bundle Test Conditions [9] .......................................... 16 Table 3: BFBT Benchmark phases [18]............................................................................ 22 Table 4: Cases for Exercise I-4 [19] ................................................................................. 27 Table 5: Uncertainty Input Parameters [18]...................................................................... 29 Table 6: Predicted-to-Measured Void Distribution at Reference Conditions [19] ........... 31

Table 7: Coverage Ratio Calculated With Experimental Uncertainty of 8% [19] ........... 31 Table 8: Conditions of CTF Test Runs [20] ..................................................................... 34 Table 9: Comparison of Predicted and Measured Critical Power and Dry-out location [20]

................................................................................................................................... 34

Table 10: Steady-State Critical Power Measurement COnditions for experiment

Assembly [18] ........................................................................................................... 35

Table 11: Operating Conditions ........................................................................................ 40 Table 12: Model Variation ................................................................................................ 40

Table 13: Model Assumptions [21] .................................................................................. 40 Table 14: BFBT benchmark phases [18] .......................................................................... 61 Table 15: BFBT void distribution test conditions [18] ..................................................... 63

Table 16: Radial power profile for assembly types 1-3 [18] ............................................ 66 Table 17: Radial power profile for assembly type 4 [18] ................................................. 67 Table 18: Axial power profile [18] ................................................................................... 67

Table 19: Dakota sensitivity analysis parameters ............................................................. 78 Table 20: BFBT critical power test conditions [18] ......................................................... 84

Table 21: Comparison of experimental to simulation critical power ............................... 89

xiii

List of Abbreviations

BFBT Boiling water reactor Full-size Fine-mesh Bundle Test Benchmark

BWR Boiling water reactor

CASL The Consortium for Advanced Simulation of LWRs

CHF Critical Heat Flux

COBRA-TF Coolant Boiling in Rod Arrays – Two Fluids

CTF COBRA-TF: Coolant Boiling for Rod Arrays Three Field

DNB Departure from Nucleate Boiling

DOE United States Department of Energy

GE General Electric

NEA-OECD Nuclear Energy Agency

NRC United States Nuclear Regulatory Commission

OECD Organization for Economic Co-operation and Development

ORNL Oak Ridge National Laboratory

PSU The Pennsylvania State University

PWR Pressurized water reactor

RDFMG Reactor Dynamics and Fuel Management Group

TH Thermal-Hydraulics

xiv

List of Publications

1. C. Gosdin, M. Avramova, R. Salko, “CTF Application to BWR Modeling and Simulations”

NURETH-16, Chicago, Illinois, 2015.

xv

Acknowledgments

First and most important, I would like to acknowledge Dr. Maria Avramova for her

assistance, instruction, and supervision during my time as a graduate student at The

Pennsylvania State University. I would also like to thank Dr. Kostadin Ivanov for his

support and knowledge during my time as a member of the Reactor Dynamics and Fuel

Management Group (RDFMG) at Penn State. I am grateful for working with them, and

believe this thesis would not be able to be completed anywhere else.

1

Chapter 1: Introduction

In 1942 history was made when the first man-made nuclear reactor went critical.

This accomplishment by the scientists in Chicago paved the way for nuclear power being

a major factor in the power grid for the United States [1]. The United States currently

employs Light Water Reactors (LWRs) which are broken up into two types, Boiling Water

Reactor (BWRs) and Pressurized Water Reactor (PWRs). The main difference between the

reactors is how they treat the water that is heated by the core. In PWRs, the loop is kept

under pressure, to keep the water from boiling as shown in Figure 1.

Figure 1: Sample PWR design [2]

On the other hand, BWRs have a lower pressure to allow the water to boil and use steam

effectively using only 1 loop rather then 2, which is shown in Figure 2

2

Figure 2: Sample BWR design [2]

BWRs main difference is the usage of boiling flow along the saturation line of water, while

PWRs use pressurizers to ensure no to very little boiling occurs. This change has a large

effect on the neutronics, material interactions, and power distribution/generation in a

reactor. The geometry of BWRs are different, creating different flow patterns. One example

are the ducts containing water that surround each fuel assembly. Also BWRs require water

rods within the assembly, which take up a considerable amount of water flow area and

increase the local power due to more efficient neutron moderation. These rods will then

lead to differences in neutronics and the general heat transfer in the area. The boiling will

also cause the acceleration term to have a larger impact in pressure change when compared

to non-boiling models. Therefore it is important to test any code designed to model LWRs,

to ensure its validity is still acceptable for both BWRs and PWRs [2].

CTF is a best-estimate thermal-hydraulic sub-channel code based on the COBRA-

TF family codes. COBRA-TF (COolant Boiling in Rod Array-Two Fluid) was established

at The Pacific Northwest National Laboratory (PNNL) [3]. CTF has been further

developed, verified, maintained, and validated by the Reactor Dynamics and Fuel

3

Management Group (RDFMG) at The Pennsylvania State University. The code provides a

three-dimensional, two-fluid, three-field representation of two-phase flow. The liquid

phase contains a continuous field and an entrained liquid drop field. The last field is

continuous vapor. CTF solves for each spatial dimension, three momentum conservation

equations, four mass conservation equations (including an explicit non-condensable gasses

mass conservation equation), and two energy conservation equations [4]. The continuous

liquid field assumes that it is in thermal equilibrium with the droplet field [5].

There are currently specific versions of COBRA-TF that have been developed

worldwide, which shows the code capabilities of modeling both PWRs and in particular

BWRs. The first example is found in [6] which models the heat transfer effects of the

spacer grids. The grids are needed to maintain the space between fuel rods and as support

in the core. They will also act as flow obstructions in the bundles and as a result increase

the overall pressure losses due to form drag and skin friction. Heat transfer within and

downstream of the grid spacers are the main heat transfer effects. Since the spacers take up

area, they contract flow and then expand it downstream, creating an increase in heat transfer

[7]. The entrained droplets are broken up into smaller drops, therefore increasing the drop

surface area. Rewetting of the liquid film on the grid leads to cooling of the vapor flow [6].

Therefore heat transfer will be predicted more accurately since the code consider interfacial

heat transfer between the continuous vapor field and the entrained liquid droplets field.

Since multiple fields flow is extensively present within BWR cores, the accurate modeling

of multi-phase multi-field flow is of critical importance for BRWs simulations.

In 2003 Penn State transferred their version of COBRA-TF to AREVA NP within

the framework of a joint project. AREVA NP officially re-branded the code to F-COBRA-

4

TF, with goals of modeling PWRs and BWRs [8]. Since then a large amount of in-house

development was done to the point where it has been verified and validated and used for

both types of LWRs [9]. The code was validated using the BFBT benchmark database as

well as in-house measurements. Also a methodology to derive spacer pressure loss

coefficients was also introduced into the code. These achievements lead to the results being

extremely sufficient.

The ability to correctly predict pressure losses in two phase-flow is vital to

modeling of BWRs. This includes effects from wall drag, interfacial drag, and form losses

due to the presence of spacer grids. CTF includes a two-phase pressure drop model based

on the work of Wallis and grids are treated using simple velocity head losses [10]. Spacer

grids also have an impact on rod heat transfer due to enhanced turbulence and boundary

layer disruption within and downstream of the grid [11]. In very high void conditions,

entrained droplets are broken up into smaller drops, which increases the droplet surface

area and interfacial heat transfer. Additionally, rewetting of the spacer grid in accident

conditions leads to cooling of the superheated vapor flowing through the core [6]. An

analysis of steady state and transient void distribution predictions for Phase I of the

OECD/NRC BFBT benchmark were performed using CTF as a part of the coupled

CTF/NEM code system [12]. The CTF validation to the OECD/NRC BFBT benchmark

single- and two-phase pressure drop exercises has proven the code capabilities of

predicting pressure losses in a BWR environment [13].

1.1 Impetus

The current RDFMG version of CTF is being jointly improved, maintained, and tested by

PSU and ORNL for applications in the US DOE program Consortium for Advanced

5

Simulation of Light Water Reactors (CASL). Department of Energy sponsored CASL

Energy Innovation Hub. During Phase I of CASL, CTF was utilized primarily for

modeling and simulation of PWRs. However, its application is being currently extended to

BWR analysis, in Phase II of the program. Therefore CTF must be further validated under

CASL’s strict guidelines by simulating and modeling different BWR cases. The main

issues that will be discussed hereafter are the bypass interactions, the void distribution, and

the onset of dryout. The data collected during this project will allow CASL to further their

validation of CTF with BWRs during Phase II of the CASL’s project plan. A sample of

CTF input deck for BWR fuel bundle is shown in Appendix A: Sample CTF Input Deck

for BFBT BWR Fuel Assembly.

The mission of CASL is to “Provide coupled, higher-fidelity, usable modeling and

simulation capabilities needed to address light water reactor operational and safety

performance-defining phenomena.” [14]. This is done by creating a suite comprised of

verified and validated simulation tools that can be used and applied for virtual environment

for reactor applications (VERA). CTF is just one tool that is used in this suite and must be

able to simulate and model all types of LWRs [14].

1.2 Thesis Structure

This thesis is comprised of five chapters. This section outlines each chapter’s

purpose and the overall goal of this thesis.

Chapter 2 comprises of a comprehensive literature review of past BWR verification

and validation using CTF and other versions of COBRA-TF. An overview of important

benchmarks that have been completed and are vital for verifying and validating codes will

6

be presented. The last section of chapter 2 will be a detailed overview of computational

tools used.

Chapter 3 gives an in depth look at modeling and simulating internal, external, and

water bypasses in BWRs. There are three different cases with varying detail to thoroughly

examine the capabilities of CTF of modeling and simulating BWRs. This chapter mainly

uses CTF with some comparisons to other codes, such as TRACE for example [15].

Chapter 4 discusses the validation of CTF using BFBT benchmark specifications

for critical power and void distribution. A sensitively study was also completed for void

distribution using Dakota tool [16].

Chapter 5 provides a summary of the work, conclusions, and discussion of future

work needed for CASL’s plans for CTF in VERA.

7

Chapter 2: Literature Review

This chapter will serve as a literature review of several past CTF verification and

validation studies in modeling BWRs. Also all benchmark information that was used will

be introduced and discussed. Last, the computational tools used and needed to complete

this work are discussed.

2.1 Verification of CTF

Verification involves confirming that processes or models, including computer

codes, performs as envisioned. This is extremely important for CTF since it is simulating

nuclear reactors. BWRs are also more complicated due to the use of steam in the first loop.

Therefore verifying the ability of simulating three fields in CTF is imperative. For that

reason, it is vital that the mathematical accuracy of the numerical solutions CTF uses are

correct with accordance to BWRs. To achieve this verification, the models, turbulent

mixing, void drift, and spacer grid must be confirmed [7]. To verify code requires code

verification and solution verification. Code verification involves finding and removing

mistakes and errors in the source code and numerical algorithms, and improving software

using software quality assurance practices. This is an ongoing process that has been

scrutinized over the years to perfect the code. Solution verification deals with the accuracy

of input data for the problem of interest, estimating the numerical solution and other errors,

and the accuracy of the output data for the problem of interest. Therefore the following

sections will discuss the modules implemented in CTF and the results specifically related

to BWRs ensuring proper code verification.

8

Turbulent mixing is inter-channel mixing due to turbulence effects in the fluid flow.

This will cause momentum and energy transfer between the sub-channels most often with

zero net mass transfer. Lateral pressure gradients may also cause diversion cross-flow in a

non-equilibrium flow. This may result from different geometry or obstructions such as

spacer grids which are modeled by CTF. When two-phase flow conditions happen, void

drift will also disrupt the above processes. Since this work main focus is on BWRs, void

drift is a vital module that has to be verified. It is cross flow resulting from a two-phase

flow reaching an equilibrium condition and thusly causing a net transfer of liquid and vapor

from one sub-channel to a different sub-channel. This effect is called vapor diffusion, or

void drift. Two-phase flow also changes the simple definition of turbulent mixing because

zero net mass transfer is technically incorrect now. The equal mass exchange model is

replaced by an equal volume exchange model in order to explain energy transport. The

models are necessary if two-phase flow is going to be accurately modeled, which is

substantial in BWRs. Both flow conditions are lumped into a net mixing model, since they

both result in mass, energy, and momentum transfer between sub-channels and occur in the

absence of pressure gradients. Another feature is that the mixing rate is dependent on the

flow regime. Hence mixing is greatest when close to the slug-annular transition point [9].

Next, the spacer grids, which were originally used to maintain proper geometrical

configurations of the fuel rod bundles, also have a large impact on the fluid dynamics and

heat transfer in the system. As discussed earlier, spacer grids increase the overall pressure

losses due to form drag and skin friction, and change the flow area by contracting and

expanding it. In general though, spacer grids have an overall positive effect on the heat

transfer and delay or avoid the critical power occurrence in BWR fuel assemblies. CTF

9

includes a model for de-entrainment on the grid spacers. However it does not have any

models for spacer caused entrainment or downstream deposition effects. CTF has been

modified to improve entrainment and deposition modeling of liquid film with a focus on

BWR fuel rod dry-out [7].

2.2 Validation of CTF using Small Scale Tests

2.2.1 CTF Test of GE Nine-Rod Bundle Experiment

The General Electric (GE) nine-rod bundle experimental facility was created to

study sub-channel and flow-structure measurement. The local heat flux distributions were

able to replicate a typical BWR peaking pattern. Note instead of spacer grids, small pins

were used for holing the relative radial position of the rods. Table 1 below shows the test

conditions used. It must be noted that the sub-channel sampling was not done

simultaneously, and therefore continuity errors as large as 5% have been found.

10

Table 1: GE Nine-Rod Bundle Test Conditions [9]

The CTF model requires an amount of mixing between adjoined sub-channels in

the input deck. The value of 0.04 is used based on previous studies. A single-phase

calculation was used to find the value of 0.02 for the Mixing Staton Number, which was

used for all calculations. The model is divided into sixteen sub-channels, consisting of four

corner, eight side, and four center sub-channels. Two axial boundary conditions are applied

to the test. They are flow rate and enthalpy on the bottom and pressure and enthalpy on the

top. The first part of the experiment consists of 13 uniformly-heated cases with a wide

range of velocities and qualities. The comparisons are shown in Figure 3 to Figure 12. The

results show strong agreement. Figure 11Figure 12 show the results of non-uniformly-heat

cases, which are not as good as uniformly-heated, but still predicted within the realms of

acceptance [9].

11

Figure 3: Comparison of Bundle Average Mass Fluxes in two-phase tests [9]

Figure 4: Comparison of Bundle Average Quality in Two-Phase Tests [9]

12

Figure 5: Comparison of Corner Sub-channel Mass Fluxes in Two-Phase Tests [9]

Figure 6: Comparison of Corner Sub-channel Quality in Two-Phase Tests [9]

13

Figure 7: Comparison of Side Sub-channel Mass Fluxes in Two-Phase Tests [9]

Figure 8: Comparison of Side Sub-channel Quality in Two-Phase Tests [9]

14

Figure 9: Comparison of Center Sub-channel Mass Fluxes in Two-Phase Tests [9]

Figure 10: Comparison of Center Sub-channel Quality in Two-Phase Tests [9]

15

Figure 11: Comparison of Sub-channel Mass Fluxes in Two-Phase, Non-Uniform Heated Tests [9]

Figure 12: Comparison of Sub-channel Qualities in Two-Phase, Non-Uniform Heated Tests [9]

16

2.1.2 CTF Test of PELCO’s Sixteen-Rod Test Section Experiment

The PELCO-S is a heated test section designed in a test facility by Centro Informationi,

Studi ed Esperienze, Centre for Information, Research and Experiemnts in Italy. As with

the above simulation, both the two-phase flow conditions and geometrical characteristics

are close to that of a BWR. The experiment measured mass flow rate and quality

distribution in a 4x4 (16 rod) model. The test is performed at slightly above normal pressure

of 7 MPa. The exit qualities varied from 2% to 31%, and mass velocities of roughly 1000,

1500, and 2000 kg/m2. The bundle test conditions are listed below in Table 2 [9].

Table 2: PELCO-S Sixteen-Rod Bundle Test Conditions [9]

The CTF model consists of 25 sub-channels, including four corner, twelve side, eight

internal, and one center sub-channel. As above, a value of 0.02 for the Mixing Stanton

Number is used. The same boundary conditions are applied as above, flow rate and

enthalpy on the bottom and pressure and enthalpy on the top. 16 test cases were simulated

17

using the above geometry. The results are below in figures 11 – 20. The results show strong

agreement, however it must be noted that there is an over prediction present at the corner

sub-channel values. One possible reason is that the liquid film is thicker along the unheated

wall [9].

Figure 13: Comparison of Bundle Average Velocity [9]

18

Figure 14: Comparison of Bundle Average Quality [9]

Figure 15: Comparison of Corner Sub-channel Velocity [9]

19

Figure 16: Comparison of Corner Sub-channel Quality [9]

Figure 17: Comparison of Side Sub-channel Velocity [9]

20

Figure 18: Comparison of Side Sub-channel Quality [9]

Figure 19: Comparison of Internal Sub-channel Velocity [9]

21

Figure 20: Comparison of Internal Sub-sub-channel Quality [9]

Figure 21: Comparison of Center Sub-channel Velocity [9]

22

Figure 22: Comparison of Center Sub-channel Quality [9]

2.3 Benchmarks: Introduction and Previous Validation Work

2.3.1 Void Distribution and Uncertainty

Part of the OECD/NRC BWR Full-size Fine-mesh Bundle Test (BFBT) has been

modeled using an older version of CTF which was part of CTF/NEM, RDFMG’s coupled

thermal hydraulics and neutronics code. The CTF part of the coupled code was applied to

specific exercises of the BFBT Benchmark shown below in Table 3. Previous work at Penn

State included work on Exercises 1 and 3 of phase 1 and phase 0 of phase 2 [17].

Table 3: BFBT Benchmark phases [18]

Phase I Void Distribution Benchmark

Exercise 1 Steady-state sub-channel grade benchmark

23

Exercise 2 Steady-state microscopic grade benchmark

Exercise 3 Transient macroscopic grade benchmark

Exercise 4 Uncertainty analysis of the void distribution benchmark

Phase II Critical Power Benchmark

Exercise 0 Steady-state pressure drop benchmark

Exercise 1 Steady-state critical power benchmark

Exercise 2 Transient benchmark

The OECD/NRC BFBT Benchmark heavily focuses and encourages the

advancement in sub-channel analysis of two-phase flow in rod bundles. The main goal is

to provide a strong database of benchmark specifications that can be used to analyze and

compare numerical models for sub-channel void distribution and critical power to the

experimental database. The advancement in computational codes that have the capability

of modeling BWR is expanding at fast within the last decade. It is expected to expand even

more in the next decade, and therefore the BFBT specifications aims to be one of the best

experimental databases for new sub-channel codes. The procedure has been documented

carefully and states that all participants detail how they model each phase to ensure the best

comparisons possible [18].

Figure 24 show calculated void fractions at the CT (computer tomography) scanner

position are compared to the experimental data. The figures show a slight over-prediction

of bundle average void fraction. This agrees with the results of the two phase pressure drop

data where the total pressure drop was slightly over-predicted shown in Figure 23 [17]. It

is assumed that the cause of the over prediction is most likely overestimated interfacial

drag forces therefore an overestimation of the slip. As a result under-predicted vapor

velocity yields a higher void fraction. However the spacer grid models created since the

experiment may increase the accuracy of the results [7]. Next experiments were performed

24

by Nuclear Power Engineering Corporation (NUPEC), Japan on four different transient

cases: re-circulation pump trip, re-circulation pump stick, turbine trip without bypass, and

malfunction of pressure control system. Of those four, the re-circulation pump trip and the

turbine trip without bypass were simulated to compare as benchmark exercise cases. The

space-averaged instantaneous axial void fraction profiles were supplied for comparisons

between the code and the data. CTF was applied to both scenarios, with the results shown

in Figure 25 and Figure 26 for the re-circulation pump trip and the turbine trip without

bypass respectively. Measurements were taken at four different elevations along the heat

length. Due to boiling conditions, the vapor volume fraction is higher at high velocity

regions. Therefore the sub-channel void fractions observed were overestimated at the upper

part of the bundle when measured with an X-ray densitometer. On the contrary, the lower

part of the bundle could see opposite results since bubbles would be highly concentrated

near heated surfaces. When comparing the results to CTF, it is seen that it is quite capable

of reproducing the transient behavior of the bundle average void fraction in each scenario.

It is apparent that the results are in better agreement at higher axial elevations. Looking at

the CT scanner results, it is shown that CTF overestimates the bundle void fraction, similar

to the steady-state comparisons [17].

25

Figure 23: Two Phase Pressure Drop [17]

Figure 24: Predicted vs. Measured Sub-channel and Bundle Average Void Fractions [17]

26

Figure 25: Predicted vs. Measured Bundle Average Void Fraction during Pump Trip Transient [17]

Figure 26: Predicted vs. Measured Bundle Average Void Fraction during Turbine Trip [17]

As a precaution, it is important to look at the uncertainties of the void distribution

predictions discussed above. The BFBT data excels in developing modeling capabilities by

taking into account the uncertainty analysis in the benchmark. Thus allowing a stronger

analysis with CTF’s predictions. Most simulated results have sources of error mainly from

27

uncertainties in input decks. As a result it is important to compare uncertainties from

simulations from CTF to measurement uncertainties from the BFBT Benchmark data.

Therefore a detailed uncertainty analysis was performed by Penn State in cooperation with

the GRS mbH, which provided the GRS methodology which has been used in the past for

a wide range of problems [19]. The goal of the project is to look at the performed

uncertainty and sensitivity analysis in the framework of Exercise 4 of Phase I of the

OECD/NRC BFBT Benchmarks [18]. The cases looked at for exercise four are presented

below in Table 4 followed by the BWR bundle radial and axial power distributions for the

test cases in Figure 27 and Figure 28 respectively [19].

Table 4: Cases for Exercise I-4 [19]

Figure 27: BWR Bundle Radial Power Distribution [19]

28

Figure 28: BWR Bundle Axial Power Distribution [19]

Using the created CTF model, Figure 29, and analyzing them with the GRS method

requires multiple steps to ensure proper results. The CTF model is for high-burnup 8x8

BWR assembly, consisting of eighty (80) sub-channels. It is import to acknowledge that

the GRS method, requires no priori reduction in the number of uncertain input parameters.

Therefore all potentially important parameters should be included in the uncertainty

analysis as a safety measure. This method takes into account all of the influence from

identified input uncertainties on the results. Also note that the number of calculations

needed is not dependent on the number of uncertain parameters accounted for in the study.

The chosen uncertainty inputs are shown in Table 5 [18].

29

Figure 29: CTF Model [19]

Table 5: Uncertainty Input Parameters [18]

Only three of the four cases were analyzed due to the first case in Table 4having an unstable

CTF convergence. Therefore the comparison results of the cases 4101-13, 4101-69, and

4101-86, are given in Table 6. Note there are some discrepancies present below. These are

must likely due to the over-prediction of the void fraction discussed earlier. The other

possible factor are the unsymmetrical void measurements in the regions with otherwise

similar symmetrical power loads. Looking at the corner sub-channels and sub-channels

connected to the water rod, the deviations are the largest. Therefore sub-channels next to

30

large cold walls show a larger discrepancy. However, while noticeable, the discrepancy

does not disprove CTF’s capabilities since the error is not large [19]. Thus among the

selected boundary conditions input parameters, pressure, is shown to strongly affect the

predicted sub-channel void distribution. However note that this is on the uncertainty range

of 1%. Another difference is that the BFBT specifications show the sub-channel void

fractions have a measurement uncertainty of 3% [18]. In the calculations however, 8% was

used for mainly 2 reasons. The measured void fractions were evaluated by averaging the

CT scanner local measurements over the cross-sectional area, and the local void fractions

have and uncertainty of 8%. Next it is apparent that if 3% uncertainty were used, it will

hide the sensitivity of the codes predictions. The convergence for two of the cases are

shown below as an example to further evaluate the above conclusions [19].

31

Table 6: Predicted-to-Measured Void Distribution at Reference Conditions [19]

Table 7: Coverage Ratio Calculated With Experimental Uncertainty of 8% [19]

2.3.2 Critical Heat Flux and Dry-Out Location Analysis

The critical heat flux is caused by annular film dry-out in the annular flow condition.

Film dry-out is an intricate function of the film flow rate, the entrainment from the liquid

film to vapor region, applied heat flux, and the deposition of droplets back to the liquid

32

film. Also, In BWRs, the spacer grids have a significant influence on the bundle critical

power. Thus, modeling the spacer grids effects on cross-flow and liquid film thickness is

required to achieve valid results [20]. Spacer grids are currently not modeled in certain

balance of plant system codes like TRACE, pushes the need for validated sub-channel

codes [21].

