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MONTHYEARDCL-13-038, ASME Section XI Inservice Inspection Program Relief Request NDE-RCS-SE-1R18 to Allow Use of Alternative Depth Sizing Criteria2013-04-11011 April 2013 ASME Section XI Inservice Inspection Program Relief Request NDE-RCS-SE-1R18 to Allow Use of Alternative Depth Sizing Criteria Project stage: Request ML13123A0412013-05-0202 May 2013 Acceptance Review Email, Relief Request NDE-RCS-SE-1R18 - Alternative to Requirements to ASME Code, Section XI, Appendix Viii, Suppl. 2 and 10 as Modified by CC N-695 and CC N-696 to Allow Use of Alternative Depth-Sizing Criteria Project stage: Acceptance Review ML13191A0832013-07-0909 July 2013 Request for Additional Information Email, Relief Request NDE-RCS-SE-1R18, Alternative to ASME Code, Section XI, App. Viii, Suppl. 2 and 10 as Modified by CC N-695 and CC N-696, to Allow Use of Alternative Depth-Sizing Criteria Project stage: RAI DCL-13-078, Response to NRC Request for Additional Information Regarding Request for Relief NDE-RCS-SE-1R18 to Allow Use of Alternative Depth Sizing Criteria2013-08-0606 August 2013 Response to NRC Request for Additional Information Regarding Request for Relief NDE-RCS-SE-1R18 to Allow Use of Alternative Depth Sizing Criteria Project stage: Response to RAI ML13350A1512014-01-0303 January 2014 Relief Request NDE-RCS-SE-1R18, Alternative to ASME Code, Section XI, App. Viii, Suppl. 2 and 10 as Modified by CC N-695 and CC N-696, to Allow Use of Alternative Depth-Sizing Criteria Project stage: Other 1CAN041603, Request for Relief from ASME Section XI, Table IWB-2500-1 Requirements2016-04-22022 April 2016 Request for Relief from ASME Section XI, Table IWB-2500-1 Requirements Project stage: Request DCL-16-102, ASME Section XI Inservice Inspection Program Relief Request NDE-RCS-SE-1R20 to Allow Use of Alternative Depth Sizing Criteria2016-10-10010 October 2016 ASME Section XI Inservice Inspection Program Relief Request NDE-RCS-SE-1R20 to Allow Use of Alternative Depth Sizing Criteria Project stage: Request 2013-08-06
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Category:Letter type:DCL
MONTHYEARDCL-24-010, Nuclear Material Transaction Report for New Fuel2024-01-29029 January 2024 Nuclear Material Transaction Report for New Fuel DCL-24-009, Nuclear Material Transaction Report for New Fuel2024-01-17017 January 2024 Nuclear Material Transaction Report for New Fuel DCL-24-008, Schedule Considerations for Review of the DCPP License Renewal Application2024-01-17017 January 2024 Schedule Considerations for Review of the DCPP License Renewal Application DCL-24-004, Supplement to License Amendment Request 23-01 Revision to Technical Specifications to Adopt Risk-Informed Completion Times TSTF-505, Revision 2, Provide Risk-Informed Extended Completion Times - RITSTF Initiative 4b2024-01-15015 January 2024 Supplement to License Amendment Request 23-01 Revision to Technical Specifications to Adopt Risk-Informed Completion Times TSTF-505, Revision 2, Provide Risk-Informed Extended Completion Times - RITSTF Initiative 4b DCL-23-129, Nuclear Material Transaction Report for New Fuel2023-12-27027 December 2023 Nuclear Material Transaction Report for New Fuel DCL-23-122, Request for Exemption from Enhanced Weapons, Firearms Background Checks, and Security Event Notifications Implementation2023-12-14014 December 2023 Request for Exemption from Enhanced Weapons, Firearms Background Checks, and Security Event Notifications Implementation DCL-23-128, Emergency Plan Update2023-12-13013 December 2023 Emergency Plan Update DCL-23-125, Core Operating Limits Report for Unit 1 Cycle 252023-12-0606 