ML22115A175
| ML22115A175 | |
| Person / Time | |
|---|---|
| Site: | North Anna  |
| Issue date: | 04/25/2022 |
| From: | Lawrence D Virginia Electric & Power Co (VEPCO) |
| To: | Document Control Desk, Office of Nuclear Reactor Regulation |
| References | |
| 22-113 | |
| Download: ML22115A175 (12) | |
Text
VIRGINIA ELEcrRIC AND POWER COMPANY RICHMOND, VIRGINlA 23261 April 25, 2022 U.S. Nuclear Regulatory Commission Attention: Document Control Desk Washington, D.C. 20555 Serial No.:
NRA/ENC:
Docket No.:
License No.:
22-113 R1 50-339 NPF-4 VIRGINIA ELECTRIC AND POWER COMPANY (DOMINION ENERGY VIRGINIA)
NORTH ANNA POWER STATION UNIT 2 ASME SECTION XI INSERVICE INSPECTION PROGRAM RELIEF REQUEST N2-14-LMT-004 FOURTH INTERVAL THIRD PERIOD LIMITED EXAMINATIONS RESPONSE TO REQUEST FOR ADDITIONAL INFORMATION By letter dated December 13, 2021 (Agencywide Documents Access and Management System {ADAMS) Accession No. ML21348A711), Virginia Electric and Power Company (Dominion Energy Virginia) requested relief from the examination coverage requirements of Section XI, "Rules for lnservice Inspection of Nuclear Power Plant Components," of the American Society of Mechanical Engineers Boiler and Pressure Vessel Code {ASME Code) for the North Anna Power Station Unit 2 (NAPS2) fourth 10-year lnservice Inspection {ISi) interval.
Pursuant to 10 CFR 50.55a(g)(5)(iii), Dominion Energy Virginia requested relief from the ASME Code,Section XI, requirement for "essentially 100 percent" volumetric examination coverage of certain risk-informed piping welds performed during ISi examinations in the third period of the fourth 10-year ISi interval for NAPS2 on the basis that the applicable ASME Code requirements are impractical. Examinations of these welds were performed to meet the requirements of the 2004 Edition of ASME Code Section XI with no Addenda and the Risk-Informed/Safety-Based lnservice Inspection {RI-ISi) Program Plan based on Code Case N-716, "Alternative Piping Classification and Examination Requirements."
Limited access and configuration of these components prevents full volumetric examination coverage of these welds.
The NRC indicated additional information was necessary to complete their review of the requested alternatives by email on March 24, 2022. The NRC desires a response to their request for additional information (RAI) by April 25, 2022. The Enterprise Project Identifier (EPID) referenced for this request is L-2021-LLR-0088.
Serial No.: 22-113 Docket No.: 50-339 Page 2 of 3 Dominion Energy Virginia's response to the NRC's RAI is provided in Attachment 1. While developing its response to the NRC's RAI, Dominion Energy Virginia identified three (3) errors in the December 13, 2021, relief request. A marked-up version of the affected pages is included in Attachment 2. A clean copy of the corrected pages is included in Attachment
- 3. These two (2) pages replace the same two (2) pages of the relief request submitted on December 13, 2021.
If you have any questions or require additional information, please contact Erica Combs at (804 )-273-3386.
Vice President - Nuclear Engineering & Fleet Support Dominion Energy Virginia Attachments:
- 1. Response to NRC Request for Additional Information
- 2. Corrected Pages for Relief Request: N2-14-LMT-004 (Marked-up)
- 3. Clean Copy of Corrected Pages for Relief Request: N2-14-LMT-004 Commitments made in this letter: None.
cc:
Regional Administrator, Region II U.S. Nuclear Regulatory Commission Marquis One Tower 245 Peachtree Center Ave., NE, Suite 1200 Atlanta, Georgia 30303-1257 G. E. Miller NRC Senior Project Manager - North Anna Power Station U.S. Nuclear Regulatory Commission Mail Stop 09 E-3 One White Flint North 11555 Rockville Pike Rockville, Maryland 20852-2738 Old Dominion Electric Cooperative R-North-Anna-Correspondence@odec.com NRC Senior Resident Inspector North Anna Power Station Serial No.: 22-113 Docket No.: 50-339 Page 3 of 3
ATTACHMENT 1 Serial No.: 22-113 Docket No.: 50-339 Response to NRC Request for Additional Information Virginia Electric and Power Company (Dominion Energy Virginia)
North Anna Power Station Unit 2
Serial No.: 22-113 Docket No.: 50-339 Page 1 of 2 RESPONSE TO NRC REQUEST FOR ADDITIONAL INFORMATION REGARDING RELIEF REQUEST N2-14-LMT-004:
ASME SECTION XI INSERVICE INSPECTION PROGRAM FOURTH INTERVAL THIRD PERIOD LIMITED EXAMINATIONS By letter dated December 13, 2021 (Agencywide Documents Access and Management System (ADAMS) Accession No. ML21348A711), Virginia Electric and Power Company (Dominion Energy Virginia) requested relief from the examination coverage requirements of Section XI, "Rules for lnservice Inspection of Nuclear Power Plant Components," of the American Society of Mechanical Engineers Boiler and Pressure Vessel Code (ASME Code) for the North Anna Power Station Unit 2 (NAPS2) fourth 10-year lnservice Inspection (ISi) interval.
