assessment of predictions of rtndt and upper shelf energy ... · technical)letter)report)...

Technical Letter Report

TLR-RES/DE/CIB-2014-011

Assessment of Predictions of RTNDT and Upper Shelf Energy made using Branch Technical

Position 5-3

Date:

Submitted for Review: December 18, 2014

Finalized and Published: March 23, 2017

Prepared by:

Mark Kirk Senior Materials Engineer, RES/DE/CIB

Division of Engineering Office of Nuclear Regulatory Research U.S. Nuclear Regulatory Commission Washington, DC 20555–0001


Assessment of BTP 5-3 |

ABSTRACT

NRC Branch Technical Position (BTP) 5-3 and a similar procedure described in Ref. [1] of this report both provide various provisions useful for estimating transition temperature and upper shelf energy metrics for reactor pressure vessel steels when the data required by the American Society of Mechanical Engineers and ASTM International (formerly the American Society of Testing and Materials) are incomplete, which is often the case for nuclear power plants licensed before 1972. In January 2014, AREVA notified the NRC that some of these provisions might not provide conservative estimates of these metrics, as claimed by BTP 5-3. This report summarizes part of the staff’s assessment of the AREVA letter. Specifically, NRR requested RES to assist in its evaluation by performing an assessment of all provisions of BTP 5-3, including AREVA’s determination that one provision of BTP 5-3 may be non-conservative and, if so, to develop revised relationships that are conservative. This report summarizes only RES’s evaluation;; it does not provide an assessment of the potential impact on operating plants. Such an assessment is the topic of on-going activities being led by NRR. The staff investigated AREVA’s findings by assembling a database of information on unirradiated nuclear-grade steel plates and forgings reported to the NRC as part of 10 CFR 50 Appendix H surveillance programs. These source data were selected because they are available in the public domain, they are directly representative of the U.S. operating fleet, and they have both raw nil-ductility transition temperature (NDTT) data and Charpy V-notch (CVN) data in both the transverse and longitudinal directions. The analysis performed herein demonstrates that, in all but a few cases, the provisions of BTP 5-3 and the Ref. [1] procedure do not provide conservative estimates. Overall, the plate data were found to be better predicted than the forging data. However, depending on the specific provision of BTP 5-3 or the Ref. [1] procedure used, the amount of data that are non-conservatively predicted is as high as 66% for plates and 72% for forgings. The data assembled were therefore used to develop conservative estimates, which were defined as being 2σ (i.e., two standard deviations) from the mean of the data. The use of 2σ as a conservative estimate is consistent with the NRC’s approach in other aspects of the assessment of nuclear reactor pressure vessel integrity (e.g., Regulatory Guide 1.99, Revision 2). These estimates provide the basis for adjustment factors that can be used to modify current estimates of transition temperature and upper shelf energy made using either BTP 5-3 or the Ref. [1] procedure to restore their conservatism. In all cases, the magnitude of adjustment needed to transform these estimates to a conservative estimate for plates is considerably smaller than the adjustment needed for forgings. Also, under certain conditions, current BTP 5-3 or Ref. [1] procedure estimates are more conservative than a 2σ bound. The adjustments developed herein also correct for this situation. The adjustments reported herein are expected to be useful to NRR in their assessment of plant-specific impact, and in developing a revision to BTP 5-3 should a revision be necessary.



CONTENTS

ABSTRACT .................................................................................................................................. 2 CONTENTS .................................................................................................................................. 3 LIST OF TABLES ......................................................................................................................... 4 LIST OF FIGURES ....................................................................................................................... 4 ABBREVIATIONS AND SYMBOLS ............................................................................................. 7 1.0 Background, Objective, and Scope .................................................................................. 8 2.0 Outline of this Report ...................................................................................................... 11 3.0 Charpy V-notch and Nil-ductility transition temperature tests ......................................... 12 3.1 Charpy V-notch tests .................................................................................................. 12 3.2 Nil-ductility transition temperature tests ...................................................................... 14

4.0 RTNDT and USE Definitions ............................................................................................. 15 4.1 Definitions of RTNDT and USE when all required data are available ........................... 16 4.1.1 RTNDT defined in ASME Code, Section III, Paragraph NB-2331 ......................... 16 4.1.2 USE defined in ASTM E2215 .............................................................................. 17

4.2 Estimates of RTNDT and USE when all required data are incomplete ......................... 18 4.2.1 BTP 5-3 Position 1.1(1) ....................................................................................... 18 4.2.2 BTP 5-3 Position 1.1(2) ....................................................................................... 18 4.2.3 BTP 5-3 Position 1.1(3) ....................................................................................... 19 4.2.4 BTP 5-3 Position 1.1(4) ....................................................................................... 19 4.2.5 BTP 5-3 Position 1.2 ........................................................................................... 21

4.3 Ref. [1] Procedure ....................................................................................................... 22 4.3.1 Text from the Ref. [1] .......................................................................................... 22 4.3.2 Formulae used in this report ............................................................................... 22

5.0 Data Analysis Procedures .............................................................................................. 23 6.0 Data Sources .................................................................................................................. 31 7.0 Assessment of BTP 5-3 Position 1.1(1) .......................................................................... 42 8.0 Assessment of BTP 5-3 Position 1.1(2) .......................................................................... 44 9.0 Assessment of BTP 5-3 Position 1.1(3) .......................................................................... 46 9.1 Part a: Scale Longitudinal CVN data by 65% ............................................................ 46 9.2 Part b: Add 20 °F to longitudinal transition temperature ............................................. 49

10.0 Assessment of BTP 5-3 Position 1.1(4) .......................................................................... 52 10.1 Equation (19) .............................................................................................................. 53 10.2 Equation (20) .............................................................................................................. 57

11.0 Assessment of BTP 5-3 Position 1.2 .............................................................................. 60 12.0 Assessment of the Ref. [1] Procedure ............................................................................ 63 12.1 TNDT estimate for A533B Class 1 Plates ..................................................................... 63 12.2 TNDT estimate for A508 Class 2 Forgings .................................................................... 64 12.3 Add 30 °F to longitudinal CVN transition temperature ................................................ 66 12.4 2 °F/ft-lb longitudinal CVN transition slope ................................................................. 68 12.5 3 °F/ft-lb transverse CVN transition slope ................................................................... 69

13.0 Adjustments .................................................................................................................... 71 13.1 Summary of Adjustments ............................................................................................ 71 13.2 Example Application of these Adjustments for BTP 5-3 Position 1.1(3) ..................... 77

14.0 Summary ........................................................................................................................ 79



15.0 Citations .......................................................................................................................... 80

LIST OF TABLES

Table 5-1. Use of mean or minimum values in the language of ASME, ASTM, BTP 5-3, and Ref. [1]. .................................................................................................................... 27

Table 6-1. Nil-ductility temperature data. .................................................................................. 32 Table 6-2. Longitudinally oriented Charpy energy data. ............................................................ 34 Table 6-3. Longitudinally oriented Charpy lateral expansion data. ........................................... 36 Table 6-4. Transversely oriented Charpy energy data. ............................................................. 38 Table 6-5. Transversely oriented Charpy lateral expansion data. ............................................. 40 Table 13-1. Values of T for the various linear fits in Sections 7.0 through 12.0 ........................ 73 Table 13-2. Adjustments to transition temperatures and USE values estimated using the

methods in BTP 5-3 and the Ref. [1] procedure to provide conservative (2s) estimates. ................................................................................................................ 74

Table 13-3. Assessment of conservatism of Ref. [1] procedure for estimates of Charpy energy transition curve slope for plates and forgings. ......................................................... 77

LIST OF FIGURES

Figure 1-1. Schematic illustration of RTNDT and USE on a CVN transition curve. ....................... 8 Figure 1-2. ASME requirements for the orientation of CVN specimens tested before and after

1972. ...................................................................................................................... 9 Figure 1-3. Example of different CVN transition curves that can be generated using

longitudinally versus transversely oriented CVN specimens. ................................. 9 Figure 3-1 Charpy V-notch (CVN) impact test specimen .......................................................... 12 Figure 3-2 Definition of coefficients in the hyperbolic tangent (tanh) equation. ......................... 14 Figure 3-3 Nil-ductility temperature test specimen .................................................................... 14 Figure 3-4 NDT specimens exhibiting “break” versus “no break” performance. ......................... 15 Figure 4-1 Illustration of the spectrum of meanings implied by BTP 5-3 Position 1.1(4). ........... 21 Figure 5-1. Effect of number of observation on (top) the mean value, and (bottom) the minimum

estimated from finite numbers of observations drawn randomly from a standard normal distribution. ............................................................................................... 25

Figure 5-2. Schematic illustration showing that the adjustment factor for BTP 5.3 Position 1.1(4) is insensitive to the use of mean values or minimum values in its definition when Charpy data defines RTNDT. .................................................................................. 28

Figure 5-3. Schematic illustration showing that the adjustment factor for BTP 5.3 Position 1.1(4) is sensitive to the use of mean values or minimum values in its definition when TNDT data defines RTNDT. ...................................................................................... 29

Figure 5-4. Comparison of the difference in transition temperatures determined based on the mean versus the average of several measurements. Charpy data used here is shown for purpose of illustration only, it is not comprehensive. ........................... 30



Figure 5-5. Schematic illustration showing that the slope of the Charpy transition curve is insensitive to the use of mean values or minimum values in its definition. .......... 31

Figure 6-1. Distribution between different forging and plate ASTM grades of the 59 data sets taken from REAP. ................................................................................................. 32

Figure 7-1. Comparison of data with the predictions of BTP 5-3 Position 1.1(1) (black line) and mean and 2s fit to the data (blue lines). Top: plot of actual TNDT values (vertical axis) vs. BTP estimates using Eq. (7) (horizontal axis). Bottom: Distribution of BTP prediction errors (errors above 0 °F are non-conservative). ......................... 43

Figure 8-1. Comparison of data with the predictions of BTP 5-3 Position 1.1(2) (black line) and mean and 2s fits to the data (blue lines). Top: plot of actual TNDT values (vertical axis) vs. BTP estimates using Eq. (8) (horizontal axis). Bottom: Distribution of BTP prediction errors (errors above 0 °F are non-conservative). ......................... 45

Figure 9-1. Comparison of data with the predictions of BTP 5-3 Position 1.1(3a) (black lines) and mean and 2s fits to the data (blue lines). Top: all (both plate and forging) data. Middle and bottom: plates and forgings, respectively with mean and 2s fits (blue lines). ........................................................................................................... 47

Figure 9-2. Distribution of estimation errors associated with BTP 5-3 Position 1.1(3a). Errors exceeding 0 °F indicate a non-conservative prediction. Top: plates, Bottom: forgings. ................................................................................................................ 48

Figure 9-3. Comparison of data with the predictions of BTP 5-3 Position 1.1(3b) (black lines) and mean and 2s fits to the data (blue lines). Top: all data. Middle and bottom: plates and forgings, respectively with mean and 2s bounds (blue lines). ............ 50

Figure 9-4. Distribution of estimation errors associated with BTP 5-3 Position 1.1(3b). Errors exceeding +20 °F indicate a non-conservative prediction. Top: plates, Bottom: forgings. ................................................................................................................ 51

Figure 10-1. Illustration of the effect of index, or test, temperature on the non-conservatism of BTP 5-3 Position 1.1(4). ....................................................................................... 52

Figure 10-2. Comparison of data with the predictions of BTP 5-3 Position 1.1(4), eq. (19) (black lines) and mean and 2s curve fits to the data (blue lines). Top: all data. Middle and bottom: plates and forgings, respectively with mean and 2s bounds (blue lines). .................................................................................................................... 55

Figure 10-3. Distribution of estimation errors associated with BTP 5-3 Position 1.1(4), eq. (19). Errors exceeding 0 °F indicate a non-conservative prediction. Top: plates, Bottom: forgings. .................................................................................................. 56

Figure 10-4. Comparison of data with the predictions of BTP 5-3 Position 1.1(4), eq. (20) (black lines) and mean and 2s curve fits to the data (blue lines). Top: all data. Middle and bottom: plates and forgings, respectively with mean and 2s bounds (blue lines). .................................................................................................................... 58

Figure 10-5. Distribution of estimation errors associated with BTP 5-3 Position 1.1(4), eq. (20). Errors exceeding 0 °F indicate a non-conservative prediction. Top: plates, Bottom: forgings. .................................................................................................. 59

Figure 11-1. Comparison of USE data with the USE predictions of BTP 5-3 Position 1.2 (black lines). Top: all data. Middle and bottom: plates and forgings, respectively with mean and 2s bounds (blue lines). ........................................................................ 61

Figure 11-2. Distribution of transverse/longitudinal USE ratios. Ratios below 0.65 indicate a non-conservative prediction using BTP 5-3 Position 1.2. Top: plates, Bottom: forgings. ................................................................................................................ 62

Figure 12-1. Comparison of data with the predictions of TNDT for A533B Class 1 plates (black lines) and with mean and 2s curve fits to the data (blue lines). Top: plot of measured TNDT values (vertical axis) vs. estimates of TNDT values using the Ref. [1]



procedure from Eq. (14) (horizontal axis). Bottom: Distribution of Ref. [1] prediction errors (errors above 0 °F are non-conservative). ................................. 64

Figure 12-2. Comparison of data with the predictions of TNDT for A508 Class 2 forgings (black lines) and mean and 2s curve fits to the data (blue lines). Top: plot of measured TNDT values (vertical axis) vs. estimates of TNDT values using the Ref. [1] procedure from Eq. (15) (horizontal axis). Bottom: Distribution of Ref. [1] prediction errors (errors above 0 °F are non-conservative). ................................. 65

Figure 12-3. Comparison of data with the predictions, using the Ref. [1] procedure (black lines), of the transverse Charpy transition temperature from longitudinal Charpy transition temperature. Top: all data. Middle and bottom: plates and forgings, respectively with mean and 2s bounds (blue lines). ................................................................ 67

Figure 12-4. Distribution of estimation errors associated with the Ref. [1] procedure estimate of transverse Charpy transition temperature from longitudinal Charpy transition temperature. Errors exceeding +30 °F indicate a non-conservative prediction. Top: plates, Bottom: forgings. .............................................................................. 68

Figure 12-5. Top: Comparison of measured data for longitudinal transition slope to estimated values using the Ref. [1] procedure (black line). Bottom: Distribution of errors in the prediction of the Ref. [1] procedure for the longitudinal transition slope (values exceeding 2 °F/ft-lb indicate non-conservative estimates). .................................. 69

Figure 12-6. Top: Comparison of measured data for transverse transition slope to estimated values using the Ref. [1] procedure (black line). Bottom: Distribution of errors in the prediction of the Ref. [1] procedure for the longitudinal transition slope (slopes exceeding 3 °F/ft-lb indicate non-conservative estimates). .................................. 70

Figure 13-1. Summary of the percent of available data that is non-conservatively predicted by the various BTP 5-3 and Ref. [1] positions. .......................................................... 71

Figure 13-2. Summary of conservative (2σ upper bound) transition temperature estimates for the various BTP and Ref. [1] positions plotted as a function of the current estimates. The new estimates are plotted only over the X-axis range exhibited by current estimates of transition temperature made using the BTP 5-3 or Ref. [1] procedures. .......................................................................................................... 75

Figure 13-3. Summary of adjustments (additions) to BTP and Ref. [1] index temperature estimates to make them follow a 2σ upper bound. The adjustment factors are plotted only over the X-axis range exhibited by estimates of transition temperature made using the BTP 5-3 or Ref. [1] procedures. .................................................. 76

Figure 13-4. Summary of new conservative (2σ) bounds (top) and adjustments (additions) to BTP USE estimates to make them follow a 2σ lower bound (bottom). The graphs are plotted only over the X-axis range exhibited by estimates of USE made using the BTP 5-3. ......................................................................................................... 77

Figure 13-5. Example application of adjustment factors to RTNDT estimates based on BTP 5-3 Position 1.1(3). ..................................................................................................... 78



ABBREVIATIONS AND SYMBOLS

Abbreviation Definition ART Adjusted Reference Temperature ASME American Society for Mechanical Engineers ASTM American Society for Testing and Materials BTP Branch Technical Position CVN Charpy V-notch DE Division of Engineering ft-lbs Foot-Pounds NDTT Nil-ductility transition temperature NRC Nuclear Regulatory Commission NRR Office of Nuclear Reactor Regulation NRO Office of New Reactors ORNL Oak Ridge National Laboratory PTS Pressurized Thermal Shock RES Office of Nuclear Regulatory Research REAP Reactor Embrittlement Archive Project RG Regulatory Guide RPV Reactor Pressure Vessel

Symbol Definition ART Adjusted Reference Temperature (°F) CVE Charpy V-notch energy (ft-lbs) RTNDT Reference temperature of nil ductility transition (°F) TNDT Nil ductility transition temperature (°F)

T50&35 Charpy V-notch transition temperature measured at 50 ft-lbs and 35 mills lateral expansion

TYY Charpy V-notch transition temperature measured at YY ft-lbs USE Upper shelf Energy (ft-lbs) XX(L) Refers to the index XX being measured in the longitudinal orientation XX(T) Refers to the index XX being measured in the transverse orientation



1.0 Background, Objective, and Scope

Two parameters used to characterize the toughness of nuclear reactor pressure vessel (RPV) ferritic steel include the following:

RTNDT is the Reference Temperature for Nil Ductility Transition. This value will be defined more precisely later;; with reference to Figure 1-1 RTNDT indicates the lower knee of the toughness transition curve.

USE is the Upper Shelf Energy. This value will be defined more precisely later;; with reference to Figure 1-1 USE indicates the average energy needed to fracture a standard Charpy V-notch (CVN) specimen when it is tested on the upper shelf.

Procedures to determine RTNDT and USE are found in American Society of Mechanical Engineers (ASME) Boiler and Pressure Vessel (B&PV) Code NB-2331 [2] and in ASTM E185 [3], respectively. Values of RTNDT and USE are needed as inputs to calculations required either as inputs to or to demonstrate compliance with several regulations (i.e., 10 CFR 50.61, 10 CFR 50.61a, 10 CFR 50 Appendix G [4,5,6]) and to demonstrate compliance with these regulations as documented in regulatory guides (i.e., RG 1.99, RG 1.161 [7,8]).

Figure 1-1. Schematic illustration of RTNDT and USE on a CVN transition curve.

Before 1972, Charpy specimens were used for material qualification to Section III of the ASME Code, which required that these specimens be oriented with their long-axis parallel to the working direction of the plate or forging. In 1972, the ASME Code changed the required orientation for these material qualification specimens, now requiring them to be oriented with their long-axis oriented perpendicular to the working direction. These Charpy specimens were also used to estimate RTNDT, an index temperature for the fracture toughness curve first introduced in 1972. The pre- and post-1972 requirements for CVN specimen orientation are illustrated in Figure 1-2, which also shows the ASTM E1823 terminology for specimen orientation in plates and in ring forgings [9]. Due to the elongation of grains in the working direction of the steel, the different specimen orientation results in a finer grain structure along the fracture path of longitudinally oriented CVN specimens compared to transversely oriented CVN specimens. As illustrated in Figure 1-3, this difference causes CVN transition curves generated using longitudinal specimens to have (generally) lower transition temperatures and

0

25

50

75

100

125

150

-200 -100 0 100 200 300Impact Energy [ft-lbs]

Temperature [oF]

tanh Fit Data

USE

RTNDT



(generally) higher energy absorption on the upper shelf than is measured using transverse specimens.

