RS-23-056, Response to Request for Additional Information to Braidwood Station, Unit 1, and Byron Station, Unit 1, for Steam Generator License Renewal Response to Commitment 10
| ML23110A124 | |
| Person / Time | |
|---|---|
| Site: | Byron, Braidwood  |
| Issue date: | 04/20/2023 |
| From: | Lueshen K Constellation Energy Generation |
| To: | Office of Nuclear Reactor Regulation, Document Control Desk |
| Shared Package | |
| ML23110A123 | List: |
| References | |
| RS-23-056 | |
| Download: ML23110A124 (1) | |
Text
4300 Winfield Road Warrenville, IL 60555 630 657 2000 Office Attachments 4 and 5 contain Proprietary Information. Withhold from public disclosure under 10 CFR 2.390. When separated, this document is decontrolled.
Proprietary Information - Withhold from Public Disclosure Under 10 CFR 2.390 RS-23-056 April 20, 2023 U. S. Nuclear Regulatory Commission ATTN: Document Control Desk Washington, DC 20555-0001 Braidwood Station, Units 1 Renewed Facility Operating License Nos. NPF-72 NRC Docket Nos. STN 50-456 Byron Station, Unit 1 Renewed Facility Operating License No. NPF-37 NRC Docket No. STN 50-454
Subject:
Response to Request for Additional Information to Braidwood Station, Unit 1, and Byron Station, Unit 1, for Steam Generator License Renewal Response to Commitment 10
References:
- 1. Letter from K. Lueshen (Constellation Energy Generation, LLC) to U.S.
NRC, Braidwood and Byron Stations, Unit 1 Steam Generator License Renewal Response to Commitment 10 - Evaluation of Possible PWSCC Crack Initiation and Propagation in the Steam Generator Channel Head Assembly and Tube-to-Tubesheet Welds, dated June 7, 2022
- 2. Email from C. Tyree (U.S. NRC) to K. Lueshen (Constellation Energy Generation, LLC),
Subject:
Byron and Braidwood Commitment #10 -
Request for Additional Information, dated March 6, 2023 In Reference 1, Constellation Energy Generation, LLC (CEG) submitted a response to Braidwood and Byron Stations, Unit 1 Steam Generator License Renewal Commitment 10. The NRC conducted an audit on October 3 - November 10, 2022, to gain a better understanding of CEGs selected options to fulfill Commitment 10.
In Reference 2, the NRC requested additional information to complete the review of a response to Commitment 10 of the Braidwood Station, Unit 1 and Byron Station, Unit 1 safety evaluation report, NUREG-2190 Volume 1 (ML15350A038) and Volume 2 (ML15350A041). Attachment 4 to this letter provides the additional information requested, and Attachment 5 contains a revised BWXT report supporting the responses in Attachment 4. Attachments 1 and 2 are non-proprietary versions of Attachments 4 and 5, respectively, where the proprietary information has been redacted.
April 20, 2023 U.S. Nuclear Regulatory Commission Page 2 Attachments 4 and 5 contain Proprietary Information. Withhold from public disclosure under 10 CFR 2.390. When separated, this document is decontrolled.
Attachments 4 and 5 contain information proprietary to BWXT and is supported by an Affidavit signed by BWXT, the owner of the information. The Affidavit, found in Attachment 3, sets forth the basis on which the information may be withheld from public disclosure by the Nuclear Regulatory Commission (NRC) and addresses with specificity the considerations listed in paragraph (b)(4) of Section 2.390 of the Commissions regulations. Accordingly, it is respectfully requested that the information which is proprietary to BWXT be withheld from public disclosure in accordance with 10 CFR Section 2.390.
There are no regulatory commitments contained in this letter. Should you have any questions concerning this letter, please contact Brian Seawright at (630) 657-2814.
I declare under penalty of perjury that the foregoing is true and correct. Executed on the 20th day of April 2023.
Respectfully, Kevin Lueshen Sr. Manager - Licensing Constellation Energy Generation, LLC Attachments:
- 1. Response to Request for Additional Information (Non-Proprietary Version)
- 2. BWXT Report Number M2004-SR-01, Revision 2 (Non-Proprietary Version)
- 4. Response to Request for Additional Information (Proprietary Version)
- 5. BWXT Report Number M2004-SR-01, Revision 2 (Proprietary Version) cc:
NRC Regional Administrator - Region III NRC Senior Resident Inspector - Braidwood Station NRC Senior Resident Inspector - Byron Station Illinois Emergency Management Agency - Division of Nuclear Safety
- Lueshen, Kevin Digitally signed by Lueshen, Kevin Date: 2023.04.20 05:50:10 -05'00'
ATTACHMENT 1 Response to Request for Additional Information (Non-Proprietary Version)
BWXT Canada Ltd.
BWXT Memo: M2302-MEMO-001-NP R00 Date:
April 17, 2023
Subject:
Responses to NRC RAI C10-1 and RCI C10-1 and -2
Reference:
FORWARD BWXT Report M2004-SR-01, "BYRON / BRAIDWOOD UNIT 1 FLAW TOLERANCE EVALUATION AT PRIMARY HEAD / TUBESHEET / DIVIDER PLATE TRIPLE POINT ANALYSIS REPORT" This document contains BWXT Canada Ltd. (BWXT) proprietary information and data which has been identified by brackets. Coding (a, band c) associated with the brackets sets forth information which is considered proprietary.
The proprietary information and data contained within the brackets in this report were obtained at considerable BWXT expense and its release could seriously affect our competitive position. This information is to be withheld from public disclosure in accordance with the Rules of Practice 10 CFR 2.390(a)(4) and the information presented herein is safeguarded in accordance with 10 CFR 2.390.
Withholding of this information does not adversely affect the public interest.
This information has been provided for your internal use only and should not be released to persons or organizations outside the Directorate of Regulation and the Advisory Committee on Reactor Safeguards (ACRS) without the express written approval of BWXT. Should it become necessary to release this information to such persons as part of the review procedure, please contact BWXT, which will make the necessary arrangements required to protect the Company's proprietary interests.
Proprietary information is identified and bracketed. For each of the bracketed locations, the reason for the proprietary classification is provided, using a standardized system. The proprietary brackets are labeled with three (3) different letters, "a", "b", and "c" which stand for:
- a. The information reveals the distinguishing aspects of a process or component, structure, tool, method, etc. The prevention of its use by BWXT's competitors, without license from BWXT, gives BWXT a competitive economic advantage.
- b. The information is trade secrets or commercial information obtained from a third party and has been provided to BWXT in confidence.
- c. The information, if used by a competitor, would reduce the competitor's expenditure of resources or improve the competitor's advantage in the design, manufacture, shipment, installation, assurance of quality, or licensing of a similar product.
58 1 Coronation Boulevard CD.mbndge, Ontario Canada, N 1 R 5V3 t: +1519.6212130 I +1 519621.9681 wwwbwxt.com People Strong INNOVATION DRIVEN >
BWXT Memo: M2302-MEMO-001-NP R00 2 l P a g e The following responses are provided to address the NRC requests documented in [R-1]. These requests and responses pertain to BWXT Report M2004-SR-01 R01 [R-2].
RAI C10-1 Issue Section 7.3, End-of-Life Flaw Size, in Revision 1 of BWXT Report No. M2004-SR-01, Byron /
Braidwood Unit 1 Flaw Tolerance Evaluation at Primary Head / Tubesheet / Divider Plate Triple Point Analysis Report, states that a value of ((
was used for the upper shelf fracture toughness (KIC) of the steam generator primary head base material and is based on the equation in A-4200 and Figure A-4200-1 in Section XI of the American Society of Mechanical Engineers Boiler and Pressure Vessel Code (ASME Code). However, the staff is unclear on why this value is appropriate.