Since CTF uses the three-field approach discussed earlier, the hydrodynamic

equations should be able to predict dry-out by solving directly from the film dry-out as a

process instead of using correlations. More specific, dry-out is forced by the hydraulic

calculation and the prediction is the result from effects of entrainment, deposition, and wall

heat transfer [22].

The Siemens 9x9 BWR rod bundle is modeled in CTF as a full 9x9 BWR fuel

assembly using one-half symmetry. Resulting in thirty-six (36) of the seventy-two (72)

rods modeled in a 9x9 square array with a 3x4 water channel. The assembly is divided into

four axial sections, with the first section representing the heated section with twenty (20)

channels and includes spacer grids at seven axial locations. The next two axial sections are

used to combine channels from the end sections so that the uppermost forth section consists

of only a single channel. A pressure boundary condition is applied at the top channel (#31).

Sections 2 and 4 only model hydraulics, thus they contain no heat structures. The channels

are connected in the horizontal plane through gaps so that the model accurately models

cross-flow [20].

For the validation tests, the CTF model simulation is run with the results being

compared to the experimental database. For this test steady state single-phase and two-

phase are tested. A single-phase grid loss coefficient is needed to accurately predict the

33

pressure drop [22]. Therefore, the coefficient is found directly from the test data as a

function of Reynolds Number. Now CTF uses the coefficient found for modeling the spacer

grid pressure drop. Figure 30 shows the total pressure drop compared with the measured

pressure drop. While the single-phase results show strong agreement, the two-phase show

an over-prediction at higher values [20].

Figure 30: Comparison of Single-phase and Two-phase Pressure Drops [20]

Next the validation tests of the dry-out experiments will be discussed. The experiments

were performed as quasi-steady state calculations assuming power was gradually increased

by steps until dry-out was shown. The steps were advanced only after quasi-steady state

conditions were met during each step. Four different runs were chosen to be analyzed and

are listed below in Table 8 with the dry-out location results listed in Table 9. For the results

an entrainment enhancement factor of five (5) is used to match the CTF calculations with

the measured critical power. This is used to adjust the entrainment rate due to the spacer

grids not being modeled exactly as they were in the experiment. The results below show

strong agreement with the measured data [20].

34

Table 8: Conditions of CTF Test Runs [20]

Table 9: Comparison of Predicted and Measured Critical Power and Dry-out location [20]

Next, newer CTF critical heat flux results are assessed with the OECD/NRC BFBT

benchmarks. While earlier sections discussed Phase I of the BFBT benchmarks, this section

will focus on Phase II Exercise 1: Steady-State Critical Power. The full scale test bundle,

representing an 8x8 high burn-up fuel assembly, was used in the test section. The following

three combinations of radial and axial power shapes were tested: beginning of cycle radial

power pattern/cosine axial shape, end of cycle radial power pattern/cosine axial power

shape, and beginning of cycle radial power pattern/inlet peaked axial power shape. The

parameters studied were pressure drop and critical power [13]. The results for single-phase

and two-phase pressure drop have already been discussed.. It was found that CTF showed

outstanding agreement for single-phase and a small over-prediction for two-phase pressure

drop due to overestimated interfacial drag forces [17]. Therefore the critical power will be

the only data value analyzed.

35

The Critical power was measured by increasing the bundle power in small increments of

time, while analyzing the individual heater rod thermocouple signals. The experiment

defined the critical power when the peak rod surface temperature became 14°C above the

steady-state temperature level before dry-out showed. The radial and axial profiles of the

experiment assembly are given in Table 10 [18].

Table 10: Steady-State Critical Power Measurement COnditions for experiment Assembly [18]

To further evaluate the code, a sensitivity study was performed by selecting and

using the three different turbulent mixing options available in CTF. The three options are:

no turbulent mixing, Lahey and Moody model with user-defined single-phase mixing

coefficient, and Lahey and Moody model with a single-phase mixing coefficient by Rogers

and Rosehart’s correlation and Beus’ model for two-phase mixing enchantment [22].

The comparison of CTF’s results and the measured results are shown below in

Figures 29 to 32. It is apparent that the best agreement between prediction and measured

is with no cross flow by turbulent mixing and void drift modeled. The code predictions has

a mean relative error of roughly 3.4%. The increased turbulence in flow, shows an adverse

36

effect on CTF’s accuracy of the prediction of the dry-out location causing an

overestimation of the critical power. One possible reason for the discrepancy, is the spacers

along the bundle are ferrule type spacers. This means they are not designed to increase the

turbulence of the flow. While in the CTF simulations, saw the lateral pressure gradient

from the spacers is explained by applying sub-channel-based loss coefficients in axial and

transverse directions [13]. The results show fairly accurate predictions for the critical

power. However a small bias is clearly present with the pressure.

Figure 31: Predicted versus Measured Critical Power for Experiment Assembly Using 3 Different Turbulent

Mixing Models

37

Figure 32: Predicted over Measured Critical Power versus Flow Rate

Figure 33: Predicted over Measured Critical Power versus Pressure

Figure 34: Predicted over Measured Critical Power versus Subcooling

38

2.3 Oskarshamn-2 1999 BWR Stability Event Benchmark

In 1999, the Oskarshamn-2 Nuclear Power Plant experienced a stability event. An

international NEA-OECD/U.S. NRC benchmark was developed based on this event. The

event itself was a loss of feedwater flow and low feedwater temperature without a reactor

scram. There was also an additional event with the interaction of the automatic power and

flow control system. This second event caused the plants systems to enter a low flow-

high power regime. These events caused diverging power oscillations, which are what

triggered the automatic scram at high power. The power oscillations can be seen in [23].

Figure 35: Oskarshamn-2 Power Oscillations [23]

39

Chapter 3: CTF Application to BWR Modeling and

Simulations

This chapter focuses on application of CTF to mini- and whole-core BWR

calculations on the pin-cell resolved level as well as demonstrating that CTF can properly

model bypass flow. To increase the confidence in CTF’s BWR modeling capabilities,

extensive simulations have been performed using the international NEA-OECD/U.S. NRC

Oskarshamn-2 benchmark, including modeling of a single assembly and a 2x2 assembly

array on a pin-by-pin level; and a full core model on assembly level. Each model is varied,

with an increasing amount of detail. The results demonstrate that CTF is capable of

modeling basic and complex BWR simulations. Using the three Oskarshamn-2 simulations,

CTF’s capabilities of modeling BWRs was further verified.

3.1 CTF Models

This section discusses the results obtained from three different BWR CTF models:

single assembly on a pin-cell resolved level (model 1), 2x2 array on pin-cell resolved level

(model 2), and full core on assembly-cell resolved level (model 3). Each model had three

levels of detail that investigated effects of internal flow, external flow, and flow inside

water rods. All tests were modeled at steady state conditions and follow the Oskarshamn-

2 specifications [24].

The three models discussed are presented in Table 11 along with the operating

conditions. Table 12 shows the variation in detail that each model has undergone. Internal

bypass was defined as a bypass region between assemblies, while external bypass was

defined as a bypass region that surrounds the assembly shown in Figure 37 and Figure 38.

40

The water channel was defined as a bypass region that is located at the center of the

assembly. This acts similar to a water rod, but is inherently a bypass region. Finally Table

13 lists all assumptions used for each model.

Table 11: Operating Conditions

Pressure

(bar)

Linear Heat

Rate (kw/m)

Assemblies Resolution Partial Rod

Model 1 70.2 14.8946 1 Pin-cell level Two sections

Model 2 70.2 14.8946 4 Pin-cell level Geometry

variation

Model 3 71.66 15.8319 444 Assembly-cell

level

Two sections

Table 12: Model Variation

Internal

bypass External bypass

Water channel

bypass

Base case Not included Not included Not included

Bypass case Included Included Not included

Water Channel Included Included Included

Table 13: Model Assumptions [21]

General Assumptions [21]

1. The corners of the assembly in Figure 1 are square in the model. This is due to insufficient

information given including the radius of curvature for the corners. As a result, it is expected

to increase the flow area of the corner sub-channel increasing the flow and reducing the void

generation with the same bundle flow conditions.

2. The default material properties for UO2 in CTF are used instead of the properties in the

specifications. The reason for this assumption is convergence issues when pre-specified

properties are used - one noticeable difference is the thermal conductivity, which differs by a

large amount. These properties were taken from MATPRO-11 [22].

3. The assembly boxes are modeled using the same material as the fuel cladding. This

assumption is made due to no information on the actual material referenced in the

specifications. This assumption should not affect the models by any substantial amount since

most boxes are made from similar material as the cladding; and when steady state conditions

are assumed

4. The external bypass realistically would contain objects protruding from the walls of the

adjacent tanks, acting as structural supports. These supports are not modeled in the area.

5. A constant gap conductance of 11356.0 btu/(h ft2 oF) was used. A constant radial power

distribution in the fuel pellet was used.

6. Plenums are not being modeled, meaning the bypass regions do not connect at the top and

bottom of the assemblies.

Full Core Assumptions

41

7. All transverse gaps between sub-channels are removed from the model inputs. This

simplification is needed to reduce the complexity of the model allowing it to converge. This

should not cause any substantial effects due to the assumed small amount of flow between the

internal bypass channels and small temperature gradients.

8. The dimensions for water rods in Type 1 assemblies are not given in the specifications, as a

result approximations were taken from a previous model at PSU.

3.1.1 Single Assembly on a Pin-Cell Resolved Level

The first and simplest model was a single assembly consisting of ninety-one (91)

fuel rods (eight (8) partial length rods and eighty-three (83) full length rods), shown in

Figure 36. The rods colored red indicate a partial length rod, which is a fuel rod that is not

the full rod length. Figure 39 below shows the difference between the rod types, these are

used as a way of controlling the reactor. An ATRIUM-10 assembly from the Oskarshamn-

2 specification was used for all input values [10]. The model had three variations, shown

below in Figure 37. The initial model consisted of just the assembly, with the area the water

rod acting as a solid adiabatic surface. Each subsequent variation added detail to the

previous. The first addition was a bypass that surrounds the assembly. The next addition

was a water rod, which was modeled as a water channel bypass, at roughly the center of

the assembly that took the place of nine (9) fuel rods.

42

Figure 36: Single BWR assembly pattern

CTF was able to model partial length rods in two different structures. Since BWRs

typically contain partial length rods that are paramount to the design, it was important

simulations are created to model them as close to realistically possible. This single

ATRIUM-10 assembly model had two axial sections: one containing all ninety-one (91)

rods, and the second upper section containing only the tops of the full length rods.

Figure 37: Varying models of complexity for single BWR assembly

43

3.1.2 2x2 Array Assemblies on Pin-cell Resolved Level

The second model was an expansion of the previous model. The single assembly was

expanded into a 2x2 array following the same path of detail as shown below in Figure 38.

Since the model contained multiple assemblies, the bypass was subdivided into internal

and external sections. Each bypass section was created the same way as was done for the

single assembly case. However, instead of subdividing the rods into two axial sections, the

partial length rods were captured using the axial geometry variation feature. By changing

the size of the channels and gaps around the partial rods at a specific height (in this case

the point at which they end), it effectively creates a new area without splitting the rods into

two sections. The expansion modeling can be seen in Figure 39, note that this method will

show little change in the overall pressure loss, but local flow and enthalpy distributions

may be slightly different. Graphics in Figure 39 depict the two different possible modeling

techniques used for this simulation.

Figure 38: Varying models of complexity for 2x2 BWR array

44

Figure 39: Possible modeling schemes for CTF

3.1.3 Full Core on Assembly-Cell Resolved Level

The last model represents the core on an assembly-level rather than pin-by-pin.

Therefore the fuel pins for each assembly were modeled as one single channel, meaning

each assembly simulated one single lumped fuel rod with the flow through the entire

assembly represented as a single channel. The last model was originally developed within

the European Community NURESAFE project [24] and was subsequently updated by PSU

[21]. There were four hundred and seventy (470) assemblies consisting of four (4) different

assembly types in the input, which are shown in Figure 40. The difference between

assembly types 2 and 3 was the loss coefficient in the spacers.

45

Figure 40: Full core assembly types [21]

The full core model followed the same trend as the previous decks of increasing

detail. The first model was a basic model that does not model either water rods or bypass

regions of the core. The second model has both internal and external bypass regions of the

core. The last model takes the model 2 design and adds in water rods as another level of

detail. The water rods in each assembly have Zircaloy cladding surrounding them and are

a different size and shape for each assembly type.

3.2 Results

Each case was run until completion using the CTF internal pseudo-steady-state

convergence criteria that checks engineering parameters of interest, including fluid and

solid energy balance and storage. Each model was then analyzed by examining the

following in bundle channel fluid properties for each variation: pressure and vapor void

fraction. For models 1 and 2, channel #39 was analyzed, located next to the water channel.

For the full core, three different channels, were analyzed, one for each type of different

assembly. It was also significant to look at the similarities between the single and 2x2 array

due to the difference in setting up the partial rod structure in CTF.

46

3.1.1 Single Assembly

The addition of internal bypass, external bypass, and water channels requires the

use of unheated conductors in the assembly. It was expected that this would reduce internal

assembly coolant temperatures compared to cases without bypass flow because the canister

boundaries were no longer adiabatic. Consequently, the pressure may also see small

deviations, since the water rod is modeled as a solid adiabatic square rod, the coolant

recirculates through the fuel rod leading to a slightly higher pressure drop when compared

to the third model with the water rod. However for these models, pressure was used as the

outlet boundary condition and therefore should end at the same value. If anything, small

variations would be at the lower portions of the axial position. Therefore any small changes

are due to liquid sub cooling and recirculation flow. Figure 41 shows very little change

between the pressures with each case.

Figure 41: Pressure over the axial position for single BWR assembly

70.2

70.3

70.4

70.5

70.6

70.7

70.8

70.9

71

71.1

71.2

71.3

0 1 2 3 4 5

Pre

ssu

re (

bar

)

Axial Position (m)

Base Case

Internal and External Bypass

Internal, External, and WaterChannel Bypass

47

The effect of the variation becomes more apparent when graphing the void fraction

shown in Figure 42, in which a small difference was seen in the maximum amount of vapor

generated and the location at onset of significant void. The inclusion of the bypass

theorized that the void vapor faction would be slightly less than that of the model without

it. This agrees with the recirculation theory discussed above. Therefore, the location of

significant void would be expected to be upstream with the presence of the bypass, since

the bypass would allow removal of heat. However note that with the bypass, less coolant

would circulate through the fuel rods and thus increase the void generation, which can be

seen at the end. However, as shown, the void increases slightly at the end, which was likely

due to the mass flow rate being kept constant with each variation. Adding a water channel

to the internal/external bypass model has little effect because the internal and external

bypass have a larger surface area in contact with the sub-channels when compared to the

water channel.

48

Figure 42: Vapor Void Fraction over axial position for single BWR assembly

3.2.3 2x2 Assembly

The second model was expected to show similar results to the first model, however

note that since this model contains multiple assemblies, internal and external bypasses are

simulated. Unheated conductors that are between assemblies are considered internal, while

surrounding ones are considered external. This was not expected to change the overall trend.

It did change the difference between the variations, specifically the base case and the other

two. Looking at Figure 38 the base case was similar to the original model in that it behaves

like one very large flow channel since the assemblies do not connect at the bottom and top

of the model. The pressure change over the axial position presented in Figure 43 showed

similar pressure change over the axial position.

-0.1

0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

1

0 1 2 3 4 5

Vap

or

Vo

id F

ract

ion

Axial Position (m)

Base Case



49

Figure 43: Pressure over axial position for 2x2 BWR array

The void fraction drop between variations did not show any substantial change. We

see slight differences in the void in Figure 44, but not a discernable amount. The void

would be expected to change only slightly like the first model. Therefore, a small change

between the models did occur, which will be discussed in the next section. The modeling

of the geometry variation in model 2 showed the same trends saw in model one, which lead

to the observation that both modeling techniques were verified. Conversely, there was no

discernable change between the additions of the water channel in the model 2 results. This

could be due to its size compared to the size of the total bypass. One possible reason may

deal with the heat conduction between the two. There was also the possibility that the

bypass changes the void fraction to the point of maximum and as result any more details

will show diminishing returns (water channels in this case). Comparing these results to the

70.2

70.3

70.4

70.5

70.6

70.7

70.8

70.9

71

71.1

71.2

0 1 2 3 4 5

Pre

ssu

re (

bar

)

Axial Position (m)

Base Case



50

full core will conclude whether or not the water channel has a strong effect due to the

multiple types of assemblies.

Figure 44: Vapor void fraction over axial position for 2x2 BWR array

3.2.3 Overall Comparisons between Models 1 and 2

The first two models had the same operating parameters, with the only difference

being 1 assembly versus 4 assemblies. However the first used subdivided sections within

CTF and the second model was created using geometry variation for the partial rods. Even

though, it was expected that the pressure and void results be the same. Figure 45 shows the

same overall trends. The Pressure showed a slight difference between the variations, but it

was close. Theoretically, the values between the two models should have been identical.

Similar results were found when graphing the void fraction, however a small difference

was expected here due to the removing of heat from additional bypass regions. Therefore

a comparison between the pressure in bypass regions and in the bundle region for both

-0.1

0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

0 1 2 3 4 5

Vap

or

Vo

id F

ract

ion

Axial Position (m)

Base Case



51

models was created and shown in Figure 47. The results should have been identical for

each data set, however it was predicted that the models would not match due to reasons

discussed above. The pressure in the bypass region for model 1 shows a noticeable

difference. This was due to either a difference in the wetted perimeter or the flow rate. If

the bypass region has less wetted perimeter (less wall friction), than the bundle average

must be lower. The total mass flow rate was kept at 0 for the initial operating conditions of

each variation. Also the boundary conditions for the mass flow rate did not change between

variations. Realistically, the regions are connected and, therefore, would have the exact

same pressure drop. To stabilize the fact that there was less wetted perimeter in the bypass

region, the flow velocity would increase in that region, which is what drives the bypass

flow rate. Therefore it should theoretically increase too. Since it does not, small changes

between the pressure in models one and two were not surprising.

Figure 45: Pressure over axial pressure for single and 2x2 BWR assembly

70.2

70.3

70.4

70.5

70.6

70.7

70.8

70.9

71

71.1

71.2

71.3

0 1 2 3 4 5

Pre

ssu

re (

bar

)

Axial Position (m)

Single Base case

Single Bypass

Single Water channel

2x2 Base Case

2x2 Bypass

2x2 Water Channel

52

Figure 46: Vapor void fraction over axial pressure for single and 2x2 BWR assembly

Figure 47: Pressure over axial position for bundle and bypass regions

-0.1

0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

1

0 1 2 3 4 5

Vap

or

Vo

id F

ract

ion

Axial Position (m)

Single Base Case

Single Bypass

Single Water

2x2 Base Case

2x2 Bypass

2x2 Water Channel

70

70.2

70.4

70.6

70.8

71

71.2

0 1 2 3 4 5

Single Bypass Region

Single Bundle Region

2x2 Bypass Region

2x2 Bundle Region

53

3.2.4 Full Core

The full core model was able to be rebuilt in the systems code TRACE, allowing

for further comparison. The TRACE model was originally used with the neutronics code

PARCS, therefore minor alterations were made to the model to allow it to be used for single

steady state analysis [21]. Note that the data taken from CTF for the axial position goes to

the top of the rod, 3.712 m. However the results gathered from TRACE end at the last

spacer position in channel 4, 3.3953 m. The model defined the bypass regions in the same

format as the full core model, on assembly level.

The full core model showed similar trends to the previous models due to the similar

input values. However, note that this was on assembly level and not pin level like the

previous models were. Also there were four (4) different types of assemblies, and therefore

each were analyzed. As said earlier, the four assembly types have different patterns and

loss coefficients. Some differences were expected, and some assumptions were added as

shown in Table 13. Figure 48 through Figure 50 below show similar drop in pressure

between the variations at low axial levels which converge on the same values as the

position increase. It was apparent that the addition of the water channels did have a small

effect on the pressure drop. This was most likely due to the multiple assembly types and

core configuration. It agreed with the results from the previous tests in that very little

actually changed between the two and most likely due to the diminishing returns since the

bypass itself caused a noticeable drop in pressure.

The results of each assembly in TRACE are extremely close to each other. This is

most likely due to how the systems code works and models the assembly when compared

54

to how a sub-channel code like CTF models the assembly. It is shown that a sub-channel

code will show finer details within the reactor vessel while a systems code is more for

overall reactor operations. This is clearly shown here and therefore may be a large indicator

why CTF and TRACE behave differently. Also note that TRACE has an abrupt change at

around 0.25 m, which is most likely due to the iterative nature of the code disagreeing with

the initial conditions set by the specifications.

When compared to TRACE, the results showed a large discrepancy for all four

assembly types. This difference was found to be attributed to the spacer grid loss

coefficients associated with the assemblies. Type 2 and 3 assemblies had the highest loss

coefficient, while type 1 had the lowest. This directly correlates to how large of a difference

CTF and TRACE were in the plots. So it can be seen that having a higher loss coefficient,

the pressure drop was greater [21]. According to the TRACE User’s Manual, TRACE does

not currently allow spacer grids with CHAN components, which are what were used for

the model [22].

55

Figure 48: Pressure over axial position for type 4 assemblies

Figure 49: Pressure over axial position for type 2 and 3 assemblies

70.6

70.7

70.8

70.9

71

71.1

71.2

71.3

71.4

71.5

0 1 2 3 4 5

Pre

ssu

re (

bar

)

Axial Height (m)

Base Case

Internal and ExternalBypass

Internal, External, andWater Channel Bypass

TRACE

70.6

70.7

70.8

70.9

71

71.1

71.2

71.3

71.4

71.5

0 1 2 3 4 5

Pre

ssu

re (

bar

)

Axial Position (m)

Base Case



TRACE

56

Figure 50: Pressure over axial position for type 1 assemblies

The void fraction results were consistent with the other two models and showed

similar results. The void fraction changed slightly based on each assembly structure. It was

assumed to be the same reason as before being that the addition of the bypass causes a

slight change to the void. As a result verifying the usage of pin by pin and assembly levels,

since the results are expected to be similar. It was clear that there are small dips present in

the void fraction that show up mainly in the full core design (while the other two are

unnoticeable). One possible reason was the location of spacer grids were more evident here

and caused a slight change in the void fraction due to mixing. Note that spacer grid losses

were only listed in bundle channels, no losses were added to internal, external or water

channel bypass regions. The mixing will increase heat transfer, but reduce the enthalpy

imbalance between the sub-channels. As a result there would be an overall reduction in the

void fraction until it would travel further down till it reaches the next mixing vanes and

70.6

70.7

70.8

70.9

71

71.1

71.2

71.3

71.4

0 1 2 3 4 5

Pre

ssu

re (

bar

)

Axial Position (m)

Base Case



TRACE

57

repeat. Overall the fluid properties show consistent phenomena expected in BWRs, and it

is important to note that on assembly level, the full core BWR shows a small change, but

noticeable effect with the addition of water channels.

The TRACE comparison showed similar differences again here that were present

with the pressure comparisons. The main reason a difference was shown is likely due to

the spacer grids causing a slight change in the amount of void in the system. Another

observation was the response to rapid change between the two codes. Looking at Figure 52

and Figure 53, the TRACE prediction is slightly above CTF’s prediction until roughly 1m,

which then CTF shows the void fraction increase rapidly, while TRACE shows a more

gradual increase. Therefore, this difference in how each code handles rapid change, can

greatly affect the overall trend. It is apparent, that both codes predict the same trends, but

CTF shows slightly adaptability. However this may be due to the modeling scheme used

in TRACE, since it does not support spacer grids at the time.

58

Figure 51: Vapor void fraction over axial position for type 4 assemblies

Figure 52: Vapor void fraction over axial position for type 2 and 3 assemblies

0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

1

0 1 2 3 4 5

Vap

or

Vo

id F

ract

ion

Axial Position (m)

Base Case



TRACE

0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

1

0 1 2 3 4 5

Vap

or

Vo

id F

ract

ion

Axial Position (m)

Base Case



TRACE

59

Figure 53: Vapor void fraction over axial position for type 4 assemblies

3.3 Observations

The simulations discussed within this paper represent different models of BWRs.