Figure 1-2. ASME requirements for the orientation of CVN specimens tested before and after

1972.

Figure 1-3. Example of different CVN transition curves that can be generated using longitudinally

versus transversely oriented CVN specimens. Because of this change in the ASME Code, nuclear power plants for which the vessel was ordered prior to 1972 may not have all of the necessary material tests to determine RTNDT or USE in accordance with the post-1972 requirements. To address this matter, the Materials Engineering Branch of the Office of Nuclear Reactor Regulation, Division of Engineering (NRR/DE/MEB) developed Branch Technical Position (BTP) MTEB No. 5-2 (METB 5-2 has since been re-designated BTP 5-3, which appears within the NUREG-0800 standard review

Principa

l Working

Direction

Longitudinal(pre-‐1972)

Transverse(post-‐1972)

ASTM Designation: LT

ASTM Designation: TL

Plates

Principa

l Working

Direction

Longitudinal(pre-‐1972)

Transverse(post-‐1972)

ASTM Designation: LC

ASTM Designation: CL

Forgings

0

25

50

75

100

125

150


Temperature [oF]

Longitudinal tanh fit Longitudinal Data

0

25

50

75

100

125

150


Temperature [F]

Transverse tanh fit Transverse data

Longitudinal

Transverse



plan) [10]. BTP 5-3 provides several methods by which RTNDT can be estimated from limited data (here “limited data” means “less than all of the data required by ASME NB-2331 from 1972 onward”), and one method by which USE can be estimated from limited data. The Background section of BTP 5-3 makes the following statements:

NRC requirements regarding fracture toughness, pressure-temperature limits, material surveillance, and pressurized thermal shock (PTS) (PWR only) are contained in Appendices A, G, and H to 10 CFR Part 50 and in 10 CFR 50.61;; these requirements also refer to relevant sections of the ASME Code. The purpose of this branch technical position is to summarize these requirements and provide guidance, as necessary. Since many of these requirements were not in force when some plants were designed and built, this position also provides guidance for applying these requirements to older plants. Also included is a description of acceptable procedures for making the conservative estimates and assumptions for older plants that may be used to show compliance with the new requirements.

In early January 2014, AREVA sent the NRC a letter [11]. This letter summarized the results of a recent study that indicated some of the positions in BTP 5-3 might not be conservative. AREVA’s letter contained the following statement:

During evaluation of adjusted reference temperatures (Reference 1†) for reactor vessel extended beltline materials, AREVA Inc. (AREVA) considered invoking Paragraph 1.1(4) of Branch Technical Position 5-3 (Reference 2) to estimate the initial RTNDT (reference temperature for nil ductility transition) for these materials. In this assessment, AREVA determined that this position is not bounding of AREVA’s measured initial RTNDT database, as Reference 3 [i.e., BTP 5-3] implies.

The objective of this report is to asess AREVA’s determination that some of the BTP 5-3 procedures may be non-conservative and, if so, to develop revised relationships that are conservative. BTP 5-3 does not include a mathematical definitoin of the phrase “conservative estimate.” In this report a “conservative estimate” is defined as a value that lies 2 standard deviations, or 2s from the mean of the available data. The use of 2σ as a conservative estimate is consistent with other common and accepted practices in the assessment of nuclear RPV integrity. For example, Revision 2 of RG 1.99 [7] recommend adding a margin term based on the 2σ bound to account for the uncertainty in adjusted reference temperature (ART) values. Also, an analysis by Wallin [12] demonstrated that the ASME KIc curve, which is used to establish heatup and cooldown limits for nuclear RPVs following the requirements of 10 CFR Part 50 Appendix G (which incorporates ASME Code, Section XI, Nonmandatory Appendix G by reference) represents an approximate 5% lower bound (which is 2σ for a normal distribution) to KIc data. To begin this effort, the staff performed a literature survey to assess the availability of information pertinent to this topic. This literature review revealed reference [13] that contained the following statement:

Paragraphs B.l(l) and B.l(2) of the Nuclear Regulatory Commission Branch Technical Position MTEB 5-2 provided the bases for the correlations evaluated [in this paper].

† These refer to references in AREVA’s letter, which is ref. [11] of this document.



Due to the relevance of the investigation underlying [13] to this study, one of the authors of [13] was contacted to determine if a technical report existed containing more details of the analysis underlying those documented in [13]. The author responded by providing a 1983 technical report [14] developed by EG&G Idaho (now Idaho National Engineering and Environmental Laboratory) under contract to NRC/NRR in 1983‡. This report states the following:

“This report compares the current criteria stated In MTEB 5-2 against available data;; many of the current MTEB 5-2 criteria were found to be nonconservative. For several current MTEB 5-2 criteria, more than 20% of the material studied had data outside the current criteria.”

The data analyzed in [14] showed that while some BTP 5-3 Positions produced conservative estimates, some, including the position identified by AREVA, did not. The EG&G report [14] provided more details concerning the data used and the investigative strategy than the associated journal article [13]. However, a complete listing of the raw data (i.e., CVN data, nil-ductility transition temperature (NDTT) data) and a complete description of the materials were not included. Therefore, in this report the staff has assessed of AREVA’s findings using CVN transition and NDTT data reported to the NRC in 10 CFR 50 Appendix H [15] surveillance program test reports. These data were selected because they are available in the public domain, they are directly representative of the U.S. operating fleet, and they have both NDTT data and raw CVN in both the transverse and longitudinal directions. In addition, while researching this issue, the staff discovered procedures similar to those of BTP 5-3 in [1], hereinafter referred to as the “Ref. [1] Procedure.” Because the Ref. [1] Procedure has positions similar to those of BTP 5-3, an assessment of the conservatism of this procedure is also performed in this report.

2.0 Outline of this Report

Section 3.0 of this report provides a description of the mechanical tests whose results are used to define RTNDT and USE. Section 4.0 reviews the definitions of RTNDT and USE based on these tests that appear in ASME, ASTM, BTP 5-3, and the Ref. [1] procedure. Section5.0 describes the data analysis procedure while Section 6.0 summarizes the sources of CVN and TNDT data used in this report. Sections 7.0 through 12.0 are each dedicated to assessing the conservatism of each of the positions of BTP 5-3 and the Ref. [1] procedure relative to these data. Section 13.0 summarizes the adjustments needed to current BTP and Ref. [1] estimates to make them conservative, these adjustments being based on the analyses presented in Sections 7.0 through 12.0. Finally, Section 14.0 summarizes the results of this report.

‡ Despite extensive searches performed in ADAMS, no copy of, review or, or reference to [14] has been found anywhere in the NRC documentation systems.



3.0 Charpy V-notch and Nil-ductility transition temperature tests

RTNDT and USE are determined based on information obtained by testing CVN specimens to define a transition curve, and by testing NDTT specimens to define the temperature that distinguishes “break” from “no-break” performance. These tests, and the metrics derived from them that are used in the various definitions of RTNDT and USE, are described in the following sections. 3.1 Charpy V-notch tests ASTM E23 describes the test method for CVN specimens [16]. As illustrated in Figure 3-1, CVN specimens measure 10 mm square and 55 mm in length, and are notched in the center with a 2-mm deep “V-notch” of specified notch tip radius. Each specimen is tested by chilling or heating it to the desired test temperature, quickly transferring it to an impact machine that supports the specimen on each end, and then breaking the specimen using a freely swinging pendulum. The following measurements quantify the test result: (a) the energy absorbed by breaking the specimen (measured in foot-pounds or joules) (b) the lateral expansion of the sides of the specimen caused by plastic flow (measured in milli-inches (mils) or millimeters), and (c) the percentage of the fractured surface having a shear (or dimpled) fracture appearance.

Figure 3-1 Charpy V-notch (CVN) impact test specimen

As illustrated in Figure 1-2, ferritic RPV steels undergo a transition from brittle behavior at low temperatures to ductile behavior at higher temperatures. To characterize this behavior, ASTM E185, “Standard Practice for Design of Surveillance Programs for Light-Water Moderated Nuclear Power Reactor Vessels,” requires that a sufficient number of CVN specimens be included in surveillance capsules to characterize this “transition temperature curve.” ASTM E185 defines this curve as follows [3]:

“A graphic or curve-fitted, or both, presentation of absorbed energy, lateral expansion, or fracture appearance as a function of test temperature, extending over a range including the lower shelf (5% or less shear fracture appearance), transition region, and the upper shelf (95% or greater shear fracture appearance).”

ASTM E2215-10, “Standard Practice for Evaluation of Surveillance Capsules from Light-Water Moderated Nuclear Power Reactor Vessels,” makes the following statements at various places in the Standard (not in the order of their occurrence) concerning the analysis and interpretation of CVN data taken from surveillance capsules [17]:

10mm square

55mm



i. “Average curves shall be drawn through the Charpy data to describe the Charpy impact energy, lateral expansion, and percent shear fracture appearance as a function of the test temperature.”

ii. “The preferred method for determining the average curves is statistical fitting to a hyperbolic tangent function.”

iii. “[An] index temperature [is a] temperature corresponding to a predetermined level of absorbed energy, lateral expansion, or fracture appearance obtained from the best-fit (average) Charpy transition curve.”

iv. “[The] Charpy upper-shelf energy level [is] the average energy value for all Charpy specimen tests (preferably three or more) whose test temperature is at or above the Charpy upper-shelf onset;; specimens tested at temperatures greater than 83°C (150°F) above the Charpy upper-shelf onset shall not be included, unless no data are available between the onset temperature and onset +83°C (+150°F). [The] Charpy upper-shelf onset [is] the test temperature above which the fracture appearance of all Charpy specimens tested is at or above 95% shear.”

ASTM E2215 guidelines were followed in the analysis of CVN data performed in this report, according to the following procedure:

1. The CVN energy or lateral expansion data were plotted as a function of temperature. 2. A hyperbolic tangent (tanh) curve fit, as shown in Figure 3-2, was made to these data

using the method of least squares. The tanh curve is defined as follows:

𝑌 = 𝐴 + 𝐵 × 𝑡𝑎𝑛ℎ𝑇 − 𝐷𝐶

(1)

where T is temperature in °F, Y is CVN energy or lateral expansion (as appropriate) and the values A and B are defined as follows

𝐴 =𝐿𝑆 + 𝑈𝑆

2 (2)

𝐵 = 𝐴 − 𝐿𝑆 (3)

Value Energy Curve Lateral Expansion Curve LS

(lower shelf) 2 ft-lbs (see NOTE 1) 0 mills

US (upper shelf) average of all measurements ≥ 95% shear

Note 1: Values from 1-3 ft-lbs have been used. These exert negligible influence on the transition temperatures determined at much higher energies in this investigation.

3. Having estimated values for A, B, C, and D, index temperatures were calculated as

follows:

𝑇4 = 𝐶 ∙ 𝑡𝑎𝑛ℎ67𝛽 − 𝐴𝐵

+ 𝐷 (4)

where β is the index value for Y of interest. Typical index values include 30 and 50 ft-lbs, 35 mills, etc.



3.2 Nil-ductility transition temperature tests Tests to determine the nil-ductility transition temperature (TNDT) follow the requirements of ASTM E208 [18] using a test specimen like that shown in Figure 3-3. The specimen is prepared by depositing a brittle weld on the surface of the specimen, and then saw cutting a notch to serve as a crack starter that, during impact loading, can initiate a brittle crack into the material to determine if the material will resist propagation of the crack. The test is conducted by dropping a weight onto the un-welded side (bottom side in the figure) of the specimen. By conducting tests over a range of temperatures, the temperature that delineates “break” from “no break” performance is determined (see Figure 3-4). TNDT is defined by ASTM E208 as the highest temperature where a specimen breaks, provided that two specimens exhibit “no-break” performance at a temperature at least 10 °F higher.

Figure 3-2 Definition of coefficients in the hyperbolic tangent (tanh) equation.

Figure 3-3 Nil-ductility temperature test specimen

0

50

100

150

-200 -100 0 100 200 300

Temperature [C]

Y

Note: The slope of the tanhcurve at mid-transition, i.e., at (D,A), is B/C.

D

A = ½(YUS+YLS) 2B

YUS

YLS

2Cþýü

îíì -

×+=CDTBAY tanh

5-in.

5/8-in.

2-in.

Sawcut notch

Brittle weld bead



(a) NDT specimen exhibiting a “break.”

The fracture (dark region) extends to both sides of the specimen.

(b) NDT specimens exhibiting “no break.”

The fracture (dark region) does not extend to both sides of the specimen.

Figure 3-4 NDT specimens exhibiting “break” versus “no break” performance.

4.0 RTNDT and USE Definitions

The RTNDT and USE definitions in ASME, ASTM, BTP 5-3, and the Ref. [1] procedure are expressed using words rather than using mathematical formulae. As such, these definitions are subject to interpretation. Therefore, Sections 4.1, 4.2, and 4.3 provides the text from these source documents that defines each transition temperature or USE value followed by a formula that defines how each transition temperature and USE was calculated from the Charpy and NDTT data in this investigation. Three items of relevance throughout this report should be noted:

• Nomenclature: Due to the many definitions of Charpy index temperature used in this report, a self-consistent descriptive nomenclature is adopted, as follows:

T(X)yy&zz where

(X) is either L or T, indicating a longitudinal or transverse orientation, respectively

yy indicates the index energy, in ft-lbs &zz indicates the index lateral expansion measured in milli-inches (sometimes

referred to as “mills”) This nomenclature is self-consistent in this report but, in many cases, differs from that of the source ASME, ASTM, and BTP publications. The source publications are neither consistent among themselves nor as descriptive as this system adopted by this report.

• Charpy Orientation: Some of the positions in BTP 5-3 and the Ref. [1] procedure are not explicit concerning the orientation of the Charpy specimens. Nevertheless, as evidenced by the following quotations, both procedures were developed with the intention of providing a means to interpret pre-1972 data in terms of post-1972 ASME NB-2331 requirements.

TemperatureNDT is the lowest temperature of “no-break” performance

No-Break: Fracture (darkened region) does not extend to the sides of the specimen

Break: Crack completely severs tension surface of specimen.









From BTP 5-3 The fracture toughness test requirements for plants with construction permits prior to August 15, 1973 may not comply with the new Codes and Regulations in all respects.

From the Ref. [1] procedure This procedure describes the method to be used for establishing the initial reference temperature (RTNDT) for ferritic steels for older plants where fracture toughness data may be incomplete.

Consequently, when the orientation of the Charpy specimens are not explicitly stated by the BTP or Ref. [1] procedures it is assumed that the orientation is longitudinal because longitudinal Charpy specimens were required prior to 1972.

• Minimum versus Mean values: Some of the positions in BTP 5-3 and the Ref. [1] procedure are not explicit concerning the procedure that should be used to analyze Charpy data, specifically with regard to whether mean or minimum values of the various transition temperature and upper shelf energy metrics should be calculated. For consistency mean values are always used in this report. The reason for this approach and its impact on the results are both discussed in Section 5.0.

4.1 Definitions of RTNDT and USE when all required data are available 4.1.1 RTNDT defined in ASME Code, Section III, Paragraph NB-2331 4.1.1.1 Relevant Paragraphs from ASME Code NB-2300 (2013 Edition) NB-2321.1 Drop Weight Tests The drop weight test, when required, shall be performed in accordance with ASTM E208. Specimen types P-No. 1, P-No. 2, or P-No. 3 may be used. The results, orientation, and location of all tests performed to meet the requirements of NB-2330 shall be reported in the Certified Material Test Report.

NB-2321.2 Charpy V-Notch Tests The Charpy V-notch test (Cv), when required, shall be performed in accordance with SA-370. Specimens shall be in accordance with SA-370, Figure 11, Type A. A test shall consist of a set of three full-size 10 mm x 10 mm specimens. The lateral expansion and absorbed energy, as applicable, and the test temperature, as well as the orientation and location of all tests performed to meet the requirements of NB-2330 shall be reported in the Certified Material Test Report.

NB-2322.2 Orientation of Impact Test Specimens (a) Specimens for Cv impact tests shall be oriented as follows:

(1) Specimens for forgings, other than bolting and bars used for pressure-retaining parts of vessels, pumps, and valves, shall be oriented in a direction normal to the principal direction in which the material was worked. Specimens are neither required nor prohibited from the thickness direction

NB-2331 Material for Vessels Pressure-retaining material for vessels, other than bolting, shall be tested as follows:



(a) Establish a reference temperature RTNDT;; this shall be done as follows: (1) Determine a temperature TNDT that is at or above the nil-ductility transition

temperature by drop weight tests. (2) At a temperature not greater than TNDT + 60°F (TNDT + 33°C), each specimen of the

Cv test (NB-2321.2) shall exhibit at least 35 mils (0.89 mm) lateral expansion and not less than 50 ft-lb (68 J) absorbed energy. Retesting in accordance with NB-2350 is permitted. When these requirements are met, TNDT is the reference temperature RTNDT.

(3) In the event that the requirements of (2) above are not met, conduct additional Cv tests in groups of three specimens (NB-2321.2) to determine the temperature, TC, at which they are met. In this case the reference temperature RTNDT = TC - 60°F (TC - 33°C). Thus, the reference temperature RTNDT is the higher of TNDT and [TC - 60°F (TC -33°C)].

(4) When a Cv test has not been performed at TNDT + 60°F (TNDT + 33°C), or when the

Cv test at TNDT + 60°F (TNDT + 33°C) does not exhibit a minimum of 50 ft-lb (68 J) and 35 mils (0.89 mm) lateral expansion, a temperature representing a minimum of 50 ft-lb (68 J) and 35 mils (0.89 mm) lateral expansion may be obtained from a full Cv impact curve developed from the minimum data points of all the Cv tests performed.

4.1.1.2 Formula used in this report The formula for RTNDT is as follows:

𝑅𝑇:;< = 𝑀𝐴𝑋 𝑇:;<, 𝑇 < @A&C@ − 60 (5) where

TNDT is the nil-ductility transition temperature defined by ASTM E208. T(T)50&35 is the temperature at which the mean§ tanh curves fit to transverse CVN data

exhibit both 50 ft-lbs absorbed energy and 35 mills lateral expansion. 4.1.2 USE defined in ASTM E2215 4.1.2.1 Text from ASTM E2215 The definition of USE in E2215, as stated in Section 3.1, is the average energy of all specimens tested that exhibit greater than 95% shear area excluding specimens tested at temperatures more than 150 °F above the Charpy upper-shelf onset. 4.1.2.2 Formula used in this report The formula for USE is as follows:

𝑈𝑆𝐸 =1𝑛IJ

𝐶𝑉𝐸L

MNO

LP7

(6)

§ The use of a mean value is inconsistent with the ASME text but, as explained in Section 5.0, has no effect on the adjustment factors developed in this report.



where nUS is the number of specimens that exhibit greater than 95% shear area and CVEi is the Charpy V-notch energy for each of these specimens. 4.2 Estimates of RTNDT and USE when all required data are incomplete BTP 5-3 [10] and the Ref. [1] procedure provide a number of procedures to estimate RTNDT, the component parts of RTNDT (i.e., TNDT or T(T)50&35)), or USE depending upon which of the required data are not available from testing. The following sections describe these estimates. 4.2.1 BTP 5-3 Position 1.1(1) 4.2.1.1 Text from BTP 5-3

If dropweight tests were not performed, but full Charpy V-notch curves were obtained, the TNDT for SA-533 Grade B, Class 1 plate and weld material may be assumed to be the temperature at which 41 J (30 ft-lbs) was obtained in Charpy V-notch tests, or -18 °C (0 °F), whichever was higher.