Request Please discuss:
- 1. The basis for using ((
)) by addressing the following, (i) the impacts of the toughness selection on the analysis conservatism as compared to the analyses in EPRI Report 3002002850, Steam Generator Management Program: Investigation of Crack Initiation and Propagation in Steam Generator Channel Head Assembly, which uses a value of 200 ksi-¥in for the same material; (ii) it is unclear to the staff how the technical paper1 referenced in the audit shows that KIC would be at least ((
)) for all forgings; and (iii) according to PVP2011-57173, A Proposal for the Maximum KIC for Use in ASME Code Flaw and Fracture Toughness Evaluations, even 200 ksi-¥in can be a non-conservative value, especially at higher temperatures.
BWXT Response:
i)
The analysis performed in BWXT Report No. M2004-SR-01 [R-2] has some significant conservatism compared to the analysis in EPRI Report 3002002850.
Some of the larger sources of conservatism are discussed below. These sources of conservatism, if removed, would lead to a lower final crack size and therefore lower KI which would offset any potential non-conservatism for the acceptance criteria based on the KIC value. The BWXT Report M2004-SR-01 [R-2] is revised (Rev. 02) to partially remove the conservatism associated with item c) and the results are shown acceptable using an upper shelf fracture toughness of 200 ksi ¥in.
a.
[
BWXT Memo: M2302-MEMO-001-NP R00 3 l P a g e
]a b.
The flaw modeled between the divider plate and the tubesheet, which leads to more load passing through the primary head wall and therefore higher stresses is conservatively considered as being approximately [
]a of the steam generator radius in BWXT Report No. M2004-SR-01, which is larger than considered in EPRI Report 3002002850 (approximately one-quarter of the steam generator radius per Section 4.3.1 of EPRI Report 3002002850).
c.
[
]a
[
]a
BWXT Memo: M2302-MEMO-001-NP R00 4 l P a g e The BWXT Report M2004-SR-01 [R-2] is revised (Rev. 02) to remove this one source of conservatism and consider the upper shelf fracture toughness of 200 ksi
¥in. Other sources of conservatism identified above are not removed. The EPRI Report 3002002850 modeled the cladding directly and so did not have the initial conservatism of [
]c ii)
The technical paper referenced is from Japan Steel Works (JSW) [R-4]. [
]c The paper demonstrates that JSW is capable of producing forgings that exceed 220 ksi-¥in in the timeframe when the particular forgings for the Byron and Braidwood Unit 1 RSGs were produced. In addition, the paper indicates that the RTNDT values for the steels are -25°C (-12°F) which is lower than the [
]b specified in the design specification and considered in the analysis in BWXT Report No. M2004-SR-01 which indicates improved non-ductile toughness for the material.
Please note that BWXT Report No. M2004-SR-01 [R-2] is revised (Rev. 02) to consider 200 ksi ¥in.
iii)
The previous EPRI Report 3002002850 did not require upper shelf fracture toughness below 200 ksi-¥in to be considered.
c
BWXT Memo: M2302-MEMO-001-NP R00 5 l P a g e Please note that BWXT Report No. M2004-SR-01 [R-2] is revised (Rev. 02) to consider 200 ksi ¥in.
2.
Regarding the use of [
], if a lower fracture toughness value was determined to be appropriate based on the response to 1 above, what would be the effect on the end-of-life flaw acceptability if the critical crack size was adjusted according to [
]?
BWXT Response:
The latest revision (Rev. 02) of BWXT Report M2004-SR-01 [R-2] shows that considering a lower fracture toughness value of 200 ksi ¥in and [
]c that the end of life flaw is acceptable for the Level C/D transients where the [
]c is used. The [
]c as per Item 1 i) c) is also considered in this assessment. [
]c The results for the circumferential flaw are shown below. The axial flaw results are driven by lower stresses and therefore did not need to consider the [
]c Therefore, they remain acceptable.
c
BWXT Memo: M2302-MEMO-001-NP R00 6 l P a g e RCI C10-1 Issue:
Section 5.0, Materials and Properties, in Revision 1 of BWXT Report No. M2004-SR-01 states that the material properties used in the flaw tolerance evaluation were taken from Part D in Section II of the ASME Code. However, during the audit, CEG stated that the material properties were taken from Division 1 Appendices in Section III of the ASME Code.
Request:
Please confirm that the material properties used for the flaw tolerance evaluation were taken from Division 1 Appendices in Section III of the ASME Code, not Part D in Section II of the ASME code as stated in Section 5.0 of Revision 1 of BWXT Report No. M2004-SR-01 (Attachments 5 (non-proprietary) and 6 (proprietary)) of the response to Commitment 10, dated June 7, 2022.
BWXT Response:
The yield and tensile strength values used are shown in Section 8.0 of M2004-B003.
These values have been taken from Section III, Division 1 - Appendices 1986 Edition.
M2004-SR-01 contained a typo as it should be pointing to Section III, Division 1 -
Appendices, not Part D. This error has been corrected in the latest revision (Rev. 02) of [R-2].
RCI C10-2 Issue:
The Byron Unit 1 and Braidwood Unit 1 checklist in Appendix A of Revision 2 of BWXT Report No. M1702-LR-01, Steam Generator Divider Plate Design for Possibility of Cracking, states that the minimum channel head thickness is ((
However, during the audit, CEG stated that the minimum channel head thickness is ((
)).
Request:
Please confirm that the minimum channel head thickness is ((
)), not ((
))
as stated in Appendix A of Revision 2 of BWXT Report No. M1702-LR-01 (Attachment 7 (proprietary)) of the response to Commitment 10 dated June 7, 2022.
BWXT Response:
The primary head (channel head) near the tubesheet juncture is [
]a as shown in Figure 1.2 of M2004-B001 (variable "HST") [R-2]. This is the minimum thickness in the juncture. The thickness transitions to [
]a for the remainder of the primary head.
Path 3, 4, 7 and 8 have the lower thickness of [
]a as they are near the minimum wall thickness. Path 1, 2, 5 and 6 are above the radius and therefore have a higher wall thickness. This can be seen from Figure 9.11 in M2004-B002.
BWXT Memo: M2302-MEMO-001-NP R00 7 l P a g e The M1702-LR-01 report is not used in the flaw tolerance analysis documented in [R-2]. It reports that the minimum channel head thickness is [
]a, which is the value generally applicable to the head. This was stated in the context of completing a questionnaire to confirm that the item in question exceeds the thickness of 5.2 inches that was analyzed for EPRI in a previous flaw tolerance evaluation [R-3]. A local thinner allowance is provided for the primary head at the tubesheet ( [
]a) to accommodate for local grinding and fit-up of the weld. However, this is still greater than the limit of 5.2 inches in the questionnaire and therefore there is no impact on the conclusions of M1702-LR-01 or any of the analysis documented in M2004-SR-01.
Prepared by:
Derek Hartman Manager, Engineering Qualification and Analysis BWXT Canada Approved by:
Steve Fluit Manager, Engineering Services BWXT Canada
References:
[R-1]
Braidwood Station, Unit 1 and Byron Station, Unit 1 Request for Additional Information - Steam Generator License Renewal Response to Commitment 10 - Docket Nos. 50-456 and 50-454.
[R-2]
BWXT Report M2004-SR-01 R01, BYRON / BRAIDWOOD UNIT 1 FLAW TOLERANCE EVALUATION AT PRIMARY HEAD / TUBESHEET / DIVIDER PLATE TRIPLE POINT ANALYSIS REPORT.
[R-3]
EPRI Report 3002002850, Steam Generator Management Program: Investigation of Crack Initiation and Propagation in the Stream Generator Channel Head Assembly, October 2014.