The single assembly on pin-by-pin level represents CTF’s capabilities of detailed flow

modeling within BWR assemblies. The results demonstrate the effects of adding a bypass

and water channel within the model. For the single assembly, a clear difference is shown

once the bypass is added. The bypass results demonstrated a clear impact on the overall

bundle pressure. The addition of the water channel did not display as strong of a drop. This

change is much more dominant in the void fraction, which reduces substantially, which is

expected due to the bypasses and water channels acting as unheated conductors. The single

assembly model is developed by dividing the CTF input into two sections due to the partial

fuel rods being present as in most BWRs. The second model shows strong agreement with

the first, and it must be noted that it is modeling using geometry variation inside of

subdividing the total bundle length into two sections. Therefore, CTF is capable of

0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

0 1 2 3 4 5

Vap

or

Vo

id F

ract

ion

Axial Position (m)

Base Case



TRACE

60

modeling common BWR geometry in multiple ways allowing for more diversity. The

results shown are for bundle average fluid properties and therefore, the effects of the water

channel are not as clear as the bypass, since the size of the bypass (internal and external)

are much larger than that of the water channel. The full core analysis showed similar results

as the previous models, however the water channels do show a slight change here. One

important comparison is looking at the outer assemblies versus the inner ones where the

external bypass not affect them as much. Overall CTF models key fluid property

parameters very well and shows the changes when additional detail is added.

The results from CTF simulations of BWR fuel bundles under steady state

conditions as provided by the Oskarshamn-2 benchmark specifications show strong

representation of fluid properties in current BWR models. The pervious CTF simulations

and validations show its versatility and strength in modeling BWRs.

61

Chapter 4: CTF Validation of BFBT

This chapter discusses the results of the BFBT benchmark using the newest

version of CTF by RGFMG and CASL. Exercises 1 and 4 of Phase I and Exercise 2 of

Phase II are examined and listed in Table 14. Exercise 0 of Phase II is already included in

the CTF validation matrix.

Table 14: BFBT benchmark phases [18]

Phase I Void Distribution Benchmark

Exercise 1 Steady-state sub-channel grade benchmark

Exercise 2 Steady-state microscopic grade benchmark

Exercise 3 Transient macroscopic grade benchmark

Exercise 4 Uncertainty analysis of the void distribution benchmark

Phase II Critical Power Benchmark

Exercise 0 Steady-state pressure drop benchmark

Exercise 1 Steady-state critical power benchmark

Exercise 2 Transient benchmark

4.1 Void Distribution

There were sixteen (16) tests performed for the void distribution tests. These cases

can be further broken up into types of assemblies. The assembly type refers to the location

of unheated rods, guide tubes, water rod, and power configurations. Type 0-1, 0-2, and 0-

3 geometry information is listed in Figure 54. All tests involving these assemblies have

uniform axial and radial power profiles. The only difference between them is the number

and placement of unheated rods. Following is Figure 55 showing all information pertaining

to assembly types 1, 2, and 3. Note for this evaluation only assembly type 1 is used. The

only difference between assembly 0-1 and 1 is that assembly 1 has a cosine axial power

62

profile and beginning of cycle radial power profile. These are shown in Table 16 through

Table 18.

The last assembly type’s information is found in Figure 56 which shows the

geometry for assembly types 4, C2A, C2B, and C3. The first is the only one used for this

void distribution test. The rest are used in the critical power test section. These assemblies

are different from the previous in that there is one large water rod in the middle instead of

two small water rods and two heated/unheated rods. The radial power profile for assembly

4 is shown by Table 17.

The experimental results were measured using two different methods. The first was

using an x-ray densitometer at serval axial locations. The second was using a CT scanner

to gather a fine-mesh void distribution measurement 50 mm over the end of the heated

length. The latter is what was used for validating CTF results. Each method is shown in

Figure 57.

4.1.1 CTF Model

The CT scanner is the best choice for validation with CTF due to the process used.

The scanner swept over the bundle at a fixed height and gathered void measurements in

small bits. The measurements were then post processed to make a set of sub-channel

averaged void measurements. The scanner made serval sweeps for the same test condition

and the results were averaged. This was needed to remove any effects of two-phase

oscillations. The benchmark lists the sub-channel accuracy as 3% and the bundle average

void accuracy to be 2% [18].

63

The channel area and wetted perimeter for each assembly type are presented in

Figure 58 and Figure 59. The main difference is the inner areas surrounding the water

channel. The spacer grid information follows in Figure 60. Note originally in [13] the

spacer grid data by Shiralker’s method, the coefficients were not symmetric. It was agreed

upon that this was a mistake and the results below use a symmetric map as shown in Figure

60. The spacer grid model can be seen in Figure 61.

Table 15: BFBT void distribution test conditions [18]

Test Assembly Type Pressure

[MPa]

Inlet

Subcooling

[kJ/kg]

Flow Rate

[ton/hr]

Power

[MW]

0011-55 0-1 7.18 52.6 54 1.9

0011-58 0-1 7.17 51 54.9 3.51

0011-61 0-1 7.21 50.9 54.8 6.44

0021-16 0-2 7.19 54 54.9 1.91

0021-18 0-2 7.17 49.8 54.9 3.51

0021-21 0-2 7.18 51.4 54.9 6.45

0031-16 0-3 7.18 52.4 55 1.92

0031-18 0-3 7.18 50 54.8 3.52

0031-21 0-3 7.17 49.4 54.9 6.45

1071-55 1 7.19 52.8 54.6 1.92

1071-58 1 7.16 50.3 55.1 3.52

1071-61 1 7.2 51.8 54.7 6.48

4101-53 4 7.159 50.2 55 2

4101-55 4 7.2 52.9 54.6 1.92

4101-58 4 7.15 50.6 54.6 3.52

4101-61 4 7.18 52.5 54.7 6.48

64

Item Data

Assembly

0-1 0-2 0-3

Simulated fuel assembly type 88

Number of heated rods 62 60 55

Number of unheated rods 0 2 7

Heated rods outer diameter (mm) 12.3

Heated rods pitch (mm) 16.2

Axial heated length (mm) 3708

Number of water rods 2

Water rods outer diameter (mm) 15.0

Channel box inner width (mm) 132.5

Channel box corner radius (mm) 8.0

In channel flow area (mm2) 9781

Spacer type Grid

Number of spacers 7

Spacer pressure loss coefficients 1.2

Spacer location (mm) 455, 967, 1479, 1991, 2503, 3015, 3527

(Distance from bottom of heated length to spacer bottom face)

Radial power shape Uniform

Axial power shape Uniform

: Heated rod : Unheated rod : Water rod: no flow in water rods

Figure 54: Description of BFBT assembly types 0-1, 0-2, and 0-3 [18]

W

W

132.5mm

W

W

W

W

65

Item Data

Assembly

1 2 3

Simulated fuel assembly type 88

Number of heated rods 62



Axial heated length (mm) 3708 1747 3708






Spacer type Grid

Number of spacers 7




Radial power shape Simulation pattern for beginning of operation

Axial power shape Cosine Half-cosine Inlet Peak

: Heated rod : Unheated rod : Water rod: no flow in water rods Figure 55: Description of BFBT assembly types 1,2, and 3 [18]

W

W

W

W

W

W

66

Item Data

Test assembly

4 C2A C2B C3

Simulated fuel assembly type High burn-up 88

Number of heated rods 60



Axial heated length (mm) 3708






Spacer type Ferrule

Number of spacers 7




Radial power shape A A B A

Axial power shape Uniform Cosine Cosine Inlet-peak

: Heated rod : Water rod: no flow in water rods

A: Simulation pattern for beginning of operation

B: Simulation pattern for middle of operation Figure 56: Description of BFBT assembly type 4 [18]

Table 16: Radial power profile for assembly types 1-3 [18]

1.15 1.30 1.15 1.30 1.30 1.15 1.30 1.15

1.30 0.45 0.89 0.89 0.89 0.45 1.15 1.30

1.15 0.89 0.89 0.89 0.89 0.89 0.45 1.15

1.30 0.89 0.89 0.89 0.89 0.89 1.15

1.30 0.89 0.89 0.89 0.89 0.89 1.15

1.15 0.45 0.89 0.89 0.89 0.89 0.45 1.15

1.30 1.15 0.45 0.89 0.89 0.45 1.15 1.30

67

1.15 1.30 1.15 1.15 1.15 1.15 1.30 1.15

Table 17: Radial power profile for assembly type 4 [18]

1.15 1.30 1.15 1.30 1.30 1.15 1.30 1.15

1.30 0.45 0.89 0.89 0.89 0.45 1.15 1.30

1.15 0.89 0.89 0.89 0.89 0.89 0.45 1.15

1.30 0.89 0.89 0.89 0.89 1.15

1.30 0.89 0.89 0.89 0.89 1.15

1.15 0.45 0.89 0.89 0.89 0.89 0.45 1.15

1.30 1.15 0.45 0.89 0.89 0.45 1.15 1.30

1.15 1.30 1.15 1.15 1.15 1.15 1.30 1.15

Table 18: Axial power profile [18]

Node Relative power

Cosine Inlet-peak Half-cosine

(Bottom)

1

2

3

4

5

6

7

8

9

10

11

12

13

14

15

16

17

18

19

20

21

22

23

24

(Top)

0.46

0.58

0.69

0.79

0.88

0.99

1.09

1.22

1.22

1.34

1.34

1.40

1.40

1.34

1.34

1.22

1.22

1.09

0.99

0.88

0.79

0.69

0.58

0.46

0.53

0.83

1.00

1.17

1.28

1.34

1.37

1.39

1.40

1.39

1.37

1.34

1.28

1.21

1.10

1.00

0.89

0.79

0.71

0.64

0.58

0.53

0.46

0.40

0

0

0

0

0

0

0

0

0

0

0

0

0.46

0.58

0.69

0.79

0.88

0.99

1.09

1.22

1.22

1.34

1.34

1.40

68

Figure 57: Void measurement locations and techniques used in BFBT facility [18]

1 2 3 4 5 6 7 8 9 Area (cm^2) Pw (m)

10 11 12 13 14 15 16 17 18 0.4776 2.5327

19 20 21 22 23 24 25 26 27 0.9530 3.5552

28 29 30 31 32 33 34 35 36 1.4360 3.8642

37 38 39 40 41 42 43 44 1.4535 3.8810

45 46 47 48 49 50 51 52 53 0.6964 3.6200

54 55 56 57 58 59 60 61 62

63 64 65 66 67 68 69 70 71

72 73 74 75 76 77 78 79 80

Figure 58: Channel map for assembly types 4, C2A, C2B, and C3 with area and wetted perimeter

69

1 2 3 4 5 6 7 8 9 Area (cm^2) Pw (m)

10 11 12 13 14 15 16 17 18 0.4776 2.5327

19 20 21 22 23 24 25 26 27 0.9530 3.5552

28 29 30 31 32 33 34 35 36 1.4360 3.8642

37 38 39 40 81 41 42 43 44 1.2910 4.0762

45 46 47 48 49 50 51 52 53 1.1467 4.2883

54 55 56 57 58 59 60 61 62

63 64 65 66 67 68 69 70 71

72 73 74 75 76 77 78 79 80

Figure 59: Channel map for assembly types 0-1, 0-2, and 0-3 with area and wetted perimeter

1 2 3 4 5 6 7 8 9 Loss coefficients

10 11 12 13 14 15 16 17 18 K =1.348

19 20 21 22 23 24 25 26 27 K = 1.222

28 29 30 31 32 33 34 35 36 K = 1.304

37 38 39 40 41 42 43 44 K = 0.778

45 46 47 48 49 50 51 52 53 K = 0.856

54 55 56 57 58 59 60 61 62 K = 1.278

63 64 65 66 67 68 69 70 71 K = 1.606

72 73 74 75 76 77 78 79 80 K = 0.748

K = 0.926

Figure 60: Channel Map of loss coefficient for spacer grids calculated by Shiralkar and Radcliffe [13]

70

Figure 61: BFBT spacer grid design [18]

4.1.2 Results

To completely analyze the results from the CTF simulations, a multiple step

approach is taken. First the CTF predicted bundle-average void at the exit and thermal

equilibrium quality are compared. The comparison process used area weighted averages.

71

The first comparison showing CTF-predicted and the experimental measured bundle

averaged exit void is given in Figure 62. It is apparent that CTF over-predicts the bundle-

averaged void. This is more serve at lower levels of power and therefore lower levels of

void at the outlet, which indicates deficiencies in the CTF subcooled boiling model. On the

other hand, the predicted void is very close to the experimental value at higher void values.

The outlet values for each case are expected to match exactly with the experimental values.

Other possible reason for the small discrepancy may be unmeasured heat loss in the

experimental facility along the axial length. These physical losses are not simulated in CTF

and therefore a discrepancy is not a major cause for concern.

The comparison between the CTF-predicted and measured bundle-averaged

thermal equilibrium quality is shown in Figure 63. The observed quality comparison does

not match the data shown in Figure 62. Since CTF over predicts the void, it is expected

that the thermal quality would also be over-predicted. However, the opposite is seen here.

Upon further research, the benchmark does not specify how the exit flow and enthalpy was

measured or how the thermal equilibrium was calculated. Therefore the results cannot be

further evaluated on why this discrepancy is that large.

Figure 64 shows the overall comparison between the CTF-prediction and

experimental measurements of the sub-channel void. There are 10% error lines on each

end of direct matching. First note that the comparison never fall below the bottom error

line, which agrees with the CTF tendency to over-predict void at the exit as shown above.

This is also observed looking at the top error line, where at multiple points CTF over-

predicts the void causing the results to go above the line. A common observation is the

symmetry of the experimental results versus the CTF results. The average void

72

measurements for four different channel categories in each test case was found for the

experimental values shown in Figure 65. The results for the experiments show asymmetric

symmetry throughout each case, while CTF has much more symmetric results in general.

The lack of symmetry in the experimental data indicates large uncertainties in the

measurement. This is therefore a large contributor to why there are clear discrepancies in

Figure 64.

Figure 62: Comparison of measured and predicted bundle-averaged exit void [25]

0

20

40

60

80

100

0 20 40 60 80 100

CT

F O

utl

et A

ver

age

Vo

id [

%]

Measured Outlet Average Void [%]

Assem 0-1

Assem 0-2

Assem 0-3

Assem 1

Assem 4

73

Figure 63: CTF-predicted and measured bundle-averaged thermal equilibrium quality [25]

`

Figure 64: CTF void predictions vs experimental measurement of sub-channels for all BFBT test cases

0

5

10

15

20

25

30

0 5 10 15 20 25 30

CT

F O

utl

et E

qu

ilib

riu

m Q

ual

ity

[%

]

Measured Outlet Equilibrium Quality [%]

Assem 0-1

Assem 0-2

Assem 0-3

Assem 1

Assem 4

0

10

20

30

40

50

60

70

80

90

100

0 20 40 60 80 100

CT

F V

oid

[-]

Measured Void [-]

Assem 0-1

Assem 0-2

Assem 0-3

Assem 1

Assem 4

74

Figure 65: Average void measurements for specific channel categories in experiment [25]

75

Figure 66 through Figure 69 show the code-to-data comparisons for each channel

type. It is clear that corner and inner sub-channels show the strongest agreement with the

experimental results. Slide channels, channels colored blue in Figure 58, show strong

agreement except for areas where the void was roughly 30-40%. The largest difference

appears to be with channels touching the unheated rods. The rods themselves show a much

stronger affect during the experimental cases then the CTF simulations. This may also

come into place with the asymmetry experienced in the experimental cases but not the CTF

simulations.

Figure 66: CTF void predictions vs experimental measurement of all corner sub-channels for all BFBT test cases

0

10

20

30

40

50

60

70

80

90

100

0 20 40 60 80 100

CT

F V

oid

[-]

Measured Void [-]

Assem 0-1

Assem 0-2

Assem 0-3

Assem 1

Assem 4

76

Figure 67: CTF void predictions vs experimental measurement of all side sub-channels for all BFBT test cases

Figure 68: CTF void predictions vs experimental measurement of all normal inner sub-channels for all BFBT

test cases

0

10

20

30

40

50

60

70

80

90

100

0 20 40 60 80 100

CT

F V

oid

[-]

Measured Void [-]

Assem 0-1

Assem 0-2

Assem 0-3

Assem 1

Assem 4

0

10

20

30

40

50

60

70

80

90

100

0 20 40 60 80 100

CT

F V

oid

[-]

Measured Void [-]

Assem 0-1

Assem 0-2

Assem 0-3

Assem 1

Assem 4

77

Figure 69: CTF void predictions vs experimental measurement of all sub-channels touching unheated

conductors for all BFBT test cases

4.1.3 Sensitivity Analysis

Using the code Dakota, a sensitivity analysis was done for seven different variables

in the test cases. Dakota, Design Analysis Kit for Optimization and Terascale Applications,

is a toolkit that allows the user to use sensitivity and uncertainty methods for simulation

codes [16]. For this section the tests from 0-1, 0-2, 0-3, and 4 assembly types were

performed Channels 1, 4, 5, 31, 32, and 81 shown in Figure 59were chosen as important

locations to analyze due to the above results. The seven chosen parameters and their bounds

are shown in Table 19. For each test perimeter, 6 CTF simulations were run. Therefore

each parameter was varied five (5) times according to the table shown below. The first four

parameters are initial conditions, which are varied depending on each parameters

uncertainty value shown in Table 5. The last three parameters are based around CTF default

values, allowing the results to show information pertaining to the CTF void drift results.

0

10

20

30

40

50

60

70

80

90

100

0 20 40 60 80 100

CT

F V

oid

[-]

Measured Void [-]

Assem 0-1

Assem 0-2

Assem 0-3

Assem 1

Assem 4

78

Table 19: Dakota sensitivity analysis parameters

Parameter Lower Bound Upper Bound

Mass flow rate (GTOT) Nominal*0.99 Nominal*1.01

Linear heat rate (AFLUX) Nominal*0.985 Nominal*1.015

Pressure (PREF) Nominal*0.99 Nominal*1.01

Enthalpy (HIN) Nominal*0.985 Nominal*1.015

Equilibrium distribution weighting factor

(AAAK) 0.0 2.8

Constant (two-phase) turbulent mixing

coefficient (BETA) 0.0 0.1

Ratio between max two-phase turbulent

mixing coefficient and single-phase

turbulent mixing coefficient (THETA) 0.0 10.0

The first four parameters for the first case (0011-53) are shown in Figure 70 through

Figure 73. All four initial condition parameters decrease normally with slight increases

with the flow rate. It is apparent that as flow rate increases, mixing increases, and therefore

temperature and thusly void will decrease slightly. This is seen in each channel with almost

no difference. The increase in power slows a basic increase in void in all channels. This

trend is the same as discussed above, except here the power causes an increase in void

instead of a decrease. The specific channels themselves show similar trends with the first

two plots as well. The pressure plots show some differences between the first two, mainly

the void values in each channel. However the overall trends are the exact same as the first

two. The last plot showing enthalpy reveals that the channels themselves were all very

close results wise, and an increase in the enthalpy caused a small increase in the void.

The three parameters varying void drift properties are next. Void drift is a factor in

crossflow effects between sub-channels. This leads to the transferring of the basic

equations CTF solves: mass, momentum, and energy. These results are found in Figure 74

through Figure 76. The first plot shows the equilibrium distribution weighting factor, which

starts at 0. When it is set to zero, the simulation runs assuming no void drift. Therefore the

79

first run shows what the void is assuming turbulent mixing only. The next data point shows

a major difference in the results when void drift is enabled, and continuously changes as it

increases. The channels behave differently here as well. It is apparent that corner, side, and

center are affect much more than the inner channels here. The sensitivity results from the

following plots show a strong convergence in all channel types as the parameter is

increased. These only show a noticeable change when the parameter is set to zero. The rest

of the test cases show similar results and can be found in Appendix B: Void Distribution

Sensitivity Plots.

Figure 70: Mass flow rate sensitivity test

0.455

0.46

0.465

0.47

0.475

0.48

0.485

0.49

0.495

0.5

0.505

14.6 14.7 14.8 14.9 15 15.1 15.2 15.3 15.4

Vo

id [

-]

GTOT kg/s]

Ch1 Ch4 Ch5 Ch31 Ch32 Ch81

80

Figure 71: Power sensitivity test

Figure 72: Pressure sensitivity test

0.45

0.455

0.46

0.465

0.47

0.475

0.48

0.485

0.49

0.495

0.5

0.505

7.9 8 8.1 8.2 8.3 8.4 8.5 8.6

Vo

id [

-]

AFLUX [kW/m]


0.44

0.45

0.46

0.47

0.48

0.49

0.5

0.51

0.52

70 70.5 71 71.5 72 72.5 73 73.5

Vo

id [

-]

PREF [bar]

Ch4 Ch5 Ch31 Ch32 Ch81

81

Figure 73: Enthalpy sensitivity test

Figure 74: Equilibrium distribution weighting factor sensitivity test

0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

1180 1190 1200 1210 1220 1230 1240 1250 1260 1270

Vo

id [

-]

HIN [kJ/kg]


0.44

0.45

0.46

0.47

0.48

0.49

0.5

0.51

0.52

0 0.5 1 1.5 2 2.5 3

Vo

id [

-]

AAAK [-]


82

Figure 75: Turbulent mixing coefficient sensitivity test

Figure 76: THETA sensitivity test

0

0.1

0.2

0.3

0.4

0.5

0.6

0 0.02 0.04 0.06 0.08 0.1 0.12

Vo

id [

-]

BETA [-]


0.42

0.43

0.44

0.45

0.46

0.47

0.48

0.49

0.5

0 2 4 6 8 10 12

Vo

id [

-]

THETA[-]


83

4.2 Critical Power

There were twenty-two (22) tests performed for the critical power tests. These cases

were all for assembly C2A. The geometry for C2A was presented above and can been

found in Figure 56. The experimental DNB test conditions are shown in Table 20. All C2A

assemblies used a cosine axial power profile and a specific radial power profile called Type

A. These are shown in Figure 77 and Figure 78.

The experiment was run by slowly increasing the bundle power while monitoring

the temperature at specific rodded locations. Thermocouples were used at three different

elevation points shown in Figure 79. Using the above instrumentation, the group defined

critical power as “when the peak rod surface temperature became 14 ºC higher than the

steady-state temperature level before the dry-out occurred” [18].

4.2.1 CTF Model

To achieve comparable results, Dakota was used with CTF. Each case was ran

starting at 50% of the experimental critical power and incremented by 1% power up to

100% experimental critical power. CTF breaks rod surface temperature up into four

quadrants for each rod, which allowed detailed simulation results for finding critical

power. All surface rod temperatures were outputted for each power and compared to the

previous steady state power. Once a location that matches the experimental thermocouple

locations had a 14 ºC, it was defined as the first location to each the critical heat flux.

Note CTF has shown that the results are much more symmetrical then the experimental

results. Therefore it was expected to see multiple critical power locations at the same

time.

84

Table 20: BFBT critical power test conditions [18]

1.15 1.30 1.15 1.30 1.30 1.15 1.30 1.15

1.30 0.45 0.89 0.89 0.89 0.45 1.15 1.30

1.15 0.89 0.89 0.89 0.89 0.89 0.45 1.15

1.30 0.89 0.89 0.89 0.89 1.15

1.30 0.89 0.89 0.89 0.89 1.15

1.15 0.45 0.89 0.89 0.89 0.89 0.45 1.15

1.30 1.15 0.45 0.89 0.89 0.45 1.15 1.30

1.15 1.30 1.15 1.15 1.15 1.15 1.30 1.15

Figure 77: Radial power profile for assembly type C2A [18]

Test Assembly Type Pressure

[MPa]

Inlet Subcooling

[kJ/kg]

Flow Rate

[ton/hr]

Power

[MW]

SA505500 C2A 5.49 50.95 20.16 6.13

SA510500 C2A 5.48 56.41 55.06 9.72

SA510600 C2A 5.51 96.16 54.7 10.09

SA510800 C2A 5.51 134.97 54.81 10.2

SA510900 C2A 5.52 35.33 54.7 9.56

SA612500 C2A 7.16 55.66 65.36 9.29

SA516500 C2A 5.51 55.98 44.85 9.15

SA605500 C2A 7.16 50.55 20.09 5.77

SA607500 C2A 7.13 48.35 30.02 7.04

SA610503 C2A 7.17 59.39 55.2 8.85

SA610600 C2A 7.18 89.53 55.05 9.2

SA610700 C2A 7.13 107.61 55.2 9.37

SA610800 C2A 7.24 137.26 55.3 9.52

SA610900 C2A 7.27 37.73 55.1 8.66

SA611500 C2A 7.13 54.89 60.23 9.1

SA616500 C2A 7.13 54.21 45.17 8.3

SA805500 C2A 8.63 51 20.3 5.29

SA810501 C2A 8.62 54.89 55.15 7.84

SA810600 C2A 8.56 83.85 55 8.17

SA810800 C2A 8.64 130.3 55.28 8.49

SA810900 C2A 8.66 30.97 55.38 7.52

SA812500 C2A 8.64 58.08 65.25 8.23

SA816500 C2A 8.61 52.22 45.24 7.27

85

Figure 78: Axial power profile for assembly type C2A [18]

86

Figure 79: Thermocouple locations for critical power experiments using assembly C2A [18]

4.2.2 Results

Phase II Exercise 1 is meant to analyze the critical power found with the BFBT benchmark.

