Thermal Hydraulic Studies for PFBR using PHOENICS

U. PARTHA SARATHY

Indira Gandhi Centre for Atomic ResearchKalpakkam

May 3-5 th 2004

2 U. Partha Sarathy, IGCAR 05/05/2004

PROTOTYPE FAST BREEDER REACTOR(PFBR)

Power - 500 MWe, 1250 MWth

Fuel – Mixture of UO2 (79 %) and PuO2 (21 %)

Coolant – Sodium (liquid metal) in Pry and Secy Circuits

– Water in Tertiary Circuit

High Temperatures

High Velocities

Problems –

High temperatures leading to creep, fatigue damage

Flow induced vibrations

Thermal striping

Gas entrainment

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PFBR Primary Circuit

IHXPUMP

CORE

Nuclear heat

Hot Pool

Cold Pool Grid Plate

Inner Vessel

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Schematic PFBR Flow Sheet

•Primary Circuit •Secondary Circuit •Steam/Water circuit

HYDRAULIC ANALYSIS OFGRID PLATE- e Page

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HYDRAULIC ANALYSIS OF GRID PLATE

• Consists of 1758 sleeves

• Receives flow from four pipes

• Distributes flow to various

subassemblies

Objectives

Flow and pressure distribution

Pressure drop in GP

Velocity over sleeves

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SECTION A - A

PLAN

Modelling

2-D model in cylindrical co-ordinates (r- θ)

Sleeves modeled through porosity in radial and circumferential directions (Porous body formulation)

Inlet as Velocity BC

Outlets as mass sinks

Pressure drop due to sleeves modeled through Zukauskas correlation

Addition of resistance terms in the momentum equation using ‘ground’ subroutine.

K-E Turbulence model

HYDRAULIC ANALYSIS OF GRID PLATE

Schematic of Grid Plate

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Results of Grid Plate Analysis

Results

Predicted ΔP is 4.6 m of sodium

Similar to that extrapolated from 1:3 scale air experiments.

Pressure contours are concentric – uniform flow through fuel SA

Maximum cross flow velocity is 8.5 m/s

Flow Distribution in Grid Plate

Thermal Analysis of Hot and Cold Pools- Title Page

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Thermal Analysis of Hot and Cold Pools

Objectives

Inner Vessel temperature distribution

Stratification In sodium pools

Hot pool free surface velocity & temperature

CORE

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CFD Model and Boundary Conditions

Modelling 2-D model in cylindrical co-

ordinates (r-z)

Core is modeled as a block

Porous body approximation for immersed components – IHX, Pump

Mass sink at IHX & PUMP inlets

Velocity BC at IHX and Core outlets

Conjugate thermal hydraulic analysis of hot & cold pools including IV

K-E Turbulence model

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Flow Distribution in Hot and Cold Pools

Good mixing in hot and cold pools

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Results

Tmax in IV is 534 OC

ΔT across thickness is 64 K

Max hot pool free surface temperature is 572 OC

Temperature Distribution in Inner Vessel

Hot Pool Free Surface Temperature Distribution

Flow Distribution in SG Inlet Plenum- Title Page

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Objective:To identify flow distribution devices and reduce maximum radial velocity over tubes from FIV considerations.

Schematic of PFBR SG

R

= 0°

= 180°

1200

OUTER SHELL

800

EXIT

ID 520

OD 356 NOZZLE

INLET

SHROUD

TUBE BUNDLE

TOP PLATE

460

3/5 scale model of SG Inlet Plenum

16 U. Partha Sarathy, IGCAR 05/05/2004

Modelling

3/5 scale model

3-D cylindrical coordinates

180 O symmetric model

K-E turbulence model

Inlet as velocity BC

R

= 0°

= 180°

1200

OUTER SHELL

800

EXIT

ID 520

OD 356 NOZZLE

INLET

SHROUD

TUBE BUNDLE

TOP PLATE

460

3/5 scale model of SG Inlet Plenum

17 U. Partha Sarathy, IGCAR 05/05/2004

7.88 E + 00

Max. : 5.19 E + 00

Min. : 1.87 E - 01

INLET

SHELLINNER

Flow distribution in SG Inlet Plenum – Basic Configuration

Flow distribution in Inlet window region at 1430 mm from inlet

=0

1200

1300

1400

1500

1600

1700

-1 -0.5 0 0.5 1 1.5 2 2.5 3Velocity, m/s

Hei

gh

t fro

m In

let,

mm

Theta = 15 Theta = 45 Theta = 60Theta = 75 Theta = 90

Fig. 5 Radial Velocity Profile Along the Window with Basic ConfigurationRadial Velocity Profile along the Window with Basic Configuration

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Axial Velocity in the Annulus at 575 mm – Basic Configuration

0.0

0.5

1.0

1.5

2.0

2.5

3.0

3.5

4.0

0 30 60 90 120 150 180Angle, degrees

Ax

ial V

elo

cit

y, m

/s

Basic Configuration

Axial Velocity in the Annulus at a height of 575 mm from inlet with various Porous Plates

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Porous plate used as a Flow distribution devices

30° 15

°

Porosity = 58%

Plate thickness = 10 mm

Material = Carbon steel

Radial pitch = 26 mm

Porosity = 55%d6 (Ø22.5)

d5 (Ø24)

Porosity = 63%

(Typ

) Porosity = 95%

R = 193

R = 178

Por

osity

= 6

5%

d3 (

Ø25

)

d4 (Ø25)

Porosity = 60%

d2 (Ø25)

48

58

34 34

4

2

45

55

5

R = 245

R = 260

R = 219

( = 0°)( = 180°)