[R-4]
Suzuki, K et al, Application of high strength MnMoNi steel to pressure vessels for nuclear power plant, Nuclear Engineering and Design 206 (2001), 261-278.
Digitally signed by Derek Hartman Date: 2023.04.17 10:25:59 -04'00' Digitally signed by Steve Fluit Date: 2023.04.17 10:33:06 -04'00'
ATTACHMENT 2 BWXT Report Number M2004-SR-01 Revision 2 (Non-Proprietary Version)
BWXT Canada Ltd.
Page 1 of 55 ELECTRIC POWER RESEARCH INSTITUTE BYRON / BRAIDWOOD UNIT 1 FLAW TOLERANCE EVALUATION AT PRIMARY HEAD / TUBESHEET / DIVIDER PLATE TRIPLE POINT ANALYSIS REPORT (NON-PROPRIETARY)
BWXT CANADA REPORT NO.: M2004-SR-01-NP REVISION 2 APRIL 2023 Engineering Specification: 18-1229648-008 Prepared By:
Date: _See Electronic Signature__
D. Hartman, P. Eng.
Manager, Engineering Analysis and Qualification Verified By:
Date: _See Electronic Signature__
A. Cameron, P. Eng Engineering Analyst Approved By:
Date: __See Electronic Signature__
R. MacEacheron, P. Eng.
Project Engineer Approved By:
Date: _See Electronic Signature__
S. Fluit, P. Eng.
Manager, Engineering Services 2023 BWXT CANADA LTD. ALL RIGHTS RESERVED.
This document is the property of BWXT Canada Ltd. (BWXT Canada).
Digitally signed by Derek Hartman Date: 2023.04.12 08:13:07
-04'00' Digitally signed by Adriana Cameron Date: 2023.04.12 08:33:33 -04'00' Digitally signed by Robert G MacEacheron Date: 2023.04.13 14:06:54 -04'00' Project Engineer Digitally signed by Steve Fluit Date: 2023.04.17 10:24:54
-04'00'
M2004-SR-01-NP, Rev. 2 Page 2 BWXT Canada Ltd.
INDEPENDENT DESIGN VERIFICATION BY DESIGN REVIEW NEF008 Rev. 02 Design Review Verification Criteria (as applicable)
Rev. 0 Rev. 1 Rev. 2 Rev. 3 Rev. 4 Rev. 5
- 1. Are the design inputs (including customer specification requirements and other customer supplied inputs, drawings or other analysis) correctly selected and incorporated into the design?
Yes Yes Yes
- 2. Are the design inputs (including customer specification requirements and other customer supplied inputs, drawings or other analysis) verified?
Yes Yes Yes
- 3. Are verified customer supplied design inputs located in either the CIS or project services database?
Yes Yes Yes
- 4. Are assumptions necessary to perform the design activity reasonable and adequately described? Where necessary, are the assumptions identified for subsequent reverification when the detailed design activities are complete?
Yes Yes Yes
- 5. Is the design method and computer program(s) used appropriate?
Yes Yes Yes
- 6. Were all design inputs correctly incorporated into the design?
Yes Yes Yes
- 7. Is the design output reasonable compared to design input?
Yes Yes Yes
- 8. Are the necessary design inputs and verification requirements for interfacing organizations specified in the design documents or in supporting procedures or instructions?
N/A N/A N/A Rev Verified By Date Rev Verified By Date 0
A. Cameron 2021-08-19 3
1 A. Cameron 2021-10-07 4
2 See Electronic Signature 5
Digitally signed by Adriana Cameron Date: 2023.04.12 08:33:57 -04'00'
M2004-SR-01-NP, Rev. 2 Page 3 BWXT Canada Ltd.
LIST OF REVISIONS Rev. Sec. / Page Description 0
All Original Release. See M2004-SR-01 report.
1 All Issued in conjunction with M2004-SR-01 Rev. 1. This is a non-proprietary version of that report and the contents are identical with the exception of redactions.
2 All Issued in conjunction with M2004-SR-01 Rev. 2. This is a non-proprietary version of that report and the contents are identical with the exception of redactions.
M2004-SR-01-NP, Rev. 2 Page 4 BWXT Canada Ltd.
TABLE OF CONTENTS 1.0 ABSTRACT................................................................................................................................................... 5
2.0 INTRODUCTION
.......................................................................................................................................... 7 3.0 ACCEPTANCE CRITERIA............................................................................................................................ 8 4.0 LOADING CONDITIONS.............................................................................................................................. 9 5.0 MATERIALS AND PROPERTIES............................................................................................................... 12 6.0 TRANSIENT STRESSES........................................................................................................................... 13 7.0 FATIGUE CRACK GROWTH ANALYSIS................................................................................................... 15 8.0 PRIMARY STRESS ANALYSIS.................................................................................................................. 23 9.0 VERIFICATION OF ASSUMPTIONS.......................................................................................................... 24
10.0 CONCLUSION
S.......................................................................................................................................... 24
11.0 REFERENCES
, DESIGN DRAWINGS AND COMPUTER CODES........................................................... 25 12.0 LIST OF DETAILED ANALYSIS CALCULATIONS..................................................................................... 27 13.0 FIGURES.................................................................................................................................................... 28
M2004-SR-01-NP, Rev. 2 Page 5 BWXT Canada Ltd.
FORWARD This document contains BWXT Canada Ltd. (BWXT) proprietary information and data which has been identified by brackets. Coding (a, b and c) associated with the brackets sets forth information which is considered proprietary.
The proprietary information and data contained within the brackets in this report were obtained at considerable BWXT expense and its release could seriously affect our competitive position. This information is to be withheld from public disclosure in accordance with the Rules of Practice 10 CFR 2.390(a)(4) and the information presented herein is safeguarded in accordance with 10 CFR 2.390.
Withholding of this information does not adversely affect the public interest.
This information has been provided for your internal use only and should not be released to persons or organizations outside the Directorate of Regulation and the Advisory Committee on Reactor Safeguards (ACRS) without the express written approval of BWXT. Should it become necessary to release this information to such persons as part of the review procedure, please contact BWXT, which will make the necessary arrangements required to protect the Companys proprietary interests.
Proprietary information is identified and bracketed. For each of the bracketed locations, the reason for the proprietary classification is provided, using a standardized system. The proprietary brackets are labeled with three (3) different letters, a, b, and c which stand for:
a.
The information reveals the distinguishing aspects of a process or component, structure, tool, method, etc. The prevention of its use by BWXTs competitors, without license from BWXT, gives BWXT a competitive economic advantage.
b.
The information is trade secrets or commercial information obtained from a third party and has been provided to BWXT in confidence.
- c. The information, if used by a competitor, would reduce the competitors expenditure of resources or improve the competitors advantage in the design, manufacture, shipment, installation, assurance of quality, or licensing of a similar product.
M2004-SR-01-NP, Rev. 2 Page 6 BWXT Canada Ltd.
1.0 ABSTRACT This report presents the flaw tolerance evaluation at the triple point (intersection of the divider plate, primary head and tubesheet) of the primary head assembly for the Bryon / Braidwood Unit 1 Replacement Steam Generators (RSG). The evaluation demonstrates the structural integrity of the RSG primary head wall in the presence of a postulated crack at the triple point that is hypothesized to propagate from the divider plate assembly through the cladding into the primary head wall. Both axial and circumferential flaws are considered. This report is prepared to demonstrate that cracking in the triple point region due to primary water stress corrosion cracking is not a concern; to avoid in-service Non-Destructive Examination (NDE) of this region and to support Exelons license renewal efforts. This report is prepared to ensure that the Bryon /
Braidwood Unit 1 RSGs are analyzed using a similar approach as EPRI Report 3002002850 [8] which was accepted by the NRC as substantiating that visual examination of divider plate to tubesheet welds are adequate to ensure structural integrity of the steam generator channel head. This evaluation is completed in accordance with the specified criteria of ASME Boiler and Pressure Vessel Code,Section XI, 2017 Edition
[4]. This is a document approved for incorporation by reference as per 10CFR50.55(a)(1)(ii)(c)(55). A code reconciliation to the 2007 Edition with 2008 Addenda and 2013 Edition is performed for the acceptance criteria.