Pursuant to 10 CFR 50.55a(g)(5)(iii), Dominion Energy Virginia requested relief from the ASME Code,Section XI, requirement for "essentially 100 percent" volumetric examination coverage of certain risk-informed piping welds performed during ISi examinations in the third period of the fourth 10-year ISi interval for NAPS2 on the basis that the applicable ASME Code requirements are impractical. Examinations of these welds were performed to meet the requirements of the 2004 Edition of ASME Code Section XI with no Addenda and the Risk-Informed/Safety-Based lnservice Inspection (RI-ISi) Program Plan based on Code Case N-716, "Alternative Piping Classification and Examination Requirements."
Limited access and configuration of these components prevents full volumetric examination coverage of these welds.
The NRC indicated additional information was necessary to complete their review of the requested alternatives by email on March 24, 2022. The NRC desires a response to their request for additional information (RAI) by April 25, 2022. The Enterprise Project Identifier (EPID) referenced for this request is L-2021-LLR-0088.
Dominion Energy Virginia's response to the NRC request for additional information (RAI) is provided below.
NRC RAI:
What are the ASME code classes for welds 10, 19, and 8 in Section R2 "Elements Subject to lntergranular or Transgranular Stress Corrosion Cracking" of the RR N2-14-LMT-003? 1 1 The title of Dominion Energy Virginia's letter dated December 13, 2021 (ADAMS Accession No. ML21348A711}, contains a typographical error, and incorrectly states "Relief Request N2-I4-LMT-003". The corrected title is "Relief Request N2-I4-LMT-004". There are no other instances of this typographical error in the December 13, 2021, letter. The NRC's RAI refers to the incorrect title in the December 13, 2021, letter, however the NRC's RAI and Dominion Energy Virginia's response are regarding Relief Request N2-I4-LMT-004, Fourth Interval Third Period Limited Examinations.
Dominion Energy Virginia's Response:
Serial No.: 22-113 Docket No.: 50-339 Page 2 of 2 The ASME Code Class for welds 10, 19, and 8 are Class 1. See table below.
Weld Line No.
Class 10 6"-S1-416 1
19 6"-S1-532 2 1
8 12"-S1-469 1
2 The table in Section R2, "Elements Subject to lntergranular or Transgranular Stress Corrosion Cracking,"
of the December 13, 2021, request contains an error in which the system designation for weld 19 is incorrectly reported as "RC". The line number for weld 19 should be "6"-Sl-532". This error also appears in the discussion in Section 4.R2, Impracticality of Compliance. An additional error was identified upon further review, also in the discussion in Section 4.R2, in which weld 8 is incorrectly identified as "6"-SI-469". The correct pipe size for weld 8 is 12". There is only one instance of this error and the line number for weld 8 is correctly identified as "12"-Sl-469" in the remainder of the December 13, 2021, request. These errors were captured in the station's Corrective Action Program (CR1197168). of this RAI response contains marked-up copies identifying the errors in the December 13, 2021, request. Clean copies of the corrected pages are provided in Attachment 3 of this RAI response.
ATTACHMENT 2 Corrected Pages for Relief Request: N2-14-LMT-004 (Mark-up)
Virginia Electric and Power Company (Dominion Energy Virginia)
North Anna Power Station Unit 2 Serial No.: 22-113 Docket No.: 50-339
Serial No.: 21 -087 Docket No.: 50-339 Attachment Page 28 of 68 R2.
Risk-Informed Piping Welds Subject to lntergranular or Transgranular Stress Corrosion Cracking (IGSCC or TGSCC) 4.R2 IMPRACTICALITY OF COMPLIANCE In accordance with 10 CFR 50.55a(g)(5)(iii), relief is requested from the "essentially 100 percent" volumetric examination coverage requirement for the identified piping welds.
This requirement is considered impractical primarily due to single-sided access for these components.
Weld Line No.