3/5 scale model of SG Inlet plenum with Flow distribution devices

= 180°

R

TOP PLATE

60 % porosity

20 % porosity

TUBE BUNDLE

SHROUD

OUTER SHELL

120

0

460

800

EXIT

450

ID 520

OD 356NOZZLE

INLET

230

230

= 0°

Porous body formulation for porous plate and porous shell

Porous plate

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Axial Velocity in the Annulus at 575 mm from Inlet with Different Porous Plates

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1200

1300

1400

1500

1600

-2.5 -2 -1.5 -1 -0.5 0 0.5 1 1.5 2 2.5 3Velocity, m/s

He

igh

t fr

om

Inle

t, m

m

Theta = 15 deg Theta = 75 deg Theta = 135 deg

Fig. 9 Radial Velocity Profile Along the Window with Porous Plate (80 % to 55 %)

22 U. Partha Sarathy, IGCAR 05/05/2004

Flow distribution in SG Inlet plenum with Flow distribution devices

6.42 E + 00

Max. : 4.44 E + 00Min. : 4.61 E - 02

Inlet

Porus plate

Inner shell

(= 0)

Flow distribution in Inlet window region at 1430 mm from inlet

3/5 scale model of SG Inlet plenum with Flow distribution devices

= 180°

TOP PLATE

60 % porosity

20 % porosity

TUBE BUNDLE

SHROUD

OUTER SHELL

1200

460

800

EXIT

450

ID 520

OD 356NOZZLE

INLET

230

230

= 0°

23 U. Partha Sarathy, IGCAR 05/05/2004

Velocity Profile Along the Window at 135 deg

700

900

1100

1300

1500

1700

-1 -0.5 0 0.5 1 1.5 2 2.5 3

Velocity, m/s

He

igh

t fr

om

In

let,

mm

Basic configuration With Porous Plate With Porous Plate and Shell

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RESULTS Combination of graded porous plate and porous shell render as

uniform flow both axially and circumferentially.

The distributions of porosity in the plate and shell have been identified.

Maximum radial velocity is 0.75 m/s (average is 0.45 m/s) whereas the same is 3 m/s in basic configuration

Inter-Wrapper flow Studies-Title Page

26 U. Partha Sarathy, IGCAR 05/05/2004

Inter-Wrapper flow Studies - Steady State

Inter Wrapper flow

Sub-Assembly Steel hexagonal Wrapper

Objectives

•Effect of IWF on SA clad hotspot

•Flow distribution in IWS

•To develop a model for studying various design basis events which will give detailed temperature distribution in hot and cold pools

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Sodium Flow in Primary Circuit

CORE

DHX

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Modeling

2-D cylindrical coordinates (r-z)

Inlets as velocity BC

Outlets as mass sink

Porous body formulation for core and other immersed structures

Coupling with 1-D model for neutronics, heat transfer calculations in core, IHX, DHX etc.CFD model for IWS and Hot and

Cold Pools

29 U. Partha Sarathy, IGCAR 05/05/2004

Schematic of Fuel SASchematic of the SA Computational

Model

Sub Assembly Bottom

1010SA INLET REGION

-IWS

-

SSA -

BOTTOM AXIAL BLANKET

ACTIVE CORE

TOP AXIAL BLANKET

SA OUTLET REGION

300

1000

FU

EL

1

300

FU

EL

2

CLA

D

1290

Sub Assembly Top

calculated temperature

Inter-wrapper space

Storage subassembly

Hea

t tra

nsfe

r to

IWS

SA

SO

DIU

M

30 U. Partha Sarathy, IGCAR 05/05/2004

CORE FLOW

SA OUTLET TEMP.

HEAT TRANSFERRED

TO IWS

PRIMARY PUMP FLOW

IHX PRIMARY FLOW

IHX and DHX PRIMARY

OUTLET TEMPERATURES

DHX PRIMARY INLET TEMP

IHX PRIMARY INLET TEMP

IWS TEMPERATURE

PRIMARY PUMP INLET TEMP

1 D CODE

PRIMARY HYDRAULICS

CORE

IHX

DECAY HEAT

REMOVAL SYSTEMIV and MV

INCLUDING IWS,

AND COLD POOLS

MODEL OF HOT

PHOENICS

TWO DIMENSIONAL

Exchange of Results between 1-D and 2-D PHOENICS Models for

Boundary Conditions

31 U. Partha Sarathy, IGCAR 05/05/2004

Flow Chart for Coupled 1D Code – PHOENICS code Calculations

START

ID code

steady state

Heat transfer to IWS

Flow and temperatures

of SA, IHX and DHX

2D

PHOENICS

Inlet temperatures of

IHX, Pump and DHX

IWS temperature

convergence

Check for

STOP

BC

NO

YES

BC

iter = 0

of Pump inlet, IWS

Guess the temperatures

iter = iter +1

Hot and Cold pools

1-D

2-D

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Flow Distribution in Hot and Cold pools

Temperature Contours in Hot and Cold pools

m/s

m/s

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Temperature and Velocity Distribution in Inter-Wrapper Space

m/s

m/s

395 OC

415

405555

425

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Temperature Distribution in IV

Temperature Distribution in MV

Results

•SSA outlet temperature increases by about 2 K

•Total heat transferred to IWS is 370 kW

•Axial temperature gradient of hot/cold interface is 150 K/m

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Inter-Wrapper flow Studies - Transient Analysis (under progress)

Station blackout incident

All pumps trip

Primary circuit flow coasts down

Secondary circuits not available

Reactor trips only at 2.5 s

Temperature inside SA goes up

Good amount of heat is taken away by the IWF

Results

Transient Evolution of Temperatures in Ho

t and Cold Pools