Both classical techniques and FE analysis with ANSYS [5] are used in the analyses. The analysis concludes that:
1.
All components meet the ASME Code Section XI requirements for the postulated crack under normal (including upset and test) conditions considering the end-of-life flaw size.
2.
All components meet the ASME Code Section XI requirements for the postulated crack under emergency and faulted conditions considering the end-of-life flaw size.
M2004-SR-01-NP, Rev. 2 Page 7 BWXT Canada Ltd.
2.0 INTRODUCTION
The divider plate seat bar / weld build-up potentially has some susceptibility to primary water stress corrosion cracking (PWSCC), based on the conclusions of EPRI Report 3002002850 [8] and as discussed in Section 5.0. As a result, it is postulated that a crack may initiate in the divider plate weld build-up and then propagate into the cladding of the primary head at the triple point (intersection of the divider plate, primary head and tubesheet) due to PWSCC. It is further hypothesized that the crack can then propagate through the primary head wall thickness due to fatigue crack growth. The locations of the cracks and the triple point geometry can be seen in Figure 6. The flaw tolerance evaluation in this report considers the growth of this postulated planar flaw over the design life of the Byron Unit 1 and Braidwood Unit 1 RSGs. The analysis approach closely follows the approach used in EPRI Report 3002002850 [8], noting that only the flaw evaluation of the primary head is performed. Both axial and circumferential flaws are considered.
A postulated flaw in the divider plate weld build-up is included in a three dimensional finite element model of the primary head assembly, which can be seen in Figure 1. This postulated flaw is conservatively considered as being approximately [
]a of the steam generator radius, which is larger than considered in EPRI Report 3002002850 [8]. The flaw is modeled from near the primary head inside surface at the triple point towards the centre of the tubesheet. This finite element model is then used for all Level A to D transients to calculate the through-wall thickness stress distribution at the triple point due to pressure and thermal loading. More details on the finite element model and the thermal transient analysis are given in Section 6.0.
The initial crack size in the primary head is considered to be equal to the primary head cladding thickness in depth and the width of the divider plate weld build-up in length. This initial crack size is then considered in a crack growth analysis in accordance with ASME Boiler and Pressure Vessel Code (B&PVC),Section XI, 2017 Edition, Non-Mandatory Appendix A [4]. The stress distributions through the primary head wall thickness for all Level A and B transients are used to propagate the crack for the design life of the RSG. Self-equilibrating residual stress due to welding is also added to the stresses due to pressure and thermal loading for each transient. These stresses are used to calculate the Stress Intensity Factor (KI). Postulated circumferential and axial flaws on the inside surface of a cylinder are both considered using standard formulations from Non-Mandatory Appendix A [4]. The growth of these two crack types is modeled using a Paris Law fatigue crack growth model in accordance with Non-Mandatory Appendix A [4]. More details on the crack growth analysis are given in Section 7.0.
From the fatigue crack growth analysis, the final flaw size (af and lf) is known at the end of the RSG life. With this final flaw size, the acceptability of the flaw is assessed per the acceptance criteria of IWB-3600 [4]. The maximum stress intensity factor for each transient, including normal and emergency and faulted conditions, at the final end-of-life flaw size geometry is compared against the acceptance criteria. Details can be seen in Section 7.3.
The primary stress criteria per NB-3000 [2] are also verified with local area reduction in the primary head due to the final crack geometry. [
]a More details on the primary stress evaluation are given in Section 8.0.
The report conclusions are described in Section 10.0. The references, design drawings and computer codes used in the detailed analysis calculations included in this report are described in Section 11.0. These detailed analysis calculations are identified in Section 12.0. All figures mentioned in this report are contained in Section 13.0.
M2004-SR-01-NP, Rev. 2 Page 8 BWXT Canada Ltd.
3.0 ACCEPTANCE CRITERIA The acceptance criteria of the ASME Code Section XI, IWB-3600 [4] are used to show the pressure boundary component acceptability. The acceptability criteria for ferritic steel components, 4 in and greater in thickness is given in IWB-3610 [4]. The flaw category is Category 2, surface flaw in both the cladding and ferritic material, as per IWB-3610 [4]. A code reconciliation is given in Section 3.3 for the 2007 Edition with 2008 Addenda and 2013 Edition.
3.1 Flaw Size A flaw size that exceeds the size requirements of IWB-3500 [4], is acceptable if the following conditions are met as per IWB-3612 [4], as specified per IWB-3610(d)(1) [4].
KI < KIC / ¥10 For normal conditions (including upset and test)
KI < KIC / ¥2 For emergency and faulted conditions Where:
KI is the applied stress intensity factor for the flaw dimensions af and lf.
KIC is the fracture toughness based on crack initiation for the corresponding crack tip temperature.
af is the end of evaluation period flaw depth lf is the end of evaluation period flaw length 3.2 Primary Stress As per IWB-3610(d)(2) [4], the primary stress limits of NB-3000 [2] must be met, assuming a local area reduction of the pressure retaining membrane equal to the area of the flaw. There are no requirements on secondary stresses or fatigue usage factors specified in IWB-3600.
3.3 ASME Code Reconciliation Exelon has Nuclear Regulatory Commission (NRC) approval to use ASME Section XI, 2007 Edition with 2008 Addenda [14] for Bryon and ASME Section XI, 2013 Edition [15] for Braidwood for in-service inspection activities. The evaluation documented in this report was compared to ASME Section XI, 2017 Edition [4]. The relevant Paragraph in Section XI, 2017 edition [4], used to evaluate the flaw, is IWB-3610
- Analytical Evaluation of Planar Flaws, Acceptance Criteria for Ferritic Steel Components 4 in (100 mm) and Greater in Thickness. Upon comparing the requirements from this paragraph for the earlier Code Editions [14] [15] with the later Code Edition [4], it is concluded that there are no changes in technical requirements. Therefore, the requirements of the earlier editions (2008A and 2013E) [14] [15] are met.
M2004-SR-01-NP, Rev. 2 Page 9 BWXT Canada Ltd.
4.0 LOADING CONDITIONS 4.1 Transient Conditions The transient conditions for the Byron / Braidwood Unit 1 Replacement Steam Generators (RSGs) at 3672 MWt MUR uprate conditions are specified in the CDS [1]. These Level A and B transient conditions have been analyzed for the steam generator in B&W Canada Report 236R-SR-01 [10], which is the Analysis of Record for the Byron / Braidwood Unit 1 RSGs. As a result, the same transient analysis files are used in this analysis. [
]a The transients [
]a analyzed can be seen in Table 1.
The primary side temperature for the primary hydrotest transient has been modified from the transients in B&W Canada Report 236R-SR-01 [10] to reflect the field hydrotest minimum temperature of [
]b. The full [
]b cycles have been considered as field hydrotests. Similarly, the secondary side temperature for the secondary hydrotest transient has been modified from the transients in B&W Canada Report 236R-SR-01 [10] to reflect the field hydrotest minimum temperature of [
]b. The full [
]b cycles have been considered as field hydrotests.
The thermal and structural analysis of the [
]a.b Level A and B (normal, upset and test) transients listed in Table 1 is performed as discussed in Section 6.2. The bounding Level C and D (emergency and faulted) transients are listed in Table 2 and the structural analysis is performed as discussed in Section 6.2.