4.2.1.2 Formula used in this report The formula for TNDT of A533-B Class 1 plates is as follows:

𝑇:;< = 𝑀𝐴𝑋 0 °F, 𝑇(T)CA (7) where T(L)30 is the mean 30 ft-lb transition temperature of the longitudinal Charpy curve. 4.2.2 BTP 5-3 Position 1.1(2) 4.2.2.1 Text from BTP 5-3

If dropweight tests were not performed on SA-508, Class II forgings, the TNDT may be estimated as the lowest of the following temperatures:

(a) 33 °C (60 °F). (b) The temperatures of the Charpy V-notch upper shelf. (c) The temperature at which 136 J (100 ft-lbs) was obtained on Charpy V-notch tests if

the upper-shelf energy values were above 136 J (100 ft-lbs). 4.2.2.2 Formula used in this report The formula for TNDT of A508 Class 2 forgings is as follows:

𝑇:;< = 𝑀𝐼𝑁 +60 °F, 𝑇(T)7AA, 𝑇IXXJYZ[\ (8)



where T(L)100 is the mean 100 ft-lb transition temperature of the longitudinal Charpy curve and TUppShelf is the temperature at the upper-knee** of the mean energy transition curve for longitudinal Charpy curve. 4.2.3 BTP 5-3 Position 1.1(3) 4.2.3.1 Text from BTP 5-3

If transversely-oriented Charpy V-notch specimens were not tested, the temperature at which 68 J (50 ft-lbs) and 0.89 mm (35 mils) LE would have been obtained on transverse specimens may be estimated by one of the following criteria:

(a) Test results from longitudinally-oriented specimens reduced to 65% of their value to provide conservative estimates of values expected from transversely oriented specimens.

(b) Temperatures at which 68 J (50 ft-lbs) and 0.89 mm (35 mils) LE were obtained on longitudinally-oriented specimens increased 11 °C (20 °F) to provide a conservative estimate of the temperature that would have been necessary to obtain the same values on transversely-oriented specimens.

4.2.3.2 Formulae used in this report For provision (a), the following formula is used to estimate T(T)50&35:

𝑇 < @A&C@ = 𝑇 T]A._@ @A&C@ (9) where T(Lx0.65)50&35 designates the temperature at which the mean tanh curves fit to longitudinal CVN data that have been scaled to 65% of their measured values exhibit both 50 ft-lbs absorbed energy and 35 mills lateral expansion. For provision (b) the following formula is used to estimate T(T)50&35:

𝑇 < @A&C@ = 𝑇 T @A&C@ + 20 °F (10) where T(L)50&35 designates the temperature at which the mean tanh curves fit to longitudinal CVN data exhibit both 50 ft-lbs absorbed energy and 35 mills lateral expansion. 4.2.4 BTP 5-3 Position 1.1(4) 4.2.4.1 Text from BTP 5-3

If limited Charpy V-notch tests were performed at a single temperature to confirm that at least 41 J (30 ft-lbs) was obtained, that temperature may be used as an estimate of the RTNDT provided that at least 61J (45 ft-lbs) was obtained if the specimens were longitudinally oriented. If the minimum value obtained was less than 61 J (45 ft-lbs), the RTNDT may be estimated as 11 °C (20 °F) above the test temperature.

** In this report, the parameter TUppShelf was determined by visual examination of the mean tanh curve. It should be noted that in no case reported herein did TUppShelf control the value of TNDT estimated by Eq. (8).



4.2.4.2 Formulae used in this report Of all the estimates provided in BTP 5-3 and in Ref. [1], the text Position 1.1(4) is the most difficult to interpret as an equation. In fact this position describes two different equations that apply over a different range of conditions, as can be illustrated by parsing the key words of Position 1.1(4) onto a number line representing the measured CVN energy (see Figure 4-1). Figure 4-1 may be explained as follows:

• Charpy energy less than 30 ft-lbs: Since the statement is made that the Charpy testing has been performed “to confirm that at least… 30 ft-lbs was obtained” Position 1.1(4) should not be applied to measured CVN energies below 30 ft-lbs.

• Charpy energy between 30 and 45 ft-lbs: The statement “If the minimum value obtained was less than 61 J (45 ft-lbs), the RTNDT may be estimated as … 20 °F above the test temperature.” indicates that in this range RTNDT is estimated as follows:

𝑅𝑇:;< = 𝑇 T `<Zab + 20 °F (11)

where TTest is the test temperature. The subscript “(L)” indicates that the Charpy specimen is longitudinally oriented while the subscript “E” indicates the absorbed energy measured in the Charpy test (which, by definition is in this case above 30 and less than 45 ft-lbs). This nomenclature is adopted to permit its interpretation with respect to transition temperatures developed from full Charpy transition curves where, for example, T(L)30 denotes the transition temperature at 30 ft-lbs measured using longitudinal specimens.

• Charpy energy 45 ft-lbs and greater: The statement “that temperature may be used as an estimate of the RTNDT provided that at least … 45 ft-lbs was obtained” indicates that for measured Charpy energies of 45 ft-lbs and above RTNDT is estimated as follows:

𝑅𝑇:;< = 𝑇 T `<Zab (12)

where the nomenclature just described again applies. Eqs. (11) and (12) demonstrate that Position 1.1(4) describes a spectrum of equations to estimate RTNDT. All other positions of BTP 5-3 specify Charpy index temperatures at specific energies;; in contrast, Position 1.1(4) uses whatever energy was measured by the Charpy test. When assessing the conservatism of these estimates, this approach creates a spectrum of possible outcomes. For example, if Eq. (12) is used to estimate RTNDT the resultant estimate is more likely to be conservative if the measured energy was, for example, 75 ft-lbs rather than 45 ft-lbs. A further examination of this position is performed in Section 10.0.



Figure 4-1 Illustration of the spectrum of meanings implied by BTP 5-3 Position 1.1(4).

4.2.5 BTP 5-3 Position 1.2 4.2.5.1 Text from BTP 5-3

For the beltline region of reactor vessels, the upper shelf toughness must account for the effects of neutron radiation. Reactor vessel beltline materials must have Charpy upper shelf energy, in the transverse direction for base material and along the weld for weld material according to the ASME Code, of no less than 102 J (75 ft-lbs) initially and must maintain Charpy upper shelf energy throughout the life of the vessel of no less than 68 J (50 ft-lbs). If Charpy upper shelf energy values were not obtained, conservative estimates should be made using results of tests on specimens from the first surveillance capsule removed. If tests were only made on longitudinal specimens, the values should be reduced to 65% of the longitudinal values to estimate the transverse properties.

4.2.5.2 Formulae used in this report The following formula is used to estimate USE(T):

𝑈𝑆𝐸 < = 0.65 × 𝑈𝑆𝐸 T (13) where USE(T) and USE(L) indicate, respectively, the upper shelf energy values associated with transversely and longitudinally oriented CVN specimens.

“to$confirm$that$at$least$41$J$(30$56lbs)$was$obtained”!

“that$temperature$may$be$used$as$an$es@mate$of$the$RTNDT$provided$that$at$least$61J$(45$56lbs)$was$obtained”!

“If$the$minimum$value$obtained$was$less$than$61$J$(45$56lbs),$the$RTNDT$may$be$es@mated$as$11$°C$(20$°F)$above$the$test$temperature.”!

CVN$Energy$[,-lbs]!0! 30! 45!

!"!"# = ! ! !!"#$ + !"!°!

!"!"# = ! ! !!"#$

BTP$5.3$Posi:on$1.1(4)$“If!limited!Charpy!V4notch!tests!were!performed!at!a!single!temperature!to$confirm$that$at$least$41$J$(30$56lbs)$was$obtained,!that$temperature$may$be$used$as$an$es@mate$of$the$RTNDT$provided$that$at$least$61J$(45$56lbs)$was$obtained!if!the!specimens!were!longitudinally!oriented.!If$the$minimum$value$obtained$was$less$than$61$J$(45$56lbs),$the$RTNDT$may$be$es@mated$as$11$°C$(20$°F)$above$the$test$temperature.”!



4.3 Ref. [1] Procedure 4.3.1 Text from the Ref. [1] Vessel Plate (SA-533 Gr. B Cl. 1)

Usual data available – NDT and/or longitudinal CVN at +10 or +40 °F RTNDT prediction method –

Operate on lowest longitudinal CVN ft-lb to get at least 50 ft-lb [transition temperature] T.T. by adding 2 °F per ft-lb or by plotting a curve (ft-lb versus temperature), where possible. Add additional 30 °F to convert from longitudinal to transverse 50 ft-lb T.T††. NOTE: Where transverse CVN impact data are available, but the 50 ft-lb T.T. is not

met, operate on lowest CVN ft-lb to get at least 50 ft-lb T.T. by adding 3 °F per ft-lb or by plotting a curve (ft-lb versus temperature), where possible. This extrapolation is valid for CVN test temperatures only in the range -25 ° to +50 °F.

Derive NDT, where missing, as equal to longitudinal CVN 35 ft-lb T.T. RTNDT is higher of NRT or transverse CVN 50 ft-lb T.T. - 60 °F

Forgings (SA-508 Cl. 2)

Usual data available – NDT and/or CVN at single temperature RTNDT prediction method –

Derive CVN 50 ft-lb T.T. as for plate. When only CVN are available, estimate NDT as the lower of +70 °F or the CVN test temperature where at least 100 ft-lb or 50% shear is achieved. RTNDT is higher of NDT or transverse CVN 50 ft-lb T.T. - 60 °F

4.3.2 Formulae used in this report The following formulae were used in this report:

𝑇:;< = 𝑇 T C@ for A533B Cl. 1 plate (14)

𝑇:;< = MIN +70 °𝐹, 𝑇 T 7AA, 𝑇@A% for A508 Cl. 2 forgings (15)

𝑇 < @A = 𝑇 T @A + 30 °F for A533B Cl. 1 plate or A508 Cl. 2 forgings (16)

†† Even though the RTNDT definition of ASME NB-2331 requires knowledge of both the 50 ft-lb energy and the 35 mil lateral expansion transition temperature the Ref. [1] procedure does not consider lateral expansion.



𝑆𝐿𝑂𝑃𝐸 T CA6@A =𝑇 T @A − 𝑇 T CA

50 − 30=

2 °Fft − lb

for A533B Cl. 1 plate or A508 Cl. 2 forgings (17)

𝑆𝐿𝑂𝑃𝐸 < CA6@A =𝑇 < @A − 𝑇 < CA

50 − 30

=3 °Fft − lb

for A533B Cl. 1 plate or A508 Cl. 2 forgings (18)

where

T(X)YY is the “YY” ft-lb transition temperature for the Charpy energy curve determined from specimens taken in the “X” orientation, as determined by Eq. (4)

T50% is the transition temperature associated with 50% shear fracture appearance While not identical, Eqs. (14), (15), and (16) are similar to BTP 5-3 Positions 1.1(1), 1.1(2), and 1.1(3b), respectively. Equations (17) and (18) have no clear parallel in BTP 5-3. Each provides an estimate of the inverse slope of the CVN transition curve. This slope is defined here as a linear average of the slope of the mean tanh curve between 30 and 50 ft-lbs absorbed energy to provide a consistent means of processing of Charpy data in this report. The upper value of 50 ft-lbs was selected because this is the energy to which this part of the Ref. [1] procedure is extrapolating. The lower value of 30 ft-lbs was selected because this is the energy value the Charpy testing is intended to confirm. In plant-specific applications, the Ref. [1] procedure may have a different lower value that serves as the starting point for extrapolation.

5.0 Data Analysis Procedures

As evident from the text in Sections 4.1, 4.2, and 4.3 copied from ASME, ASTM, BTP 5.3, and Ref. [1] these documents are oftentimes not explicit concerning the data analysis procedures to use when calculating index temperature and USE metrics from Charpy V-notch data. Additionally, BTP 5-3 and Ref. [1] sometimes aim to interpret data that do not fully characterize the behavior of interest (e.g., some positions require as little input information as Charpy data at a single temperature). To evaluate the conservatism, or lack thereof, of these various estimates in a robust and consistent manner only data sets for which full Charpy transition curves (i.e., having data from lower shelf thought upper shelf) were available in both the transverse and longitudinal orientations were used (see Section 6.0). For most of these data sets TNDT values were also available. In this report, the transition index temperatures and USE metrics were calculated from the mean tanh curve fit to the data, a practice recommended by ASTM E2215 [17]. This use of the mean of the Charpy data is sometimes at variance with the definitions of the transition temperature metrics provided in the ASME Code, BTP 5-3, and Ref. [1]. Nevertheless, as explained in the remainder of this section, adjustment factors developed based on mean curves fit to the Charpy data can be appropriately and accurately used to correct plant data that may have been developed based on minimum values.



The discussion of this section is organized as follows:

• First it is explained why an analysis based on means rather than on minimums produces more consistent adjustment factors.

• Second, the language of each provision from ASME, ASTM, BTP 5-3, and Ref. [1] is reviewed to determine in what cases the use of mean values is specified, in what cases the use of minimum values is specified, and in what cases no specification is provided by these documents.

• Third, it is demonstrated that in the cases where minimum values are specified by ASME, ASTM, BTP 5-3, and Ref. [1] it is appropriate and accurate to develop adjustment factors based on analysis of mean values.

Figure 5-1 provides the results of a Monte Carlo simulation that illustrates the accuracy and consistency with which means and minimums can be estimated from data sets containing a finite number of observations. The simulation was conducted by drawing 2,000 random samples of sizes ranging from 3 to 20 observations from a standard normal distribution. The top graph in the figure demonstrates that the mean values estimated from sample sizes as small as three are, on average, unbiased relative to the expected value (the normal distribution is symmetric, so the mean occurs at the 50th percentile). The bottom graph in the figure shows the percentile of the standard normal distribution that is estimated when the minimum value in a finite sample (for example, the minimum of three observations) is used to estimate the minimum of the distribution‡‡. This graph illustrates the strong effect of sample size on such estimates. Comparing the top and bottom panels, sample size clearly affects estimates of minimum values much more strongly than estimates of mea values. The experimental data sets used in this study (see Section 6.0 for details) have within them a variety of sample sizes. To promote consistent comparisons across sample sizes mean values, rather than minima, are therefore used in this report.

‡‡ The “minimum of n observations” is used as an estimate of the minimum of the distribution because both ASME NB-2331 and by BTP 5.3 Position 1.1(4) adopt this type of estimate.



Figure 5-1. Effect of number of observation on (top) the mean value, and (bottom) the minimum

estimated from finite numbers of observations drawn randomly from a standard normal distribution.

Table 5-1 was constructed by reviewing the language of the relevant documents from ASME and ASTM, and also BTP 5-3 and Ref. [1] that were summarized in Section 4.0 to determine in what cases means are specified, in what cases minimums are specified, and in what cases no specification is made, or even implied, by the language of these source documents. Table 5-1 demonstrates that in most cases these documents provide no guidance on this topic. In these cases the mean curve drawn through the data is used in this report for the reasons discussed in the preceding paragraph. One document, ASTM Standard Guide E185, includes an explicit recommendation to use the mean curve. Finally, there are two situations for which these documents recommend the use of minimum values, as described below: • Estimate of RTNDT(u) based on BTP 5.3 Position 1.1(4): BTP 5-3 Position 1.1(4) recommends the use of minimum Charpy values in the definition of RTNDT as, indeed, does the ASME definition provided in NB-2331. RTNDT is determined from both Charpy and TNDT data (see eq. (5)), thus it is possible for either the Charpy data or for the TNDT data to determine the RTNDT value. These two cases are considered separately. o Charpy data determines RTNDT: This situation is illustrated in Figure 5-2. While the

absolute values of RTNDT defined by means and minimums differ, the difference between the value of RTNDT based on NB-2331 and the value estimated by Position

20%$

40%$

60%$

80%$

3$ 4$ 5$ 6$ 7$ 8$ 9$ 10$ 11$ 12$ 13$ 14$ 15$ 16$ 17$ 18$ 19$ 20$

Theo

re&cal*Gau

ssian*

Percen

&le*of*Es&mated

*Mean*Va

lue*

Data*Set*Size*

20%$

40%$

60%$

80%$

3$ 4$ 5$ 6$ 7$ 8$ 9$ 10$ 11$ 12$ 13$ 14$ 15$ 16$ 17$ 18$ 19$ 20$

Theo

re&cal*Gau

ssian*

Percen

&le*of*Es&mated

*Mean*Va

lue*

Data*Set*Size*

Symbol'shows'the'average'of'2,000'random'samples'having!n!observa9ons'each.''

Ver9cal'bar'shows'±'1σ'confidence'bounds'on'this'average.'

0%#

20%#

40%#

60%#

3# 4# 5# 6# 7# 8# 9# 10# 11# 12# 13# 14# 15# 16# 17# 18# 19# 20#

Theo

re&cal*Gau

ssian*

Percen

&le*of*M

inim

um*

Value*

n:*Number*of*Observa&ons*in*each*Random*Sample*



1.1(4) is not influenced significantly by the use of mean versus minimum values (see the yellow box in the figure). Therefore the adjustment factors developed herein, which depend on these differences and not on the absolute values, are similarly unaffected.

o TNDT data determines RTNDT: This situation is illustrated in Figure 5-3, which shows that the adjustment factors developed herein (see the yellow box in the figure) will depend on whether means or minimums are employed in their definition. In this case the adjustment factors developed herein based on mean values somewhat over-estimate adjustment factors needed to correct to RTNDT estimates based on minimum values using Position 1.1(4). However, as illustrated in Figure 5-4, the magnitude of this over adjustment depends on the particulars of the Charpy data. The figure demonstrates that data sets exist for which the magnitude of this over-adjustment is negligible, suggesting that a generic adjustment factor is best developed from analysis of transition temperatures determined using the mean curve, as is performed herein. Consideration of the extra margin that may be provided by the use of minimum data is best undertaken on a plant-specific basis, and will depend on the particulars of the available Charpy data.

• Estimate of transition curve slope based on Ref. [1]: The language of Ref. [1] suggests that the transition curve slopes of 2 °F/ftŊlb (for longitudinally oriented specimens) and 3 °F/ftŊlb (for transversely oriented specimens) are based on the minimum of a small number of Charpy specimens tested at the same temperature. Nevertheless, as illustrated in Figure 5-5 the transition curve slope is not strongly affected by the use of mean versus minimum values. Therefore the analysis and adjustment factors reported and developed herein, which are based on means, can be accurately applied to adjust plant values that would be based on minimums.

In summary, the adjustment factors developed herein based on means can be accurately and appropriately applied to plant data. For RTNDT estimates that have been developed using Position 1.1(4) situations may exist where additional plant-specific adjustments can be justified, but these require detailed examination of the available Charpy data.



Table 5-1. Use of mean or minimum values in the language of ASME, ASTM, BTP 5-3, and Ref. [1].

Reference SectionValue/to/be/Estimated Estimate/Using

Mean/or/Min/Stated/in/Definition?