Scan Enclosure Exam1 Exam Angle Mode Frequency Coverage Date
(%)2 (degree)
(MHz)
Up/CW/CCW 45 Shear 1.5 50%
Up/CW/CCW 60 Shear 1.5 10 6"-Sl-416 R2-1 3/21/2019
+3.6% BE Dwn 60 Longitudinal 2.0 Up/CW/CCW 45 Shear 1.5 50%
Up/CW/CCW 60 Shear 1.5 19 6" RC 532 R2-2 3/21/2019
+25% BE Dwn 60 Longitudinal 2.0 16"-S1-532 1 Up/CW/CCW 45 Shear 1.5 50%
Dwn 60 Longitudinal 2.0 8
12"-Sl-469 R2-3 3/13/2019
+14.75%BE NOTES:
1 Up Axial scan on the upstream side of weld Own Axial scan on the downstream side of weld CW Circumferential scan in the clockwise direction CCW Circumferential scan in the counterclockwise direction 2
BE Best Effort non-Code coverage used to gain additional information These examinations were performed manually using advanced ASME Section XI, Appendix VIII demonstrated procedures and techniques in accordance with the performance demonstration requirements. Based on access and physical limitations of theses welds, alternative or other advanced technologies would not have provided complete coverage of the examination volume at the time of this examination.
The attached enclosures include the complete Ultrasonic Examination Data Record for the Category R-A, Item R 1.16, examinations included in this request. The report includes
Serial No.: 21-087 Docket No.: 50-339 Attachment Page 29 of 68 details of the UT scanning apparatus, including transducer size, frequency, angle, wave modality and insonification angles. Also included are scan plots for the examinations showing the piping configuration and percent coverage for each individual scan. There were no recordable indications identified for these examinations.
Weld 10 (6" -Sl-416) was a single-sided examination due to the pipe-to-valve configuration, limiting downstream scans. Weld 10 is considered a R1.16 element subject to IGSCC as the most likely degradation mechanism. The weld is on the upstream side of Low Head SI check valve, 2-Sl-125, in the safety injection pipe to RCS hot leg (29"-
RC-407). An additional "Best Effort" (non-Code) scan with a 60-degree Longitudinal search unit obtained an additional 3.6 percent total coverage of the downstream side of the weld. Weld 10 in Line# 6"-Sl-416, is 1,500 lb., Type 316 seamless stainless-steel piping, with welding filler metal SFA 5.4 E316L-16, SFA 5.9 ER316L, and/or SFA 5.30 1 N316L procuf6*~§j:532 fO FN delta ferrite and 75 ksi minimum tensile strength.
Weld 19 (6" RC 532) was a single-sided examination due to the pipe-to-valve configuration, limiting downstream scans. Weld 19 is considered a R1.16 element subject to IGSCC as the most likely degradation mechanism. The weld is on the upstream side of Low Head SI check valve, 2-Sl-106, in the safety injection pipe to the RCS cold leg (27.5"-RC-409).
An additional "Best Effort" (non-Code) scan with a 60-degree Longitudinal search unit obtained an additional 25 percent total coverage of the downstream side of the weld. Weld 19 in Line# 6"-Sl-532, is 1,500 lb., Type 316 seamless stainless-steel piping, with welding filler metal SFA 5.4 E316L-16, SFA 5.9 ER316L, and/or SFA 5.30 1N316L procured with 8-20 FN delta ferrite and 75 ksi minimum tensile strength.
Weld 8 (12"-Sl-469) was a single-sided examination due to the elbow-to-valve configuration, limiting downstream scans. Weld 8 is considered a R1.16 element subject to IGSCC as the most likely degradation mechanism. The weld is on the upstream side of Low Head SI check valve, 2-Sl-187, in the safety injection pipe to the RCS cold leg (27.5"-RC-409). An additional "Best Effort" (non-Code) scan with a 60-degree Longitudinal search unit obtained an additional j12"-Sl-469 ~ent total coverage of the downstream side of the weld. Weld 8 in Line# 6" SI 416, is 1,500 lb., Type 316 seamless stainless-steel piping, with welding filler metal SFA 5.4 E316L-16, SFA 5.9 ER316L, and/or SFA 5.30 1 N316L procured with 8-20 FN delta ferrite and 75 ksi min tensile strength.
Similar relief was granted for NAPS1 weld 12 (6"-Sl-133), 50 percent coverage, during the Fourth Interval [Reference 8]. Relief was granted for three similar welds for the NAPS2 Third Interval [Reference 5].
ATTACHMENT 3 Clean Copy of Corrected Pages for Relief Request: N2-14-LMT-004 Virginia Electric and Power Company (Dominion Energy Virginia)
North Anna Power Station Unit 2 Serial No.: 22-113 Docket No.: 50-339
Serial No.: 21-087 Docket No.: 50-339 Attachment Page 28 of 68 R2.
Risk-Informed Piping Welds Subject to lntergranular or Transgranular Stress Corrosion Cracking (IGSCC or TGSCC) 4.R2 IMPRACTICALITY OF COMPLIANCE In accordance with 10 CFR 50.55a(g)(5)(iii), relief is requested from the "essentially 100 percent" volumetric examination coverage requirement for the identified piping welds.