[
]a
M2004-SR-01-NP, Rev. 2 Page 10 BWXT Canada Ltd.
Table 1 Level A and B Transients for Normal (including Upset and Test) Conditions a,b
M2004-SR-01-NP, Rev. 2 Page 11 BWXT Canada Ltd.
Table 2 Level C and D Transient (Emergency and Faulted) Conditions a,b
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5.0 MATERIALS AND PROPERTIES The material designations for the components for the Byron/Braidwood Unit1 RSGs are specified in the B&W Canada Drawing 7720A035 [7] and summarized in Table 3. Details of material mechanical properties used in a specific component/assembly analysis are given in the corresponding calculation for that component/assembly. The properties are taken from the ASME B&PVC Section III, Appendices [3]. The reference nil ductility temperature (RTNDT) for the primary head material is [
]b [1, Section 3.5.1]. A corrosion allowances of [
]b is considered for the shell secondary side only [6][1, Section 3.5.5].
The divider plate seat bar / weld build-up is constructed from [
]c. The chromium composition for this material is [
]a,c [3]. Based on the Section 3.7 of EPRI Report 3002002850 [8],
the resistance to Primary Water Stress Corrosion Cracking (PWSCC) is related to the chromium content of the material. Chromium contents below 24% can have PWSCC occur in nominal environments but chromium contents at 20% or higher are quite resistance to cracking. Therefore, the divider plate seat bar / weld build-up could have some susceptibility to PWSCC but its resistance would be fairly high. As a result, a crack is postulated to occur in this weld build-up due to PWSCC and as such is analyzed in this report.
Table 3 Component Materials Component Material Primary Head, Tubesheet
[
]c Primary Divider Plate Seat Bar (1)
[
]c Primary Divider Plate
[
]c Secondary Shell
[
]c Notes:
1)
[
]c The [
]c material is one of the materials listed in A-4200 [4] from which the data was derived and therefore the material properties and fracture toughness curve given in A-4300 and A-4200 [4]
respectively are applicable. An upper shelf KIC value of [
]c is considered in the analysis [8].
For WRC175 analysis where minimum properties are not conservative, the actual yield and ultimate strength values from certified material test reports (CMTRs) has been considered, with conservative values selected from amongst the data.
M2004-SR-01-NP, Rev. 2 Page 13 BWXT Canada Ltd.
6.0 TRANSIENT STRESSES 6.1 Finite Element Model A 3D half-symmetrical primary head / tubesheet / divider plate / secondary shell assembly FE model of the Byron / Braidwood Unit 1 Replacement Steam Generator is employed for transient and structural analysis.
The FE model is developed using ANSYS [5] and is documented in BWXT Canada Calculation M2004-B001.
The developed FE model is shown in Figure 1, which includes the primary head, tubesheet, divider plate, and secondary shell with a sufficient extension length. [
]a The inner perforated region of the tubesheet is represented with equivalent solid properties
[
]a. Detailed dimensions can be seen in Figure 2 to Figure 4. The materials for the model are as discussed in Section 5.0 and listed in Table 3. Figure 5 and Figure 6 show the FE model with the material colours. As shown in Figure 7, a divider plate crack from divider plate edge toward the tubesheet centre is modelled. This is the assumed crack in the divider plate to tubesheet weld due to PWSCC, as detailed in Section 2.0. This crack then propagates into the cladding and primary head wall through fatigue crack growth. [
]a A crack at the divider plate edge provides results at the triple-point that are bounding compared to a similar crack located centrally along the divider plate.
6.2 Transient Thermal and Structural Analysis The FE model described in Section 6.1 is used for the transient and structural analysis of the primary head assembly. The following is the procedure that is used. This procedure is documented in BWXT Canada Calculation M2004-B002.
[
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]a
[
]a
[
]a
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7.0 FATIGUE CRACK GROWTH ANALYSIS 7.1 Analysis Overview The following is a brief overview of Non-Mandatory Appendix A [4] as it pertains to the flaws and stresses considered in the evaluation of this report. For a more detailed description of the process for analytical evaluation of flaws, Non-Mandatory Appendix A [4] should be consulted.
The flaw shape is considered as an elliptical planar area surface flaw with the initial depth (a) of the crack equal to the cladding thickness on the primary head (0.2) and the initial length of the crack (l) equal to the width of the divider plate weld build-up at the triple point (2.0). This shape is in accordance with A-2000 [4].
This corresponds to a longer flaw than if the aspect ratio (a/l) of 0.167 as recommended by L-3211(a) [4] was used. An illustration of the surface flaw is seen in Figure 18.
The crack tip stress intensity factor is then calculated in accordance with A-3000 [4]. A 4th order polynomial is fit over the wall thickness to provide an accurate stress distribution in accordance with A-3212 [4]. An illustration of the stress distribution over the wall thickness is seen in Figure 19. The stress results through the wall thickness from each transient and each transient substep (critical time point) are read from the ANSYS results. The stresses are added to the weld residual stress (seen in Figure 22) and a 4th order polynomial stress distribution through the wall thickness is fit. The stress intensity factor is then calculated based on the following equation given in A-3411(c) [4].
KI = [(B0 + Bp) G0 + B1 (a/t) G1 + B2 (a/t)2 G2 + B3 (a/t)3 G3 + B4 (a/t)4 G4] ¥( a / Q)
Where B0 to B4 are the coefficients of the 4th order polynomial of the stress distribution through the wall thickness Bp is the inside surface pressure G0 to G4 are the coefficients dependent on the flaw size and specimen geometry Q is a flaw shape parameter The stress intensity factor is calculated for the circumferential flaw on the inside of a cylinder seen in Figure 20 and the axial flaw on the inside of a cylinder seen in Figure 21. The stress intensity factor is also calculated for both Point 1 (deepest point) and Point 2 (surface point) as seen in Figure 18. Note that for the circumferential flaw, the axial stress distribution through the wall thickness is used. For the axial flaw, the hoop stress distribution though the wall thickness is used.
The G0 to G4 coefficients are dependent on the specimen geometry and the flaw size. They are calculated according to A-3413(a) [4] for Point 1 and A-3413(b) [4] for Point 2. The coefficients used in these equations are calculated according to A-3532 [4] for the circumferential flaw and A-3552 [4] for the axial flaw. These coefficients are dependent on the crack size to wall thickness ratio, inside radius to wall thickness ratio and crack depth to length ratio.
With the stress intensity factor calculated based on the stress distribution for each transient substep, the stress intensity factor range (KI) is calculated based on the maximum and minimum KI for each transient and used with the Paris Law type fatigue crack growth rate given in A-4300 [4]. The material property coefficients (C0, n) used in the crack growth rate model consider the more conservative of the growth rate for air and for light water environments. They are also dependent on the stress ratio for the transient and the
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appropriate material property coefficients are used based on the stress ratio. If the stress intensity factor range (KI) is less than the threshold value (Kth), no growth is considered as discussed in A-4300 [4]. The threshold values considered are given in A-4300 [4].
The crack growth rate for both Point 1 and Point 2 is calculated (a and l) which is then added to initial crack size to give the new crack size at the end of the transient. This process is then repeated for each transient and each application of the transient to get the final crack size at the end of the design life. The transient order is based on dividing up the transients in to blocks which give an even distribution of the transients over the design life. The crack growth analysis is performed for the normal (including upset and test) conditions only per A-5200 [4].
The crack growth analysis is performed through encoding all of the necessary equations from Non-Mandatory Appendix A [4] into Excel. More details on this analysis approach and the tool used are given in BWXT Canada Calculation M2004-B004.