Quote/(if/stated)

RTNDT

TNDT

%&%T(T)50&35

not%applicable

TNDT

ASTM%E208 not%applicable

T(T)50&35

<<< Min

When%a%Cv%test%has%not%been%performed%at%TNDT%+%60°F%(TNDT%+%

33°C),%or%when%the%Cv%test%at%TNDT%+%60°F%(TNDT%+%33°C)%does%not%

exhibit%a%minimum%of%50%ft<lb%(68%J)%and%35%mils%(0.89%mm)%lateral%

expansion,%a%temperature%representing%a%minimum%of%50%ft<lb%(68%J)%

and%35%mils%(0.89%mm)%lateral%expansion%may%be%obtained%from%a%

full%Cv%impact%curve%developed%from%the%minimum%data%points%of%

all%the%Cv%tests%performed

ASTM%E208 TNDT

<<< <<< <<<

ASTM%E185 USE(T)

<<< Mean The%Charpy%upper%shelf%energy%[is]%the%average%value%…1.1(1) A533B%Cl.%1%T

NDTT(L)30

not%stated

1.1(2) A508%Cl.%2%TNDT

T(L)100%

&%TUppShelf

not%stated

1.1(3) T(T)50&35

T(L)50&35

not%stated

1.1(4) RTNDT

T(L)45%

or%other%

Charpy%index%

temperatures

Min

If%limited%Charpy%V<notch%tests%were%performed%at%a%single%

temperature%to%confirm%that%at%least%41%J%(30%ft<lbs)%was%obtained,%

that%temperature%may%be%used%as%an%estimate%of%the%RTNDT%

provided/that/at/least/61J/(45/ftElbs)/was/obtained%if%the%specimens%were%longitudinally%oriented.%If/the/minimum/value/obtained/was/less/than/61/J/(45/ftElbs),%the%RTNDT%may%be%

estimated%as%11%°C%(20%°F)%above%the%test%temperature.

1.2 USE(T)

USE(L)

not%stated

<<< A533B%Cl.%1%TNDT

T(L)35

not%stated

<<< A508%Cl.%2%TNDT

T(L)100%

&%T50%

not%stated

<<< T(T)50&35

T(L)50&35

not%stated

<<<

Slope%of%Longitudinal%

Charpy%Transition%

Curve

fixed%value:%

2o

F/ft<lb

Min

Operate/on/lowest/longitudinal/CVN/ftElb%to%get%at%least%50%ft<lb%[transition%temperature]%T.T.%by%adding%2%°F%per%ft<lb%

<<<

Slope%of%Transverse%

Charpy%Transition%

Curve

fixed%value:%

3o

F/ft<lb

Min

Where%transverse%CVN%impact%data%are%available,%but%the%50%ft<lb%

T.T.%is%not%met,%operate/on/lowest/CVN/ftElb/to%get%at%least%50%ft<lb%T.T.%by%adding%3%°F%per%ft<lb%

Ref.%[14]

ASME%NB<

2331ASME%or%

ASTM

BTP%5<3



Figure 5-2. Schematic illustration showing that the adjustment factor for BTP 5.3 Position 1.1(4) is

insensitive to the use of mean values or minimum values in its definition when Charpy data defines RTNDT.

TNDT$

CVE$Temp.$,$60$oF$

minimum$

mean$

minimum$

mean$

Longitudinal$

Transverse$

ASME,NB/2331,Index,Energy$

CVE$

BTP,5.3,Posi>on,1.1(4),Index,Energy$

minimum$

mean$

minimum$

mean$

Longitudinal$

Transverse$

ASME,NB/2331,Index,Energy$

CVE$

BTP,5.3,Posi>on,1.1(4),Index,Energy$

Adjustment$based$on$mean$

Adjustment$based$on$minimum$

CVE$Temp.$,$60$oF$

based$on$mean$

based$on$minimum$

Comparison$of$Adjustments$

Case$1:$$RTNDT$is$defined$by$Charpy$data$



Figure 5-3. Schematic illustration showing that the adjustment factor for BTP 5.3 Position 1.1(4) is sensitive to the use of mean values or minimum values in its definition when TNDT data defines

RTNDT.

Case%2:%%RTNDT%is%defined%by%TNDT%data%

TNDT%

CVE%Temp.%7%60%oF%

minimum%

mean%

minimum%

mean%

Longitudinal%

Transverse%

ASME-NB02331-Index-Energy%

CVE%

BTP-5.3-Posi?on-1.1(4)-Index-Energy%

minimum%

mean%

minimum%

mean%

Longitudinal%

Transverse%

ASME-NB02331-Index-Energy%

CVE%

BTP-5.3-Posi?on-1.1(4)-Index-Energy%

Adjustment%based%on%mean%

Adjustment%based%on%minimum%

CVE%Temp.%7%60%oF%

based%on%mean%

based%on%minimum%

Comparison%of%Adjustments%



Figure 5-4. Comparison of the difference in transition temperatures determined based on the

mean versus the average of several measurements. Charpy data used here is shown for purpose of illustration only, it is not comprehensive.

0

40

80

120

160

-200 -100 0 100 200 300

Impa

ct E

nerg

y [f

t-lbs

]

Temperature [oF]

Heat C4487-1, Longitudinal

tanh Fit

Data

0

40

80

120

160

-100 0 100 200 300

Impa

ct E

nerg

y [f

t-lbs

]

Temperature [oF]

Heat C6940-1, Longitudinal

tanh Fit

Data

Negligible'difference''

Larger'difference'(≈30'oF)''



Figure 5-5. Schematic illustration showing that the slope of the Charpy transition curve is

insensitive to the use of mean values or minimum values in its definition.

6.0 Data Sources

All data used in this investigation are from unirradiated RPV steels. These data were reported as part of 10 CFR 50 Appendix H surveillance programs and are recorded in surveillance reports that are archived in the REAP (Reactor Embrittlement Archive Project) database [19]. REAP was developed and is maintained by the Oak Ridge National Laboratory under contract to the NRC. Figure 6-1 shows the distribution of the data used among different plate and forging steel grades. These data, or tanh fits to these data, appear in the following tables:

Table 6-1 provides the TNDT data Table 6-2 provides the tanh fit coefficients for the energy transition curves of the

longitudinally-oriented Charpy specimens Table 6-3 provides the tanh fit coefficients for the lateral expansion transition curves

of the longitudinally-oriented Charpy specimens Table 6-4 provides the tanh fit coefficients for the energy transition curves of the

transversely-oriented Charpy specimens Table 6-5 provides the tanh fit coefficients for the lateral expansion transition curves

of the transversely-oriented Charpy specimens

Temperature)

minimum)

mean)

Transi-on)slope)based)on)minimums)

Transi-on)slope)based)on)means)

Charpy)Ene

rgy )



Figure 6-1. Distribution between different forging and plate ASTM grades of the 59 data sets taken

from REAP. The information in these tables, along with the formulae provided in this report, was used to calculate the index temperature or USE parameters discussed previously.

Table 6-1. Nil-ductility temperature data. Product Form Grade Heat TNDT [oF]

Forging A5082 ANH161 #N/A Forging A5082 5P-5933 40 Forging A5082 411343 -40 Forging A5082 123J398 #N/A Forging A5082 526840 -4 Forging A5082 990400 -12 Forging A5082 990496 -48 Forging A5082 3P2359 20 Forging A5082 4P1885 -10 Forging A5082 522194 20 Forging A5082 522314 20 Forging A5082 990710 #N/A Forging A5082 980919 5 Forging A5082 288757 -22 Forging A5082 527536 -22 Forging A5082 527828 14 Forging A5083 49D867-1 -20 Forging A5083 MK24-3 -30 Forging A5083 49D330 -20 Forging A5083 21918 14 Forging A5083 22642 -13

27%$

9%$10%$

54%$

Forging:$A50832$Forging:$A50833$Plate:$A302B$Plate:$A533B$



Product Form Grade Heat TNDT [oF]

Plate A302B C2800-2 20 Plate A302B C3265-1 0 Plate A302B C2789-2 10 Plate A302B C3307-1 -10 Plate A302B P2130 #N/A Plate A302B Mod C1279-3 -10 Plate A533B1 C5114-1 10 Plate A533B1 C5114-2 -20 Plate A533B1 C8009-3 0 Plate A533B1 C6317-1 -50 Plate A533B1 C4487-1 10 Plate A533B1 C4489-1 10 Plate A533B1 C4441-1 10 Plate A533B1 C5286-1 10 Plate A533B1 C3506-1 -10 Plate A533B1 C5521-2 10 Plate A533B1 C4499-2 0 Plate A533B1 C4533-2 -30 Plate A533B1 C5522-2 -20 Plate A533B1 C4344-1 -10 Plate A533B1 C5161-1 -40 Plate A533B1 C6940-1 -20 Plate A533B1 C7466-1 -30 Plate A533B1 A1768-1 -20 Plate A533B1 C4387-2 -30 Plate A533B1 C5667-1 -10 Plate A533B1 B7955-1 -10 Plate A533B1 C4186-2 -20 Plate A533B1 C5935-2 0 Plate A533B1 A8490-2 0 Plate A533B1 B4197-2 -10 Plate A533B1 C4339-1 -10 Plate A533B1 C5583-1 0 Plate A533B1 B8628-1 -20 Plate A533B1 A9154-1 -20 Plate A533B1 C4935-2 -20 Plate A533B1 B7835-1 -20 Plate A533B1 C4007-1 10



Table 6-2. Longitudinally oriented Charpy energy data. Product Form Grade Heat n A [ft-lb] B [ft-lb] C [oF] D [oF]

Forging A5082 ANH161 18 72.000 70.000 108.927 33.359 Forging A5082 5P-5933 18 84.750 82.750 91.190 -14.960 Forging A5082 411343 18 84.917 82.917 70.348 45.659 Forging A5082 123J398 18 78.679 76.679 65.890 17.405 Forging A5082 526840 18 78.167 76.167 72.481 -28.863 Forging A5082 990400 18 68.542 66.542 78.312 42.808 Forging A5082 990496 18 58.571 56.571 100.675 31.206 Forging A5082 3P2359 26 74.063 72.063 67.944 16.436 Forging A5082 4P1885 27 80.955 78.955 48.074 13.704 Forging A5082 522194 30 88.444 86.444 79.993 60.748 Forging A5082 522314 27 77.750 75.750 91.462 11.676 Forging A5082 990710 20 68.333 66.333 84.504 -1.898 Forging A5082 980919 20 58.938 56.938 91.756 16.543 Forging A5082 288757 20 67.556 65.556 100.276 3.499 Forging A5082 527536 18 66.750 64.750 109.290 13.448 Forging A5082 527828 18 88.500 86.500 62.093 8.766 Forging A5083 49D867-1 18 84.125 82.125 99.615 2.870 Forging A5083 MK24-3 28 84.944 82.944 66.909 32.479 Forging A5083 49D330 22 85.700 83.700 69.553 22.627 Forging A5083 21918 23 80.250 78.250 91.975 31.055 Forging A5083 22642 21 74.833 72.833 58.966 14.055

Plate A302B C2800-2 19 59.625 57.625 96.754 55.647 Plate A302B C3265-1 21 72.250 70.250 85.438 47.242 Plate A302B C2789-2 29 64.350 62.350 91.917 45.153 Plate A302B C3307-1 27 88.950 86.950 79.190 67.276 Plate A302B P2130 17 55.393 53.393 58.344 2.159 Plate A302B Mod C1279-3 16 78.375 76.375 71.942 53.262 Plate A533B1 C5114-1 27 66.444 64.444 78.650 31.775 Plate A533B1 C5114-2 27 71.611 69.611 76.210 39.373 Plate A533B1 C8009-3 17 80.250 78.250 60.773 46.929 Plate A533B1 C6317-1 18 67.917 65.917 82.209 51.044 Plate A533B1 C4487-1 23 71.000 69.000 80.879 54.094 Plate A533B1 C4489-1 27 65.000 63.000 70.650 55.902 Plate A533B1 C4441-1 18 69.725 67.725 79.694 59.719 Plate A533B1 C5286-1 18 71.813 69.813 67.342 57.814 Plate A533B1 C3506-1 24 64.083 62.083 81.717 58.389 Plate A533B1 C5521-2 21 64.667 62.667 64.494 65.305 Plate A533B1 C4499-2 18 63.813 61.813 66.820 38.295 Plate A533B1 C4533-2 18 64.900 62.900 108.927 33.359 Plate A533B1 C5522-2 30 58.444 56.444 93.528 42.357 Plate A533B1 C4344-1 15 62.250 60.250 94.225 43.442 Plate A533B1 C5161-1 18 67.333 65.333 68.322 51.009



Product Form Grade Heat n A [ft-lb] B [ft-lb] C [oF] D [oF]

Plate A533B1 C6940-1 18 69.500 67.500 80.104 31.011 Plate A533B1 C7466-1 16 66.100 64.100 84.835 31.748 Plate A533B1 A1768-1 16 71.300 69.300 63.071 66.978 Plate A533B1 C4387-2 18 70.893 68.893 68.915 56.430 Plate A533B1 C5667-1 17 66.688 64.688 48.897 72.237 Plate A533B1 B7955-1 17 78.675 76.675 78.048 51.844 Plate A533B1 C4186-2 18 62.000 60.000 74.544 70.437 Plate A533B1 C5935-2 19 70.500 68.500 74.685 58.420 Plate A533B1 A8490-2 24 67.833 65.833 109.825 63.733 Plate A533B1 B4197-2 20 43.900 41.900 93.384 84.667 Plate A533B1 C4339-1 23 62.792 60.792 84.733 50.792 Plate A533B1 C5583-1 22 59.000 57.000 73.947 22.969 Plate A533B1 B8628-1 27 45.450 43.450 76.616 37.192 Plate A533B1 A9154-1 18 66.750 64.750 74.602 26.367 Plate A533B1 C4935-2 18 75.167 73.167 69.002 24.902 Plate A533B1 B7835-1 24 70.821 68.821 75.712 45.950 Plate A533B1 C4007-1 21 62.750 60.750 59.702 68.970



Table 6-3. Longitudinally oriented Charpy lateral expansion data. Product Form Grade Heat n A [mills] B [mills] C [oF] D [oF]

Forging A5082 ANH161 18 44.667 44.667 94.326 12.628 Forging A5082 5P-5933 18 45.500 45.500 66.742 -38.436 Forging A5082 411343 18 44.167 44.167 20.421 16.517 Forging A5082 123J398 18 43.000 43.000 53.086 8.964 Forging A5082 526840 18 44.417 44.417 62.638 -48.763 Forging A5082 990400 18 41.417 41.417 60.847 25.521 Forging A5082 990496 18 39.714 39.714 97.009 24.065 Forging A5082 3P2359 26 34.833 34.833 38.175 -12.157 Forging A5082 4P1885 27 34.318 34.318 34.230 -16.854 Forging A5082 522194 30 35.389 35.389 32.224 16.875 Forging A5082 522314 27 35.125 35.125 46.104 -35.429 Forging A5082 990710 20 44.000 44.000 77.760 -9.982 Forging A5082 980919 20 39.938 39.938 89.555 1.853 Forging A5082 288757 20 42.500 42.500 99.704 -20.450 Forging A5082 527536 18 40.500 40.500 89.009 2.774 Forging A5082 527828 18 46.125 46.125 45.809 -9.720 Forging A5083 49D867-1 18 46.375 46.375 63.409 -22.285 Forging A5083 MK24-3 28 44.056 44.056 50.844 10.755 Forging A5083 49D330 22 44.600 44.600 52.128 -6.801 Forging A5083 21918 23 48.250 48.250 68.017 -4.805 Forging A5083 22642 21 38.833 38.833 37.307 -6.607

Plate A302B C2800-2 19 33.618 33.618 79.138 23.419 Plate A302B C3265-1 21 34.738 34.738 69.728 10.189 Plate A302B C2789-2 29 34.962 34.962 86.946 11.580 Plate A302B C3307-1 27 33.867 33.867 46.159 14.978 Plate A302B P2130 17 39.545 39.545 72.681 -7.859 Plate A302B Mod C1279-3 16 43.827 43.827 61.535 22.505 Plate A533B1 C5114-1 27 33.056 33.056 79.697 2.958 Plate A533B1 C5114-2 27 34.278 34.278 58.980 10.706 Plate A533B1 C8009-3 17 47.250 47.250 59.130 30.362 Plate A533B1 C6317-1 18 43.083 43.083 70.715 38.355 Plate A533B1 C4487-1 23 45.500 45.500 77.527 39.955 Plate A533B1 C4489-1 27 39.583 39.583 63.119 50.138 Plate A533B1 C4441-1 18 46.000 46.000 88.470 39.360 Plate A533B1 C5286-1 18 45.750 45.750 66.627 36.845 Plate A533B1 C3506-1 24 45.500 45.500 82.705 41.630 Plate A533B1 C5521-2 21 42.167 42.167 62.112 56.520 Plate A533B1 C4499-2 18 38.063 38.063 64.408 31.345 Plate A533B1 C4533-2 18 41.300 41.300 59.332 12.518 Plate A533B1 C5522-2 30 39.889 39.889 84.588 43.100 Plate A533B1 C4344-1 15 44.000 44.000 110.225 29.143 Plate A533B1 C5161-1 18 42.500 42.500 74.517 30.414



Product Form Grade Heat n A [mills] B [mills] C [oF] D [oF]




Table 6-4. Transversely oriented Charpy energy data. Product Form Grade Heat n A [ft-lb] B [ft-lb] C [oF] D [oF]

Forging A5082 ANH161 18 65.429 63.429 84.795 33.033 Forging A5082 5P-5933 18 73.500 71.500 101.960 0.873 Forging A5082 411343 18 68.125 66.125 88.641 38.445 Forging A5082 123J398 18 65.500 63.500 79.460 23.675 Forging A5082 526840 18 48.188 46.188 97.601 21.888 Forging A5082 990400 18 43.313 41.313 81.171 69.153 Forging A5082 990496 18 36.875 34.875 92.893 72.325 Forging A5082 3P2359 26 63.923 61.923 65.123 8.779 Forging A5082 4P1885 27 68.175 66.175 72.389 28.748 Forging A5082 522194 30 73.167 71.167 55.554 33.724 Forging A5082 522314 27 55.792 53.792 77.832 38.888 Forging A5082 990710 20 39.611 37.611 65.448 35.000 Forging A5082 980919 20 33.500 31.500 83.695 50.239 Forging A5082 288757 20 45.222 43.222 112.899 29.868 Forging A5082 527536 18 31.800 29.800 90.234 50.468 Forging A5082 527828 18 55.875 53.875 115.579 18.538 Forging A5083 49D867-1 18 77.000 75.000 91.172 22.912 Forging A5083 MK24-3 28 77.389 75.389 87.662 41.422 Forging A5083 49D330 22 78.000 76.000 85.487 16.637 Forging A5083 21918 23 72.542 70.542 95.664 35.731 Forging A5083 22642 21 54.083 52.083 84.778 41.144 Plate A302B C2800-2 21 60.550 58.550 116.235 68.643 Plate A302B C3265-1 21 54.417 52.417 102.995 61.502 Plate A302B C2789-2 27 48.864 46.864 80.786 60.146 Plate A302B C3307-1 27 55.833 53.833 81.221 71.759 Plate A302B P2130 24 37.800 35.800 74.915 12.079 Plate A302B Mod C1279-3 15 51.800 49.800 71.233 51.557 Plate A533B1 C5114-1 27 47.182 45.182 99.771 49.482 Plate A533B1 C5114-2 27 53.917 51.917 74.264 50.963 Plate A533B1 C8009-3 17 67.875 65.875 72.934 62.660 Plate A533B1 C6317-1 18 40.944 38.944 82.635 41.609 Plate A533B1 C4487-1 23 62.667 60.667 89.742 63.406 Plate A533B1 C4489-1 27 51.143 49.143 82.370 46.801 Plate A533B1 C4441-1 18 54.750 52.750 76.927 61.607 Plate A533B1 C5286-1 18 58.188 56.188 77.703 77.607 Plate A533B1 C3506-1 24 49.083 47.083 96.782 61.051 Plate A533B1 C5521-2 21 44.167 42.167 87.483 55.409 Plate A533B1 C4499-2 18 52.813 50.813 107.310 33.772 Plate A533B1 C4533-2 18 39.964 37.964 85.626 24.021 Plate A533B1 C5522-2 30 42.778 40.778 107.441 22.503 Plate A533B1 C4344-1 15 46.750 44.750 87.202 52.304 Plate A533B1 C5161-1 18 46.583 44.583 100.070 65.133