In the experiments, critical power was considered by checking the rod surface temperatures

for a difference in temperature greater than 14ºC. The same criterion was used in CTF

87

predictions. However CTF lists the heat transfer regimes at the locations which gives more

information for the rod surface temperature. Therefore the main comparison for when the

critical power occurs will be when the temperature changes by 14 ºC or more. However

the heat transfer regimes may also be used to further detail the critical power found using

the CTF simulations.

Table 21 shows the critical power results and departure from nucleate boiling

(DNB) location from the CTF simulations along with the experimental values. Note not all

simulation cases converged. It was apparent that as the power was increased, more cases

did not converge. For these cases, all convergence criteria was set to below 1 %. Therefore

it must be warned that some of the CTF simulations had convergence issues, however each

case did have simulations that converged.

Similar to the void distribution results, the rod surface temperatures for CTF are

much more symmetric then the experimental values. It was noticed that usually rods 2, 9,

7, 16, 45, 54, 52, and 59 all had critical heat flux (CHF) appearing at the same power and

almost always elevation. Therefore the location listed in the table lists the closet ones to

the experimental value. This can be seen in Figure 80, which shows the measured and

predicated locations. The location of the experimental value was usually found in rods 4,

53, 59, 45, and a few other single spots. However these spot were the most common and

appear close to or adjacent (same rod different angle) CTF simulated location. It should

also be noted that DNB did tend to occur on the locations that the experimental value was

found on, but just at a higher power. For example the first case, CTF found the critical

power to be 5.88 MW with the location of rod 2. However at a power of 6.37 MW, DNB

occurs at rod 4 which is where the experimental location was with a power of 6.13 MW.

88

The results are very close for the actual critical power, but the location does seem

to be slightly off. One of the main possibilities is due to the experimental conditions

causing slight asymmetry to the assembly. Since CTF is a deterministic code, it will predict

the solution it has with all the given conditions. Therefore it will mostly predict multiple

locations of CHF since the assembly is mostly symmetric. However the experimental

condition has multiple small factors such as uncounted for heat losses or bundle vibrations

and small effects when the power was increased. The simulation for CTF assumes perfect

conditions and the exact increase in power with each increment, while the experiment may

of seen power increases very close to the suggested increment but not exactly the same.

The critical power comparison appears to be generally closest at low pressures.

There is a slight increase between the first six cases, which are have pressures around 5.5

MPA, and the second set, which have pressures around 7.15 MPA. However, cases with

pressure around 8.6, the percent difference between experimental and simulation are

highest. This is likely due to the fact that modeling BWR geometry with high pressure may

cause slight discrepancies in the results. CTF also appears to predict a higher critical power

for almost every case where the pressure is high, while predicting above and below powers

for the low pressure cases. All cases had roughly the same convergence rate, with the higher

pressure having a slightly better number of simulations converging. It appeared to have 1-

3 more runs on average than the overall average.

To further investigate, a rod surface temperature heat map of case SA510800 is shown below in

Figure 81 through Figure 83. The figure shows the temperature of each rod surface the

three different thermocouple heights. Each square box in the figure represents a rod, and

each cell represents a quadrant of the rod. Figure 84 through Figure 86 follow with the

temperature difference between the shown case (critical power) and the case before it

89

(steady state case right before critical power). Using this data, it is clear that the symmetry

is very much prominent in the simulation cases compared to the experimental cases. It also

appears very little heat increase happens at the lowest thermocouple height and just slightly

more at the middle height. The experimental test show multiple cases showing DNB at the

middle level and none at the lower level. However, CTF only shows DNB at the highest

level.

Table 21: Comparison of experimental to simulation critical power

Test # Experimental critical Power

Experimental DNB

Location

CTF simulation

critical Power

Percent differnce

CTF simulation DNB Location

SA505500 6.13 04-A240 5.88 4.00 02-A330 & 09-A150

SA510500 9.72 53-A150 9.33 4.01 54-A240 & 45-A150

SA510600 10.09 59-B45 10.70 -6.00 59-A224 & 52-A150

SA510800 10.2 53-A150 10.81 -5.98 54-A240 & 45-A150

SA510900 9.56 59-B45 8.99 6.00 59-A240 & 52-A150

SA612500 9.29 53-A150 10.29 -10.76 54-A240 & 45-A150

SA516500 9.15 04-A240 8.42 8.00 02-A330 & 09-A150

SA605500 5.77 04-A240 5.54 3.99 02-A330 & 09-A150

SA607500 7.04 04-A240 6.34 9.94 02-A330 & 09-A150

SA610503 8.85 53-A150 9.20 -3.95 54-A240 & 45-A150

SA610600 9.2 45-B240 9.94 -8.04 54-A240 & 45-A150

SA610700 9.37 53-A150 10.40 -10.99 54-A240 & 45-A150

SA610800 9.52 53-A150 10.57 -11.00 54-A240 & 45-A150

SA610900 8.66 45-B240 8.66 0.00 54-A240 & 45-A150

SA611500 9.1 53-A150 9.83 -8.00 54-A240 & 45-A150

SA616500 8.3 45-B240 7.97 4.00 54-A240 & 45-A150

SA805500 5.29 04-A240 4.87 7.94 02-A330 & 09-A150

SA810501 7.84 45-B240 8.70 -10.97 54-A240 & 45-A150

SA810600 8.17 53-A150 9.48 -16.03 54-A240 & 45-A150

SA810800 8.49 53-A150 10.36 -22.03 54-A240 & 45-A150

SA810900 7.52 45-B240 8.42 -11.97 54-A240 & 45-A150

SA812500 8.23 08-B330 10.04 -21.99 07-A45 & 16-A240

SA816500 7.27 45-B240 7.71 -6.05 54-A240 & 45-A150

90

Figure 80: Experimental DNB location (green) compared to CTF simulation DNB location

Figure 81: Temperature map of all rods in Test Case SA510800 at height 3.521m

281.09 280.34 280.97 509.46 482.43 280.38 281.02 521.96 521.96 283.49 282.71 485.14 512.72 280.94 280.3 281.01

280.34 279.77 280.58 280.57 279.76 280.16 280.95 281.89 281.89 280.56 279.75 280.75 281.51 281.9 281.17 280.3

280.97 280.58 274.8 274.78 278.22 278.6 278.6 279.74 279.74 278.38 274.75 275.79 280.75 281.17 281.9 280.93

509.51 280.58 274.78 276.93 279.99 279.06 279.06 278.24 278.24 280.01 277.06 276.87 281.29 279.43 280.26 512.83

482.46 279.77 278.49 279.99 279.99 279.06 279.06 278.24 278.24 280.01 280.01 279.93 276.87 274.43 279.43 485.47

280.38 280.16 278.59 279.06 279.06 272.13 272.13 278.98 278.98 276.43 276.43 279.37 276.55 277.19 281.06 281.23

281.02 280.95 278.59 279.06 279.06 272.13 276.43 279.37 279.37 279.83 281.06 281.23

521.95 281.88 279.73 278.27 278.27 279 279.03 278.3 278.3 280.06 281.4 280.24

521.95 281.88 279.73 278.27 278.27 279 279.03 278.3 278.3 280.06 281.4 280.24

283.51 280.54 278.32 280.02 280.02 275.84 276.41 279.38 279.38 279.98 281.23 281.04

282.72 279.73 274.73 277.11 280.02 275.84 275.84 279.05 279.05 276.41 276.41 279.38 276.75 277.27 281.23 281.04

485 280.74 275.84 276.85 279.92 279.38 279.38 278.31 278.31 279.39 279.39 279.99 277.04 274.57 279.56 486.93

512.55 281.5 280.74 281.28 276.85 277.04 279.38 278.31 278.31 279.39 276.8 277.04 281.32 279.56 280.39 514.58

280.94 281.9 281.17 279.43 274.44 277.19 279.83 280.06 280.06 279.98 277.27 274.57 279.56 281.17 281.9 280.93

280.3 281.17 281.9 280.26 279.43 281.06 281.06 281.4 281.4 281.23 281.23 279.56 280.38 281.9 281.17 280.3

281.01 280.3 280.93 513.1 485.71 281.22 281.22 280.24 280.24 281.03 281.03 487.21 514.88 280.93 280.3 281.1

91



Figure 84: Difference in temperature between the critical power case and the steady state case before at height

3.521m

284.65 283.75 284.58 284.66 283.83 283.77 284.6 284.63 284.63 284.61 283.79 283.82 284.65 285.09 284.26 284.26

283.75 284.41 285.36 285.37 284.42 284.7 285.63 285.94 285.94 285.34 284.39 284.87 285.79 286.01 285.11 284.22

284.58 285.36 278.28 278.28 282.56 282.88 282.88 283.29 283.29 282.53 278.23 279.07 284.87 285.11 286.01 285.05

284.66 285.37 278.29 279.74 283.34 282.21 282.21 282.7 282.7 283.3 279.68 279.65 284.98 284.17 285.14 284.64

283.83 284.42 282.56 283.34 283.34 282.21 282.21 282.7 282.7 283.3 283.3 283.31 279.65 277.05 284.17 283.82

283.77 284.69 282.88 282.22 282.22 280.14 280.14 282.29 282.29 280.82 280.82 283.21 279.35 279.75 284.89 284.72

284.6 285.63 282.88 282.22 282.22 280.14 280.82 283.21 283.21 283.27 284.89 284.72

284.63 285.94 283.28 282.72 282.72 282.23 282.2 282.56 282.56 283.39 285.08 283.66

284.63 285.94 283.28 282.72 282.72 282.23 282.2 282.56 282.56 283.39 285.08 283.66

284.61 285.33 282.52 283.29 283.29 280.8 280.79 283.2 283.2 283.31 284.95 284.63

283.79 284.38 278.21 279.69 283.29 280.8 280.8 282.2 282.2 280.79 280.79 283.2 279.34 279.76 284.95 284.63

283.82 284.87 279.07 279.65 283.31 283.21 283.21 282.57 282.57 283.2 283.2 283.29 279.67 279.3 284.24 283.81

284.65 285.79 284.87 284.98 279.65 279.36 283.21 282.57 282.57 283.2 279.34 279.67 284.94 284.24 285.2 284.63

285.09 286.01 285.11 284.17 277.05 279.75 283.27 283.39 283.39 283.31 279.76 279.3 284.24 285.09 286 284.95

284.26 285.11 286.01 285.14 284.17 284.89 284.89 285.08 285.08 284.95 284.95 284.24 285.2 286 285.09 284.12

284.25 284.22 285.05 284.64 283.82 284.72 284.72 283.66 283.66 284.63 284.63 283.81 284.63 284.94 284.11 284.31

287.11 287.06 288.05 287.62 286.63 286.6 287.59 287.61 287.61 287.6 286.61 286.63 287.62 288.39 287.39 286.94

287.06 287.93 289.02 289.02 287.93 288.06 289.13 289.21 289.21 288.99 287.9 288.1 289.17 289.28 288.22 287.32

288.05 289.02 281.14 281.16 285.84 285.99 285.99 286.11 286.11 285.8 281.11 281.48 288.1 288.22 289.28 288.32

287.62 289.02 281.16 281.71 285.85 285.67 285.67 285.9 285.9 285.92 281.7 281.71 287.86 287.79 288.89 287.59

286.63 287.93 285.84 285.85 285.85 285.67 285.67 285.9 285.9 285.92 285.92 285.92 281.71 280.89 287.79 286.6

286.6 288.06 285.99 285.67 285.67 284.71 284.71 284.55 284.55 285.06 285.06 285.98 281.62 281.76 287.9 287.5

287.59 289.13 285.99 285.67 285.67 284.71 285.06 285.98 285.98 285.96 287.9 287.5

287.61 289.21 286.1 285.92 285.92 284.53 284.52 285.79 285.79 286.05 288.03 287.13

287.61 289.21 286.1 285.92 285.92 284.53 284.52 285.79 285.79 286.05 288.03 287.13

287.6 288.99 285.8 285.91 285.91 285.06 285.03 285.97 285.97 285.97 287.92 287.46

286.61 287.9 281.1 281.7 285.91 285.06 285.06 284.52 284.52 285.03 285.03 285.97 281.61 281.75 287.92 287.46

286.63 288.1 281.48 281.71 285.92 285.98 285.98 285.78 285.78 285.97 285.97 285.89 281.69 280.93 287.81 286.59

287.62 289.17 288.1 287.86 281.71 281.63 285.98 285.78 285.78 285.97 281.61 281.69 287.83 287.81 288.9 287.58

288.39 289.28 288.22 287.79 280.89 281.76 285.96 286.05 286.05 285.97 281.75 280.93 287.81 288.2 289.26 288.28

287.39 288.22 289.28 288.89 287.79 287.9 287.9 288.03 288.03 287.92 287.92 287.81 288.9 289.26 288.2 287.28

286.94 287.32 288.32 287.59 286.6 287.5 287.5 287.13 287.13 287.46 287.46 286.59 287.58 288.28 287.28 286.93

0.94 -0.88 -0.91 228.55 202.14 -0.38 -0.37 241.12 241.12 2.69 2.54 204.87 231.82 -0.75 -0.66 0.83

-0.88 -0.77 -0.72 -1.16 -1.25 -1.19 -1.09 0.05 0.05 -1.17 -1.25 -0.59 -0.52 -0.22 -0.28 -0.77

-0.91 -0.72 -0.67 -1.53 -1.37 -1.43 -1.43 -0.22 -0.22 -1.21 -1.55 -1.28 -0.59 -0.28 -0.22 -0.85

228.6 -1.15 -1.53 1.9 1.5 -0.44 -0.44 0.73 0.73 0.67 -0.12 1.69 1.03 -1.91 -1.76 231.95

202.17 -1.24 -1.1 1.5 1.5 -0.44 -0.44 0.73 0.73 0.67 0.67 1.21 1.69 -2.68 -1.91 205.22

-0.37 -1.19 -1.43 -0.41 -0.41 -1.11 -1.11 0 0 0.15 0.15 -0.04 0.53 1.4 0.31 1.1

-0.37 -1.09 -1.43 -0.41 -0.41 -1.11 0 0 0 0 0.15 -0.04 -0.04 0.55 0.31 1.1

241.11 0.05 -0.22 0.78 0.78 0.04 0 0 0 0 0.07 0.26 0.26 0.06 0.12 0.1

241.11 0.05 -0.22 0.78 0.78 0.04 0 0 0 0 0.07 0.26 0.26 0.06 0.12 0.1

2.71 -1.19 -1.27 0.68 0.68 -0.43 0 0 0 0 -0.1 0.14 0.14 0.55 0.36 0.92

2.55 -1.27 -1.57 0.3 0.68 -0.43 -0.43 0.16 0.16 -0.1 -0.1 0.14 0.39 1.22 0.36 0.92

204.73 -0.6 -1.23 1.67 1.2 -0.04 -0.04 0.24 0.24 0.14 0.14 0.66 -0.08 -2.42 -1.75 206.71

231.65 -0.53 -0.6 1.02 1.67 1.01 -0.04 0.24 0.24 0.14 0.49 -0.08 0.54 -1.75 -1.6 233.73

-0.75 -0.22 -0.28 -1.91 -2.68 1.34 0.54 0.06 0.06 0.55 1.22 -2.42 -1.75 -0.26 -0.19 -0.79

-0.66 -0.28 -0.22 -1.76 -1.91 0.31 0.31 0.12 0.12 0.36 0.36 -1.75 -1.61 -0.19 -0.26 -0.7

0.82 -0.77 -0.86 232.22 205.46 1.09 1.09 0.1 0.1 0.91 0.91 206.99 234.03 -0.79 -0.7 0.92

92


3.009m


2.497m

1.16 -0.98 -1 0.21 0.2 -0.65 -0.65 0.22 0.22 -0.16 -0.16 0.2 0.21 -0.62 -0.58 0.76

-0.98 -0.37 -0.32 -0.4 -0.46 -0.27 -0.21 0.16 0.16 -0.44 -0.5 -0.09 -0.04 0.11 0.07 -0.62

-1 -0.32 -0.8 -1.07 -0.61 -0.43 -0.43 -0.01 -0.01 -0.65 -1.16 -0.55 -0.09 0.07 0.11 -0.66

0.21 -0.4 -1.06 0.9 0.48 -0.9 -0.9 0.56 0.56 0.22 0.42 0.82 0.36 -0.78 -0.68 0.22

0.2 -0.46 -0.61 0.48 0.48 -0.9 -0.9 0.56 0.56 0.22 0.22 0.46 0.82 -2.57 -0.78 0.22

-0.65 -0.28 -0.43 -0.88 -0.88 -0.39 -0.39 0.12 0.12 0.18 0.18 0.11 0.05 0.55 0.09 1.05

-0.65 -0.21 -0.43 -0.88 -0.88 -0.39 0 0 0 0 0.18 0.11 0.11 0.2 0.09 1.05

0.22 0.16 -0.02 0.59 0.59 0.1 0 0 0 0 0.03 0.19 0.19 0.14 0.18 0.13

0.22 0.16 -0.02 0.59 0.59 0.1 0 0 0 0 0.03 0.19 0.19 0.14 0.18 0.13

-0.16 -0.45 -0.66 0.21 0.21 0.17 0 0 0 0 -0.08 0.15 0.15 0.2 0.12 0.87

-0.15 -0.51 -1.18 0.43 0.21 0.17 0.17 0.11 0.11 -0.08 -0.08 0.15 0.14 0.48 0.12 0.87

0.2 -0.09 -0.55 0.82 0.46 0.11 0.11 0.21 0.21 0.15 0.15 0.23 0.45 -0.28 -0.7 0.23

0.21 -0.04 -0.09 0.36 0.82 0.05 0.11 0.21 0.21 0.15 0.13 0.45 0.15 -0.7 -0.61 0.23

-0.62 0.11 0.07 -0.78 -2.57 0.55 0.2 0.14 0.14 0.2 0.48 -0.28 -0.7 0.07 0.12 -0.74

-0.58 0.07 0.11 -0.68 -0.78 0.09 0.09 0.18 0.18 0.12 0.12 -0.7 -0.61 0.12 0.07 -0.69

0.75 -0.62 -0.66 0.22 0.22 1.06 1.06 0.13 0.13 0.87 0.87 0.23 0.23 -0.75 -0.7 0.82

0.84 -0.49 -0.51 0.13 0.12 -0.7 -0.7 -0.41 -0.41 -0.53 -0.53 -0.01 0 -0.32 -0.3 0.66

-0.49 0.03 0.07 0.08 0.03 0.16 0.2 0.32 0.32 0.07 0.01 0.2 0.24 0.28 0.25 -0.33

-0.51 0.07 -0.3 -0.39 -0.07 0.05 0.05 0.18 0.18 -0.1 -0.44 -0.15 0.2 0.25 0.28 -0.34

0.13 0.08 -0.39 0.29 0.02 -0.15 -0.15 0.32 0.32 0.1 0.21 0.35 0.06 -0.1 -0.03 0.01

0.12 0.03 -0.07 0.02 0.02 -0.15 -0.15 0.32 0.32 0.1 0.1 0.13 0.35 -0.73 -0.1 0

-0.7 0.16 0.05 -0.14 -0.14 0.06 0.06 0.16 0.16 0.17 0.17 0.16 0.11 0.29 0.05 0.48

-0.7 0.2 0.05 -0.14 -0.14 0.06 0 0 0 0 0.17 0.16 0.16 0.1 0.05 0.48

-0.41 0.32 0.17 0.35 0.35 0.14 0 0 0 0 0.17 0.19 0.19 0.17 0.19 0.23

-0.41 0.32 0.17 0.35 0.35 0.14 0 0 0 0 0.17 0.19 0.19 0.17 0.19 0.23

-0.53 0.07 -0.1 0.09 0.09 0.18 0 0 0 0 -0.02 0.16 0.16 0.1 0.07 0.43

-0.53 0.01 -0.45 0.21 0.09 0.18 0.18 0.17 0.17 -0.02 -0.02 0.16 0.13 0.24 0.07 0.43

-0.01 0.2 -0.15 0.35 0.13 0.16 0.16 0.18 0.18 0.16 0.16 0.05 0.19 -0.67 -0.07 -0.16

0 0.24 0.2 0.06 0.35 0.12 0.16 0.18 0.18 0.16 0.13 0.19 0 -0.07 -0.01 -0.15

-0.32 0.28 0.25 -0.1 -0.73 0.29 0.1 0.17 0.17 0.1 0.24 -0.67 -0.07 0.24 0.28 -0.36

93

Chapter 5: Conclusions and Future Work

5.1 Conclusions

The Consortium for Advanced Simulation of LWRs was created to provide a strong

suite that has options that includes coupled, higher-fidelity, and usable modeling and

simulation capabilities. These allow the suite to effectively address operational and safety

occurrences in light water reactors in the U.S. [14]. The toolkit called VERA will provide

all the above goals and will be created using a large amount of codes, including CTF. The

toolkit components is shown below in Figure 87. It is important that CTF is capable of

accomplishing all requirements asked by CASL to complete its purpose in VERA. The

main goal of this thesis is to demonstrate CTF modeling and simulation capabilities for

BWRs applications.

Figure 87: CASL toolkit VERA for LWR reactor core simulations [14]

94

The simulations discussed within this paper represent different models of BWRs.

The single assembly on pin by pin level represents CTF’s capabilities of detailed flow

modeling within BWR assemblies. The results demonstrate the effects of adding a bypass

and water channel within the model. For the single assembly, a clear difference is shown

once the bypass is added. The bypass results demonstrated a clear impact on the overall

bundle pressure. The addition of the water channel did not display as strong of a drop. This

change is much more dominant in the void fraction, which reduces substantially, which is

expected due to the bypasses and water channels acting as unheated conductors. The single

assembly model is developed by dividing the CTF input into two sections due to the partial

fuel rods being present as in most BWRs. The second model shows strong agreement with

the first, and it must be noted that it is modeling using geometry variation inside of splitting

the input into two sections. Therefore, CTF is capable of modeling common BWR

geometry in multiple ways allowing for more diversity. The results shown are for bundle

average fluid properties and therefore, the effects of the water channel are not as clear as

the bypass, since the size of the bypass (internal and external) are much larger than that of

the water channel. The full core analysis showed similar results as the previous models,

however the water channels do show a slight change here. One important comparison is

looking at the outer assemblies versus the inner ones where the external bypass not affect

them as much. Overall CTF models key fluid property parameters very well and shows the

changes when additional detail is added.

95

The results from CTF simulations of the Oskarshamn-2 benchmark specifications

show strong representation of fluid properties in current BWR models. The pervious CTF

simulations and validations show its versatility and strength in modeling BWRs.

The validation of CTF against BFBT benchmark, shows strong support in using

CTF in CASL VERA suite due to the large amount of well documented data in the BFBT

benchmark and the good code-to-data agreement. The BFBT benchmark is considered to

be one of the most detailed and useful databases for validation work due to its

comprehensive documentation. The benchmark is broken up into multiple sections that

allow validation of vital information when using sub-channel codes like CTF.

The void distribution results show strong agreement in corner, side, and inner sub-

channels. However there appears to slight differences when looking at channels next to

unheated rods. However note that the experiment most likely has some small heat losses

during the experiment that create the discrepancies show in the plots in Chapter 4. This is

apparent when looking at how different the channels void at exit are when the assembly is

symmetric. CTF showed much more symmetric results as well compared to the

experimental values. However, the results still show strong agreement and even some cases

appear to be the same.

The DNB cases match closely with the critical power, however the location shows

a visible difference. CTF simulates the situations precisely, which leads to the symmetrical

results shown in Chapter 4. However, the experimental results show one location for each

case, and do not show how close other locations were to reaching CHF. Therefore the

location is useful for comparing, but it is important to realize that this just shows the first

location and not much more about the other thermocouples. The location for DNB to appear

96

for the CTF simulations is always around the same specific rods. However, note the only

difference between the cases is the initial conditions which mainly will change when it

occurs and not really where. It is almost always expected to occur in the same location,

assuming all physical objects are the same. There is also an issue of CTF converging at

higher powers in the DNB simulations. In most cases, the highest power simulation did not

converge

In summary, by improving computer codes, including CTF, modeling capabilities

to simulate void distribution and critical power within BWR bundles, ensures the safety of

LWRs built and being built in the United States.