7.2 Fatigue Crack Growth Each of the paths (8 total) defined in Section 6.2 are then considered for crack growth analysis. Both axial and circumferential flaws are considered independently for each path location and therefore the hoop and axial stresses respectively are used for these flaws. All 8 paths with the two flaw types are run through the crack growth analysis. The final crack sizes for all 8 paths and both flaw types can be seen in Table 4. [
]a The maximum and minimum stresses for each transient are plotted as seen in Figure 23 to Figure 25 for the axial stress and Figure 26 to Figure 28 for the hoop stress. Note that the stresses correspond to the stress distribution through the primary head wall without any postulated crack included in the primary head wall within the FE model. The stresses are therefore the nominal stress distribution as required for linear elastic fracture mechanics. [
]a Weld residual stress is considered in the analysis due to the proximity to the primary head seam weld. This is a self equilibrating through-wall weld residual stress profile for post weld heat treated vessel plate seam welds from EPRI Report TR-100251 [9], as seen in Figure 22. [
]a With the through-wall stress distribution, including weld residual stress, the stress intensity factor range for
M2004-SR-01-NP, Rev. 2 Page 17 BWXT Canada Ltd.
each transient is calculated as described in Section 7.1, for both the deepest point (Point 1) and the surface point (Point 2). From this stress intensity factor range, the end of transient flaw depth growth (a) and the end of transient flaw length growth (l) are calculated. This gives the new flaw geometry and the process is repeated for the next transient. [
]a After all of the normal (including upset and test) transients have been applied, the final crack length and depth are known for each path, as seen in Table 4. The crack depth and length growth versus time can be seen in Figure 29 and Figure 30 for the circumferential and axial flaw respectively. With the final crack size, the acceptance criteria for the flaws is as discussed in Section 7.3.
Table 4: Final Crack Sizes for all Paths Figure 31 to Figure 33 show the calculated stress intensity factor range for each transient for paths 1, 2 and 4 respectively for the circumferential flaw. Similarly, Figure 34 to Figure 36 show the calculated stress intensity factor range for each transient for paths 1, 2 and 4 respectively for the axial flaw. [
]a
[
c
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]a
[
]a More details on the crack growth analysis are given in BWXT Canada Calculation M2004-B003.
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7.3 End-of-Life Flaw Size From the fatigue crack growth analysis, the final flaw size (af and lf) is known at the end of the RSG life. With this final flaw size, the acceptability of the flaw is assessed per the acceptance criteria of IWB-3600 [4] as documented in Section 3.1. The maximum stress intensity factor for each transient, including normal and emergency and faulted conditions, at the final end-of-life flaw size geometry is compared against the acceptance criteria. The results are seen in Table 5 and Table 6 for normal conditions, for the axial flaw and circumferential flaws respectively at Path 4. Similarly, Table 7 and Table 8 contain the results for emergency and faulted conditions for the axial flaw and circumferential flaws respectively at Path 4. These bound the results for all other paths.
[
]a The fracture toughness, KIC, is calculated based on the equation given in A-4200 and curve seen in Figure A-4200-1 [4]. An upper shelf fracture toughness of [
]c is used [8].
Figure 37 to Figure 39 show representative maximum stress intensity factors for each transient for paths 1, 2 and 4 respectively for the circumferential flaw. Similarly, Figure 40 to Figure 42 show the representative maximum stress intensity factor for each transient for paths 1, 2 and 4 respectively for the axial flaw. [
]a The end-of-life analysis, as seen in Table 5 and Table 6, accurately calculates the KI value considering the actual crack a/l, calculates KI values for both Pt. 1 and 2 and considers the plastic zone correction factor. Additionally, the allowable shown on these figures is applicable for most transients. A few transients or transient time points have a lower allowable based on the primary side temperature.
The maximum stress intensity factor calculation for the emergency and faulted conditions follows the same approach as the normal conditions. Considering the final end-of-life flaw geometry and the appropriate stresses from the transient analysis, as described in Section 6.2, the maximum stress intensity factor is calculated. The maximum stress intensity factor is then compared to emergency and faulted condition acceptance criteria. The transient stresses for the emergency and faulted condition consider both pressure and thermal stresses. [
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]a As can be seen in Table 5 and Table 6, all circumferential and axial end-of-life flaws meet the acceptance criteria, for all Level A and B transients (normal and upset, including test conditions), as defined in Section 3.1. The acceptance criteria is calculated using the equation for normal conditions, as given in Section 3.1, at the appropriate transient temperature from the KIC curve given in in A-4200 [4]. As can be in Table 7 and Table 8, all circumferential and axial end-of-life flaws meet the acceptance criteria, for all Level C and D transients (emergency and faulted conditions), as defined in Section 3.1. The acceptance criteria is calculated using the equation for emergency and fault conditions, as given in Section 3.1, at the appropriate transient temperature from the KIC curve given in in A-4200 [4].
More details on the end-of-life flaw analysis are given in BWXT Canada Calculation M2004-B003 and the analysis is performed through the analysis tool described in BWXT Canada Calculation M2004-B004.
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Table 5 Fracture Mechanics Flaw Size Acceptance for Axial Flaw, Path 4 for Normal Conditions Table 6 Fracture Mechanics Flaw Size Acceptance for Circ Flaw Path 4 for Normal Conditions c
c
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Table 7 Fracture Mechanics Flaw Size Acceptance for Axial Flaw, Path 4 for Emergency and Faulted Conditions Table 8 Fracture Mechanics Flaw Size Acceptance for Circumferential Flaw, Path 4 for Emergency and Faulted Conditions c
c
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8.0 PRIMARY STRESS ANALYSIS The primary stress limits of NB-3000, assuming a local area reduction to the pressure retaining membrane that is equal to the area of the flaw must be met in accordance with IWB-3610 [4]. Table 9 lists the primary stress for the Design, Test and Level C and D conditions compared to the primary stress limits.
Table 9: Primary Stress Results for Base Design
[
]a,c
[
]a,c Table 10: Prorated Primary Stress Results for Base Design c
c
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9.0 VERIFICATION OF ASSUMPTIONS There are no assumptions requiring verification made in the calculations listed in Section 12.0.
The following assumption not requiring verification is made:
1)
[
]a,c
10.0 CONCLUSION
S The postulated flaw in the divider plate, due to PWSCC, is grown into the primary head wall through fatigue crack growth considering all normal (including upset and test) transients for the full design life. Both axial and circumferential flaws are independently considered with initial depth and width equal to the cladding thickness and divider plate width respectively. Conservative inputs and stresses are used. The analyses included in this report show that both postulated flaws are acceptable for the end-of-life flaw size they produce for normal (including upset and test) conditions and emergency and faulted conditions. Additionally, the primary stresses in the primary head with the end-of-life flaws are acceptable by meeting the requirements of IWB-3600 [4] for Design and transient conditions. Therefore, the structural integrity of the Byron / Braidwood 1 replacement steam generator primary head wall has been demonstrated if a crack, initiating in the divider plate weld build-up, propagates into the cladding of the primary head at the triple point.
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11.0 REFERENCES
, DESIGN DRAWINGS AND COMPUTER CODES 11.1 References 1.
Areva NP Document No. 18-1229648-008, Certified Design Specification for Replacement Steam Generator Byron and Braidwood Unit 1.
2.
ASME Boiler and Pressure Vessel Code Section III, Subsection NB, 1986 Edition with No Addenda.
3.
ASME Boiler and Pressure Vessel Code Section II Part C and Section III, Appendices, 1986 Edition with No Addenda.
4.
ASME Boiler and Pressure Vessel Code Section XI, 2017 Edition with No Addenda.
5.
BWXT Canada List of Approved Codes for Nuclear Analysis, June 11, 2021.
6.
B&W Canada Drawing 7720E001, Rev. 06, Steam Generator Arrangement.
7.