Product Form Grade Heat n A [ft-lb] B [ft-lb] C [oF] D [oF]




Table 6-5. Transversely oriented Charpy lateral expansion data. Product Form Grade Heat n A [mills] B [mills] C [oF] D [oF]

Forging A5082 ANH161 18 42.500 42.500 83.331 24.177 Forging A5082 5P-5933 18 44.833 44.833 88.090 -13.697 Forging A5082 411343 18 44.500 44.500 81.873 26.224 Forging A5082 123J398 18 40.214 40.214 73.425 19.034 Forging A5082 526840 18 33.625 33.625 85.442 17.049 Forging A5082 990400 18 35.250 35.250 68.737 72.821 Forging A5082 990496 18 30.500 30.500 69.259 76.656 Forging A5082 3P2359 26 35.231 35.231 55.919 -12.436 Forging A5082 4P1885 27 36.250 36.250 64.777 -2.781 Forging A5082 522194 30 35.611 35.611 34.951 7.347 Forging A5082 522314 27 35.542 35.542 64.941 18.532 Forging A5082 990710 20 32.944 32.944 66.798 41.445 Forging A5082 980919 20 29.406 29.406 85.761 51.374 Forging A5082 288757 20 36.222 36.222 110.039 20.696 Forging A5082 527536 18 28.300 28.300 95.448 59.975 Forging A5082 527828 18 39.250 39.250 113.594 13.188 Forging A5083 49D867-1 18 44.000 44.000 90.675 8.131 Forging A5083 MK24-3 28 45.333 45.333 75.448 20.625 Forging A5083 49D330 22 41.625 41.625 48.740 -20.831 Forging A5083 21918 23 48.167 48.167 81.091 9.768 Forging A5083 22642 21 39.000 39.000 75.519 30.201 Plate A302B C2800-2 21 35.162 35.162 97.345 26.604 Plate A302B C3265-1 21 36.772 36.772 110.336 50.338 Plate A302B C2789-2 27 33.097 33.097 92.790 43.193 Plate A302B C3307-1 27 35.527 35.527 101.114 44.171 Plate A302B P2130 24 31.127 31.127 69.954 9.998 Plate A302B Mod C1279-3 15 39.245 39.245 86.148 32.571 Plate A533B1 C5114-1 27 30.409 30.409 98.363 37.871 Plate A533B1 C5114-2 27 32.917 32.917 78.644 35.462 Plate A533B1 C8009-3 17 43.375 43.375 79.053 43.551 Plate A533B1 C6317-1 18 33.333 33.333 77.918 38.082 Plate A533B1 C4487-1 23 40.833 40.833 91.714 43.834 Plate A533B1 C4489-1 27 34.357 34.357 76.330 45.941 Plate A533B1 C4441-1 18 40.500 40.500 90.622 40.987 Plate A533B1 C5286-1 18 41.625 41.625 86.932 57.049 Plate A533B1 C3506-1 24 39.667 39.667 103.276 50.635 Plate A533B1 C5521-2 21 32.167 32.167 77.153 56.413 Plate A533B1 C4499-2 18 33.125 33.125 90.912 22.527 Plate A533B1 C4533-2 18 34.214 34.214 86.821 21.141 Plate A533B1 C5522-2 30 31.778 31.778 88.215 28.887 Plate A533B1 C4344-1 15 38.583 38.583 88.407 42.783 Plate A533B1 C5161-1 18 37.667 37.667 95.743 59.330



Product Form Grade Heat n A [mills] B [mills] C [oF] D [oF]




7.0 Assessment of BTP 5-3 Position 1.1(1)

Position 1.1(1) of BTP 5-3 provides a procedure to estimate TNDT for A533B Class 1 plates. This position is defined in this report by Eq. (7). The top plot in Figure 7-1 compares measured values of TNDT (vertical axis) with the TNDT estimate of BTP 5-3 Position 1.1(1) using Eq. (7) (horizontal axis). The black line represents the values of TNDT where the measured values equal the values estimated by the BTP;; symbols above this line have TNDT values that are non-conservatively predicted (i.e., under-predicted) by the BTP. The blue lines on the plot provide linear representations of the mean curve (solid blue line) and a 2σ upper bound§§ to the data (dotted blue line). As discussed in Section 13.0, the difference between the BTP estimate and the 2σ upper bound can be used to adjust the BTP estimate to provide a conservative estimate of TNDT. This fit to the 32 data available show that there is very little relationship between Charpy and TNDT data, making Charpy data a poor predictor of TNDT. Nevertheless, the lower plot in Figure 7-1 illustrates that BTP 5-3 Position 1.1(1) conservatively predicts TNDT for 91% of the available data.

§§ The motivation for using a 2σ upper bound is discussed in Section 13.0.



Figure 7-1. Comparison of data with the predictions of BTP 5-3 Position 1.1(1) (black line) and mean and 2s fit to the data (blue lines). Top: plot of actual TNDT values (vertical axis) vs. BTP estimates using Eq. (7) (horizontal axis). Bottom: Distribution of BTP prediction errors (errors

above 0 °F are non-conservative).

!100$

!50$

0$

50$

100$

150$

!100$ !50$ 0$ 50$ 100$ 150$ 200$

T NDT$p

er$ASTM$E208$[oF]$

MAX$(0,$T(L)30)$$[oF]$

Plate$Upper$Bound:$$TNDT$=$0.19$x$MAX(0,$T(L)30)$+$19$

Forging:$A508L2$Forging:$A508L3$Plate:$A533BL1$Plate:$A302B$Plate:$A302B(Mod)$BTP$5L3$PosiNon$1.1(1)$Mean$of$Data$2$Sigma$Upper$Bound$of$Data$

0.0#

0.1#

0.2#

0.3#

0.4#

0.5#

0.6#

0.7#

0.8#

0.9#

1.0#

-60# -40# -20# 0# 20# 40# 60# 80# 100# 120# 140#

Cumula&

ve)Proba

bility)

ASTM)TNDT))7)MAX(0,)T(L)30)))[oF])

9%)of)data)non7conserva&vely)predicted)by)BTP)573)

Forging:)A50872)

Forging:)A50873)

Plate:)A533B71)

Plate:)A302B)

Plate:)A302B(Mod))

All)

BTP)573)Posi&on)1.1(1))




Position 1.1(2) of BTP 5-3 provides a procedure to estimate TNDT for A508 Class 2 forgings. This position is defined in this report by Eq. (8). The top plot in Figure 8-1 compares measured values of TNDT (vertical axis) with the TNDT estimate of BTP 5-3 Position 1.1(2) using Eq. (8) (horizontal axis). The black line represents the values of TNDT where the measured values equal the values estimated by the BTP;; symbols above this line have TNDT values that are non-conservatively predicted (i.e., under-predicted) by the BTP. The blue lines on the plot provide linear representations of the mean curve (solid blue line) and a 2σ upper bound to the data (dotted blue line). As discussed in Section 13.0, the difference between the BTP estimate and the 2σ upper bound can be used to adjust BTP estimate to provide a conservative estimate of TNDT. This fit to the 13 data available show that there is a very little relationship between Charpy and NDT data, making Charpy data a poor predictor of TNDT. The lower plot in Figure 8-1 illustrates that BTP 5-3 Position 1.1(2) conservatively predicts TNDT for 85% of the available data.



Figure 8-1. Comparison of data with the predictions of BTP 5-3 Position 1.1(2) (black line) and mean and 2s fits to the data (blue lines). Top: plot of actual TNDT values (vertical axis) vs. BTP estimates using Eq. (8) (horizontal axis). Bottom: Distribution of BTP prediction errors (errors

above 0 °F are non-conservative).

!100$

!50$

0$

50$

100$

150$

!100$ !50$ 0$ 50$ 100$ 150$ 200$

T NDT$$pe

r$ASTM$E208$$[oF]$

MIN$(+60,$T(L)100,$TUppShelf)$$[oF]$

Forging$Upper$Bound$$$TNDT$=$F0.52$x$MIN(+60,$T(L)100,$TUppShelf)$+$66$

Forging:$A508F2$Forging:$A508F3$Plate:$A533BF1$Plate:$A302B$Plate:$A302B(Mod)$BTP$5F3$PosiPon$1.1(2)$Mean$of$Data$2$Sigma$Upper$Bound$of$Data$

0.0#

0.1#

0.2#

0.3#

0.4#

0.5#

0.6#

0.7#

0.8#

0.9#

1.0#

-120# -100# -80# -60# -40# -20# 0# 20# 40# 60# 80# 100# 120# 140#

Cumula&

ve)Proba

bility)

ASTM)TNDT)7)MIN)(+60,)T(L)100,)TUppShelf)))[oF])


Forging:)A50872)

Forging:)A50873)

Plate:)A533B71)

Plate:)A302B)

Plate:)A302B(Mod))

All)

BTP)573)Posi&on)1.1(2))




9.1 Part a: Scale Longitudinal CVN data by 65% Position 1.1(3) of BTP 5-3 provides two procedures to estimate a transverse Charpy transition temperature (T(T)50&35) from longitudinal Charpy data (T(L)50&35). The first procedure, Position 1.1(3a), is defined in this report by Eq. (9). The top plot in Figure 9-1 compares measured values of T(T)50&35 (vertical axis) to estimates of T(T)50&35 made using longitudinal CVN data with BTP 5-3 Position 1.1(3a) using Eq. (9) (horizontal axis). The black line represents the values of T(T)50&35 where the measured values equal the values estimated by the BTP. Symbols that plot above this line have T(T)50&35 values that are non-conservatively predicted (i.e., under-predicted) by this position of the BTP. The middle lower plot in Figure 9-1 is identical to the upper plot except that only the plate data are shown, while the lower plot shows only the forging data. While the ASTM grades of plates and forgings examined here are metallurgically similar, and are therefore expected to represent different parts of the same property continuum, they are analyzed separately here (and elsewhere in this document) because the data available for analysis (as described in Section 6.0) indicates that the plate and forging data sometimes exhibit different trends, and the plate data consistently exhibits considerably less scatter than the forging data. The blue lines on the middle and lower plots in Figure 9-1 provide linear representations of the mean (solid lines) and a 2σ upper bounds (dashed lines) to the 38 plate and 21 forging data points. When the 2σ upper bounds exceed the BTP estimates (black dot-dash lines), the BTP estimates are non-conservative. As discussed in Section 13.0, the difference between the BTP estimate and the 2σ upper bound estimate can be used to adjust BTP estimates to make them conservative. Figure 9-2 shows the distribution of errors associated with estimates of T(T)50&35 made using BTP 5-3 Position 1.1(3a): 21% of the available plate data and 48% of the available forging data examined are non-conservatively predicted.



Figure 9-1. Comparison of data with the predictions of BTP 5-3 Position 1.1(3a) (black lines) and mean and 2s fits to the data (blue lines). Top: all (both plate and forging) data. Middle and

bottom: plates and forgings, respectively with mean and 2s fits (blue lines).

!100$

!50$

0$

50$

100$

150$

!100$ !50$ 0$ 50$ 100$ 150$ 200$

Tran

sverse(T

50&35(([

o F](

T50&35(from(Longitudinal(CVEx0.65([oF](

Forging:(A508C2(Forging:(A508C3(Plate:(A533BC1(Plate:(A302B(Plate:(A302B(Mod)(BTP(5C3([1.1(3a):(x0.65](

!100$

!50$

0$

50$

100$

150$

!100$ !50$ 0$ 50$ 100$ 150$ 200$

Tran

sverse(T

50&35(([

o F](


Plate(Upper(Bound(T(T)50&35(=(0.53(x(T(Lx0.65)50&35(+(44(

Forging:(A508L2(Forging:(A508L3(Plate:(A533BL1(Plate:(A302B(Plate:(A302B(Mod)(BTP(5L3([1.1(3a):(x0.65](Mean(of(Data(2(Sigma(Upper(Bound(of(Data(

!100$

!50$

0$

50$

100$

150$

!100$ !50$ 0$ 50$ 100$ 150$ 200$

Tran

sverse(T

50&35(([

o F](


Forging(Upper(Bound(T(T)50&35(=(0.99(x(T(Lx0.65)50&35(+(77(

Forging:(A508L2(Forging:(A508L3(Plate:(A533BL1(Plate:(A302B(Plate:(A302B(Mod)(BTP(5L3([1.1(3a):(x0.65](Mean(of(Data(2(Sigma(Upper(Bound(of(Data(



Figure 9-2. Distribution of estimation errors associated with BTP 5-3 Position 1.1(3a). Errors

exceeding 0 °F indicate a non-conservative prediction. Top: plates, Bottom: forgings.

0.0#

0.1#

0.2#

0.3#

0.4#

0.5#

0.6#

0.7#

0.8#

0.9#

1.0#

-60# -40# -20# 0# 20# 40# 60# 80# 100# 120# 140#

Cumula&

ve)Proba

bility)

T50&35(T))8)T50&35)from)Longl.)CVE)x)0.65))[oF])


Forging:)A50882)

Forging:)A50883)

Plate:)A533B81)

Plate:)A302B)

Plate:)A302B(Mod))

All)

BTP)583)[1.1(3a):)x0.65])

0.0#

0.1#

0.2#

0.3#

0.4#

0.5#

0.6#

0.7#

0.8#

0.9#

1.0#

-60# -40# -20# 0# 20# 40# 60# 80# 100# 120# 140#

Cumula&

ve)Proba

bility)

T50&35(T))8)T50&35)from)Longl.)CVE)x)0.65))[oF])


Forging:)A50882)

Forging:)A50883)

Plate:)A533B81)

Plate:)A302B)

Plate:)A302B(Mod))

All)

BTP)583)[1.1(3a):)x0.65])



9.2 Part b: Add 20 °F to longitudinal transition temperature Position 1.1(3) of BTP 5-3 provides two procedures to estimate a transverse Charpy transition temperature (T(T)50&35) from longitudinal Charpy data (i.e. T(L)50&35). The second procedure, Position 1.1(3b), is defined in this report by Eq. (10). The top plot in Figure 9-3 compares measured values of T(T)50&35 (vertical axis) with estimates of T(T)50&35 made using longitudinal CVN data with BTP 5-3 Position 1.1(3b) using Eq. (10) (horizontal axis). The black line represents the values of T(T)50&35 where the measured values equal the values estimated by the BTP. Symbols that plot above this line have T(T)50&35 values that are non-conservatively predicted (i.e., under-predicted) by this position of the BTP. The middle plot in Figure 9-3 is identical to the upper plot except that only the plate data are shown, while the lower plot shows only the forging data. The plate and forging data are analyzed separately, which is consistent with the approach taken in the analysis of Position 1.1(3a), as was discussed in Section 9.1 of this report. The blue lines on the middle and lower plots in Figure 9-3 provide linear representations of the mean (solid lines) and 2σ upper bounds (dashed lines) to the 38 plate and 21 forging data. When the 2σ upper bounds exceed the BTP estimates (black dot-dash lines), the BTP estimates are non-conservative. As discussed in Section 13.0, the difference between the BTP estimates and the 2σ upper bound estimates can be used to adjust BTP estimates to make them conservative. Figure 9-4 shows the distribution of errors associated with estimates of T(T)50&35 made using BTP 5-3 Position 1.1(3b): 66% of the available plate data and 57% of the available forging data examined are non-conservatively predicted.



Figure 9-3. Comparison of data with the predictions of BTP 5-3 Position 1.1(3b) (black lines) and mean and 2s fits to the data (blue lines). Top: all data. Middle and bottom: plates and forgings,

respectively with mean and 2s bounds (blue lines).

!100$

!50$

0$

50$

100$

150$

!100$ !50$ 0$ 50$ 100$ 150$ 200$

Tran

sverse(T

50&35(([

o F](

Longitudinal(T50&35(([oF](

Forging:(A508;2(

Forging:(A508;3(

Plate:(A533B;1(

Plate:(A302B(

Plate:(A302B(Mod)(

BTP(5;3([1.1(3b):(+20F](

!100$

!50$

0$

50$

100$

150$

!100$ !50$ 0$ 50$ 100$ 150$ 200$

Tran

sverse(T

50&35(([

o F](


Plate(Upper(Bound(T(T)50&35(=(0.65(x(T(L)50&35(+(62(

Forging:(A508G2(Forging:(A508G3(Plate:(A533BG1(Plate:(A302B(Plate:(A302B(Mod)(BTP(5G3([1.1(3b):(+20F](Mean(of(Data(2(Sigma(Upper(Bound(of(Data(

!100$

!50$

0$

50$

100$

150$

!100$ !50$ 0$ 50$ 100$ 150$ 200$

Tran

sverse(T

50&35(([

o F](


Forging(Upper(Bound(T(T)50&35(=(0.70(x(T(L)50&35(+(115(

Forging:(A508F2(Forging:(A508F3(Plate:(A533BF1(Plate:(A302B(Plate:(A302B(Mod)(BTP(5F3([1.1(3b):(+20F](Mean(of(Data(2(Sigma(Upper(Bound(of(Data(



Figure 9-4. Distribution of estimation errors associated with BTP 5-3 Position 1.1(3b). Errors exceeding +20 °F indicate a non-conservative prediction. Top: plates, Bottom: forgings.

0.0#

0.1#

0.2#

0.3#

0.4#

0.5#

0.6#

0.7#

0.8#

0.9#

1.0#

-60# -40# -20# 0# 20# 40# 60# 80#

Cumula&

ve)Proba

bility)

Transverse)4)Longitudinal)T50&35))[oF])


Forging:)A50842)

Forging:)A50843)

Plate:)A533B41)

Plate:)A302B)

Plate:)A302B(Mod))

All)

BTP)543)[1.1(3b):)+20F])

0.0#

0.1#

0.2#

0.3#

0.4#

0.5#

0.6#

0.7#

0.8#

0.9#

1.0#

-60# -40# -20# 0# 20# 40# 60# 80# 100# 120# 140#

Cumula&

ve)Proba

bility)

Transverse)4)Longitudinal)T50&35))[oF])


Forging:)A50842)

Forging:)A50843)

Plate:)A533B41)

Plate:)A302B)

Plate:)A302B(Mod))

All)

BTP)543)[1.1(3b):)+20F])




As discussed in Section 4.2.4.2, because Position 1.1(4) uses the Charpy test temperature, whatever it may be, to estimate RTNDT rather than the temperature at a specified Charpy energy value it describes a spectrum of equations, not a single equation. The graphic used previously to describe Position 1.1(4) (Figure 4-1) is combined with data in Figure 10-1 to examine the conservatism, or lack thereof, of Position 1.1(4) estimates of RTNDT. To generate this figure transition temperatures were calculated from the mean tanh curves fit to the longitudinal Charpy data over a range of index energies. Eqs. (11)*** and (12) were then applied to estimate RTNDT, values, and these were compared to RTNDT estimated by eq. (5) to determine the conservatism, or lack thereof, of the BTP 5-3 Position 1.1(4) estimates. Plate and forging data were analyzed separately, consistent with the approach taken in the analysis of Position 1.1(3a), as was discussed in Section 9.1 of this report.