5.2 Future Work

Phase II of CASL includes verification and validation of CTF when applied to

BWR models. This thesis has accomplished multiple parts of this goal. However, this phase

is not completed and requires further research.

The generation of the Oskarshamn BWR models increase the models available

within the validation matrix. Each model shows the adaptability of adding different

bypasses. To further this research, validation work is required by comparing the simulation

results with the experimental measurements listed in the specifications. Also using a

version of CTF that is coupled to a neutronics code, would allow further comparisons to

TRACE. This can only be accomplish with the cases on pin cell resolved level, however

the full core case needs CTF to be updated so that it does not to make all the assumptions

required for it to run.

The BFBT experimental and simulation results show strong comparison for the

steady state cases of the phases. Further exercises must be completed. The steady state

97

cases for void distribution are complete. However, the transient exercises, have not been

simulated yet. This would be the next step for void distribution. The critical power cases

were completed for the C2A assembly types, but not for the C3 or B2A. These must be

simulated, however CTF may show varying results for these cases due to the unique power

profiles used for them. It is highly likely, the simulations will fail to converge especially

with higher powers. Last, the transient exercise for critical power should be simulated.

It is important to actively work on validating CTF with other experiments and

updating the source code to further its modeling and simulating abilities. This work showed

using multiple benchmarks and past experiments that CTF is a strong choice as the thermal

hydraulic sub channel code to be used in the VERA suite.

98

Works Cited

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2014. [Online]. Available: http://www.ne.anl.gov/About/cp1-pioneers/. [Accessed

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2006, Vancouver, Canada, 2006.

[5] D. Todd, C. Frepoli and L. Hochreiter, "Development of a COBRA-TF Model for

the Penn State University Rod Bundle Heat Transfer Program," in ICONE-1999,

Tokyo, Japan, 1999.

[6] C. Park, L. Hochreiter, J. Kelly and R. Kohvt, "Analysis of FLETCH-SEASET 163

Rod Blocked Bundle Data using COBRA-TF," Westinghouse Electric Corporation,

Pittsburgh, 1986. No 15.

[7] M. Avramova, "Development of an Innovative Spacer Grid Model Utilizing

Computional Fluid Dynamics Within a Subchannel Analysis Tool," The

Pennsylvania State University , 2007.

[8] M. Gluck, "Validation of the sub-channel code F-COBRA-TF: Part I. Recalulation

of single-phase and two-phase pressure loss measurements," Nuclear Engeering

Design, vol. 238, no. 9, pp. 2308-2316, September 2008.

[9] M. Avramova, "COBRA-TF development, qualification, and application to light

water reactor analysis," The Pennsylvania State University, 2003.

[10] G. Wallis, "One-Dimensional two-phase flow," McGraw-Hill, 1969.

[11] J. Magedanz, M. Perin, M. Avramova and A. Pautz, "High-Fidelity Multiphysics

Simulation of BWR Assembly With Coupled TORT-TD/CTF," in PHYSOR-2012,

Knoxville, Tennessee, 2012.

[12] M. Avramova and e. al, "Analysis of Void Distribution Predictions for Phase I of

the OECD/NRC Benchmark using CTF/NEM," in NURETH-12, Pittsburgh,

Pennsylvania, 2007.

[13] M. Avramova and D. Cuervo, "Assement of CTF Boiling Transition and Critical

Heat Flux Modeling Capabilities Using The OECD/NRC BFBT and PSBT

Benchmark Databases," in NURETH-14, Toronto, Ontario, 2011.

[14] "CASL," CASL, [Online]. Available: www.casl.gov/mission.shtml. [Accessed 1 10

2015].

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[15] TRACE V5.0 User's Manual, Washington, DC: US Nuclear Regulatory Comission,

Vol. 1.

[16] B. Adams, L. Bauman, W. Bohnhoff, K. Dalbey, M. Ebeida, J. Eddy, M. Eldred, P.

Hough, K. Hu, J. Jakeman, L. Swiler and D. and Vigil, " DAKOTA, A Multilevel

Parallel Object-Oriented Framework for Design Optimization, Parameter

Estimation, Uncertainty Quantification, and Sensitivity Analysis: Version 5.4 User's

Manual," Sandia Technical Report SAND2010-2183, December 2009.

[17] M. Avramova, K. Ivanov and L. Hochreiter, "Analysis of Steady-State and

Transient Void Distribution Predictions for Phase I of the OECD/NRC BFBT

Benchmark using CTF/NEM," in NURETH-12, Pittsburgh, 2007.

[18] B. Neykov, "OECD-NEA/US-NRC//NUPEC BWR Full-size Fine-mesh Bundle

Test(BFBT) Benchmark," NEA, vol. I: Specifications, no. 5, 2006.

[19] M. Avramova, K. Ivanov, B. Krzykacz-Hausmann, K. Velkov, A. Pautz and Y.

Perin, "Uncertainty Analysis of COBRA-TF Void Distribution Predictions for the

OECD/NRC BFBT Benchmark," in M&C-2009, Saratoga Springs, New York,

2009.

[20] C. Frepoli, A. Ireland, L. Hochreiter, K. Ivanov and R. Velten, "COBRA-TF

Simulations of BWR Bundle Dryout Experiments," The Pennsylvania State

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[21] C. Keckler, T. Kozlowski, M. Avramova and K. Ivanov, "Comparisons of Thermal-

Hydraulic Modeling with CTF and TRACE using the Oskarashamn-2 Benchmark,"

The Pennsylvania State University, University Park, Pennsylvania, 2014.

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[23] T. Kozlowski, S. Roshan, I. Gajev and T. Lefvert, "BWR Stability Event

Benchmark based on Oskarshamn-2 1999 Feedwater Transient," OECD/NEA,

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[24] J. E. Jimenez and Y. Perin, "Description of the CTF Input for BWR ATWS

Analysis," NURESAFE, No. D13.22..

[25] R. Salko, M. Gergar, C. Gosdin and M. Avramova, CTF Validation Matrix, 2015.

100

Appendix A: Sample CTF Input Deck for BFBT BWR FA

*********************************************************************************************** *MAIN CONTROL DATA

***********************************************************************************************

*ICOBRA 1

*INITIAL DUMPF

1 0 ** EPSO OITMAX IITMAX COURANT

0.001000 5 40 0.800000

*TITLE <title>

***********************************************************************************************

*GROUP 1 - Calculation Variables and Initial Conditions * ***********************************************************************************************

**NGR

1 **NGAS IRFC EDMD IMIX ISOL GINIT NOTRN MESH MAPS IPRP MFLX NM12 PPV NM14

1 2 2 3 3 {GTOT} 1 1 0 0 0 0 0 0

*Card 1.2 ** GTOT AFLUX DHFRAC

{GTOT} {AFLUX} 0.0000000E+00

*Card 1.3 ** PREF HIN HGIN VFRAC1 VFRAC2

{PREF} {HIN} 300.0000000 1.0000000 0.9999000 *Card 1.4

**GTP(1) VFRAC(3) GTP(2) VFRAC(4) GTP(3) VFRAC(5) GTP(4) VFRAC(6)

air 0.0001 ***********************************************************************************************

*GROUP 2 - Channel Description *

*********************************************************************************************** **NGR

2

*Card 2.1 ** NCH NDM2 NDM3 NDM4 NDM5 NDM6 NDM7 NDM8 NDM9 NM10 NM11 NM12 NM13 NM14

81 0 0 0 0 0 0 0 0 0 0 0 0 0

*Card 2.2 ** I AN PW ABOT ATOP NMGP x y xsiz ysiz

1 0.00004776 0.02532677 0.0 0.0 0 0.00478 0.00478 0.00955 0.00955

2 0.00009530 0.03552079 0.0 0.0 0 0.01765 0.00478 0.01620 0.00955 3 0.00009530 0.03552079 0.0 0.0 0 0.03385 0.00478 0.01620 0.00955

4 0.00009530 0.03552079 0.0 0.0 0 0.05005 0.00478 0.01620 0.00955

5 0.00009530 0.03552079 0.0 0.0 0 0.06625 0.00478 0.01620 0.00955 6 0.00009530 0.03552079 0.0 0.0 0 0.08245 0.00478 0.01620 0.00955

7 0.00009530 0.03552079 0.0 0.0 0 0.09865 0.00478 0.01620 0.00955

8 0.00009530 0.03552079 0.0 0.0 0 0.11485 0.00478 0.01620 0.00955 9 0.00004776 0.02532677 0.0 0.0 0 0.12773 0.00478 0.00955 0.00955

10 0.00009530 0.03552079 0.0 0.0 0 0.00478 0.01765 0.00955 0.01620

11 0.00014362 0.03864159 0.0 0.0 0 0.01765 0.01765 0.01620 0.01620 12 0.00014362 0.03864159 0.0 0.0 0 0.03385 0.01765 0.01620 0.01620

13 0.00014362 0.03864159 0.0 0.0 0 0.05005 0.01765 0.01620 0.01620

14 0.00014362 0.03864159 0.0 0.0 0 0.06625 0.01765 0.01620 0.01620 15 0.00014362 0.03864159 0.0 0.0 0 0.08245 0.01765 0.01620 0.01620

16 0.00014362 0.03864159 0.0 0.0 0 0.09865 0.01765 0.01620 0.01620

17 0.00014362 0.03864159 0.0 0.0 0 0.11485 0.01765 0.01620 0.01620 18 0.00009530 0.03552079 0.0 0.0 0 0.12773 0.01765 0.00955 0.01620

19 0.00009530 0.03552079 0.0 0.0 0 0.00478 0.03385 0.00955 0.01620

20 0.00014362 0.03864159 0.0 0.0 0 0.01765 0.03385 0.01620 0.01620 21 0.00014362 0.03864159 0.0 0.0 0 0.03385 0.03385 0.01620 0.01620

22 0.00014362 0.03864159 0.0 0.0 0 0.05005 0.03385 0.01620 0.01620

23 0.00014362 0.03864159 0.0 0.0 0 0.06625 0.03385 0.01620 0.01620 24 0.00014362 0.03864159 0.0 0.0 0 0.08245 0.03385 0.01620 0.01620

25 0.00014362 0.03864159 0.0 0.0 0 0.09865 0.03385 0.01620 0.01620

26 0.00014362 0.03864159 0.0 0.0 0 0.11485 0.03385 0.01620 0.01620 27 0.00009530 0.03552079 0.0 0.0 0 0.12773 0.03385 0.00955 0.01620

28 0.00009530 0.03552079 0.0 0.0 0 0.00478 0.05005 0.00955 0.01620

29 0.00014362 0.03864159 0.0 0.0 0 0.01765 0.05005 0.01620 0.01620

101

30 0.00014362 0.03864159 0.0 0.0 0 0.03385 0.05005 0.01620 0.01620

31 0.00014362 0.03864159 0.0 0.0 0 0.05005 0.05005 0.01620 0.01620 32 0.00012914 0.04076216 0.0 0.0 0 0.06625 0.05005 0.01620 0.01620

33 0.00012914 0.04076216 0.0 0.0 0 0.08245 0.05005 0.01620 0.01620

34 0.00014362 0.03864159 0.0 0.0 0 0.09865 0.05005 0.01620 0.01620 35 0.00014362 0.03864159 0.0 0.0 0 0.11485 0.05005 0.01620 0.01620

36 0.00009530 0.03552079 0.0 0.0 0 0.12773 0.05005 0.00955 0.01620

37 0.00009530 0.03552079 0.0 0.0 0 0.00478 0.06625 0.00955 0.01620 38 0.00014362 0.03864159 0.0 0.0 0 0.01765 0.06625 0.01620 0.01620

39 0.00014362 0.03864159 0.0 0.0 0 0.03385 0.06625 0.01620 0.01620

40 0.00012914 0.04076216 0.0 0.0 0 0.05005 0.06625 0.01620 0.01620 41 0.00012914 0.04076216 0.0 0.0 0 0.08245 0.06625 0.01620 0.01620

42 0.00014362 0.03864159 0.0 0.0 0 0.09865 0.06625 0.01620 0.01620

43 0.00014362 0.03864159 0.0 0.0 0 0.11485 0.06625 0.01620 0.01620 44 0.00009530 0.03552079 0.0 0.0 0 0.12773 0.06625 0.00955 0.01620

45 0.00009530 0.03552079 0.0 0.0 0 0.00478 0.08245 0.00955 0.01620

46 0.00014362 0.03864159 0.0 0.0 0 0.01765 0.08245 0.01620 0.01620 47 0.00014362 0.03864159 0.0 0.0 0 0.03385 0.08245 0.01620 0.01620

48 0.00012914 0.04076216 0.0 0.0 0 0.05005 0.08245 0.01620 0.01620

49 0.00012914 0.04076216 0.0 0.0 0 0.06625 0.08245 0.01620 0.01620 50 0.00014362 0.04076216 0.0 0.0 0 0.08245 0.08245 0.01620 0.01620

51 0.00014362 0.03864159 0.0 0.0 0 0.09865 0.08245 0.01620 0.01620

52 0.00014362 0.03864159 0.0 0.0 0 0.11485 0.08245 0.01620 0.01620 53 0.00009530 0.03552079 0.0 0.0 0 0.12773 0.08245 0.00955 0.01620

54 0.00009530 0.03552079 0.0 0.0 0 0.00478 0.09865 0.00955 0.01620

55 0.00014362 0.03864159 0.0 0.0 0 0.01765 0.09865 0.01620 0.01620 56 0.00014362 0.03864159 0.0 0.0 0 0.03385 0.09865 0.01620 0.01620

57 0.00014362 0.03864159 0.0 0.0 0 0.05005 0.09865 0.01620 0.01620 58 0.00014362 0.03864159 0.0 0.0 0 0.06625 0.09865 0.01620 0.01620

59 0.00014362 0.03864159 0.0 0.0 0 0.08245 0.09865 0.01620 0.01620

60 0.00014362 0.03864159 0.0 0.0 0 0.09865 0.09865 0.01620 0.01620 61 0.00014362 0.03864159 0.0 0.0 0 0.11485 0.09865 0.01620 0.01620

62 0.00009530 0.03552079 0.0 0.0 0 0.12773 0.09865 0.00955 0.01620

63 0.00009530 0.03552079 0.0 0.0 0 0.00478 0.11485 0.00955 0.01620 64 0.00014362 0.03864159 0.0 0.0 0 0.01765 0.11485 0.01620 0.01620

65 0.00014362 0.03864159 0.0 0.0 0 0.03385 0.11485 0.01620 0.01620

66 0.00014362 0.03864159 0.0 0.0 0 0.05005 0.11485 0.01620 0.01620 67 0.00014362 0.03864159 0.0 0.0 0 0.06625 0.11485 0.01620 0.01620

68 0.00014362 0.03864159 0.0 0.0 0 0.08245 0.11485 0.01620 0.01620

69 0.00014362 0.03864159 0.0 0.0 0 0.09865 0.11485 0.01620 0.01620 70 0.00014362 0.03864159 0.0 0.0 0 0.11485 0.11485 0.01620 0.01620

71 0.00009530 0.03552079 0.0 0.0 0 0.12773 0.11485 0.00955 0.01620

72 0.00004776 0.02532677 0.0 0.0 0 0.00478 0.12773 0.00955 0.00955 73 0.00009530 0.03552079 0.0 0.0 0 0.01765 0.12773 0.01620 0.00955

74 0.00009530 0.03552079 0.0 0.0 0 0.03385 0.12773 0.01620 0.00955

75 0.00009530 0.03552079 0.0 0.0 0 0.05005 0.12773 0.01620 0.00955 76 0.00009530 0.03552079 0.0 0.0 0 0.06625 0.12773 0.01620 0.00955

77 0.00009530 0.03552079 0.0 0.0 0 0.08245 0.12773 0.01620 0.00955

78 0.00009530 0.03552079 0.0 0.0 0 0.09865 0.12773 0.01620 0.00955 79 0.00009530 0.03552079 0.0 0.0 0 0.11485 0.12773 0.01620 0.00955

80 0.00004776 0.02532677 0.0 0.0 0 0.12773 0.12773 0.00955 0.00955

81 0.00011467 0.04288274 0.0 0.0 0 0.06625 0.06625 0.01620 0.01620 ***********************************************************************************************