B&W Canada Drawing 7720A035, Rev. 03, Materials and Parts List.
8.
EPRI Report 3002002850, Steam Generator Management Program: Investigation of Crack Initiation and Propagation in the Stream Generator Channel Head Assembly, October 2014.
9.
EPRI Report TR-100251, White Paper on Reactor Vessel Integrity Requirements for Level A and B Conditions, January 1993.
- 10. B&W Canada Report 236R-SR-01, Rev. 1, Exelon Byron and Braidwood Unit 1 Replacement Steam Generators MUR Power Uprate Structural Analysis Report.
- 11. B&W Canada Report 222-7720-SR-1, Rev. 4, Exelon Company Byron and Braidwood Station Replacement Steam Generator Design Condition Report.
- 12. B&W Canada Report 222-7720-SR-2, Rev. 6, Exelon Company Byron and Braidwood Stations Replacement Steam Generators Transient Analysis Report.
- 13. Welding Research Council Bulletin 175, August 1972 PVRC Recommendations on Toughness Requirements for Ferritic Materials.
- 14. ASME Boiler and Pressure Vessel Code Section XI, 2007 Edition with 2008A Addenda.
- 15. ASME Boiler and Pressure Vessel Code Section XI, 2013 Edition with No Addenda.
- 16. B&W Canada Calculation 236R-B02, Rev. 1, Byron and Braidwood Primary Head / Tubesheet / Shell Assembly Level A to D and Fatigue Analysis for MUR Uprate.
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11.2 Design Drawings The design drawings used in the analyses are the latest revisions and are listed in Table 11.
Table 11 List of Design Drawings B&W Canada Design Drawings Drawing No.
Rev. No.
Title 7720E001 06 ComEd Steam Generator Arrangement 7720E004 03 ComEd Primary Head & T/S D. L 7720A035 03 ComEd Materials and Parts List 7720E110 00 ComEd Tubesheet Drilling Pattern 11.3 Computer Codes The computer programs listed in Table 12 are used in the analyses.
Table 12 List of Computer Codes Program Name Program Version No.
Users Guide Rev. No.
Program Description System ANSYS 15.0 On-line Manuals General Purpose Finite Element Program for structural, seismic and thermal analysis of various nuclear pressure vessel components Windows 10 x64 on DP T5810 This code is qualified by BWXT for Nuclear Analysis. All User Guide limitations and computer program notifications, as applicable, have been reviewed to ensure there is no impact on this calculation. The computer code listed in Table 12 are part of BWXTs List of Approved Codes for Nuclear Analysis [5].
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12.0 LIST OF DETAILED ANALYSIS CALCULATIONS Calculation Rev.
Title M2004-B001 0
Byron / Braidwood Unit 1 Replacement Steam Generator Model Development for Tubesheet / Primary Head / Divider Plate Assembly.
M2004-B002 1
Byron / Braidwood Unit 1 Replacement Steam Generator Transient Analysis for Tubesheet / Primary Head / Divider Plate Assembly.
M2004-B003 2
Byron / Braidwood Unit 1 Replacement Steam Generator Flaw Analysis at Divider Plate Triple Point.
M2004-B004 0
Divider Plate Crack Growth Analysis Tool.
M2004-B005 0
Byron / Braidwood Unit 1 Replacement Steam Generator Limit Analysis for Tubesheet / Primary Head / Divider Plate Assembly with Postulated Primary Head Flaw The detailed engineering analysis is propriety to BWXT. They are available at BWXT Canada Cambridge office or via secure electronic data room, upon request, on a platform such as Firmex.
M2004-SR-01-NP, Rev. 2 Page 28 BWXT Canada Ltd.
13.0 FIGURES Figure 1 FE Model of Divider Plate Assembly.............................................................................................. 29 Figure 2 Divider Plate Assembly Model Dimensions (a).............................................................................. 30 Figure 3 Divider Plate Assembly Model Dimensions (b).............................................................................. 31 Figure 4 Divider Plate Assembly Model Dimensions (c).............................................................................. 32 Figure 5 Divider Plate Assembly with Materials........................................................................................... 33 Figure 6 Divider Plate Assembly Triple Point............................................................................................... 33 Figure 7 Exaggerated Crack Opening Displaced Shape due to Internal Pressure (psi).............................. 34 Figure 8 Thermal Boundary Conditions (Applied HTCs and Temperatures)................................................ 35 Figure 9 Temperature Contour Plot - Heatup/Cooldown (°F)...................................................................... 36 Figure 10 Temperature History Plot for the Heatup / Cooldown Transient.................................................. 37 Figure 11 Structural Boundary Conditions................................................................................................... 38 Figure 12 Stress Plot for Transient Heatup/Cooldown (at 32060.1 sec) (a)................................................. 39 Figure 13 Stress Plot for Transient Heatup/Cooldown (at 32060.1 sec) (b)................................................. 39 Figure 14 Path Locations for Through-Wall Stress Distributions. View from Inlet Side................................ 40 Figure 15 Path Locations for Through-Wall Stress Distributions. View from Outlet Side............................. 40 Figure 16 Path Locations at Triple Point for Through-Wall Stress Extraction. View along Divider Plate and Section at Tubesheet / Primary Head Junction............................................................................................ 41 Figure 17 Path Locations at Triple Point for Through-Wall Stress Extraction. Section through Primary Head
/ Tubesheet Juncture................................................................................................................................... 41 Figure 18 Surface Flaw Geometry [4].......................................................................................................... 42 Figure 19 Stress Distribution Through-Wall Thickness [4]........................................................................... 42 Figure 20 Circumferential Flaw Geometry on the Inside Surface of a Cylinder [4]....................................... 43 Figure 21 Axial Flaw Geometry on the Inside Surface of a Cylinder [4]....................................................... 43 Figure 22 Self Equilibrating Weld Stress Distribution [9].............................................................................. 44 Figure 23 Axial Stress Through-Wall Distribution at Path 1......................................................................... 45 Figure 24 Axial Stress Through-Wall Distribution at Path 2......................................................................... 45 Figure 25 Axial Stress Through-Wall Distribution at Path 4......................................................................... 46 Figure 26 Hoop Stress Through-Wall Distribution at Path 1........................................................................ 46 Figure 27 Hoop Stress Through-Wall Distribution at Path 2........................................................................ 47 Figure 28 Hoop Stress Through-Wall Distribution at Path 4........................................................................ 47 Figure 29 Circumferential Flaw Crack Growth............................................................................................. 48 Figure 30 Axial Flaw Crack Growth............................................................................................................. 49 Figure 31 Circumferential Flaw Stress Intensity Factor Range, Path 1 (Representative)............................ 50 Figure 32 Circumferential Flaw Stress Intensity Factor Range, Path 2 (Representative)............................ 50 Figure 33 Circumferential Flaw Stress Intensity Factor Range, Path 4 (Representative)............................ 51 Figure 34 Axial Flaw Stress Intensity Factor Range, Path 1 (Representative)............................................. 51 Figure 35 Axial Flaw Stress Intensity Factor Range, Path 2 (Representative)............................................. 52 Figure 36 Axial Flaw Stress Intensity Factor Range, Path 4 (Representative)............................................. 52 Figure 37 Circumferential Flaw Maximum Stress Intensity Factor, Path 1 (Representative)....................... 53 Figure 38 Circumferential Flaw Maximum Stress Intensity Factor, Path 2 (Representative)....................... 53 Figure 39 Circumferential Flaw Maximum Stress Intensity Factor, Path 4 (Representative)....................... 54 Figure 40 Axial Flaw Maximum Stress Intensity Factor, Path 1 (Representative)........................................ 54 Figure 41 Axial Flaw Maximum Stress Intensity Factor, Path 2 (Representative)........................................ 55 Figure 42 Axial Flaw Maximum Stress Intensity Factor, Path 4 (Representative)........................................ 55
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Figure 1 FE Model of Divider Plate Assembly
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Figure 2 Divider Plate Assembly Model Dimensions (a) a,c
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Figure 3 Divider Plate Assembly Model Dimensions (b) a,c
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Figure 4 Divider Plate Assembly Model Dimensions (c) a,c
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Figure 5 Divider Plate Assembly with Materials Figure 6 Divider Plate Assembly Triple Point a,c
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Figure 7 Exaggerated Crack Opening Displaced Shape due to Internal Pressure (psi) c
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Figure 9 Temperature Contour Plot - Heatup/Cooldown (°F) c
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Figure 11 Structural Boundary Conditions a,c
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Figure 12 Stress Plot for Transient Heatup/Cooldown (at 32060.1 sec) (a)
Figure 13 Stress Plot for Transient Heatup/Cooldown (at 32060.1 sec) (b) c c
M2004-SR-01-NP, Rev. 2 Page 40 BWXT Canada Ltd.