Figure 10-1. Illustration of the effect of index, or test, temperature on the non-conservatism of

BTP 5-3 Position 1.1(4).

*** Eq. (11) is applied to Charpy energies below 30 ft-lbs for purpose of illustration only.

BTP$5.3$Posi+on$1.1(4)$“If$limited$Charpy$V2notch$tests$were$performed$at$a$single$temperature$to#confirm#that#at#least#41#J#(30#45lbs)#was#obtained,$that#temperature#may#be#used#as#an#es>mate#of#the#RTNDT#provided#that#at#least#61J#(45#45lbs)#was#obtained$if$the$specimens$were$longitudinally$oriented.$If#the#minimum#value#obtained#was#less#than#61#J#(45#45lbs),#the#RTNDT#may#be#es>mated#as#11#°C#(20#°F)#above#the#test#temperature.”$

“to#confirm#that#at#least#41#J#(30#45lbs)#was#obtained”$

“that#temperature#may#be#used#as#an#es>mate#of#the#RTNDT#provided#that#at#least#61J#(45#45lbs)#was#obtained”$

“If#the#minimum#value#obtained#was#less#than#61#J#(45#45lbs),#the#RTNDT#may#be#es>mated#as#11#°C#(20#°F)#above#the#test#temperature.”$!"!"# = ! ! !

!"#$ + !"!°!

!"!"# = ! ! !!"#$

0%#

10%#

20%#

30%#

40%#

50%#

60%#

70%#

80%#

90%#

100%#

0# 20# 40# 60# 80# 100# 120# 140#

%"of"D

ata"Non

*Con

serva0

vely"

Pred

icted"by"BTP

"5*3"Posi0on

"1.1(4)"

E:"foot*pound"value"for"index,"or"test,"temperture"T(L)E""

"Plates"(Te"+"20F)"

"Plates"(Te)"

"Forgings"(Te"+"20F)"

"Forgings"(Te)"T(L)E$+$20$oF$$

evaluated$here$to$show$trends$

14%$5%$

72%$ 72%$



Figure 10-1 shows how the portion of the plate and forging data that is non-conservatively predicted by eqs. (11) and (12) changes as a function of the Charpy index temperature (or, in the language of BTP 5-3 Position 1.1(4), the test temperature). As expected, the index, or test, temperature influences significantly the portion of the data predicted non-conservatively, with higher index, or test, temperatures resulting in a smaller population of non-conservative predictions. Because of the variation shown in Figure 10-1 the adjustments needed to correct for these non-conservatisms depends on the absorbed energy measured at the Charpy test temperature. Adjustments incorporating this dependency are not developed in this report for several reasons. First, an on-going review of docketed licensing material for operating nuclear power plants has not revealed extensive use of Position 1.1(4). As such it is not clear that the effort needed to developing such adjustments is warranted. Additionally, the discussion in this section coupled with that of Section 5.0 suggests that the adjustments needed to restore conservatism to a Position 1.1(4) estimate of RTNDT are best developed in consideration of the particulars of plant-specific data. Such development can occur in the future if it is needed. In this report a bounding assessment of the non-conservatism of Position 1.1(4), and associated adjustment factors, are developed. These adjustments provide a screening tool to identify if situations exist where a more detailed plant-specific analysis is warranted. Figure 10-1 makes clear that the percentage of data non-conservatively predicted and, thereby, the magnitude of the non-conservatism increases decreases in the absorbed energy that is used to define the index tempertaure. As was discussed in Section 4.2.4.2 two formulae define Position 1.1(4): eq. (11) applies over the range from 30 to 45 ft-lbs while eq. (12) applies at and above 45 ft-lbs. Thus, the maximum non-conservatism occurs at 30 ft-lbs for eq. (11) and at 45 ft-lbs for eq. (12);; these being illustrated by the orange and purple circles on Figure 10-1. Thus, for the purposes of developing adjustment factors, eqs. (11) and (12) can be particularized into eqs. (19) and (20), respectively, as follows:

𝑅𝑇:;< = 𝑇 T CA + 20 °F (19) 𝑅𝑇:;< = 𝑇 T q@ (20)

where T(L)30 and T(L)45 designate, respectively, the temperature at which the mean tanh curve fit to longitudinal CVN data exhibits 30 or 45 ft-lbs absorbed energy. Adjustments are developed based on eqs. (19) and (20) in the following sections. 10.1 Equation (19) The top plot in Figure 10-2 compares measured values of RTNDT (vertical axis) with estimates of RTNDT made using longitudinal CVN data along with BTP 5-3 Position 1.1(4a) using Eq. (19) (horizontal axis). The black line represents the values of RTNDT where the measured values equal the values estimated by the BTP. Symbols that plot above this line have RTNDT values that are non-conservatively predicted (i.e., under-predicted) by this position of the BTP. The middle plot in Figure 10-2 is identical to the top plot except that only plate data are shown, while the lower plot shows only the forging data. The plate and forging data are analyzed



separately, which is consistent with the approach taken in the analysis of Position 1.1(3a), as was discussed in Section 9.1 of this report. The blue lines on the middle and lower plots in Figure 10-2 provide linear representations of the mean (solid lines) and 2σ upper bound (dashed lines) to the 38 plate and 21 forging data. While there is some relationship between the longitudinal Charpy energy data and RTNDT for plates, there is no significant relationships between these two quantities for forgings, indicating that longitudinal Charpy energy data is a poor indicator of forging RTNDT values. When the 2σ upper bounds (blue dashed lines) exceed the BTP estimates (black dot-dash lines), the BTP estimates are non-conservative. As discussed in Section 13.0, the difference between the BTP estimates and the 2σ upper bound estimates can be used to adjust BTP estimates to make them conservative. Figure 10-3 shows the distribution of errors associated with estimates of RTNDT made using BTP 5-3 Position 1.1(4a): 14% of the available plate data and 72% of the available forging data examined are non-conservatively predicted.



Figure 10-2. Comparison of data with the predictions of BTP 5-3 Position 1.1(4), eq. (19) (black

lines) and mean and 2s curve fits to the data (blue lines). Top: all data. Middle and bottom: plates and forgings, respectively with mean and 2s bounds (blue lines).

!100$

!50$

0$

50$

100$

150$

!100$ !50$ 0$ 50$ 100$ 150$ 200$

RTNDT%%per%ASM

E%NB.2331%[oF]%

Longitudinal%T30%+%20oF%%[oF]%

Forging:%A508.2%

Forging:%A508.3%

Plate:%A533B.1%

Plate:%A302B%

Plate:%A302B(Mod)%

BTP%5.3%[1.1(4a):%T30L+20F]%

!100$

!50$

0$

50$

100$

150$

!100$ !50$ 0$ 50$ 100$ 150$ 200$

RTNDT%%per%ASM

E%NB.2331%[oF]%


Plate%Upper%Bound:%%RTNDT%=%0.5%x%(T(L)30%+%20)%+%19%

Forging:%A508.2%Forging:%A508.3%Plate:%A533B.1%Plate:%A302B%Plate:%A302B(Mod)%BTP%5.3%[1.1(4a):%T30L+20F]%Mean%of%Data%2%Sigma%Upper%Bound%of%Data%

!100$

!50$

0$

50$

100$

150$

!100$ !50$ 0$ 50$ 100$ 150$ 200$

RTNDT%%per%ASM

E%NB.2331%[oF]%


Forging%Upper%Bound:%%RTNDT%=%.0.15%x%(T(L)30%+%20)%+%62%

Forging:%A508.2%Forging:%A508.3%Plate:%A533B.1%Plate:%A302B%Plate:%A302B(Mod)%BTP%5.3%[1.1(4a):%T30L+20F]%Mean%of%Data%2%Sigma%Upper%Bound%of%Data%



Figure 10-3. Distribution of estimation errors associated with BTP 5-3 Position 1.1(4), eq. (19). Errors exceeding 0 °F indicate a non-conservative prediction. Top: plates, Bottom: forgings.

0.0#

0.1#

0.2#

0.3#

0.4#

0.5#

0.6#

0.7#

0.8#

0.9#

1.0#

-60# -40# -20# 0# 20# 40# 60# 80# 100# 120# 140#

Cumula&

ve)Proba

bility)

(T30(L))+)20oF)):)ASME)RTNDT))[oF])

14%)of)data)non:conserva&vely)predicted)by)BTP)5:3)

Forging:)A508:2)

Forging:)A508:3)

Plate:)A533B:1)

Plate:)A302B)

Plate:)A302B(Mod))

All)

BTP)5:3)[1.1(4a):)T30L+20F])

0.0#

0.1#

0.2#

0.3#

0.4#

0.5#

0.6#

0.7#

0.8#

0.9#

1.0#

-60# -40# -20# 0# 20# 40# 60# 80# 100# 120# 140#

Cumula&ve)Probability)

ASME)RTNDT))9)(T(L)30)+)20oF))[oF])


Forging:)A50892)

Forging:)A50893)

Plate:)A533B91)

Plate:)A302B)

Plate:)A302B(Mod))

All)

BTP)593)[1.1(4a):)T30L+20F])



10.2 Equation (20) The top plot in Figure 10-4 compares measured values of RTNDT (vertical axis) with estimates of RTNDT made using longitudinal CVN data along with BTP 5-3 Position 1.1(4b) using Eq. (20) (horizontal axis). The black line represents values of RTNDT where the measured values equal the values estimated by the BTP. Symbols that plot above this line have RTNDT values that are non-conservatively predicted (i.e., under-predicted) by this position of the BTP. The middle plot in Figure 10-4 is identical to the top plot except that only the plate data are shown, while the lower plot shows only the forging data. The plate and forging data are analyzed separately, which is consistent with the approach taken in the analysis of Position 1.1(3a), as was discussed in Section 9.1 of this report. The blue lines on the middle and lower plots in Figure 10-4 provide linear representations of the mean (solid lines) and 2σ upper bounds (dashed lines) to the 38 plate and 21 forging data. While there is some relationship between the longitudinal Charpy energy data and RTNDT for plates, there is no relationship evident between these two quantities for forgings, indicating that longitudinal Charpy energy data do not provide a reliable indication of RTNDT values for forgings. When the 2σ upper bounds exceed the BTP estimates (black dot-dash lines), the BTP estimates are non-conservative. As discussed in Section 13.0, the difference between the BTP estimates and the 2σ upper bound estimates can be used to adjust BTP estimates to make them conservative. Figure 10-5 shows the distribution of errors associated with estimates of RTNDT made using BTP 5-3 Position 1.1(4b): 5% of the available plate data and 72% of the available forging data examined are non-conservatively predicted.



Figure 10-4. Comparison of data with the predictions of BTP 5-3 Position 1.1(4), eq. (20) (black

lines) and mean and 2s curve fits to the data (blue lines). Top: all data. Middle and bottom: plates and forgings, respectively with mean and 2s bounds (blue lines).

!100$

!50$

0$

50$

100$

150$

!100$ !50$ 0$ 50$ 100$ 150$ 200$

RTNDT%%per%ASM

E%NB.2331%[oF]%

Longitudinal%T(L)45%%[oF]%

Forging:%A508.2%

Forging:%A508.3%

Plate:%A533B.1%

Plate:%A302B%

Plate:%A302B(Mod)%

BTP%5.3%[1.1(4b):%T45L]]%

!100$

!50$

0$

50$

100$

150$

!100$ !50$ 0$ 50$ 100$ 150$ 200$

RTNDT%%per%ASME%NB.2331%[oF]%

Longitudinal%T(L)45

%%[oF]%

Plate%Upper%Bound:%%RTNDT

%=%0.59%x%T(L)45

%+%13%

Forging:%A508.2%

Forging:%A508.3%

Plate:%A533B.1%

Plate:%A302B%

Plate:%A302B(Mod)%

BTP%5.3%[1.1(4b):%T45L]]%

Mean%of%Data%

2%Sigma%Upper%Bound%of%Data%

!100$

!50$

0$

50$

100$

150$

!100$ !50$ 0$ 50$ 100$ 150$ 200$

RTNDT%%per%ASM

E%NB.2331%[oF]%

Longitudinal%T(L)45%%[oF]%

Forging%Upper%Bound:%%RTNDT%=%.0.01%x%T(L)45%+%65%

Forging:%A508.2%

Forging:%A508.3%

Plate:%A533B.1%

Plate:%A302B%

Plate:%A302B(Mod)%

BTP%5.3%[1.1(4b):%T45L]]%

Mean%of%Data%

2%Sigma%Upper%Bound%of%Data%



Figure 10-5. Distribution of estimation errors associated with BTP 5-3 Position 1.1(4), eq. (20). Errors exceeding 0 °F indicate a non-conservative prediction. Top: plates, Bottom: forgings.

0.0#

0.1#

0.2#

0.3#

0.4#

0.5#

0.6#

0.7#

0.8#

0.9#

1.0#

-60# -40# -20# 0# 20# 40# 60# 80# 100# 120# 140#

Cumula&

ve)Proba

bility)

T(L)45)7)ASME)RTNDT))[oF])


Forging:)A50872)

Forging:)A50873)

Plate:)A533B71)

Plate:)A302B)

Plate:)A302B(Mod))

All)

BTP)573)[1.1(4b):)T45L]])

0.0#

0.1#

0.2#

0.3#

0.4#

0.5#

0.6#

0.7#

0.8#

0.9#

1.0#

-60# -40# -20# 0# 20# 40# 60# 80# 100# 120# 140#

Cumula&

ve)Proba

bility)

ASME)RTNDT)))9)T(L)45))[oF])


Forging:)A50892)

Forging:)A50893)

Plate:)A533B91)

Plate:)A302B)

Plate:)A302B(Mod))

All)

BTP)593)[1.1(4b):)T45L]])



11.0 Assessment of BTP 5-3 Position 1.2

Position 1.2 of BTP 5-3 provides a procedure to estimate a transverse Charpy upper shelf energy (USE(T)) from longitudinal Charpy upper shelf energy (i.e. USE(L)), which is defined in this report by Eq. (13). The top plot in Figure 11-1 compares measured values of USE(T) (vertical axis) with measurements of USE(L) (horizontal axis). The black line represents the prediction of USE(T) based on Position 1.2 of BTP 5.3. Symbols that plot above this line have measured USE(T) values that are non-conservatively predicted (i.e., under-predicted) by this position of the BTP. The middle plot in Figure 11-1 is identical to the top plot except that only the plate data are shown, while the lower plot shows only the forging data. The plate and forging data are analyzed separately, which is consistent with the approach taken in the analysis of Position 1.1(3a), as was discussed in Section 9.1 of this report. The blue lines on the middle and lower plots in Figure 11-1 provide linear representations of the mean (solid lines) and 2σ lower bounds (dashed lines) to the 38 plate and 21 forging data. When the 2σ lower bounds fall below the BTP estimates (black dot-dash lines), the BTP estimates are non-conservative. As discussed in Section 13.0, the difference between the BTP estimates and the 2σ lower bound estimates can be used to adjust current BTP estimates to make them conservative. Figure 11-2 shows the distribution of errors associated with estimates of USE(T) made using BTP 5-3 Position 1.2: 13% of the available plate data and 33% of the available forging data examined are non-conservatively predicted. These results are consistent with a previous staff analysis [20], which reported that 15% of a population of 56 data for plates is non-conservatively predicted by BTP 5-3 Position 1.2.



Figure 11-1. Comparison of USE data with the USE predictions of BTP 5-3 Position 1.2 (black lines). Top: all data. Middle and bottom: plates and forgings, respectively with mean and 2s

bounds (blue lines).

0"

50"

100"

150"

200"

0" 50" 100" 150" 200"

Tran

sverse(USE(([-.lb](

Longitudinal(USE(([-.lb](

Forging:(A508.2(

Forging:(A508.3(

Plate:(A533B.1(

Plate:(A302B(

Plate:(A302B(Mod)(

BTP(5.3([1.2:(65%](

0"

50"

100"

150"

200"

0" 50" 100" 150" 200"

Tran

sverse(USE(([-.lb](


Plate(Lower(Bound:((USE(T)(=(0.5937(x(USE(L)(.(3.157(

Forging:(A508.2(Forging:(A508.3(Plate:(A533B.1(Plate:(A302B(Plate:(A302B(Mod)(BTP(5.3([1.2:(65%](Mean(of(Data(2(Sigma(Lower(Bound(of(Data(

0"

50"

100"

150"

200"

0" 50" 100" 150" 200"

Tran

sverse(USE(([-.lb](


Forging(Lower(Bound:((USE(T)(=(1.435(x(USE(L)(.(135.6(Forging:(A508.2(Forging:(A508.3(Plate:(A533B.1(Plate:(A302B(Plate:(A302B(Mod)(BTP(5.3([1.2:(65%](Mean(of(Data(2(Sigma(Lower(Bound(of(Data(



Figure 11-2. Distribution of transverse/longitudinal USE ratios. Ratios below 0.65 indicate a non-

conservative prediction using BTP 5-3 Position 1.2. Top: plates, Bottom: forgings.

0.0#

0.1#

0.2#

0.3#

0.4#

0.5#

0.6#

0.7#

0.8#

0.9#

1.0#

0.0# 0.1# 0.2# 0.3# 0.4# 0.5# 0.6# 0.7# 0.8# 0.9# 1.0#

Cumula&

ve)Proba

bility)

Transverse)USE)/)Longitudinal)USE)

13%)of)data)non?conserva&vely)predicted)by)BTP)5?3)

Forging:)A508?2)

Forging:)A508?3)

Plate:)A533B?1)

Plate:)A302B)

Plate:)A302B(Mod))

All)

BTP)5?3)[1.2:)65%])

0.0#

0.1#

0.2#

0.3#

0.4#

0.5#

0.6#

0.7#

0.8#

0.9#

1.0#

0.0# 0.1# 0.2# 0.3# 0.4# 0.5# 0.6# 0.7# 0.8# 0.9# 1.0#

Cumula&

ve)Proba

bility)

Transverse)USE)/)Longitudinal)USE)

33%)of)data)non>conserva&vely)predicted)by)BTP)5>3)

Forging:)A508>2)

Forging:)A508>3)

Plate:)A533B>1)

Plate:)A302B)

Plate:)A302B(Mod))

All)

BTP)5>3)[1.2:)65%])



12.0 Assessment of the Ref. [1] Procedure

12.1 TNDT estimate for A533B Class 1 Plates Equation (14) of this report defines estimates of TNDT for A533B Class 1 plates using the Ref. [1] procedure. The top plot in Figure 12-1 compares measured values of TNDT (vertical axis) with TNDT values estimated by the Ref. [1] procedure using Eq. (14) (horizontal axis). The black line represents values of TNDT where the measured values equal the values estimated by the Ref. [1] procedure using Eq. (14). Symbols that plot above this line have TNDT values that are non-conservatively predicted (i.e., under-predicted) by the Ref. [1] procedure. The blue lines on the plot provide linear representations of the mean (solid line) and a 2σ upper bound (dashed line) to the data. As discussed in Section 13.0, the difference between the Ref. [1] estimates and the 2σ upper bound estimates can be used to adjust Ref. [1] estimates to make them conservative. The fit to the 32 data available indicates that there is no reliable relationship between Charpy and TNDT data, making Charpy data a poor predictor of TNDT. The lower plot in Figure 12-1 illustrates that the Ref. [1] procedure conservatively predicts TNDT values for A533B Class 1 plates for 91% of the available data.