*GROUP 3 - Transverse Channel Connection (Gap) Data

*********************************************************************************************** **NGR

3

*Card 3.1 ** NK NDM2 NDM3 NDM4 NDM5 NDM6 NDM7 NDM8 NDM9 NM10 NM11 NM12 NM13 NM14

144 0 0 0 0 0 0 0 0 0 0 0 0 0

*Card 3.2 ** K IK JK GAP LNGT WKR FWAL IGPB IGPA FACT IGAP JGAP IGAP JGAP IGAP JGAP

*Card 3.3

**GMULT ETNR 1 1 2 0.00340 0.01287 0.50 0.5 0 0 1.0 -1 3 0 0 0 0

1.000 0.000

2 1 10 0.00340 0.01287 0.50 0.5 0 0 1.0 -1 19 0 0 0 0 1.000 0.000

3 2 3 0.00340 0.01620 0.50 0.5 0 0 1.0 1 5 0 0 0 0

1.000 0.000

102

4 2 11 0.00390 0.01287 0.50 0.0 0 0 1.0 -1 21 0 0 0 0

1.000 0.000 5 3 4 0.00340 0.01620 0.50 0.5 0 0 1.0 3 7 0 0 0 0

1.000 0.000

6 3 12 0.00390 0.01287 0.50 0.0 0 0 1.0 -1 23 0 0 0 0 1.000 0.000

7 4 5 0.00340 0.01620 0.50 0.5 0 0 1.0 5 9 0 0 0 0

1.000 0.000 8 4 13 0.00390 0.01287 0.50 0.0 0 0 1.0 -1 25 0 0 0 0

1.000 0.000

9 5 6 0.00340 0.01620 0.50 0.5 0 0 1.0 7 11 0 0 0 0 1.000 0.000

10 5 14 0.00390 0.01287 0.50 0.0 0 0 1.0 -1 27 0 0 0 0

1.000 0.000 11 6 7 0.00340 0.01620 0.50 0.5 0 0 1.0 9 13 0 0 0 0

1.000 0.000

12 6 15 0.00390 0.01287 0.50 0.0 0 0 1.0 -1 29 0 0 0 0 1.000 0.000

13 7 8 0.00340 0.01620 0.50 0.5 0 0 1.0 11 15 0 0 0 0

1.000 0.000 14 7 16 0.00390 0.01287 0.50 0.0 0 0 1.0 -1 31 0 0 0 0

1.000 0.000

15 8 9 0.00340 0.01287 0.50 0.5 0 0 1.0 13 -1 0 0 0 0 1.000 0.000

16 8 17 0.00390 0.01287 0.50 0.0 0 0 1.0 -1 33 0 0 0 0

1.000 0.000 17 9 18 0.00340 0.01287 0.50 0.5 0 0 1.0 -1 34 0 0 0 0

1.000 0.000 18 10 11 0.00390 0.01287 0.50 0.0 0 0 1.0 -1 20 0 0 0 0

1.000 0.000

19 10 19 0.00340 0.01620 0.50 0.5 0 0 1.0 2 36 0 0 0 0 1.000 0.000

20 11 12 0.00390 0.01620 0.50 0.0 0 0 1.0 18 22 0 0 0 0

1.000 0.000 21 11 20 0.00390 0.01620 0.50 0.0 0 0 1.0 4 38 0 0 0 0

1.000 0.000

22 12 13 0.00390 0.01620 0.50 0.0 0 0 1.0 20 24 0 0 0 0 1.000 0.000

23 12 21 0.00390 0.01620 0.50 0.0 0 0 1.0 6 40 0 0 0 0

1.000 0.000 24 13 14 0.00390 0.01620 0.50 0.0 0 0 1.0 22 26 0 0 0 0

1.000 0.000

25 13 22 0.00390 0.01620 0.50 0.0 0 0 1.0 8 42 0 0 0 0 1.000 0.000

26 14 15 0.00390 0.01620 0.50 0.0 0 0 1.0 24 28 0 0 0 0

1.000 0.000 27 14 23 0.00390 0.01620 0.50 0.0 0 0 1.0 10 44 0 0 0 0

1.000 0.000

28 15 16 0.00390 0.01620 0.50 0.0 0 0 1.0 26 30 0 0 0 0 1.000 0.000

29 15 24 0.00390 0.01620 0.50 0.0 0 0 1.0 12 46 0 0 0 0

1.000 0.000 30 16 17 0.00390 0.01620 0.50 0.0 0 0 1.0 28 32 0 0 0 0

1.000 0.000

31 16 25 0.00390 0.01620 0.50 0.0 0 0 1.0 14 48 0 0 0 0 1.000 0.000

32 17 18 0.00390 0.01287 0.50 0.0 0 0 1.0 30 -1 0 0 0 0

1.000 0.000 33 17 26 0.00390 0.01620 0.50 0.0 0 0 1.0 16 50 0 0 0 0

1.000 0.000

34 18 27 0.00340 0.01620 0.50 0.5 0 0 1.0 17 51 0 0 0 0 1.000 0.000

35 19 20 0.00390 0.01287 0.50 0.0 0 0 1.0 -1 37 0 0 0 0

1.000 0.000 36 19 28 0.00340 0.01620 0.50 0.5 0 0 1.0 19 53 0 0 0 0

1.000 0.000

37 20 21 0.00390 0.01620 0.50 0.0 0 0 1.0 35 39 0 0 0 0 1.000 0.000

38 20 29 0.00390 0.01620 0.50 0.0 0 0 1.0 21 55 0 0 0 0

1.000 0.000

103

39 21 22 0.00390 0.01620 0.50 0.0 0 0 1.0 37 41 0 0 0 0

1.000 0.000 40 21 30 0.00390 0.01620 0.50 0.0 0 0 1.0 23 57 0 0 0 0

1.000 0.000

41 22 23 0.00390 0.01620 0.50 0.0 0 0 1.0 39 43 0 0 0 0 1.000 0.000

42 22 31 0.00390 0.01620 0.50 0.0 0 0 1.0 25 59 0 0 0 0

1.000 0.000 43 23 24 0.00390 0.01620 0.50 0.0 0 0 1.0 41 45 0 0 0 0

1.000 0.000

44 23 32 0.00390 0.01277 0.50 0.0 0 0 1.0 27 -1 0 0 0 0 1.000 0.000

45 24 25 0.00390 0.01620 0.50 0.0 0 0 1.0 43 47 0 0 0 0

1.000 0.000 46 24 33 0.00390 0.01620 0.50 0.0 0 0 1.0 29 62 0 0 0 0

1.000 0.000

47 25 26 0.00390 0.01620 0.50 0.0 0 0 1.0 45 49 0 0 0 0 1.000 0.000

48 25 34 0.00390 0.01620 0.50 0.0 0 0 1.0 31 64 0 0 0 0

1.000 0.000 49 26 27 0.00390 0.01287 0.50 0.0 0 0 1.0 47 -1 0 0 0 0

1.000 0.000

50 26 35 0.00390 0.01620 0.50 0.0 0 0 1.0 33 66 0 0 0 0 1.000 0.000

51 27 36 0.00340 0.01620 0.50 0.5 0 0 1.0 34 67 0 0 0 0

1.000 0.000 52 28 29 0.00390 0.01287 0.50 0.0 0 0 1.0 -1 54 0 0 0 0

1.000 0.000 53 28 37 0.00340 0.01620 0.50 0.5 0 0 1.0 36 69 0 0 0 0

1.000 0.000

54 29 30 0.00390 0.01620 0.50 0.0 0 0 1.0 52 56 0 0 0 0 1.000 0.000

55 29 38 0.00390 0.01620 0.50 0.0 0 0 1.0 38 71 0 0 0 0

1.000 0.000 56 30 31 0.00390 0.01620 0.50 0.0 0 0 1.0 54 58 0 0 0 0

1.000 0.000

57 30 39 0.00390 0.01620 0.50 0.0 0 0 1.0 40 73 0 0 0 0 1.000 0.000

58 31 32 0.00320 0.01656 0.50 0.5 0 0 1.0 56 60 0 0 0 0

1.000 0.000 59 31 40 0.00320 0.01656 0.50 0.5 0 0 1.0 42 74 0 0 0 0

1.000 0.000

60 32 33 0.00320 0.01656 0.50 0.5 0 0 1.0 58 61 0 0 0 0 1.000 0.000

61 33 34 0.00390 0.01620 0.50 0.0 0 0 1.0 60 63 0 0 0 0

1.000 0.000 62 33 41 0.00320 0.01656 0.50 0.5 0 0 1.0 46 76 0 0 0 0

1.000 0.000

63 34 35 0.00390 0.01620 0.50 0.0 0 0 1.0 61 65 0 0 0 0 1.000 0.000

64 34 42 0.00390 0.01620 0.50 0.0 0 0 1.0 48 78 0 0 0 0

1.000 0.000 65 35 36 0.00390 0.01287 0.50 0.0 0 0 1.0 63 -1 0 0 0 0

1.000 0.000

66 35 43 0.00390 0.01620 0.50 0.0 0 0 1.0 50 80 0 0 0 0 1.000 0.000

67 36 44 0.00340 0.01620 0.50 0.5 0 0 1.0 51 81 0 0 0 0

1.000 0.000 68 37 38 0.00390 0.01287 0.50 0.0 0 0 1.0 -1 70 0 0 0 0

1.000 0.000

69 37 45 0.00340 0.01620 0.50 0.5 0 0 1.0 53 83 0 0 0 0 1.000 0.000

70 38 39 0.00390 0.01620 0.50 0.0 0 0 1.0 68 72 0 0 0 0

1.000 0.000 71 38 46 0.00390 0.01620 0.50 0.0 0 0 1.0 55 85 0 0 0 0

1.000 0.000

72 39 40 0.00390 0.01277 0.50 0.0 0 0 1.0 70 -1 0 0 0 0 1.000 0.000

73 39 47 0.00390 0.01620 0.50 0.0 0 0 1.0 57 87 0 0 0 0

1.000 0.000

104

74 40 48 0.00320 0.01656 0.50 0.5 0 0 1.0 59 89 0 0 0 0

1.000 0.000 75 41 42 0.00390 0.01277 0.50 0.0 0 0 1.0 -1 77 0 0 0 0

1.000 0.000

76 41 50 0.00320 0.01656 0.50 0.5 0 0 1.0 62 93 0 0 0 0 1.000 0.000

77 42 43 0.00390 0.01620 0.50 0.0 0 0 1.0 75 79 0 0 0 0

1.000 0.000 78 42 51 0.00390 0.01620 0.50 0.0 0 0 1.0 64 95 0 0 0 0

1.000 0.000

79 43 44 0.00390 0.01287 0.50 0.0 0 0 1.0 77 -1 0 0 0 0 1.000 0.000

80 43 52 0.00390 0.01620 0.50 0.0 0 0 1.0 66 97 0 0 0 0

1.000 0.000 81 44 53 0.00340 0.01620 0.50 0.5 0 0 1.0 67 98 0 0 0 0

1.000 0.000

82 45 46 0.00390 0.01287 0.50 0.0 0 0 1.0 -1 84 0 0 0 0 1.000 0.000

83 45 54 0.00340 0.01620 0.50 0.5 0 0 1.0 69 100 0 0 0 0

1.000 0.000 84 46 47 0.00390 0.01620 0.50 0.0 0 0 1.0 82 86 0 0 0 0

1.000 0.000

85 46 55 0.00390 0.01620 0.50 0.0 0 0 1.0 71 102 0 0 0 0 1.000 0.000

86 47 48 0.00390 0.01620 0.50 0.0 0 0 1.0 84 88 0 0 0 0

1.000 0.000 87 47 56 0.00390 0.01620 0.50 0.0 0 0 1.0 73 104 0 0 0 0

1.000 0.000 88 48 49 0.00320 0.01656 0.50 0.5 0 0 1.0 86 90 0 0 0 0

1.000 0.000

89 48 57 0.00390 0.01620 0.50 0.0 0 0 1.0 74 106 0 0 0 0 1.000 0.000

90 49 50 0.00320 0.01656 0.50 0.5 0 0 1.0 88 92 0 0 0 0

1.000 0.000 91 49 58 0.00390 0.01277 0.50 0.0 0 0 1.0 -1 108 0 0 0 0

1.000 0.000

92 50 51 0.00390 0.01620 0.50 0.0 0 0 1.0 90 94 0 0 0 0 1.000 0.000

93 50 59 0.00390 0.01620 0.50 0.0 0 0 1.0 76 110 0 0 0 0

1.000 0.000 94 51 52 0.00390 0.01620 0.50 0.0 0 0 1.0 92 96 0 0 0 0

1.000 0.000

95 51 60 0.00390 0.01620 0.50 0.0 0 0 1.0 78 112 0 0 0 0 1.000 0.000

96 52 53 0.00390 0.01287 0.50 0.0 0 0 1.0 94 -1 0 0 0 0

1.000 0.000 97 52 61 0.00390 0.01620 0.50 0.0 0 0 1.0 80 114 0 0 0 0

1.000 0.000

98 53 62 0.00340 0.01620 0.50 0.5 0 0 1.0 81 115 0 0 0 0 1.000 0.000

99 54 55 0.00390 0.01287 0.50 0.0 0 0 1.0 -1 101 0 0 0 0

1.000 0.000 100 54 63 0.00340 0.01620 0.50 0.5 0 0 1.0 83 117 0 0 0 0

1.000 0.000

101 55 56 0.00390 0.01620 0.50 0.0 0 0 1.0 99 103 0 0 0 0 1.000 0.000

102 55 64 0.00390 0.01620 0.50 0.0 0 0 1.0 85 119 0 0 0 0

1.000 0.000 103 56 57 0.00390 0.01620 0.50 0.0 0 0 1.0 101 105 0 0 0 0

1.000 0.000

104 56 65 0.00390 0.01620 0.50 0.0 0 0 1.0 87 121 0 0 0 0 1.000 0.000

105 57 58 0.00390 0.01620 0.50 0.0 0 0 1.0 103 107 0 0 0 0

1.000 0.000 106 57 66 0.00390 0.01620 0.50 0.0 0 0 1.0 89 123 0 0 0 0

1.000 0.000

107 58 59 0.00390 0.01620 0.50 0.0 0 0 1.0 105 109 0 0 0 0 1.000 0.000

108 58 67 0.00390 0.01620 0.50 0.0 0 0 1.0 91 125 0 0 0 0

1.000 0.000

105

109 59 60 0.00390 0.01620 0.50 0.0 0 0 1.0 107 111 0 0 0 0

1.000 0.000 110 59 68 0.00390 0.01620 0.50 0.0 0 0 1.0 93 127 0 0 0 0

1.000 0.000

111 60 61 0.00390 0.01620 0.50 0.0 0 0 1.0 109 113 0 0 0 0 1.000 0.000

112 60 69 0.00390 0.01620 0.50 0.0 0 0 1.0 95 129 0 0 0 0

1.000 0.000 113 61 62 0.00390 0.01287 0.50 0.0 0 0 1.0 111 -1 0 0 0 0

1.000 0.000

114 61 70 0.00390 0.01620 0.50 0.0 0 0 1.0 97 131 0 0 0 0 1.000 0.000

115 62 71 0.00340 0.01620 0.50 0.5 0 0 1.0 98 132 0 0 0 0

1.000 0.000 116 63 64 0.00390 0.01287 0.50 0.0 0 0 1.0 -1 118 0 0 0 0

1.000 0.000

117 63 72 0.00340 0.01287 0.50 0.5 0 0 1.0 100 -1 0 0 0 0 1.000 0.000

118 64 65 0.00390 0.01620 0.50 0.0 0 0 1.0 116 120 0 0 0 0

1.000 0.000 119 64 73 0.00390 0.01287 0.50 0.0 0 0 1.0 102 -1 0 0 0 0

1.000 0.000

120 65 66 0.00390 0.01620 0.50 0.0 0 0 1.0 118 122 0 0 0 0 1.000 0.000

121 65 74 0.00390 0.01287 0.50 0.0 0 0 1.0 104 -1 0 0 0 0

1.000 0.000 122 66 67 0.00390 0.01620 0.50 0.0 0 0 1.0 120 124 0 0 0 0

1.000 0.000 123 66 75 0.00390 0.01287 0.50 0.0 0 0 1.0 106 -1 0 0 0 0

1.000 0.000

124 67 68 0.00390 0.01620 0.50 0.0 0 0 1.0 122 126 0 0 0 0 1.000 0.000

125 67 76 0.00390 0.01287 0.50 0.0 0 0 1.0 108 -1 0 0 0 0

1.000 0.000 126 68 69 0.00390 0.01620 0.50 0.0 0 0 1.0 124 128 0 0 0 0

1.000 0.000

127 68 77 0.00390 0.01287 0.50 0.0 0 0 1.0 110 -1 0 0 0 0 1.000 0.000

128 69 70 0.00390 0.01620 0.50 0.0 0 0 1.0 126 130 0 0 0 0

1.000 0.000 129 69 78 0.00390 0.01287 0.50 0.0 0 0 1.0 112 -1 0 0 0 0

1.000 0.000

130 70 71 0.00390 0.01287 0.50 0.0 0 0 1.0 128 -1 0 0 0 0 1.000 0.000

131 70 79 0.00390 0.01287 0.50 0.0 0 0 1.0 114 -1 0 0 0 0

1.000 0.000 132 71 80 0.00340 0.01287 0.50 0.5 0 0 1.0 115 -1 0 0 0 0

1.000 0.000

133 72 73 0.00340 0.01287 0.50 0.5 0 0 1.0 -1 134 0 0 0 0 1.000 0.000

134 73 74 0.00340 0.01620 0.50 0.5 0 0 1.0 133 135 0 0 0 0

1.000 0.000 135 74 75 0.00340 0.01620 0.50 0.5 0 0 1.0 134 136 0 0 0 0

1.000 0.000

136 75 76 0.00340 0.01620 0.50 0.5 0 0 1.0 135 137 0 0 0 0 1.000 0.000

137 76 77 0.00340 0.01620 0.50 0.5 0 0 1.0 136 138 0 0 0 0

1.000 0.000 138 77 78 0.00340 0.01620 0.50 0.5 0 0 1.0 137 139 0 0 0 0

1.000 0.000

139 78 79 0.00340 0.01620 0.50 0.5 0 0 1.0 138 140 0 0 0 0 1.000 0.000

140 79 80 0.00340 0.01287 0.50 0.5 0 0 1.0 139 -1 0 0 0 0

1.000 0.000 141 32 81 0.00255 0.01287 0.50 0.0 0 0 1.0 44 91 0 0 0 0

1.000 0.000

142 40 81 0.00255 0.01287 0.50 0.0 0 0 1.0 72 75 0 0 0 0 1.000 0.000

143 41 81 0.00255 0.01287 0.50 0.0 0 0 1.0 75 72 0 0 0 0

1.000 0.000

106

144 49 81 0.00255 0.01287 0.50 0.0 0 0 1.0 91 44 0 0 0 0

1.000 0.000 *Card 3.3.5

** K X Y NORM

1 0.0 0.0 x 2 0.0 0.0 y

3 0.0 0.0 x

4 0.0 0.0 y 5 0.0 0.0 x

6 0.0 0.0 y

7 0.0 0.0 x 8 0.0 0.0 y

9 0.0 0.0 x

10 0.0 0.0 y 11 0.0 0.0 x

12 0.0 0.0 y

13 0.0 0.0 x 14 0.0 0.0 y

15 0.0 0.0 x

16 0.0 0.0 y 17 0.0 0.0 y

18 0.0 0.0 x

19 0.0 0.0 y 20 0.0 0.0 x

21 0.0 0.0 y

22 0.0 0.0 x 23 0.0 0.0 y

24 0.0 0.0 x 25 0.0 0.0 y

26 0.0 0.0 x

27 0.0 0.0 y 28 0.0 0.0 x

29 0.0 0.0 y

30 0.0 0.0 x 31 0.0 0.0 y

32 0.0 0.0 x

33 0.0 0.0 y 34 0.0 0.0 y

35 0.0 0.0 x

36 0.0 0.0 y 37 0.0 0.0 x

38 0.0 0.0 y

39 0.0 0.0 x 40 0.0 0.0 y

41 0.0 0.0 x

42 0.0 0.0 y 43 0.0 0.0 x

44 0.0 0.0 y

45 0.0 0.0 x 46 0.0 0.0 y

47 0.0 0.0 x

48 0.0 0.0 y 49 0.0 0.0 x

50 0.0 0.0 y

51 0.0 0.0 y 52 0.0 0.0 x

53 0.0 0.0 y

54 0.0 0.0 x 55 0.0 0.0 y

56 0.0 0.0 x

57 0.0 0.0 y 58 0.0 0.0 x

59 0.0 0.0 y

60 0.0 0.0 x 61 0.0 0.0 x

62 0.0 0.0 y

63 0.0 0.0 x 64 0.0 0.0 y

65 0.0 0.0 x

66 0.0 0.0 y

107

67 0.0 0.0 y

68 0.0 0.0 x 69 0.0 0.0 y

70 0.0 0.0 x

71 0.0 0.0 y 72 0.0 0.0 x

73 0.0 0.0 y

74 0.0 0.0 y 75 0.0 0.0 x

76 0.0 0.0 y

77 0.0 0.0 x 78 0.0 0.0 y

79 0.0 0.0 x

80 0.0 0.0 y 81 0.0 0.0 y

82 0.0 0.0 x

83 0.0 0.0 y 84 0.0 0.0 x

85 0.0 0.0 y

86 0.0 0.0 x 87 0.0 0.0 y

88 0.0 0.0 x

89 0.0 0.0 y 90 0.0 0.0 x

91 0.0 0.0 y

92 0.0 0.0 x 93 0.0 0.0 y

94 0.0 0.0 x 95 0.0 0.0 y

96 0.0 0.0 x

97 0.0 0.0 y 98 0.0 0.0 y

99 0.0 0.0 x

100 0.0 0.0 y 101 0.0 0.0 x

102 0.0 0.0 y

103 0.0 0.0 x 104 0.0 0.0 y

105 0.0 0.0 x

106 0.0 0.0 y 107 0.0 0.0 x

108 0.0 0.0 y

109 0.0 0.0 x 110 0.0 0.0 y

111 0.0 0.0 x

112 0.0 0.0 y 113 0.0 0.0 x

114 0.0 0.0 y

115 0.0 0.0 y 116 0.0 0.0 x

117 0.0 0.0 y

118 0.0 0.0 x 119 0.0 0.0 y

120 0.0 0.0 x

121 0.0 0.0 y 122 0.0 0.0 x

123 0.0 0.0 y

124 0.0 0.0 x 125 0.0 0.0 y

126 0.0 0.0 x

127 0.0 0.0 y 128 0.0 0.0 x

129 0.0 0.0 y

130 0.0 0.0 x 131 0.0 0.0 y

132 0.0 0.0 y

133 0.0 0.0 x 134 0.0 0.0 x

135 0.0 0.0 x

136 0.0 0.0 x

108

137 0.0 0.0 x

138 0.0 0.0 x 139 0.0 0.0 x

140 0.0 0.0 x

141 0.0 0.0 y 142 0.0 0.0 x

143 0.0 0.0 x

144 0.0 0.0 y *Card 3.4

**NLGP

0 ***********************************************************************************************

*GROUP 4 - Vertical Channel Connection Data *

*********************************************************************************************** **NGR

4

*Card 4.1 **NSEC NSIM IREB NDM4 NDM5 NDM6 NDM7 NDM8 NDM9 NM10 NM11 NM12 NM13 NM14

1 1 0 0 0 0 0 0 0 0 0 0 0 0

*Card 4.2 **ISEC NCHN NONO DXS IVAR

1 81 102 0.036352941176 17

*Card 4.3 **JLEV VARDX JLEV VARDX JLEV VARDX JLEV VARDX JLEV VARDX

11 0.0455 16 0.0505 27 0.052 31 0.050 36 0.0505

41 0.05175 46 0.0505 51 0.052 57 0.0413 60 0.030 63 0.020 69 0.0155 70 0.021 81 0.0216 95 0.0182

96 0.0195 103 0.02586428571 *Card 4.4

** I KCHA KCHA KCHA KCHA KCHA KCHA KCHB KCHB KCHB KCHB KCHB KCHB

1 1 0 0 0 0 0 1 0 0 0 0 0 2 2 0 0 0 0 0 2 0 0 0 0 0

3 3 0 0 0 0 0 3 0 0 0 0 0

4 4 0 0 0 0 0 4 0 0 0 0 0 5 5 0 0 0 0 0 5 0 0 0 0 0

6 6 0 0 0 0 0 6 0 0 0 0 0

7 7 0 0 0 0 0 7 0 0 0 0 0 8 8 0 0 0 0 0 8 0 0 0 0 0

9 9 0 0 0 0 0 9 0 0 0 0 0

10 10 0 0 0 0 0 10 0 0 0 0 0 11 11 0 0 0 0 0 11 0 0 0 0 0

12 12 0 0 0 0 0 12 0 0 0 0 0

13 13 0 0 0 0 0 13 0 0 0 0 0 14 14 0 0 0 0 0 14 0 0 0 0 0

15 15 0 0 0 0 0 15 0 0 0 0 0

16 16 0 0 0 0 0 16 0 0 0 0 0 17 17 0 0 0 0 0 17 0 0 0 0 0

18 18 0 0 0 0 0 18 0 0 0 0 0

19 19 0 0 0 0 0 19 0 0 0 0 0 20 20 0 0 0 0 0 20 0 0 0 0 0

21 21 0 0 0 0 0 21 0 0 0 0 0

22 22 0 0 0 0 0 22 0 0 0 0 0 23 23 0 0 0 0 0 23 0 0 0 0 0

24 24 0 0 0 0 0 24 0 0 0 0 0

25 25 0 0 0 0 0 25 0 0 0 0 0 26 26 0 0 0 0 0 26 0 0 0 0 0

27 27 0 0 0 0 0 27 0 0 0 0 0

28 28 0 0 0 0 0 28 0 0 0 0 0 29 29 0 0 0 0 0 29 0 0 0 0 0

30 30 0 0 0 0 0 30 0 0 0 0 0

31 31 0 0 0 0 0 31 0 0 0 0 0 32 32 0 0 0 0 0 32 0 0 0 0 0

33 33 0 0 0 0 0 33 0 0 0 0 0

34 34 0 0 0 0 0 34 0 0 0 0 0 35 35 0 0 0 0 0 35 0 0 0 0 0

36 36 0 0 0 0 0 36 0 0 0 0 0

37 37 0 0 0 0 0 37 0 0 0 0 0 38 38 0 0 0 0 0 38 0 0 0 0 0

39 39 0 0 0 0 0 39 0 0 0 0 0

40 40 0 0 0 0 0 40 0 0 0 0 0

109

41 41 0 0 0 0 0 41 0 0 0 0 0

42 42 0 0 0 0 0 42 0 0 0 0 0 43 43 0 0 0 0 0 43 0 0 0 0 0

44 44 0 0 0 0 0 44 0 0 0 0 0

45 45 0 0 0 0 0 45 0 0 0 0 0 46 46 0 0 0 0 0 46 0 0 0 0 0

47 47 0 0 0 0 0 47 0 0 0 0 0

48 48 0 0 0 0 0 48 0 0 0 0 0 49 49 0 0 0 0 0 49 0 0 0 0 0

50 50 0 0 0 0 0 50 0 0 0 0 0

51 51 0 0 0 0 0 51 0 0 0 0 0 52 52 0 0 0 0 0 52 0 0 0 0 0

53 53 0 0 0 0 0 53 0 0 0 0 0

54 54 0 0 0 0 0 54 0 0 0 0 0 55 55 0 0 0 0 0 55 0 0 0 0 0

56 56 0 0 0 0 0 56 0 0 0 0 0

57 57 0 0 0 0 0 57 0 0 0 0 0 58 58 0 0 0 0 0 58 0 0 0 0 0

59 59 0 0 0 0 0 59 0 0 0 0 0

60 60 0 0 0 0 0 60 0 0 0 0 0 61 61 0 0 0 0 0 61 0 0 0 0 0

62 62 0 0 0 0 0 62 0 0 0 0 0

63 63 0 0 0 0 0 63 0 0 0 0 0 64 64 0 0 0 0 0 64 0 0 0 0 0

65 65 0 0 0 0 0 65 0 0 0 0 0

66 66 0 0 0 0 0 66 0 0 0 0 0 67 67 0 0 0 0 0 67 0 0 0 0 0

68 68 0 0 0 0 0 68 0 0 0 0 0 69 69 0 0 0 0 0 69 0 0 0 0 0

70 70 0 0 0 0 0 70 0 0 0 0 0

71 71 0 0 0 0 0 71 0 0 0 0 0 72 72 0 0 0 0 0 72 0 0 0 0 0

73 73 0 0 0 0 0 73 0 0 0 0 0

74 74 0 0 0 0 0 74 0 0 0 0 0 75 75 0 0 0 0 0 75 0 0 0 0 0

76 76 0 0 0 0 0 76 0 0 0 0 0

77 77 0 0 0 0 0 77 0 0 0 0 0 78 78 0 0 0 0 0 78 0 0 0 0 0

79 79 0 0 0 0 0 79 0 0 0 0 0

80 80 0 0 0 0 0 80 0 0 0 0 0 81 81 0 0 0 0 0 81 0 0 0 0 0

*Card4.5

** IWDE 81

*Card 4.6

** MSIM 8262

***********************************************************************************************

*GROUP 7 - Grid Loss Coefficient Data * ***********************************************************************************************

**NGR

7 *Card 7.1

** NCD NGT IFGQF IFSDRP IFESPV IFTPE IGTEMP NFBS NDM9 NDM10 NDM11 NDM12 NDM13 NDM14

84 0 0 0 0 0 0 0 0 0 0 0 0 0 *Card 7.2

** CDL J CD1 CD2 CD3 CD4 CD5 CD6 CD7 CD8 CD9 CD10 CD11 CD12

* TYPE 1: corner sub-channels 1.348 11 1 9 72 80 0 0 0 0 0 0 0 0

1.348 21 1 9 72 80 0 0 0 0 0 0 0 0

1.348 31 1 9 72 80 0 0 0 0 0 0 0 0 1.348 41 1 9 72 80 0 0 0 0 0 0 0 0

1.348 51 1 9 72 80 0 0 0 0 0 0 0 0

1.348 70 1 9 72 80 0 0 0 0 0 0 0 0 1.348 96 1 9 72 80 0 0 0 0 0 0 0 0

*

* TYPE 2: side sub-channel 1.278 11 2 8 10 18 63 71 73 79 0 0 0 0

1.278 21 2 8 10 18 63 71 73 79 0 0 0 0

1.278 31 2 8 10 18 63 71 73 79 0 0 0 0

110

1.278 41 2 8 10 18 63 71 73 79 0 0 0 0

1.278 51 2 8 10 18 63 71 73 79 0 0 0 0 1.278 70 2 8 10 18 63 71 73 79 0 0 0 0

1.278 96 2 8 10 18 63 71 73 79 0 0 0 0

* * TYPE 3: side sub-channel

1.606 11 3 7 19 27 54 62 74 78 0 0 0 0

1.606 21 3 7 19 27 54 62 74 78 0 0 0 0 1.606 31 3 7 19 27 54 62 74 78 0 0 0 0

1.606 41 3 7 19 27 54 62 74 78 0 0 0 0

1.606 51 3 7 19 27 54 62 74 78 0 0 0 0 1.606 70 3 7 19 27 54 62 74 78 0 0 0 0

1.606 96 3 7 19 27 54 62 74 78 0 0 0 0


1.222 11 4 6 28 36 45 53 75 77 0 0 0 0

1.222 21 4 6 28 36 45 53 75 77 0 0 0 0 1.222 31 4 6 28 36 45 53 75 77 0 0 0 0

1.222 41 4 6 28 36 45 53 75 77 0 0 0 0

1.222 51 4 6 28 36 45 53 75 77 0 0 0 0 1.222 70 4 6 28 36 45 53 75 77 0 0 0 0

1.222 96 4 6 28 36 45 53 75 77 0 0 0 0


1.304 11 5 37 44 76 0 0 0 0 0 0 0 0

1.304 21 5 37 44 76 0 0 0 0 0 0 0 0 1.304 31 5 37 44 76 0 0 0 0 0 0 0 0

1.304 41 5 37 44 76 0 0 0 0 0 0 0 0 1.304 51 5 37 44 76 0 0 0 0 0 0 0 0

1.304 70 5 37 44 76 0 0 0 0 0 0 0 0

1.304 96 5 37 44 76 0 0 0 0 0 0 0 0 * TYPE 6: internal sub-channels

0.748 11 11 12 13 14 15 16 17 20 21 22 23 24

0.748 11 25 26 29 30 34 35 38 39 42 43 46 47 0.748 11 51 52 55 56 57 58 59 60 61 64 65 66