December 2023 Core Operating Limits Report for Unit 1 Cycle 25 DCL-23-121, Supplement to License Amendment Request 23-03, Revision to Technical Specification3.7.8, Auxiliary Saltwater System2023-11-16016 November 2023 Supplement to License Amendment Request 23-03, Revision to Technical Specification3.7.8, Auxiliary Saltwater System DCL-23-120, License Amendment Request 23-03 Revision to Technical Specification 3.7.8, Auxiliary Saltwater (Asw) System2023-11-14014 November 2023 License Amendment Request 23-03 Revision to Technical Specification 3.7.8, Auxiliary Saltwater (Asw) System DCL-23-118, License Renewal Application2023-11-0707 November 2023 License Renewal Application DCL-2023-520, Discharge Self-Monitoring at Diablo Canyon Power Plant (DCPP)2023-10-19019 October 2023 Discharge Self-Monitoring at Diablo Canyon Power Plant (DCPP) DCL-23-103, Independent Spent Fuel Storage Installation - Withdrawal of License Amendment Request 22-01, Request for Approval of Alternative Security Measures for Early Warning System2023-10-13013 October 2023 Independent Spent Fuel Storage Installation - Withdrawal of License Amendment Request 22-01, Request for Approval of Alternative Security Measures for Early Warning System DCL-23-092, Material Status Report for the Period Ending August 31, 20232023-09-28028 September 2023 Material Status Report for the Period Ending August 31, 2023 DCL-23-077, License Amendment Request 23-02 Application to Adopt 10 CFR 50.69, Risk-Informed Categorization and Treatment of Structures, Systems and Components for Nuclear Power Reactors2023-09-27027 September 2023 License Amendment Request 23-02 Application to Adopt 10 CFR 50.69, Risk-Informed Categorization and Treatment of Structures, Systems and Components for Nuclear Power Reactors DCL-23-083, Upcoming Meeting with Nuclear Security and Incident Response Staff2023-09-13013 September 2023 Upcoming Meeting with Nuclear Security and Incident Response Staff DCL-23-078, Nuclear Material Transaction Report for New Fuel2023-09-0606 September 2023 Nuclear Material Transaction Report for New Fuel DCL-23-070, Withdrawal of Request Regarding Senior Reactor Operator License Application2023-08-16016 August 2023 Withdrawal of Request Regarding Senior Reactor Operator License Application DCL-23-068, Nuclear Material Transaction Report for New Fuel2023-08-0909 August 2023 Nuclear Material Transaction Report for New Fuel DCL-23-066, Nuclear Material Transaction Report for New Fuel2023-08-0303 August 2023 Nuclear Material Transaction Report for New Fuel DCL-23-065, Letter DCL-23-065 Request That Exam Material Be Withheld from Public Disclosure2023-07-27027 July 2023 Letter DCL-23-065 Request That Exam Material Be Withheld from Public Disclosure DCL-23-064, Nuclear Material Transaction Report for New Fuel2023-07-26026 July 2023 Nuclear Material Transaction Report for New Fuel DCL-23-054, License Amendment Request 23-01 Revision to Technical Specifications to Adopt Risk-Informed Completion Times TSTF-505, Revision 2, Provide Risk-Informed Extended Completion Times - 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NRC Requested Notification of Withdrawal from Voluntary Program DCL-23-041, 10 CFR 50.46 Annual Report of Emergency Core Cooling System Evaluation Model Changes for Peak Cladding Temperature for 20222023-05-22022 May 2023 10 CFR 50.46 Annual Report of Emergency Core Cooling System Evaluation Model Changes for Peak Cladding Temperature for 2022 DCL-23-038, Revision to the Unit 1 Reactor Vessel Material Surveillance Program Withdrawal Schedule2023-05-15015 May 2023 Revision to the Unit 1 Reactor Vessel Material Surveillance Program