Figure 12-1. Comparison of data with the predictions of TNDT for A533B Class 1 plates (black lines)

and with mean and 2s curve fits to the data (blue lines). Top: plot of measured TNDT values (vertical axis) vs. estimates of TNDT values using the Ref. [1] procedure from Eq. (14) (horizontal axis). Bottom: Distribution of Ref. [1] prediction errors (errors above 0 °F are non-conservative). 12.2 TNDT estimate for A508 Class 2 Forgings Equation (15) of this report defines estimates of TNDT for A508 Class 2 forgings using the Ref. [1] procedure. The top plot in Figure 12-2 compares measured values of TNDT (vertical axis) with TNDT values estimated using the Ref. [1] procedure using Eq. (15) (horizontal axis). The black line represents the values of TNDT where the measured values equal the values estimated by the Ref. [1] procedure using Eq. (15). Symbols that plot above this line have TNDT values that are non-conservatively predicted (i.e., under-predicted) by the Ref. [1] procedure. The blue lines on the plot provide linear representations of the mean (solid line) and 2σ upper bound (dashed line) to the data. As discussed in Section 13.0, the difference between the Ref. [1]

!100$

!50$

0$

50$

100$

150$

!100$ !50$ 0$ 50$ 100$ 150$ 200$

T NDT$per$ASTM$E208$[oF]$

Longitudinal$T(L)35$$[oF]$

Plate$Upper$Bound:$$TNDT$=$0.19$x$T(L)35$+$19$

Forging:$A508J2$Forging:$A508J3$Plate:$A533BJ1$Plate:$A302B$Plate:$A302B(Mod)$Ref.$[1]$Procedure$[T35L]$Mean$of$Data$2$Sigma$Upper$Bound$of$Data$

0.0#

0.1#

0.2#

0.3#

0.4#

0.5#

0.6#

0.7#

0.8#

0.9#

1.0#

-60# -40# -20# 0# 20# 40# 60# 80# 100# 120# 140#

Cumula&

ve)Proba

bility)

ASTM)TNDT))7)T(L)35))[oF])

9%)of)data)non7conserva&vely)predicted)by)Ref.)[1])Procedure)

Forging:)A50872)

Forging:)A50873)

Plate:)A533B71)

Plate:)A302B)

Plate:)A302B(Mod))

All)

Ref.)[1])Procedure)[T35L])



estimates and the 2σ upper bound estimates can be used to adjust Ref. [1] estimates to make them conservative. The fit to the 13 data available show that there is an inverse relationship between Charpy and NDT data, making Charpy data a poor predictor of TNDT. The lower plot in Figure 12-2 illustrates that the Ref. [1] procedure conservatively predicts TNDT values for A508 Class 2 forgings for 85% of the available data.

Figure 12-2. Comparison of data with the predictions of TNDT for A508 Class 2 forgings (black lines) and mean and 2s curve fits to the data (blue lines). Top: plot of measured TNDT values

(vertical axis) vs. estimates of TNDT values using the Ref. [1] procedure from Eq. (15) (horizontal axis). Bottom: Distribution of Ref. [1] prediction errors (errors above 0 °F are non-conservative).

!100$

!50$

0$

50$

100$

150$

!100$ !50$ 0$ 50$ 100$ 150$ 200$

T NDT$$per$ASTM$E208$$[oF]$

MIN$(+70,$T(L)100)$$[oF]$

Forging$Upper$Bound$$$TNDT$=$C0.45$x$MIN(+70,$T(L)100)$+$65$

Forging:$A508C2$Forging:$A508C3$Plate:$A533BC1$Plate:$A302B$Plate:$A302B(Mod)$Ref.$[1]$EsRmate$Mean$of$Data$2$Sigma$Upper$Bound$of$Data$

0.0#

0.1#

0.2#

0.3#

0.4#

0.5#

0.6#

0.7#

0.8#

0.9#

1.0#

-120# -100# -80# -60# -40# -20# 0# 20# 40# 60# 80# 100# 120# 140#

Cumula&ve)Probability)

ASTM)TNDT)7)MIN)(+70,)T(L)100)))[oF])


Forging:)A50872)

Forging:)A50873)

Plate:)A533B71)

Plate:)A302B)

Plate:)A302B(Mod))

All)

Ref.)[1])Es&mate)



12.3 Add 30 °F to longitudinal CVN transition temperature

Equation (16) of this report defines estimates of transverse Charpy transition temperature (T(T)50&35) from longitudinal Charpy data (i.e. T(L)50&35) using the Ref. [1] procedure. The top plot in Figure 12-3 compares measured values of T(T)50&35 (vertical axis) with T(T)50&35 values estimated using longitudinal CVN data by the Ref. [1] procedure using Eq. (16) (horizontal axis). The black line represents values of T(T)50&35 where the measured values equal the values estimated by the Ref. [1] procedure. Symbols that plot above this line have T(T)50&35 values that are non-conservatively predicted (i.e., under-predicted) by the Ref. [1] procedure. The middle plot in Figure 12-3 is identical to the top plot except that only plate data are shown, while the lower plot shows only the forging data. The plate and forging data are analyzed separately, which is consistent with the approach taken in the analysis of Position 1.1(3a), as was discussed in Section 9.1 of this report. The blue lines on the middle and lower plots in Figure 12-3 provide linear representations of the mean (solid lines) and 2σ upper bounds (dashed lines) to the 32 plate and 16 forging data. When the 2σ upper bounds exceed the Ref. [1] estimates (black dot-dash lines), the Ref. [1] estimates are non-conservative. As discussed in Section 13.0, the difference between the Ref. [1] estimates and the 2σ upper bound estimates can be used to adjust Ref. [1] estimates to make them conservative. Figure 12-4 shows the distribution of errors associated with estimates of T(T)50&35 made using the Ref. [1] procedure using Eq. (16): 41% of the available plate data and 50% of the available forging data examined are non-conservatively predicted.



Figure 12-3. Comparison of data with the predictions, using the Ref. [1] procedure (black lines), of the transverse Charpy transition temperature from longitudinal Charpy transition temperature. Top: all data. Middle and bottom: plates and forgings, respectively with mean and 2s bounds

(blue lines).

!100$

!50$

0$

50$

100$

150$

!100$ !50$ 0$ 50$ 100$ 150$ 200$

Tran

sverse(T

50(([

o F](

Longitudinal(T50(([oF](

Forging:(A50892(

Forging:(A50893(

Plate:(A533B91(

Plate:(A302B(

Plate:(A302B(Mod)(

Ref.([1](Method([+30F](

!100$

!50$

0$

50$

100$

150$

!100$ !50$ 0$ 50$ 100$ 150$ 200$

Tran

sverse(T

50(([

o F](


Plate(Upper(Bound(T(T)50(=(0.69(x(T(L)50(+(62(

Forging:(A508F2(Forging:(A508F3(Plate:(A533BF1(Plate:(A302B(Plate:(A302B(Mod)(Ref.([1](Method([+30F](Mean(of(Data(2(Sigma(Upper(Bound(of(Data(

!100$

!50$

0$

50$

100$

150$

!100$ !50$ 0$ 50$ 100$ 150$ 200$

Tran

sverse(T

50(([

o F](


Forging(Upper(Bound(T(T)50(=(0.66(x(T(L)50(+(128(

Forging:(A508E2(Forging:(A508E3(Plate:(A533BE1(Plate:(A302B(Plate:(A302B(Mod)(Ref.([1](Method([+30F](Mean(of(Data(2(Sigma(Upper(Bound(of(Data(



Figure 12-4. Distribution of estimation errors associated with the Ref. [1] procedure estimate of transverse Charpy transition temperature from longitudinal Charpy transition temperature. Errors

exceeding +30 °F indicate a non-conservative prediction. Top: plates, Bottom: forgings.

12.4 2 °F/ft-lb longitudinal CVN transition slope The Ref. [1] procedure adopts a 2 °F/ft-lb transition slope as a bounding value for longitudinally oriented Charpy specimens. The top plot in Figure 12-5 compares values of transition slope, estimated from the tanh fits using Eq. (17), with the 2 °F/ft-lb value from the Ref. [1] procedure†††. The data demonstrate that the Ref. [1] procedure provides a non-conservative estimate of 13% of the available data. A slight adjustment of the bounding value, from 2 °F/ft-lb to 2.15 °F/ft-lb, would correspond to a 5%, or 2σ bounding value. Nevertheless, there is little practical distinction to the difference of 0.15 °F/ft-lb.

††† Here the plate and forging data are analyzed together because there is no clear distinction between

the behaviors of the two product forms.

0.0#

0.1#

0.2#

0.3#

0.4#

0.5#

0.6#

0.7#

0.8#

0.9#

1.0#

-60# -40# -20# 0# 20# 40# 60# 80# 100# 120# 140#

Cumula&

ve)Proba

bility)

Transverse)4)Longitudinal)T50))[oF])


Forging:)A50842)

Forging:)A50843)

Plate:)A533B41)

Plate:)A302B)

Plate:)A302B(Mod))

All)

Ref.)[1])Method)[+30F])

0.0#

0.1#

0.2#

0.3#

0.4#

0.5#

0.6#

0.7#

0.8#

0.9#

1.0#

-60# -40# -20# 0# 20# 40# 60# 80# 100# 120# 140#

Cumula&

ve)Proba

bility)

Transverse)4)Longitudinal)T50))[oF])


Forging:)A50842)Forging:)A50843)Plate:)A533B41)Plate:)A302B)Plate:)A302B(Mod))All)Ref.)[1])Method)[+30F])



Figure 12-5. Top: Comparison of measured data for longitudinal transition slope to estimated values using the Ref. [1] procedure (black line). Bottom: Distribution of errors in the prediction of the Ref. [1] procedure for the longitudinal transition slope (values exceeding 2 °F/ft-lb indicate

non-conservative estimates).

12.5 3 °F/ft-lb transverse CVN transition slope The Ref. [1] procedure adopts a 3 °F/ft-lb transition slope as a bounding value for transversely oriented Charpy specimens. The top plot in Figure 12-6 compares values of transition slope, estimated from the tanh fits using Eq. (18), with the 3 °F/ft-lb value from the Ref. [1] procedure‡‡‡. The data demonstrate that the Ref. [1] procedure provides a conservative upper-bound estimate of the transition slope for the available data. The lower plot in Figure 12-6 ‡‡‡ Here the plate and forging data are analyzed together because there is no clear distinction between

the behaviors of the two product forms.

0.0#

0.5#

1.0#

1.5#

2.0#

2.5#

3.0#

3.5#

(100# (50# 0# 50# 100# 150# 200#

30#50%&#lb%Lon

gl.%Transi3on

%Slope

%%[oF/&#lb]%

Longitudinal%T50%%[oF]%

Forging:%A508#2%Forging:%A508#3%Plate:%A533B#1%Plate:%A302B%Plate:%A302B(Mod)%Ref.%[1]%Method%[2F/&#lb]%

0.0#

0.1#

0.2#

0.3#

0.4#

0.5#

0.6#

0.7#

0.8#

0.9#

1.0#

0.0# 0.5# 1.0# 1.5# 2.0# 2.5# 3.0# 3.5#

Cumula&

ve)Proba

bility)

Longitudinal)Transi&on)Slope)from)30<50)><lbs))[oF/><lb])

13%)of)data)non<conserva&vely)predicted)by)Ref.)[1])Method)

Forging:)A508<2)

Forging:)A508<3)

Plate:)A533B<1)

Plate:)A302B)

Plate:)A302B(Mod))

All)

Ref.)[1])Method)[2F/><lb])



illustrates that the Ref. [1] procedure conservatively predicts the longitudinal transition slope for 96% of the available data.

Figure 12-6. Top: Comparison of measured data for transverse transition slope to estimated

values using the Ref. [1] procedure (black line). Bottom: Distribution of errors in the prediction of the Ref. [1] procedure for the longitudinal transition slope (slopes exceeding 3 °F/ft-lb indicate

non-conservative estimates).

0.0#

0.5#

1.0#

1.5#

2.0#

2.5#

3.0#

3.5#

(100# (50# 0# 50# 100# 150# 200#

30#50%&#b.%Transverse%Tran

si1o

n%Slop

e%%[oF/&#lb]%

Transverse%T50%%[oF]%

Forging:%A508#2%

Forging:%A508#3%

Plate:%A533B#1%

Plate:%A302B%

Plate:%A302B(Mod)%

Ref.%[1]%Method%[3F/&#lb]%

0.0#

0.1#

0.2#

0.3#

0.4#

0.5#

0.6#

0.7#

0.8#

0.9#

1.0#

0.0# 0.5# 1.0# 1.5# 2.0# 2.5# 3.0# 3.5#

Cumula&

ve)Proba

bility)

Transverse)Transi&on)Slope)from)30950);9lbs))[oF/;9lb])

4%)of)data)non9conserva&vely)predicted)by)Ref.)[1])Method)

Forging:)A50892)Forging:)A50893)Plate:)A533B91)Plate:)A302B)Plate:)A302B(Mod))All)Ref.)[1])Method)[3F/;9lb])



13.0 Adjustments

13.1 Summary of Adjustments In Sections 7.0 through 12.0, available data collected as part of 10 CFR Part 50 Appendix H surveillance programs (as summarized in Section 6.0) were compared to the provisions of BTP 5-3 and the Ref. [1] procedure to assess the conservatism of those predictions. As summarized in Figure 13-1, some of the BTP and Ref. [1] positions were non-conservative for most of the data evaluated while others were less so. Overall the predictions for forgings were more non-conservative than for plates. This evaluation indicates the BTP and Ref. [1] procedures frequently make non-conservative predictions of the various transition temperature metrics (i.e., TNDT, T(T)50&35, RTNDT) and of USE. Consequently the data analyzed in this report was used to develop new estimates of these metrics that can be used when the Charpy and/or TNDT data is incomplete. These conservative estimates provided the basis for adjustment factors that can be used to restore conservatism to existing BTP and Ref. [1] estimates.

Figure 13-1. Summary of the percent of available data that is non-conservatively predicted by the

various BTP 5-3 and Ref. [1] positions. In Sections 7.0 through 12.0, 2σ upper bounds were fit to transition index temperature data and 2σ lower bounds were fit to USE data. In many cases clear relationships exist between the variable on which the prediction was based and the variable being predicted. In other cases the data showed little relationship between the two, and sometimes higher values of Charpy index temperature corresponded to lower values of TNDT, which is clearly an artifact of the data rather than a physical effect. To delineate between these situations the T-statistic was computed for the slope fit to the data that appeared in Sections 7.0 through 12.0. The T-statistic can be used to determine if these slope values are sufficiently large relative to the uncertainty in their estimated values to be considered significantly different, in a statistical sense, from zero (a slope of zero would indicate no effect of the X-variable upon the Y-variable). The T-statistic is calculated as the ratio of the estimated slope to the standard error of the slope estimate.

0%

20%

40%

60%

80%

100%

1.1(1&

2)

1.1(3a)

1.1(3b

)

1.1(4a)

1.1(4b

)

1.2

GE-NDT

GE-T50

GE-Slope

%-of-D

ata-Non

<Co

nservativ

ely-Pred

icted

Plate

Forging

T NDT:%1.1(1&2)%

T (T)50&35:%1.1(3a),%65%

%

T (T)50&35:%1.1(3b),%+20%°F

%

RTNDT:%1.1(4),%eq

.%(19

)%

RTNDT:%1.1(4),%eq

.%(20

)%

USE:%1.2,%65%

%

T NDT%

T (T)50&35,%+30%°F

%

Tran

si>o

n%Slop

e%

BTP%5E3% Ref.%[1]%



Calculated values above 1.64 (or, practically speaking, 2) indicate slopes that are considered significantly different from zero (at the 0.05 level). Table 13-1 summarizes the T-statistic and slope values for each of the linear fits that appeared in Sections 7.0 through 12.0;; cells containing slopes that are positive and T-statistics that exceed the critical value of 1.64 are shaded green. If both the slope and the T-statistic cells are shaded green then this suggests that the data show a clear and physically logical relationship between the predictor and predicted variables. In this situation the recommended 2σ bound varies depending on another variable (e.g., the transverse Charpy transition temperature is predicted as a function of the longitudinal Charpy transition temperature). Conversely, if either the slope is negative or the value of the T-statistic is below 1.64 this suggests that the data do not show a statistically significant / physically logical relationship between the predictor and predicted values. In these situations the mean and standard deviation values are also reported in Table 13-1;; these are used to construct a 2σ bound that is a constant for all conditions. Table 13-2 summarizes the recommended conservative estimates for all of the BTP and Ref. [1] positions that were not found to be adequately conservative relative to their predictions of the data considered herein (the results for the two provisions of the Ref. [1] procedure that are considered adequately conservative are summarized in Table 13-3). These estimates depend on which position of the BTP or Ref. [1] procedure has been used, and on the product form (i.e., plate or forging). Equations appearing in the column headed “Conservative (2σ) Estimate” can be used to replace the current BTP and Ref. [1] positions. The table also provides adjustment factors (see rightmost column) that can be added to estimates of the transition temperature or USE metrics made using the BTP or Ref. [1] procedure to make these estimates follow the 2σ bound. The formulae in the adjustment factor column are derived directly from the formulae in the “Conservative (2σ) Estimate” column;; this is just two ways of representing the same information. The following figures provide graphical depictions of these equations:

• Figure 13-2 shows the conservative (2σ) upper bounds for all of the transition temperature metrics estimated by either BTP 5-3 or Ref. [1].

• Figure 13-3 shows the adjustments that need to be added to current estimates of transition temperature that have been based on either BTP 5-3 or Ref. [1] in order to make them conservative (2σ) upper bound values.

• The top graph in Figure 13-4 shows the conservative (2σ) lower bound for USE as estimated by BTP 5-3.

• The bottom graph in Figure 13-4 shows the adjustment that needs to be added to current USE estimates based on BTP 5-3 in order to make them conservative (2σ) lower bound values.

It should be noted that under certain conditions, the BTP and Ref. [1] estimates of transition temperature and USE are more conservative than a 2σ bound;; the adjustment factors provided here also correct for this situation.



Table 13-1. Values of T for the various linear fits in Sections 7.0 through 12.0

Product Form Position Value

Predicted Value of Slope T statistic on slope value

Mean(1) of Value

Predicted [°F]

σ(1) for Value

Predicted [°F]

Plate

BTP 1.1(1) [A533B Cl. 1 only] TNDT +0.19 0.92 -10.9 15.9

BTP 1.1(3a) T(T)50&35 +0.53 7.16 -- -- BTP 1.1(3b) T(T)50&35 +0.65 5.77 -- -- BTP 1.1(4a) RTNDT +0.50 4.24 -- -- BTP 1.1(4b) RTNDT +0.59 5.38 -- -- BTP 1.2 USE +0.5937 5.26 -- --

Ref. [1] [A533B Cl. 1 only] TNDT +0.19 1.33 -10.9 15.9

Ref. [1] T(T)50 +0.69 5.66 -- --

Forging

BTP 1.1(2) [A508 Cl. 2 only] TNDT -0.52 1.87 -3.0 25.9

BTP 1.1(3a) T(T)50&35 +0.99 3.05 -- -- BTP 1.1(3b) T(T)50&35 +0.70 1.71 -- -- BTP 1.1(4a) RTNDT -0.15 0.53 +7.7 28.1 BTP 1.1(4b) RTNDT -0.01 0.03 +7.7 28.1 BTP 1.2 USE +1.435 6.91 -- -- Ref. [1]

[A508 Cl. 2 only] TNDT -0.45 1.81 -3.0 25.9

Ref. [1] T(T)50 +0.66 1.44 +36.0 44.0 (1) Mean and σ values are only given for positions where the T statistic on the slope of the line of best fit

indicates no statistically significant relationship between the predicted and predictor variables (i.e., T<1.64).