0.748 11 67 68 69 70 0 0 0 0 0 0 0 0

0.748 21 11 12 13 14 15 16 17 20 21 22 23 24 0.748 21 25 26 29 30 34 35 38 39 42 43 46 47

0.748 21 51 52 55 56 57 58 59 60 61 64 65 66

0.748 21 67 68 69 70 0 0 0 0 0 0 0 0 0.748 31 11 12 13 14 15 16 17 20 21 22 23 24

0.748 31 25 26 29 30 34 35 38 39 42 43 46 47

0.748 31 51 52 55 56 57 58 59 60 61 64 65 66 0.748 31 67 68 69 70 0 0 0 0 0 0 0 0

0.748 41 11 12 13 14 15 16 17 20 21 22 23 24

0.748 41 25 26 29 30 34 35 38 39 42 43 46 47 0.748 41 51 52 55 56 57 58 59 60 61 64 65 66

0.748 41 67 68 69 70 0 0 0 0 0 0 0 0

0.748 51 11 12 13 14 15 16 17 20 21 22 23 24 0.748 51 25 26 29 30 34 35 38 39 42 43 46 47

0.748 51 51 52 55 56 57 58 59 60 61 64 65 66

0.748 51 67 68 69 70 0 0 0 0 0 0 0 0 0.748 70 11 12 13 14 15 16 17 20 21 22 23 24

0.748 70 25 26 29 30 34 35 38 39 42 43 46 47

0.748 70 51 52 55 56 57 58 59 60 61 64 65 66 0.748 70 67 68 69 70 0 0 0 0 0 0 0 0

0.748 96 11 12 13 14 15 16 17 20 21 22 23 24

0.748 96 25 26 29 30 34 35 38 39 42 43 46 47 0.748 96 51 52 55 56 57 58 59 60 61 64 65 66

0.748 96 67 68 69 70 0 0 0 0 0 0 0 0

* * TYPE 7: central sub-channel

0.778 11 31 33 48 50 0 0 0 0 0 0 0 0

0.778 21 31 33 48 50 0 0 0 0 0 0 0 0 0.778 31 31 33 48 50 0 0 0 0 0 0 0 0

0.778 41 31 33 48 50 0 0 0 0 0 0 0 0

0.778 51 31 33 48 50 0 0 0 0 0 0 0 0 0.778 70 31 33 48 50 0 0 0 0 0 0 0 0

0.778 96 31 33 48 50 0 0 0 0 0 0 0 0

*

111

** TYPE 8: central sub-channel. The centeral sub-channel has no blockage.

**0.0 11 81 0 0 0 0 0 0 0 0 0 0 0 **0.0 21 81 0 0 0 0 0 0 0 0 0 0 0

**0.0 31 81 0 0 0 0 0 0 0 0 0 0 0

**0.0 41 81 0 0 0 0 0 0 0 0 0 0 0 **0.0 51 81 0 0 0 0 0 0 0 0 0 0 0

**0.0 70 81 0 0 0 0 0 0 0 0 0 0 0

**0.0 96 81 0 0 0 0 0 0 0 0 0 0 0 * TYPE 9: central sub-channel

*

0.856 11 40 41 0 0 0 0 0 0 0 0 0 0 0.856 21 40 41 0 0 0 0 0 0 0 0 0 0

0.856 31 40 41 0 0 0 0 0 0 0 0 0 0

0.856 41 40 41 0 0 0 0 0 0 0 0 0 0 0.856 51 40 41 0 0 0 0 0 0 0 0 0 0

0.856 70 40 41 0 0 0 0 0 0 0 0 0 0

0.856 96 40 41 0 0 0 0 0 0 0 0 0 0 * TYPE 10: central sub-channel

0.926 11 32 49 0 0 0 0 0 0 0 0 0 0

0.926 21 32 49 0 0 0 0 0 0 0 0 0 0 0.926 31 32 49 0 0 0 0 0 0 0 0 0 0

0.926 41 32 49 0 0 0 0 0 0 0 0 0 0

0.926 51 32 49 0 0 0 0 0 0 0 0 0 0 0.926 70 32 49 0 0 0 0 0 0 0 0 0 0

0.926 96 32 49 0 0 0 0 0 0 0 0 0 0

*********************************************************************************************** *GROUP 8 - Rod and Unheated Conductor Data *

*********************************************************************************************** **NGR

8

*Card 8.1 ** NRRD NSRD NC NRTB NRAD NLTY NSTA NXF NCAN RADF W3 IHTC NDM13 NDM14

62 0 0 1 0 0 0 1 0 0 -1 1 0 0

*Card 8.2 ** N IFTY IAXP NRND DAXMIN RMULT HGAP ISECR HTAMB TAMB

*Card 8.3

**NSCH PIE NSCH PIE NSCH PIE NSCH PIE NSCH PIE NSCH PIE NSCH PIE NSCH PIE 1 1 1 0 0.00000 1.000 0.00000 1 0.000 0.000

1 0.250 2 0.250 11 0.250 10 0.250 0 0.0 0 0.0 0 0.0 0 0.0

2 1 1 0 0.00000 1.000 0.00000 1 0.000 0.000 2 0.250 3 0.250 12 0.250 11 0.250 0 0.0 0 0.0 0 0.0 0 0.0

*

3 1 1 0 0.00000 1.000 0.00000 1 0.000 0.000 3 0.250 4 0.250 13 0.250 12 0.250 0 0.0 0 0.0 0 0.0 0 0.0

*

4 1 1 0 0.00000 1.000 0.00000 1 0.000 0.000 4 0.250 5 0.250 14 0.250 13 0.250 0 0.0 0 0.0 0 0.0 0 0.0

*

5 1 1 0 0.00000 1.000 0.00000 1 0.000 0.000 5 0.250 6 0.250 15 0.250 14 0.250 0 0.0 0 0.0 0 0.0 0 0.0

*

6 1 1 0 0.00000 1.000 0.00000 1 0.000 0.000 6 0.250 7 0.250 16 0.250 15 0.250 0 0.0 0 0.0 0 0.0 0 0.0

*

7 1 1 0 0.00000 1.000 0.00000 1 0.000 0.000 7 0.250 8 0.250 17 0.250 16 0.250 0 0.0 0 0.0 0 0.0 0 0.0

*

8 1 1 0 0.00000 1.000 0.00000 1 0.000 0.000 8 0.250 9 0.250 18 0.250 17 0.250 0 0.0 0 0.0 0 0.0 0 0.0

*

9 1 1 0 0.00000 1.000 0.00000 1 0.000 0.000 10 0.250 11 0.250 20 0.250 19 0.250 0 0.0 0 0.0 0 0.0 0 0.0

*

10 1 1 0 0.00000 1.000 0.00000 1 0.000 0.000 11 0.250 12 0.250 21 0.250 20 0.250 0 0.0 0 0.0 0 0.0 0 0.0

*

11 1 1 0 0.00000 1.000 0.00000 1 0.000 0.000 12 0.250 13 0.250 22 0.250 21 0.250 0 0.0 0 0.0 0 0.0 0 0.0

*

12 1 1 0 0.00000 1.000 0.00000 1 0.000 0.000

112

13 0.250 14 0.250 23 0.250 22 0.250 0 0.0 0 0.0 0 0.0 0 0.0

* 13 1 1 0 0.00000 1.000 0.00000 1 0.000 0.000

14 0.250 15 0.250 24 0.250 23 0.250 0 0.0 0 0.0 0 0.0 0 0.0

* 14 1 1 0 0.00000 1.000 0.00000 1 0.000 0.000

15 0.250 16 0.250 25 0.250 24 0.250 0 0.0 0 0.0 0 0.0 0 0.0

* 15 1 1 0 0.00000 1.000 0.00000 1 0.000 0.000

16 0.250 17 0.250 26 0.250 25 0.250 0 0.0 0 0.0 0 0.0 0 0.0

* 16 1 1 0 0.00000 1.000 0.00000 1 0.000 0.000

17 0.250 18 0.250 27 0.250 26 0.250 0 0.0 0 0.0 0 0.0 0 0.0

* 17 1 1 0 0.00000 1.000 0.00000 1 0.000 0.000

19 0.250 20 0.250 29 0.250 28 0.250 0 0.0 0 0.0 0 0.0 0 0.0

* 18 1 1 0 0.00000 1.000 0.00000 1 0.000 0.000

20 0.250 21 0.250 30 0.250 29 0.250 0 0.0 0 0.0 0 0.0 0 0.0

* 19 1 1 0 0.00000 1.000 0.00000 1 0.000 0.000

21 0.250 22 0.250 31 0.250 30 0.250 0 0.0 0 0.0 0 0.0 0 0.0

* 20 1 1 0 0.00000 1.000 0.00000 1 0.000 0.000

22 0.250 23 0.250 32 0.250 31 0.250 0 0.0 0 0.0 0 0.0 0 0.0

* 21 1 1 0 0.00000 1.000 0.00000 1 0.000 0.000

23 0.250 24 0.250 33 0.250 32 0.250 0 0.0 0 0.0 0 0.0 0 0.0 *

22 1 1 0 0.00000 1.000 0.00000 1 0.000 0.000

24 0.250 25 0.250 34 0.250 33 0.250 0 0.0 0 0.0 0 0.0 0 0.0 *

23 1 1 0 0.00000 1.000 0.00000 1 0.000 0.000

25 0.250 26 0.250 35 0.250 34 0.250 0 0.0 0 0.0 0 0.0 0 0.0 *

24 1 1 0 0.00000 1.000 0.00000 1 0.000 0.000

26 0.250 27 0.250 36 0.250 35 0.250 0 0.0 0 0.0 0 0.0 0 0.0 *

25 1 1 0 0.00000 1.000 0.00000 1 0.000 0.000

28 0.250 29 0.250 38 0.250 37 0.250 0 0.0 0 0.0 0 0.0 0 0.0 *

26 1 1 0 0.00000 1.000 0.00000 1 0.000 0.000

29 0.250 30 0.250 39 0.250 38 0.250 0 0.0 0 0.0 0 0.0 0 0.0 *

27 1 1 0 0.00000 1.000 0.00000 1 0.000 0.000

30 0.250 31 0.250 40 0.250 39 0.250 0 0.0 0 0.0 0 0.0 0 0.0 *

28 1 1 0 0.00000 1.000 0.00000 1 0.000 0.000

33 0.250 34 0.250 42 0.250 41 0.250 0 0.0 0 0.0 0 0.0 0 0.0 *

29 1 1 0 0.00000 1.000 0.00000 1 0.000 0.000

34 0.250 35 0.250 43 0.250 42 0.250 0 0.0 0 0.0 0 0.0 0 0.0 *

30 1 1 0 0.00000 1.000 0.00000 1 0.000 0.000

35 0.250 36 0.250 44 0.250 43 0.250 0 0.0 0 0.0 0 0.0 0 0.0 *

31 1 1 0 0.00000 1.000 0.00000 1 0.000 0.000

37 0.250 38 0.250 46 0.250 45 0.250 0 0.0 0 0.0 0 0.0 0 0.0 *

32 1 1 0 0.00000 1.000 0.00000 1 0.000 0.000

38 0.250 39 0.250 47 0.250 46 0.250 0 0.0 0 0.0 0 0.0 0 0.0 *

33 1 1 0 0.00000 1.000 0.00000 1 0.000 0.000

39 0.250 40 0.250 48 0.250 47 0.250 0 0.0 0 0.0 0 0.0 0 0.0 *

34 1 1 0 0.00000 1.000 0.00000 1 0.000 0.000

41 0.250 42 0.250 51 0.250 50 0.250 0 0.0 0 0.0 0 0.0 0 0.0 *

35 1 1 0 0.00000 1.000 0.00000 1 0.000 0.000

42 0.250 43 0.250 52 0.250 51 0.250 0 0.0 0 0.0 0 0.0 0 0.0

113

*

36 1 1 0 0.00000 1.000 0.00000 1 0.000 0.000 43 0.250 44 0.250 53 0.250 52 0.250 0 0.0 0 0.0 0 0.0 0 0.0

*

37 1 1 0 0.00000 1.000 0.00000 1 0.000 0.000 45 0.250 46 0.250 55 0.250 54 0.250 0 0.0 0 0.0 0 0.0 0 0.0

*

38 1 1 0 0.00000 1.000 0.00000 1 0.000 0.000 46 0.250 47 0.250 56 0.250 55 0.250 0 0.0 0 0.0 0 0.0 0 0.0

*

39 1 1 0 0.00000 1.000 0.00000 1 0.000 0.000 47 0.250 48 0.250 57 0.250 56 0.250 0 0.0 0 0.0 0 0.0 0 0.0

*

40 1 1 0 0.00000 1.000 0.00000 1 0.000 0.000 48 0.250 49 0.250 58 0.250 57 0.250 0 0.0 0 0.0 0 0.0 0 0.0

*

41 1 1 0 0.00000 1.000 0.00000 1 0.000 0.000 49 0.250 50 0.250 59 0.250 58 0.250 0 0.0 0 0.0 0 0.0 0 0.0

*

42 1 1 0 0.00000 1.000 0.00000 1 0.000 0.000 50 0.250 51 0.250 60 0.250 59 0.250 0 0.0 0 0.0 0 0.0 0 0.0

*

43 1 1 0 0.00000 1.000 0.00000 1 0.000 0.000 51 0.250 52 0.250 61 0.250 60 0.250 0 0.0 0 0.0 0 0.0 0 0.0

*

44 1 1 0 0.00000 1.000 0.00000 1 0.000 0.000 52 0.250 53 0.250 62 0.250 61 0.250 0 0.0 0 0.0 0 0.0 0 0.0

* 45 1 1 0 0.00000 1.000 0.00000 1 0.000 0.000

54 0.250 55 0.250 64 0.250 63 0.250 0 0.0 0 0.0 0 0.0 0 0.0

* 46 1 1 0 0.00000 1.000 0.00000 1 0.000 0.000

55 0.250 56 0.250 65 0.250 64 0.250 0 0.0 0 0.0 0 0.0 0 0.0

* 47 1 1 0 0.00000 1.000 0.00000 1 0.000 0.000

56 0.250 57 0.250 66 0.250 65 0.250 0 0.0 0 0.0 0 0.0 0 0.0

* 48 1 1 0 0.00000 1.000 0.00000 1 0.000 0.000

57 0.250 58 0.250 67 0.250 66 0.250 0 0.0 0 0.0 0 0.0 0 0.0

* 49 1 1 0 0.00000 1.000 0.00000 1 0.000 0.000

58 0.250 59 0.250 68 0.250 67 0.250 0 0.0 0 0.0 0 0.0 0 0.0

* 50 1 1 0 0.00000 1.000 0.00000 1 0.000 0.000

59 0.250 60 0.250 69 0.250 68 0.250 0 0.0 0 0.0 0 0.0 0 0.0

* 51 1 1 0 0.00000 1.000 0.00000 1 0.000 0.000

60 0.250 61 0.250 70 0.250 69 0.250 0 0.0 0 0.0 0 0.0 0 0.0

* 52 1 1 0 0.00000 1.000 0.00000 1 0.000 0.000

61 0.250 62 0.250 71 0.250 70 0.250 0 0.0 0 0.0 0 0.0 0 0.0

* 53 1 1 0 0.00000 1.000 0.00000 1 0.000 0.000

63 0.250 64 0.250 73 0.250 72 0.250 0 0.0 0 0.0 0 0.0 0 0.0

* 54 1 1 0 0.00000 1.000 0.00000 1 0.000 0.000

64 0.250 65 0.250 74 0.250 73 0.250 0 0.0 0 0.0 0 0.0 0 0.0

* 55 1 1 0 0.00000 1.000 0.00000 1 0.000 0.000

65 0.250 66 0.250 75 0.250 74 0.250 0 0.0 0 0.0 0 0.0 0 0.0

* 56 1 1 0 0.00000 1.000 0.00000 1 0.000 0.000

66 0.250 67 0.250 76 0.250 75 0.250 0 0.0 0 0.0 0 0.0 0 0.0

* 57 1 1 0 0.00000 1.000 0.00000 1 0.000 0.000

67 0.250 68 0.250 77 0.250 76 0.250 0 0.0 0 0.0 0 0.0 0 0.0

* 58 1 1 0 0.00000 1.000 0.00000 1 0.000 0.000

68 0.250 69 0.250 78 0.250 77 0.250 0 0.0 0 0.0 0 0.0 0 0.0

*

114

59 1 1 0 0.00000 1.000 0.00000 1 0.000 0.000

69 0.250 70 0.250 79 0.250 78 0.250 0 0.0 0 0.0 0 0.0 0 0.0 *

60 1 1 0 0.00000 1.000 0.00000 1 0.000 0.000

70 0.250 71 0.250 80 0.250 79 0.250 0 0.0 0 0.0 0 0.0 0 0.0 *

61 1 1 0 0.00000 1.000 0.00000 1 0.000 0.000

31 0.250 32 0.250 40 0.250 81 0.250 0 0.0 0 0.0 0 0.0 0 0.0 *

62 1 1 0 0.00000 1.000 0.00000 1 0.000 0.000

81 0.250 41 0.250 49 0.250 50 0.250 0 0.0 0 0.0 0 0.0 0 0.0 *

*

***** Group 8.6 * I NRT1 NST1 NRX1

1 62 0 2

* ***** Group 8.7

*IRTAB IRTAB IRTAB IRTAB IRTAB IRTAB IRTAB IRTAB IRTAB IRTAB IRTAB IRTAB

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24

25 26 27 28 29 30 31 32 33 34 35 36

37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60

61 62 0 0 0 0 0 0 0 0 0 0

* *

***** Group 8.9 * AXIALT TRINIT

0.0000000 285.00000

3.7080000 285.00000 *

********************************************************************************

* GROUP 9.0 - Conductor Geometry Description * ********************************************************************************

*NGRP

9 *NFLT IRLF ICNF IMWR NDM5 NDM6 NDM7 NDM8 NDM9 NM10 NM11 NM12 NM13 NM14

1 0 0 0 0 0 0 0 0 0 0 0 0 0

* * I FTYP DROD DIN NFUL ITOX ITIX NDM8 NDM9 NM10 NM11 NM12 NM13 NM14

1 tube 0.01230 0.00970 1 1 1 0 0 0 0 0 0 0

* NODR MATR TREG QREG 2 1 0.00130 1.0000

********************************************************************************

* GROUP 10 - Material Properties Tables * ********************************************************************************

*NGRP

10 *NMAT NDM2 NDM3 NDM4 NDM5 NDM6 NDM7 NDM8 NDM9 NM10 NM11 NM12 NM13 NM14

1 0 0 0 0 0 0 0 0 0 0 0 0 0

* N NTDP RCOLD IMATAN 1 6 8470.57 Inconel 600

* TPROP CPF1 THCF

-73 0.377 13.40 93 0.464 15.71

204 0.485 17.44

427 0.527 20.90 649 0.586 24.79

871 0.623 28.83

* ********************************************************************************

* END GROUP 10.0

******************************************************************************** *

*

******************************************************************************** * GROUP 11.0 - Axial Power Tables and Forcing Functions *

********************************************************************************

* CARD GROUP 11

115

* NGR

11 * Card 11.1

* NQA NAXP MNXN NQ NGPF NQR NDM7 NDM8 NDM9 NM10 NM11 NM12 NM13 NM14

1 1 2 0 0 1 0 0 0 0 0 0 0 0 * Card 11.2

* Axial Power Forcing Functions

* YQA 0.0

* Card 11.3

* I NAXN 1 2

* Card 11.4

* Y AXIAL 0.00000 1.00

3.70800 1.00

* * Radial Power Forcing Functions

* YQR

0.0 ** Note: Guide tubes are NOT modeled

* FQR FQR FQR FRQ FQR FRQ FQR FRQ

1.0000 1.0000 1.0000 1.0000 1.0000 1.0000 1.0000 1.0000 1.0000 1.0000 1.0000 1.0000 1.0000 1.0000 1.0000 1.0000

1.0000 1.0000 1.0000 1.0000 1.0000 1.0000 1.0000 1.0000

1.0000 1.0000 1.0000 1.0000 1.0000 1.0000 1.0000 1.0000 1.0000 1.0000 1.0000 1.0000 1.0000 1.0000 1.0000 1.0000

1.0000 1.0000 1.0000 1.0000 1.0000 1.0000 1.0000 1.0000 1.0000 1.0000 1.0000 1.0000 1.0000 1.0000 1.0000 1.0000

1.0000 1.0000 1.0000 1.0000 1.0000 1.0000

* ********************************************************************************

* END GROUP 11.0 *

******************************************************************************** *

********************************************************************************

* GROUP 12 - Turbulent mixing data * ********************************************************************************

*NGRP

12 * Card 12.1 - Standard mixing model

*AAAK BETA THETM

{AAAK} {BETA} {THETA} *

*

******************************************************************************** * END GROUP 12.0

********************************************************************************

* ********************************************************************************

* GROUP 13 - Boundary Condition Data

******************************************************************************** * CARD GROUP 13

* NGR

13 * Card 13.1

* NBN NKBD NFUN NGBD NDM5 NDM6 NDM7 NDM8 NDM9 NM10 NM11 NM12 NM13 NM14

162 0 0 0 0 0 0 0 0 0 0 0 0 0 * Card 13.4

*-------------------Inlet Boundary Conditions-------------------------

*IBD1 IBD2 ISPC N1FN N2FN N3FN BCVALUE1 BCVALUE2 BCVALUE3 INITGAS 1 1 2 0 0 0 0.0 {HIN} 0.0 1

2 1 2 0 0 0 0.0 {HIN} 0.0 1

3 1 2 0 0 0 0.0 {HIN} 0.0 1 4 1 2 0 0 0 0.0 {HIN} 0.0 1

5 1 2 0 0 0 0.0 {HIN} 0.0 1

6 1 2 0 0 0 0.0 {HIN} 0.0 1 7 1 2 0 0 0 0.0 {HIN} 0.0 1

8 1 2 0 0 0 0.0 {HIN} 0.0 1

9 1 2 0 0 0 0.0 {HIN} 0.0 1

116

10 1 2 0 0 0 0.0 {HIN} 0.0 1

11 1 2 0 0 0 0.0 {HIN} 0.0 1 12 1 2 0 0 0 0.0 {HIN} 0.0 1

13 1 2 0 0 0 0.0 {HIN} 0.0 1

14 1 2 0 0 0 0.0 {HIN} 0.0 1 15 1 2 0 0 0 0.0 {HIN} 0.0 1

16 1 2 0 0 0 0.0 {HIN} 0.0 1

17 1 2 0 0 0 0.0 {HIN} 0.0 1 18 1 2 0 0 0 0.0 {HIN} 0.0 1

19 1 2 0 0 0 0.0 {HIN} 0.0 1

20 1 2 0 0 0 0.0 {HIN} 0.0 1 21 1 2 0 0 0 0.0 {HIN} 0.0 1

22 1 2 0 0 0 0.0 {HIN} 0.0 1

23 1 2 0 0 0 0.0 {HIN} 0.0 1 24 1 2 0 0 0 0.0 {HIN} 0.0 1

25 1 2 0 0 0 0.0 {HIN} 0.0 1

26 1 2 0 0 0 0.0 {HIN} 0.0 1 27 1 2 0 0 0 0.0 {HIN} 0.0 1

28 1 2 0 0 0 0.0 {HIN} 0.0 1

29 1 2 0 0 0 0.0 {HIN} 0.0 1 30 1 2 0 0 0 0.0 {HIN} 0.0 1

31 1 2 0 0 0 0.0 {HIN} 0.0 1

32 1 2 0 0 0 0.0 {HIN} 0.0 1 33 1 2 0 0 0 0.0 {HIN} 0.0 1

34 1 2 0 0 0 0.0 {HIN} 0.0 1

35 1 2 0 0 0 0.0 {HIN} 0.0 1 36 1 2 0 0 0 0.0 {HIN} 0.0 1

37 1 2 0 0 0 0.0 {HIN} 0.0 1 38 1 2 0 0 0 0.0 {HIN} 0.0 1

39 1 2 0 0 0 0.0 {HIN} 0.0 1

40 1 2 0 0 0 0.0 {HIN} 0.0 1 41 1 2 0 0 0 0.0 {HIN} 0.0 1

42 1 2 0 0 0 0.0 {HIN} 0.0 1

43 1 2 0 0 0 0.0 {HIN} 0.0 1 44 1 2 0 0 0 0.0 {HIN} 0.0 1

45 1 2 0 0 0 0.0 {HIN} 0.0 1

46 1 2 0 0 0 0.0 {HIN} 0.0 1 47 1 2 0 0 0 0.0 {HIN} 0.0 1

48 1 2 0 0 0 0.0 {HIN} 0.0 1

49 1 2 0 0 0 0.0 {HIN} 0.0 1 50 1 2 0 0 0 0.0 {HIN} 0.0 1

51 1 2 0 0 0 0.0 {HIN} 0.0 1

52 1 2 0 0 0 0.0 {HIN} 0.0 1 53 1 2 0 0 0 0.0 {HIN} 0.0 1

54 1 2 0 0 0 0.0 {HIN} 0.0 1

55 1 2 0 0 0 0.0 {HIN} 0.0 1 56 1 2 0 0 0 0.0 {HIN} 0.0 1

57 1 2 0 0 0 0.0 {HIN} 0.0 1

58 1 2 0 0 0 0.0 {HIN} 0.0 1 59 1 2 0 0 0 0.0 {HIN} 0.0 1

60 1 2 0 0 0 0.0 {HIN} 0.0 1

61 1 2 0 0 0 0.0 {HIN} 0.0 1 62 1 2 0 0 0 0.0 {HIN} 0.0 1

63 1 2 0 0 0 0.0 {HIN} 0.0 1

64 1 2 0 0 0 0.0 {HIN} 0.0 1 65 1 2 0 0 0 0.0 {HIN} 0.0 1

66 1 2 0 0 0 0.0 {HIN} 0.0 1

67 1 2 0 0 0 0.0 {HIN} 0.0 1 68 1 2 0 0 0 0.0 {HIN} 0.0 1

69 1 2 0 0 0 0.0 {HIN} 0.0 1

70 1 2 0 0 0 0.0 {HIN} 0.0 1 71 1 2 0 0 0 0.0 {HIN} 0.0 1

72 1 2 0 0 0 0.0 {HIN} 0.0 1

73 1 2 0 0 0 0.0 {HIN} 0.0 1 74 1 2 0 0 0 0.0 {HIN} 0.0 1

75 1 2 0 0 0 0.0 {HIN} 0.0 1

76 1 2 0 0 0 0.0 {HIN} 0.0 1 77 1 2 0 0 0 0.0 {HIN} 0.0 1

78 1 2 0 0 0 0.0 {HIN} 0.0 1

79 1 2 0 0 0 0.0 {HIN} 0.0 1

117

80 1 2 0 0 0 0.0 {HIN} 0.0 1

81 1 2 0 0 0 0.0 {HIN} 0.0 1 *-------------------Outlet Boundary Conditions-------------------------