Figure 14 Path Locations for Through-Wall Stress Distributions. View from Inlet Side.
Figure 15 Path Locations for Through-Wall Stress Distributions. View from Outlet Side.
a a
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Figure 18 Surface Flaw Geometry [4]
Figure 19 Stress Distribution Through-Wall Thickness [4]
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Figure 20 Circumferential Flaw Geometry on the Inside Surface of a Cylinder [4]
Figure 21 Axial Flaw Geometry on the Inside Surface of a Cylinder [4]
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Figure 22 Self Equilibrating Weld Stress Distribution [9].
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Figure 23 Axial Stress Through-Wall Distribution at Path 1 Figure 24 Axial Stress Through-Wall Distribution at Path 2 c
c
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Figure 25 Axial Stress Through-Wall Distribution at Path 4 Figure 26 Hoop Stress Through-Wall Distribution at Path 1 c
c
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Figure 27 Hoop Stress Through-Wall Distribution at Path 2 Figure 28 Hoop Stress Through-Wall Distribution at Path 4 c
c
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Figure 29 Circumferential Flaw Crack Growth c
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Figure 30 Axial Flaw Crack Growth c
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Figure 31 Circumferential Flaw Stress Intensity Factor Range, Path 1 (Representative)
Figure 32 Circumferential Flaw Stress Intensity Factor Range, Path 2 (Representative) c c
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Figure 33 Circumferential Flaw Stress Intensity Factor Range, Path 4 (Representative)
Figure 34 Axial Flaw Stress Intensity Factor Range, Path 1 (Representative) c c
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Figure 35 Axial Flaw Stress Intensity Factor Range, Path 2 (Representative)
Figure 36 Axial Flaw Stress Intensity Factor Range, Path 4 (Representative) c c
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Figure 37 Circumferential Flaw Maximum Stress Intensity Factor, Path 1 (Representative)
Figure 38 Circumferential Flaw Maximum Stress Intensity Factor, Path 2 (Representative) c c
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Figure 39 Circumferential Flaw Maximum Stress Intensity Factor, Path 4 (Representative)
Figure 40 Axial Flaw Maximum Stress Intensity Factor, Path 1 (Representative) c c
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Figure 41 Axial Flaw Maximum Stress Intensity Factor, Path 2 (Representative)
Figure 42 Axial Flaw Maximum Stress Intensity Factor, Path 4 (Representative) c c
ATTACHMENT 3 BWXT 10 CFR 2.390 Affidavit
BWXT Canada Ltd.
Subject:
April 19, 2023 Document Control Desk U.S. Nuclear Regulatory Commission Washington, DC 20555-0001 U.S.A.
APPLICATION FOR WITHHOLDING PROPRIETARY INFORMATION FROM PUBLIC DISCLOSURE BWXT Report M2004-SR-01, Rev. 2, "Byron/ Braidwood Unit 1 Flaw Tolerance Evaluation at Primary Head / Tubesheet / Divider Plate Triple Point Analysis Report" and BWXT Memo M2302-MEMO-01 R00, "Responses to NRC RAI C10-1 and RCI C10-1 and -2"
Reference:
M2302-LTR-002, Rev. 0
Dear Sir/Madam:
The proprietary infonnation for which withholding is being requested in the above-referenced document section is identified in the attached affidavit signed by the owner of the proprietary infonnation, BWXT Canada Ltd. The affidavit, which accompanies this letter, sets forth the basis on which the infonnation may be withheld from public disclosure by the Commission and address with specificity the considerations listed in paragraph (b)(4) of 10 CFR Section 2.390 of the Commission's regulations.
Accordingly, this letter authorizes the utilization of the accompanying affidavit by Constellation Energy Generation LLC.
Correspondence with respect to the proprietary aspects of the application for withholding or the BWXT Affidavit should reference this letter, and should be addressed to the undersigned.
Yours truly, BWXT CANADA LTD.
~
~
MarioGogic, Manager, Component Attach./
Cc:
J. Johnson D. Allingham 581 Coronation Boulevard Cambridge, Ontario Canada, NI R 5V3 t +15195212130 f +15195219581 wwwbwxtcom People Strong INNOVATION DRIVEN >
PROVINCE OF ONT ARIO REGIONAL MUNICIPALITY OF WATERLOO AFFIDAVIT OF MARIO GOGIC M2302-LTR-00I Rev. 0 I, Mario Gogic, of the City of Guelph, in the Province of Ontario, being sworn, make oath and say as follows:
I.
I am the Manager, Component Engineering of BWXT Canada Ltd. ("BWXT"), and as such, I have been specifically delegated the function of reviewing the proprietary information sought to be withheld from public disclosure in connection with nuclear power plant licensing and rulemaking proceedings, and am authorized to apply for its withholding on behalfofBWXT.
- 2.
I am making this Affidavit in conformance with the provisions of I 0CFR Section 2.390 of the Commission's regulations and in conjunction with the BWXT Canada Ltd. Application for Withholding accompanying this Affidavit.
- 3.
I have personal knowledge of the criteria and procedures utilized by BW:XT in designating information as a trade secret, proprietary or as confidential commercial or financial information.
- 4.
Pursuant to the provisions of paragraph (b)(4) of Section 2.390 of the Commission's regulations, the following is furnished for consideration by the Commission in determining whether the information sought to be withheld from public disclosure should be withheld.
(i)
The information sought to be withheld from public disclosure is owned and has been held in confidence by BWXT.
(ii)
The information is of a type customarily held in confidence by BWXT and not customarily disclosed to the public. BW:XT has a rational basis for determining the types of information customarily held in confidence by it and, in that connection, utilizes a system to determine when and whether to hold certain types of information in confidence. The application of that system and the substance of that system constitutes BWXT policy and provides the rational basis required.
Under that system, information is held in confidence if it falls in one or more of several types, the release of which might result in the loss ofan existing or potential competitive advantage, as follow:
(a)
The information reveals the distinguishing aspects of a process, component, structure, tool, method, etc., where prevention of its use by any of BWXT's competitors without license from BWXT constitutes a competitive economic advantage over other companies.
(b)
The information is trade secrets or commercial information obtained from a third party and has been provided to BWXT in confidence.
M2004-L TR-00 I, Rev. 0 types of information BWXT customarily holds in confidence identified in Sections (4)(ii)(a) through (4)(ii)(d) of this affidavit pursuant to 10 CFR 2.390(b)(I).
SWORN BEFORE ME in the
)
City of Cambridge in the ~
~
Province of
- Ontario, this) 19th day of April, 2023. )
A FREY, s.a.A., J.o.
VANi:.S$A JU\\..SIAl~"Of Notary Public Barrister, 0 ""'
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