Table 13-2. Adjustments to transition temperatures and USE values estimated using the methods

in BTP 5-3 and the Ref. [1] procedure to provide conservative (2s) estimates.

Method Eq. (C)

Variable Estimated

Conservative (2s) Estimate(3) Adjustment Factor (A) to Add to (C) to Restore Conservatism(4)

Plates (applies to A302B, A302B Modified, and A533B Class 1 unless noted otherwise) BTP 1.1(1) (1) (7) TNDT TNDT = +21 °F 𝐴 = 21 − 1×𝐶 BTP 1.1(3a) (9) T(T)50&35 𝑇 r @A&C@ = 0.53×𝑇 s×A._@ @A&C@ + 44 𝐴 = 44 − 0.47×𝐶

BTP 1.1(3b) (10) T(T)50&35 𝑇 r @A&C@ = 0.65×𝑇 s @A&C@ + 62 𝐴 = 62 − 20 − 0.35× 𝐶 − 20

or, equivalently 𝐴 = 49 − 0.35×𝐶

BTP 1.1(4) (19) RTNDT 𝑅𝑇vwr = 0.50× 𝑇 s CA + 20 °F + 19 𝐴 = 19 − 0.50×𝐶 BTP 1.1(4) (20) RTNDT 𝑅𝑇vwr = 0.59×𝑇 s q@ + 13 𝐴 = 13 − 0.41×𝐶 BTP 1.2 (13) USE(T) 𝑈𝑆𝐸(r) = 0.5937×𝑈𝑆𝐸 s − 3.157 𝐴 = −3.157 − 0.0865×𝐶 Ref. [1] (1) (14) TNDT TNDT = +21 °F 𝐴 = 21 − 1×𝐶

Ref [14] (1) (16) T(T)50 𝑇 r @A = 0.69×𝑇 s @A + 62 𝐴 = 62 − 30 − 0.31× 𝐶 − 30

or, equivalently 𝐴 = 41.3 − 0.31×𝐶

Forgings (applies to A508 Class 2 and A508 Class 3 unless noted otherwise) BTP 1.1(2) (2) (8) TNDT TNDT = +49 °F 𝐴 = 49 − 1×𝐶 BTP 1.1(3a) (9) T(T)50&35 𝑇 r @A&C@ = 0.99×𝑇 s×A._@ @A&C@ + 77 𝐴 = 77 − 0.01×𝐶

BTP 1.1(3b) (10) T(T)50&35 𝑇 r @A&C@ = 0.70×𝑇 s @A&C@ + 115 𝐴 = 115 − 20 − 0.30× 𝐶 − 20

or, equivalently 𝐴 = 101 − 0.30×𝐶

BTP 1.1(4) (19) RTNDT RTNDT = +64 °F 𝐴 = 64 − 1×𝐶 BTP 1.1(4) (20) RTNDT RTNDT = +64 °F 𝐴 = 64 − 1×𝐶 BTP 1.2 (13) USE 𝑈𝑆𝐸(r) = 1.435×𝑈𝑆𝐸 s − 135.6 𝐴 = −135.6 + 1.21×𝐶 Ref [14] (2) (15) TNDT TNDT = +49 °F 𝐴 = 49 − 1×𝐶 Ref [14] (2) (16) T(T)50 T(T)50&35 = +124 °F 𝐴 = 124 − 1×𝐶

Notes 1. Applies only to A533B Class 1 plates. 2. Applies only to A508 Class 2 forgings. 3. The conservative estimates of transition temperatures are 2σ upper bounds to available data. The

conservative estimate of USE is a 2σ lower bound to available data. 4. The adjustment factor (A) is the value added to the estimate (i.e., C) of the subject variable made using

either BTP 5-3 or the Ref. [1] procedure to make it agree with the 2s bound.



Figure 13-2. Summary of conservative (2σ upper bound) transition temperature estimates for the

various BTP and Ref. [1] positions plotted as a function of the current estimates. The new estimates are plotted only over the X-axis range exhibited by current estimates of transition

temperature made using the BTP 5-3 or Ref. [1] procedures.

Current'TNDT'Es-mate''[oF]'

Adjusted

,'or'con

serva-

ve'2σ'upp

er'bou

nd,'value

''[o F]'

Current'T(T)50&35'Es-mate''[oF]'

Current'RTNDT'Es-mate''[oF]'

0"

30"

60"

90"

120"

150"

180"

*50" 0" 50" 100" 150" 200"

New$Value

$$[o F]$

Current$TNDT$Es5mate$$[oF]$

BTP$5:3$Posi5on$1.1(1):$A533B:Cl.$1$Plates$

Ref.$[1]:$A533B:Cl.$1$Plates$

BTP$5:3$Posi5on$1.1(2):$A508:Cl.$2$Forgings$

Ref$[1]:$A508:Cl.$2$Forgings$

0"

30"

60"

90"

120"

150"

180"

*50" 0" 50" 100" 150" 200"

Adjustmen

t*(ad

di.o

n)*to

*make*es.m

ate*a*2σ

*bou

nd**

[oF]*

Current*T(T)50&35*Es.mate**[oF]*

BTP*5A3*Posi.on*1.1(3a)*[65%]:*Plates*

BTP*5A3*Posi.on*1.1(3b)*[+20F]:*Plates*

Ref.*[1],**[+30F]:*Plates*

BTP*5A3*Posi.on*1.1(3a)*[65%]:*Forgings*

BTP*5A3*Posi.on*1.1(3b)*[+20F]:*Forgings*

Ref.*[1],**[+30F]:*Forgings*

0"

30"

60"

90"

120"

150"

180"

*50" 0" 50" 100" 150" 200"

New

$Value

[oF]$

Current$RTNDT$Es5mate$$[oF]$

BTP$5:3$Posi5on$1.1(4a):$Plates$

BTP$5:3$Posi5on$1.1(4b):$Plates$

BTP$5:3$Posi5on$1.1(4a):$Forgings$

BTP$5:3$Posi5on$1.1(4b):$Forgings$



Figure 13-3. Summary of adjustments (additions) to BTP and Ref. [1] index temperature estimates to make them follow a 2σ upper bound. The adjustment factors are plotted only over the X-axis range exhibited by estimates of transition temperature made using the BTP 5-3 or Ref. [1]

procedures.

Current'TNDT'Es-mate''[oF]'

Adjustmen

t'(ad

di-o

n)'to

'current'es-mate'to'm

ake'it'a'

conserva-v

e'2σ

'Upp

er'bou

nd''[

o F]'

!60$

!30$

0$

30$

60$

90$

120$

150$

!50$ 0$ 50$ 100$ 150$ 200$

Adjustmen

t*(ad

di.o

n)*to

*make*es.m

ate*a*2σ

*bou

nd**

[oF]*

Current*TNDT*Es.mate**[oF]*

BTP*5@3*Posi.on*1.1(1):*A533B@Cl.*1*Plates*

Ref.*[1]:*A533B@Cl.*1*Plates*

BTP*5@3*Posi.on*1.1(2):*A508@Cl.*2*Forgings*

Ref*[1]:*A508@Cl.*2*Forgings*

Current'T(T)50&35'Es-mate''[oF]'!60$

!30$

0$

30$

60$

90$

120$

150$

!50$ 0$ 50$ 100$ 150$ 200$

Adjustmen

t*(ad

di.o

n)*to

*make*es.m

ate*a*2σ

*bou

nd**

[oF]*

Current*T(T)50&35*Es.mate**[oF]*

BTP*5A3*Posi.on*1.1(3a)*[65%]:*Plates*

BTP*5A3*Posi.on*1.1(3b)*[+20F]:*Plates*

Ref.*[1],**[+30F]:*Plates*

BTP*5A3*Posi.on*1.1(3a)*[65%]:*Forgings*

BTP*5A3*Posi.on*1.1(3b)*[+20F]:*Forgings*

Ref.*[1],**[+30F]:*Forgings*

Current'RTNDT'Es-mate''[oF]'!60$

!30$

0$

30$

60$

90$

120$

150$

!50$ 0$ 50$ 100$ 150$ 200$

Adjustmen

t*(ad

di.o

n)*to

*make*es.m

ate*a*2σ

*bou

nd**

[oF]*

Current*RTNDT*Es.mate**[oF]*

BTP*5@3*Posi.on*1.1(4a):*Plates*

BTP*5@3*Posi.on*1.1(4b):*Plates*

BTP*5@3*Posi.on*1.1(4a):*Forgings*

BTP*5@3*Posi.on*1.1(4b):*Forgings*



Table 13-3. Assessment of conservatism of Ref. [1] procedure for estimates of Charpy energy transition curve slope for plates and forgings.

Method Variable Estimated

% non- Conservative Bounding (2s)Estimate Adjustment

to Estimate

GE Longitudinal transition slope

13%

No new estimate made. While a 2σ bound of 2.15 °F/ft-lb is suggested by the data analyzed herein, there is no practical difference between this value and that adopted by the Ref. [1] Procedure.

None needed

GE Transverse transition slope

4% No new estimate made, the current value of 3 °F/ft-lb is conservative.

None needed

Figure 13-4. Summary of new conservative (2σ) bounds (top) and adjustments (additions) to BTP USE estimates to make them follow a 2σ lower bound (bottom). The graphs are plotted only over

the X-axis range exhibited by estimates of USE made using the BTP 5-3. 13.2 Example Application of these Adjustments for BTP 5-3 Position 1.1(3) This section provides an example of how the adjustments developed in this report could be applied to correct RTNDT values estimated using BTP 5-3 Position 1.1(3). As described in Section 4.2.3, Position 1.1(3) is used when TNDT data are available but transversely oriented Charpy data is missing. Position 1.1(3) provides formulae to estimate the transverse CVN transition temperature (T(T)50&35) from the longitudinal CVN transition temperature (T(L)50&35). These estimates of T(T)50&35 are used together with the measured TNDT data to determine RTNDT using eq. (5). Figure 13-5 shows the results of these calculations, with one plot for each of the two methods described in Position 1.1(3) to estimate T(T)50&35 from the longitudinal CVN data. The graphs

0"

20"

40"

60"

80"

100"

120"

140"

0" 25" 50" 75" 100" 125" 150"

Conserva)v

e*2σ

*bou

nd*value

*[12lb

s]*

Current*BTP*USE*Es)mate**[12lbs]*

BTP*523*Posi)on*1.2:*Plates*

BTP*523*Posi)on*1.2:*Forgings*

!50$

!40$

!30$

!20$

!10$

0$

10$

0$ 25$ 50$ 75$ 100$ 125$ 150$

Adjustmen

t*(ad

di.o

n)*to

*make*BT

P*es.m

ate*a*2σ

*lower*bou

nd**[;<lbs]*

Current*BTP*USE*Es.mate**[;<lbs]*

BTP*5<3*Posi.on*1.2:*Plates*

BTP*5<3*Posi.on*1.2:*Forgings*



compare the ASME value of RTNDT, which is plotted on the horizontal axis, with the BTP 5-3 estimates of RTNDT, which are plotted on the vertical axis. Both the current estimates of BTP 5-3 and values of these estimates after adjustment to make them conservative 2σ bounds are shown (see Table 13-3 for adjustment factors). The current estimates (solid points) tend to be non-conservative, a problem that is fixed by using the adjusted factors (open points). The magnitude of the adjustment is driven by the scatter in the data on which the adjustment was based which, as noted earlier, is much larger for the forging data than it is for plates. Should these adjustment factors be viewed as too large in certain plant-specific situations, it should be noted that other methods remain available to estimate RTNDT, such as performing Charpy tests on archive material.

Figure 13-5. Example application of adjustment factors to RTNDT estimates based on BTP 5-3

Position 1.1(3).

Non$Conserva+ve,Es+mates,

Conserva+ve,Es+mates,

Non$Conserva+ve,Es+mates,

Conserva+ve,Es+mates,

!50$

0$

50$

100$

!50$ 0$ 50$ 100$

RTNDT%es(mated%using%

BTP%543,%Before%&%A<er%

Adjustment%%[oF]%

RTNDT

%per%ASME%NB%2331,%eq.%(5)%%[oF]%

BTP%543%Es(mate%

Posi(on%1.1(3a),%65%%

Forging:%Current%BTP%543%Es(mate%

Forging:%Adjusted%(+2sigma)%Es(mate%

Plate:%Current%BTP%543%Es(mate%

Plate:%Adjusted%(+2%sigma)%Es(mate%

1:1%

!50$

0$

50$

100$

!50$ 0$ 50$ 100$

RTNDT%es(mated%using%

BTP%543,%Before%&%A<er%

Adjustment%%[oF]%

RTNDT%per%ASME%NB%2331,%eq.%(5)%%[oF]%

BTP%543%Es(mate%

Posi(on%1.1(3b),%+20%oF%

Forging:%Current%BTP%543%Es(mate%

Forging:%Adjusted%(+2sigma)%Es(mate%

Plate:%Current%BTP%543%Es(mate%

Plate:%Adjusted%(+2%sigma)%Es(mate%

1:1%



14.0 Summary

Branch Technical Position (BTP) 5-3 and a similar procedure described in Ref. [1] of this report both provide various provisions useful for estimating transition temperature and upper shelf energy metrics for reactor pressure vessel steels when the data required by the American Society of Mechanical Engineers and the American Society of Testing and Materials are incomplete, which is often the case for nuclear power plants licensed before 1972. In January 2014, AREVA notified the NRC that some of these provisions might not provide conservative estimates of these metrics, as claimed by BTP 5-3. The staff investigated AREVA’s findings by assembling a database of information on unirradiated nuclear-grade steel plates and forgings reported to the NRC as part of 10 CFR 50 Appendix H surveillance programs. These source of data were selected because they are extensive, they are available in the public domain, they are directly representative of the U.S. operating fleet, and they have both raw NDTT and CVN data in both the transverse and longitudinal orientations. The analysis performed herein demonstrates that, in all but a few cases, the provisions of BTP 5-3 and the Ref. [1] procedure do not bound enough of the available data to be referred to as “conservative.” Overall, the plate data were found to be better predicted than the forging data but, depending on the specific provision of BTP 5-3 or the Ref. [1] procedure used, the amount of data that are non-conservatively predicted is as high as 66% for plates and 72% for forgings. The data assembled were therefore used to develop conservative estimates, which were defined as being 2σ (i.e., two standard deviations) from the mean of the data. The use of 2σ as a conservative estimate is consistent with the NRC’s approach in other aspects of the assessment of nuclear reactor pressure vessel integrity (e.g., Regulatory Guide 1.99, Revision 2). These estimates provide the basis for adjustment factors that can be used to modify current estimates of transition temperature and upper shelf energy made using either BTP 5-3 or the Ref. [1] procedure to restore their conservatism. In all cases, the magnitude of adjustment needed to transform these estimates to a conservative estimate for plates is considerably smaller than the adjustment needed for forgings. Also, under certain conditions, current BTP 5-3 or Ref. [1] procedure estimates are more conservative than a 2σ bound. The adjustments developed herein also correct for this situation.



15.0 Citations

[1] “Monticello Nuclear Generating Plant, Information on Reactor Vessel Material Surveillance Program,” General Electric Company, San Jose, CA, NEDO-24197, June 1979. See pp. 86-92 of the document, entitled “Appendix B: Methods for Establishing Initial Reference Temperatures (RTNDT) for Vessel Steels for Certain Plants,” ADAMS Accession No. 7910110421.

[2] American Society of Mechanical Engineers (ASME) Boiler & Pressure Vessel Code, Section III, Rules for Construction of Nuclear Facility Components, Division 1 - Subsection NB, “Class 1 Components,” 2013 Edition.

[3] ASTM Designation E 185-10, “Standard Practice for Design of Surveillance Programs for Light-Water Moderated Nuclear Power Reactor Vessels,” ASTM International, approved March 1, 2010.

[4] Code of Federal Regulations, Title 10, Energy, Part 50, “Domestic and Licensing of Production and Utilization Facilities,” §50.61, “Fracture Toughness Requirements for Protection Against Pressurized Thermal Shock Events.”

[5] Code of Federal Regulations, Title 10, Energy, Part 50, “Domestic and Licensing of Production and Utilization Facilities,” §50.61a, “Alternate Fracture Toughness Requirements for Protection Against Pressurized Thermal Shock Events.”

[6] Code of Federal Regulations, Title 10, Energy, Part 50, “Domestic and Licensing of Production and Utilization Facilities,” Appendix G, “Fracture Toughness Requirements.”

[7] Regulatory Guide 1.99, Revision 2, “Radiation Embrittlement of Reactor Vessel Materials,” U.S. Nuclear Regulatory Commission, May 1988.

[8] Regulatory Guide 1.161, “Evaluation of Reactor Pressure Vessels with Charpy-Upper Shelf Energy Less Than 50 Ft-Lb,” June 1995.

[9] ASTM Designation E1823, “Standard Terminology Relating to Fatigue and Fracture Testing,” American Society for Testing and Materials, West Conshocoken, PA.

[10] USNRC Standard Review Plan, Branch Technical Position 5-3, “Fracture Toughness Reqhirements,” ADAMS Accession No. ML070850035.

[11] AREVA letter dates January 30, 2014, AREVA Ref. NRC-14-004, ADAMS Accession No.ML14038A265.

[12] Wallin, K., and Rintamaa, R. “Statistical Re-evaluation of the ASME KIc and KIR Fracture Toughness Reference Curves,” 23rd MPA-Seminar, Stuttgart Germany, October 1-2, 1997.

[13] A. K. Richardson, W. L. Server & W. G. Reuter, “Adequacy of Estimates and Variability of Fracture-related Properties for Reactor Pressure Vessel Materials,” International Journal of Pressure Vessels and Piping, 19 (1985) 299-315

[14] P. K. Nagata, W. G. Reuter, A. K. Richardson, and W. L. Server, “Correlation of Charpy V-Notch Data with Fracture Toughness Parameters for SA-533B-1 and SA-508-2 Steels,” EG&G Idaho, Inc., EGG-MS-6310, December 1983.

[15] Code of Federal Regulations, Title 10, Energy, Part 50, “Domestic and Licensing of Production and Utilization Facilities,” Appendix H, “Reactor Vessel Material Surveillance Program Requirements.”

[16] ASTM Designation E23, Standard Test Methods for Notched Bar Impact Testing of Metallic Materials

[17] ASTM Designation: E2215, Standard Practice for Evaluation of Surveillance Capsules from Light-Water Moderated Nuclear Power Reactor Vessels

[18] ASTM Designation: E 208, Standard Test Method for Conducting Drop-Weight Test to Determine Nil-Ductility Transition Temperature of Ferritic Steels

[19] Reactor Embrittlement Archive Project, https://reap.ornl.gov/register.



[20] USNRC Memorandum from C.Z. Serpan to C.Y. Cheng entitled “Ratio of Transverse to Longitudinal Orientation Charpy Upper Shelf Energy,” 25 June 1990, ADAMS ML14324A919.

assessment of predictions of rtndt and upper shelf energy ... · technical)letter)report)...

Documents