*IBD1 IBD2 ISPC N1FN N2FN N3FN BCVALUE1 BCVALUE2 BCVALUE3 INITGAS

1 104 1 0 0 0 0.0 {HIN} {PREF} 1 2 104 1 0 0 0 0.0 {HIN} {PREF} 1

3 104 1 0 0 0 0.0 {HIN} {PREF} 1

4 104 1 0 0 0 0.0 {HIN} {PREF} 1 5 104 1 0 0 0 0.0 {HIN} {PREF} 1

6 104 1 0 0 0 0.0 {HIN} {PREF} 1

7 104 1 0 0 0 0.0 {HIN} {PREF} 1 8 104 1 0 0 0 0.0 {HIN} {PREF} 1

9 104 1 0 0 0 0.0 {HIN} {PREF} 1

10 104 1 0 0 0 0.0 {HIN} {PREF} 1 11 104 1 0 0 0 0.0 {HIN} {PREF} 1

12 104 1 0 0 0 0.0 {HIN} {PREF} 1

13 104 1 0 0 0 0.0 {HIN} {PREF} 1 14 104 1 0 0 0 0.0 {HIN} {PREF} 1

15 104 1 0 0 0 0.0 {HIN} {PREF} 1

16 104 1 0 0 0 0.0 {HIN} {PREF} 1 17 104 1 0 0 0 0.0 {HIN} {PREF} 1

18 104 1 0 0 0 0.0 {HIN} {PREF} 1

19 104 1 0 0 0 0.0 {HIN} {PREF} 1 20 104 1 0 0 0 0.0 {HIN} {PREF} 1

21 104 1 0 0 0 0.0 {HIN} {PREF} 1

22 104 1 0 0 0 0.0 {HIN} {PREF} 1 23 104 1 0 0 0 0.0 {HIN} {PREF} 1

24 104 1 0 0 0 0.0 {HIN} {PREF} 1 25 104 1 0 0 0 0.0 {HIN} {PREF} 1

26 104 1 0 0 0 0.0 {HIN} {PREF} 1

27 104 1 0 0 0 0.0 {HIN} {PREF} 1 28 104 1 0 0 0 0.0 {HIN} {PREF} 1

29 104 1 0 0 0 0.0 {HIN} {PREF} 1

30 104 1 0 0 0 0.0 {HIN} {PREF} 1 31 104 1 0 0 0 0.0 {HIN} {PREF} 1

32 104 1 0 0 0 0.0 {HIN} {PREF} 1

33 104 1 0 0 0 0.0 {HIN} {PREF} 1 34 104 1 0 0 0 0.0 {HIN} {PREF} 1

35 104 1 0 0 0 0.0 {HIN} {PREF} 1

36 104 1 0 0 0 0.0 {HIN} {PREF} 1 37 104 1 0 0 0 0.0 {HIN} {PREF} 1

38 104 1 0 0 0 0.0 {HIN} {PREF} 1

39 104 1 0 0 0 0.0 {HIN} {PREF} 1 40 104 1 0 0 0 0.0 {HIN} {PREF} 1

41 104 1 0 0 0 0.0 {HIN} {PREF} 1

42 104 1 0 0 0 0.0 {HIN} {PREF} 1 43 104 1 0 0 0 0.0 {HIN} {PREF} 1

44 104 1 0 0 0 0.0 {HIN} {PREF} 1

45 104 1 0 0 0 0.0 {HIN} {PREF} 1 46 104 1 0 0 0 0.0 {HIN} {PREF} 1

47 104 1 0 0 0 0.0 {HIN} {PREF} 1

48 104 1 0 0 0 0.0 {HIN} {PREF} 1 49 104 1 0 0 0 0.0 {HIN} {PREF} 1

50 104 1 0 0 0 0.0 {HIN} {PREF} 1

51 104 1 0 0 0 0.0 {HIN} {PREF} 1 52 104 1 0 0 0 0.0 {HIN} {PREF} 1

53 104 1 0 0 0 0.0 {HIN} {PREF} 1

54 104 1 0 0 0 0.0 {HIN} {PREF} 1 55 104 1 0 0 0 0.0 {HIN} {PREF} 1

56 104 1 0 0 0 0.0 {HIN} {PREF} 1

57 104 1 0 0 0 0.0 {HIN} {PREF} 1 58 104 1 0 0 0 0.0 {HIN} {PREF} 1

59 104 1 0 0 0 0.0 {HIN} {PREF} 1

60 104 1 0 0 0 0.0 {HIN} {PREF} 1 61 104 1 0 0 0 0.0 {HIN} {PREF} 1

62 104 1 0 0 0 0.0 {HIN} {PREF} 1

63 104 1 0 0 0 0.0 {HIN} {PREF} 1 64 104 1 0 0 0 0.0 {HIN} {PREF} 1

65 104 1 0 0 0 0.0 {HIN} {PREF} 1

66 104 1 0 0 0 0.0 {HIN} {PREF} 1

118

67 104 1 0 0 0 0.0 {HIN} {PREF} 1

68 104 1 0 0 0 0.0 {HIN} {PREF} 1 69 104 1 0 0 0 0.0 {HIN} {PREF} 1

70 104 1 0 0 0 0.0 {HIN} {PREF} 1

71 104 1 0 0 0 0.0 {HIN} {PREF} 1 72 104 1 0 0 0 0.0 {HIN} {PREF} 1

73 104 1 0 0 0 0.0 {HIN} {PREF} 1

74 104 1 0 0 0 0.0 {HIN} {PREF} 1 75 104 1 0 0 0 0.0 {HIN} {PREF} 1

76 104 1 0 0 0 0.0 {HIN} {PREF} 1

77 104 1 0 0 0 0.0 {HIN} {PREF} 1 78 104 1 0 0 0 0.0 {HIN} {PREF} 1

79 104 1 0 0 0 0.0 {HIN} {PREF} 1

80 104 1 0 0 0 0.0 {HIN} {PREF} 1 81 104 1 0 0 0 0.0 {HIN} {PREF} 1

*

*********************************************************************************************** *GROUP 14 - Output Options

***********************************************************************************************

**NGR -14

** KEY VALUE

hdf5 0 rod_vtk 0

chan_edits 1

rod_edits 1 gap_edits 0

fluid_vtk 1 dnb_edits 1

convergence 1

end 14 ***********************************************************************************************

*GROUP 15 - Time Domain Data

*********************************************************************************************** **NGR

15

*Card 15.1 ** DTMIN DTMAX TEND EDINT DMPINT RTWFP MAXITS

0.1000E-05 0.1000E+00 20.1 1.000E+00 0.1000E+00 400.0 8000

* ** DTMIN (if negative stop)

-0.001 0.0 0.0 0.0 0.0 0.0

*********************************************************************************************** *GROUP 18 - Convergence Criteria for Steady State Solve

***********************************************************************************************

**NGR 18

*Card 18.1

**Global Energy Balance Criteria (%) 0.01

*Card 18.2

**Global Mass Balance Criteria (%) 0.01

*Card 18.3

**Fluid Energy Storage Criteria (%) 0.5

*Card 18.4

**Solid Energy Storage Criteria (%) 0.5

*Card 18.5

**Mass Storage Criteria (%) 0.5

119

Appendix B: Void Distribution Sensitivity Plots

Figure 88: Equilibrium distribution weighting factor sensitivity Test Case 0011-58

Figure 89: Power sensitivity Test Case 0011-58

Figure 90: Turbulent mixing coefficient sensitivity Test Case 0011-58

0.65

0.655

0.66

0.665

0.67

0.675

0.68

0.685

0.69

0.695

0 0.5 1 1.5 2 2.5 3

Vo

id [

-]

AAAK [-]


0.64

0.65

0.66

0.67

0.68

0.69

0.7

14.6 14.8 15 15.2 15.4 15.6 15.8

Vo

id [

-]

AFLUX [kW/m]


0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0 0.02 0.04 0.06 0.08 0.1 0.12

Vo

id [

-]

BETA [-]


120

Figure 91: Mass flow rate sensitivity Test Case 0011-58

Figure 92: Enthalpy sensitivity Test Case 0011-58

Figure 93: Pressure sensitivity Test Case 0011-58

0.65

0.655

0.66

0.665

0.67

0.675

0.68

0.685

0.69

0.695

14.9 15 15.1 15.2 15.3 15.4 15.5 15.6

Vo

id [

-]

GTOT kg/s]


0.6

0.62

0.64

0.66

0.68

0.7

0.72

0.74

1180 1200 1220 1240 1260 1280

Vo

id [

-]

HIN [kJ/kg]


0.66

0.665

0.67

0.675

0.68

0.685

0.69

0.695

0.7

70 70.5 71 71.5 72 72.5 73 73.5

Vo

id [

-]

PREF [bar]


121

Figure 94: THETA sensitivity Test Case 0011-58



0.56

0.58

0.6

0.62

0.64

0.66

0.68

0.7

0 2 4 6 8 10 12

Vo

id [

-]

THETA[-]


0.77

0.78

0.79

0.8

0.81

0.82

0.83

0.84

0 0.5 1 1.5 2 2.5 3

Vo

id [

-]

AAAK [-]


0.78

0.79

0.8

0.81

0.82

0.83

0.84

27 27.5 28 28.5 29

Vo

id [

-]

AFLUX [kW/m]


122




0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

0 0.02 0.04 0.06 0.08 0.1 0.12

Vo

id [

-]

BETA [-]


0.78

0.79

0.8

0.81

0.82

0.83

0.84

14.8 14.9 15 15.1 15.2 15.3 15.4 15.5 15.6

Vo

id [

-]

GTOT kg/s]


0.77

0.78

0.79

0.8

0.81

0.82

0.83

0.84

0.85

1180 1200 1220 1240 1260 1280

Vo

id [

-]

HIN [kJ/kg]


123




0.78

0.79

0.8

0.81

0.82

0.83

0.84

70.5 71 71.5 72 72.5 73 73.5 74

Vo

id [

-]

PREF [bar]


0.77

0.78

0.79

0.8

0.81

0.82

0.83

0.84

0 2 4 6 8 10 12

Vo

id [

-]

THETA[-]


0.44

0.45

0.46

0.47

0.48

0.49

0.5

0.51

0.52

0 0.5 1 1.5 2 2.5 3

Vo

id [

-]

AAAK [-]


124




0.45

0.46

0.47

0.48

0.49

0.5

0.51

8.3 8.4 8.5 8.6 8.7 8.8 8.9

Vo

id [

-]

AFLUX [kW/m]


0

0.1

0.2

0.3

0.4

0.5

0.6

0 0.02 0.04 0.06 0.08 0.1 0.12

Vo

id [

-]

BETA [-]


0.46

0.465

0.47

0.475

0.48

0.485

0.49

0.495

0.5

0.505

14.9 15 15.1 15.2 15.3 15.4 15.5 15.6

Vo

id [

-]

GTOT kg/s]


125




0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

1180 1200 1220 1240 1260 1280

Vo

id [

-]

HIN [kJ/kg]


0.44

0.45

0.46

0.47

0.48

0.49

0.5

0.51

0.52

0.53

70 70.5 71 71.5 72 72.5 73 73.5

Vo

id [

-]

PREF [bar]


0.43

0.44

0.45

0.46

0.47

0.48

0.49

0.5

0 2 4 6 8 10 12

Vo

id [

-]

THETA[-]


126




0.58

0.6

0.62

0.64

0.66

0.68

0.7

0.72

0 0.5 1 1.5 2 2.5 3

Vo

id [

-]

AAAK [-]


0.65

0.66

0.67

0.68

0.69

0.7

0.71

15.2 15.4 15.6 15.8 16 16.2 16.4

Vo

id [

-]

AFLUX [kW/m]


0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0 0.02 0.04 0.06 0.08 0.1 0.12

Vo

id [

-]

BETA [-]


127




0.66

0.665

0.67

0.675

0.68

0.685

0.69

0.695

0.7

0.705

14.9 15 15.1 15.2 15.3 15.4 15.5 15.6

Vo

id [

-]

GTOT kg/s]


0.6

0.62

0.64

0.66

0.68

0.7

0.72

0.74

1180 1200 1220 1240 1260 1280

Vo

id [

-]

HIN [kJ/kg]


0.67

0.675

0.68

0.685

0.69

0.695

0.7

0.705

0.71

70 70.5 71 71.5 72 72.5 73 73.5

Vo

id [

-]

PREF [bar]


128




0.58

0.6

0.62

0.64

0.66

0.68

0.7

0.72

0 2 4 6 8 10 12

Vo

id [

-]

THETA[-]


0.78

0.79

0.8

0.81

0.82

0.83

0.84

0 0.5 1 1.5 2 2.5 3

Vo

id [

-]

AAAK [-]


0.78

0.79

0.8

0.81

0.82

0.83

0.84

0.85

28 28.5 29 29.5 30

Vo

id [

-]

AFLUX [kW/m]


129




0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

0 0.02 0.04 0.06 0.08 0.1 0.12

Vo

id [

-]

BETA [-]


0.78

0.79

0.8

0.81

0.82

0.83

0.84

0.85

14.9 15 15.1 15.2 15.3 15.4 15.5 15.6

Vo

id [

-]

GTOT kg/s]


0.77

0.78

0.79

0.8

0.81

0.82

0.83

0.84

0.85

0.86

1180 1200 1220 1240 1260 1280

Vo

id [

-]

HIN [kJ/kg]


130




0.78

0.79

0.8

0.81

0.82

0.83

0.84

0.85

70 70.5 71 71.5 72 72.5 73 73.5

Vo

id [

-]

PREF [bar]


0.77

0.78

0.79

0.8

0.81

0.82

0.83

0.84

0 2 4 6 8 10 12

Vo

id [

-]

THETA[-]


0.48

0.49

0.5

0.51

0.52

0.53

0.54

0.55

0.56

0 0.5 1 1.5 2 2.5 3

Vo

id [

-]

AAAK [-]


131




0.49

0.5

0.51

0.52

0.53

0.54

0.55

9 9.1 9.2 9.3 9.4 9.5 9.6 9.7 9.8

Vo

id [

-]

AFLUX [kW/m]


0

0.1

0.2

0.3

0.4

0.5

0.6

0 0.02 0.04 0.06 0.08 0.1 0.12

Vo

id [

-]

BETA [-]


0.5

0.505

0.51

0.515

0.52

0.525

0.53

0.535

0.54

0.545

14.9 15 15.1 15.2 15.3 15.4 15.5 15.6 15.7

Vo

id [

-]

GTOT kg/s]


132




0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

1180 1200 1220 1240 1260 1280

Vo

id [

-]

HIN [kJ/kg]


0.49

0.5

0.51

0.52

0.53

0.54

0.55

0.56

70 70.5 71 71.5 72 72.5 73 73.5

Vo

id [

-]

PREF [bar]


0.46

0.47

0.48

0.49

0.5

0.51

0.52

0.53

0.54

0 2 4 6 8 10 12

Vo

id [

-]

THETA[-]


133




0.6850.69

0.6950.7

0.7050.71

0.7150.72

0.7250.73

0.735

0 0.5 1 1.5 2 2.5 3

Vo

id [

-]

AAAK [-]


0.68

0.69

0.7

0.71

0.72

0.73

0.74

16.6 16.8 17 17.2 17.4 17.6 17.8 18

Vo

id [

-]

AFLUX [kW/m]


0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0 0.02 0.04 0.06 0.08 0.1 0.12

Vo

id [

-]

BETA [-]


134




0.685

0.69

0.695

0.7

0.705

0.71

0.715

0.72

0.725

0.73

14.8 14.9 15 15.1 15.2 15.3 15.4 15.5 15.6

Vo

id [

-]

GTOT kg/s]


0.64

0.66

0.68

0.7

0.72

0.74

0.76

1180 1200 1220 1240 1260 1280

Vo

id [

-]

HIN [kJ/kg]


0.69

0.695

0.7

0.705

0.71

0.715

0.72

0.725

0.73

0.735

70 70.5 71 71.5 72 72.5 73 73.5

Vo

id [

-]

PREF [bar]


135




0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0 2 4 6 8 10 12

Vo

id [

-]

THETA[-]


0.78

0.79

0.8

0.81

0.82

0.83

0.84

0.85

0.86

0 0.5 1 1.5 2 2.5 3

Vo

id [

-]

AAAK [-]


0.78

0.79

0.8

0.81

0.82

0.83

0.84

0.85

0.86

30.5 31 31.5 32 32.5 33

Vo

id [

-]

AFLUX [kW/m]


136




0

0.2

0.4

0.6

0.8

1

0 0.02 0.04 0.06 0.08 0.1 0.12

Vo

id [

-]

BETA [-]


0.78

0.79

0.8

0.81

0.82

0.83

0.84

0.85

0.86

14.9 15 15.1 15.2 15.3 15.4 15.5 15.6

Vo

id [

-]

GTOT kg/s]


0.78

0.79

0.8

0.81

0.82

0.83

0.84

0.85

0.86

0.87

1180 1200 1220 1240 1260 1280

Vo

id [

-]

HIN [kJ/kg]


137




0.78

0.79

0.8

0.81

0.82

0.83

0.84

0.85

0.86

70 70.5 71 71.5 72 72.5 73 73.5

Vo

id [

-]

PREF [bar]


0.76

0.78

0.8

0.82

0.84

0.86

0 2 4 6 8 10 12

Vo

id [

-]

THETA[-]


0.47

0.48

0.49

0.5

0.51

0.52

0.53

0.54

0 0.5 1 1.5 2 2.5 3

Vo

id [

-]

AAAK [-]


138




0.48

0.485

0.49

0.495

0.5

0.505

0.51

0.515

0.52

8.6 8.7 8.8 8.9 9 9.1 9.2 9.3

Vo

id [

-]

AFLUX [kW/m]


0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0 0.02 0.04 0.06 0.08 0.1 0.12

Vo

id [

-]

BETA [-]


0.485

0.49

0.495

0.5

0.505

0.51

0.515

0.52

14.9 15 15.1 15.2 15.3 15.4 15.5 15.6 15.7

Vo

id [

-]

GTOT kg/s]


139




0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

1180 1200 1220 1240 1260 1280

Vo

id [

-]

HIN [kJ/kg]


0.46

0.47

0.48

0.49

0.5

0.51

0.52

0.53

0.54

70 70.5 71 71.5 72 72.5 73 73.5

Vo

id [

-]

PREF [bar]

Ch4 Ch5 Ch31 Ch32

0.45

0.46

0.47

0.48

0.49

0.5

0.51

0.52

0.53

0 2 4 6 8 10 12

Vo

id [

-]

THETA[-]


140




0.45

0.46

0.47

0.48

0.49

0.5

0.51

0.52

0 0.5 1 1.5 2 2.5 3

Vo

id [

-]

AAAK [-]


0.455

0.46

0.465

0.47

0.475

0.48

0.485

0.49

0.495

0.5

8.3 8.4 8.5 8.6 8.7 8.8 8.9 9

Vo

id [

-]

AFLUX [kW/m]


0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0 0.02 0.04 0.06 0.08 0.1 0.12

Vo

id [

-]

BETA [-]


141




0.46

0.465

0.47

0.475

0.48

0.485

0.49

0.495

0.5

14.8 14.9 15 15.1 15.2 15.3 15.4 15.5 15.6

Vo

id [

-]

GTOT kg/s]


0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

1180 1200 1220 1240 1260 1280

Vo

id [

-]

HIN [kJ/kg]


0.44

0.45

0.46

0.47

0.48

0.49

0.5

0.51

0.52

70 70.5 71 71.5 72 72.5 73 73.5 74

Vo

id [

-]

PREF [bar]

Ch4 Ch5 Ch31 Ch32

142




0.43

0.44

0.45

0.46

0.47

0.48

0.49

0.5

0.51

0 2 4 6 8 10 12

Vo

id [

-]

THETA[-]


0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0 0.5 1 1.5 2 2.5 3

Vo

id [

-]

AAAK [-]


0.655

0.66

0.665

0.67

0.675

0.68

0.685

0.69

0.695

15.2 15.4 15.6 15.8 16 16.2 16.4

Vo

id [

-]

AFLUX [kW/m]


143




0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

0 0.02 0.04 0.06 0.08 0.1 0.12

Vo

id [

-]

BETA [-]


0.655

0.66

0.665

0.67

0.675

0.68

0.685

0.69

0.695

14.8 14.9 15 15.1 15.2 15.3 15.4 15.5 15.6

Vo

id [

-]

GTOT kg/s]


0.6

0.62

0.64

0.66

0.68

0.7

0.72

0.74

1180 1200 1220 1240 1260 1280

Vo

id [

-]

HIN [kJ/kg]


144




0.665

0.67

0.675

0.68

0.685

0.69

0.695

0.7

69.5 70 70.5 71 71.5 72 72.5 73 73.5

Vo

id [

-]

PREF [bar]

Ch4 Ch5 Ch31 Ch32

0.58

0.6

0.62

0.64

0.66

0.68

0.7

0.72

0.74

0 2 4 6 8 10 12

Vo

id [

-]

THETA[-]


0.78

0.79

0.8

0.81

0.82

0.83

0.84

0 0.5 1 1.5 2 2.5 3

Vo

id [

-]

AAAK [-]


145




0.785

0.79

0.795

0.8

0.805

0.81

0.815

0.82

0.825

0.83

28 28.5 29 29.5 30 30.5

Vo

id [

-]

AFLUX [kW/m]


0.74

0.76

0.78

0.8

0.82

0.84

0.86

0.88

0.9

0 0.02 0.04 0.06 0.08 0.1 0.12

Vo

id [

-]

BETA [-]


0.79

0.795

0.8

0.805

0.81

0.815

0.82

0.825

0.83

14.8 14.9 15 15.1 15.2 15.3 15.4 15.5 15.6

Vo

id [

-]

GTOT kg/s]


146




0.77

0.78

0.79

0.8

0.81

0.82

0.83

0.84

0.85

1180 1200 1220 1240 1260 1280

Vo

id [

-]

HIN [kJ/kg]


0.79

0.795

0.8

0.805

0.81

0.815

0.82

0.825

0.83

70 70.5 71 71.5 72 72.5 73 73.5

Vo

id [

-]

PREF [bar]

Ch4 Ch5 Ch31 Ch32

0.75

0.76

0.77

0.78

0.79

0.8

0.81

0.82

0.83

0 2 4 6 8 10 12

Vo

id [

-]

THETA[-]


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