This requirement is considered impractical primarily due to single-sided access for these components.
Weld Line No.
Scan Enclosure Exam1 Exam Angle Mode Frequency Coverage Date
(%)2 (degree)
(MHz)
Up/CW/CCW 3/21/2019 45 Shear 1.5 50%
Up/CW/CCW 3/21/2019 60 Shear 1.5 10 6"-Sl-416 R2-1
+3.6%8E Dwn 3/21/2019 60 Longitudinal 2.0 Up/CW/CCW 3/21/2019 45 Shear 1.5 50%
Up/CW/CCW 3/21/2019 60 Shear 1.5 19 6"-Sl-532 R2-2
+ 25% BE Dwn 3/21/2019 60 Longitudinal 2.0 50%
Up/CW/CCW 45 Shear 1.5 8
12"-Sl-469 R2-3 3/13/2019
+14.75% BE Dwn 60 Longitudinal
2.0 NOTES
1 Up Axial scan on the upstream side of weld Own Axial scan on the downstream side of weld CW Circumferential scan in the clockwise direction CCW Circumferential scan in the counterclockwise direction 2
BE Best Effort non-Code coverage used to gain additional information These examinations were performed manually using advanced ASME Section XI, Appendix VIII demonstrated procedures and techniques in accordance with the performance demonstration requirements. Based on access and physical limitations of theses welds, alternative or other advanced technologies would not have provided complete coverage of the examination volume at the time of this examination.
The attached enclosures include the complete Ultrasonic Examination Data Record for the Category R-A, Item R 1.16, examinations included in this request. The report includes
Serial No.: 21-087 Docket No.: 50-339 Attachment Page 29 of 68 details of the UT scanning apparatus, including transducer size, frequency, angle, wave modality and insonification angles. Also included are scan plots for the examinations showing the piping configuration and percent coverage for each individual scan. There were no recordable indications identified for these examinations.
Weld 10 (6"-Sl-416) was a single-sided examination due to the pipe-to-valve configuration, limiting downstream scans. Weld 10 is considered a R 1.16 element subject to IGSCC as the most likely degradation mechanism. The weld is on the upstream side of Low Head SI check valve, 2-Sl-125, in the safety injection pipe to RCS hot leg (29"-
RC-407). Additional "Best Effort" (non-Code) scan with a 60-degree Longitudinal search unit obtained additional 3.6 percent total coverage of the downstream side of the weld.
Weld 10 in Line# 6" -Sl-416, is 1,500 lb., Type 316 seamless stainless-steel piping, with welding filler metal SFA 5.4 E316L-16, SFA 5.9 ER316L, and/or SFA 5.30 1N316L procured with 8-20 FN delta ferrite and 75 ksi minimum tensile strength.
Weld 19 (6" -Sl-532) was a single-sided examination due to the pipe-to-valve configuration, limiting downstream scans. Weld 19 is considered a R 1.16 element subject to IGSCC as the most likely degradation mechanism. The weld is on the upstream side of Low Head SI check valve, 2-Sl-106, in the safety injection pipe to the RCS cold leg (27.5"-RC-409). Additional "Best Effort" (non-Code) scan with a 60-degree Longitudinal search unit obtained additional 25 percent total coverage of the downstream side of the weld. Weld 19 in Line# 6"-Sl-532, is 1,500 lb., Type 316 seamless stainless-steel piping, with welding filler metal SFA 5.4 E316L-16, SFA 5.9 ER316L, and/or SFA 5.30 1N316L procured with 8-20 FN delta ferrite and 75 ksi minimum tensile strength.
Weld 8 (12"-Sl-469) was a single-sided examination due to the elbow-to-valve configuration, limiting downstream scans. Weld 8 is considered a R1.16 element subject to IGSCC as the most likely degradation mechanism. The weld is on the upstream side of Low Head SI check valve, 2-Sl-187, in the safety injection pipe to the RCS cold leg (27.5"-RC-409). Additional "Best Effort" (non-Code) scan with a 60-degree Longitudinal search unit obtained additional 14.75 percent total coverage of the downstream side of the weld. Weld 8 in Line# 12"-S1-469, is 1,500 lb., Type 316 seamless stainless-steel piping, with welding filler metal SFA 5.4 E316L-16, SFA 5.9 ER316L, and/or SFA 5.30 1N316L procured with 8-20 FN delta ferrite and 75 ksi min tensile strength.
Similar relief was granted for NAPS1 weld 12 (6"-Sl-133), 50 percent coverage, during the Fourth Interval [Reference 8). Relief was granted for three similar welds for the NAPS2 Third Interval [Reference 5].