Withdrawal Schedule DCL-23-034, 2022 Annual Nonradiological Environmental Operating Report2023-05-0101 May 2023 2022 Annual Nonradiological Environmental Operating Report DCL-23-036, 2022 Annual Radiological Environmental Operating Report2023-05-0101 May 2023 2022 Annual Radiological Environmental Operating Report DCL-23-025, 2022 Annual Radioactive Effluent Release Report2023-05-0101 May 2023 2022 Annual Radioactive Effluent Release Report DCL-2023-512, Submittal of Receiving Water Monitoring Program 2022 Annual Report2023-04-27027 April 2023 Submittal of Receiving Water Monitoring Program 2022 Annual Report DCL-23-035, Response to Request for Additional Information on Request Regarding Senior Reactor Operator License Application2023-04-24024 April 2023 Response to Request for Additional Information on Request Regarding Senior Reactor Operator License Application DCL-23-028, Technical Specification Bases, Revision 142023-04-24024 April 2023 Technical Specification Bases, Revision 14 DCL-2023-511, Report on Discharge Monitoring for the First Quarter of 20232023-04-20020 April 2023 Report on Discharge Monitoring for the First Quarter of 2023 DCL-23-031, Submittal of Annual Report of Occupational Radiation Exposure for 20222023-04-19019 April 2023 Submittal of Annual Report of Occupational Radiation Exposure for 2022 DCL-23-024, Independent Spent Fuel Storage Installation, Response to Nrg Request for Additional Information for Revision to License Amendment Request 22-01 Request for Approval of Alternative Security Measures for Early Warning System2023-04-0404 April 2023 Independent Spent Fuel Storage Installation, Response to Nrg Request for Additional Information for Revision to License Amendment Request 22-01 Request for Approval of Alternative Security Measures for Early Warning System DCL-23-022, 2023 Annual Statement of Insurance for Pacific Gas and Electric Companys Diablo Canyon Power Plant2023-03-29029 March 2023 2023 Annual Statement of Insurance for Pacific Gas and Electric Companys Diablo Canyon Power Plant DCL-23-023, Decommissioning Funding Report for Diablo Canyon Power Plant, Units 1 and 22023-03-28028 March 2023 Decommissioning Funding Report for Diablo Canyon Power Plant, Units 1 and 2 DCL-23-021, Independent Spent Fuel Storage Installation, Emergency Plan Update2023-03-23023 March 2023 Independent Spent Fuel Storage Installation, Emergency Plan Update DCL-23-020, Responses to NRC Questions Regarding License Renewal Efforts2023-03-17017 March 2023 Responses to NRC Questions Regarding License Renewal Efforts DCL-23-009, Owner'S Activity Report for Unit 2 Twenty-Third Refueling Outage2023-02-22022 February 2023 Owner'S Activity Report for Unit 2 Twenty-Third Refueling Outage DCL-23-008, Request Regarding Senior Reactor Operator License Application2023-02-22022 February 2023 Request Regarding Senior Reactor Operator License Application DCL-2023-503, Annual Sea Turtle Report2023-01-26026 January 2023 Annual Sea Turtle Report DCL-2023-502, (DCPP) 4th Quarter 2022 Report on Discharge Self-Monitoring2023-01-18018 January 2023 (DCPP) 4th Quarter 2022 Report on Discharge Self-Monitoring DCL-22-091, Revised Steam Generator Tube Inspection Report for Twenty-First Refueling Outage2022-12-20020 December 2022 Revised Steam Generator Tube Inspection Report for Twenty-First Refueling Outage DCL-22-089, Core Operating Limits Report for Unit 2 Cycle 242022-12-20020 December 2022 Core Operating Limits Report for Unit 2 Cycle 24 DCL-22-085, Request to Resume Review of the License Renewal Application or, Alternatively, for an Exemption from 10 CFR 2.109(b), Concerning a Timely Renewal Application2022-10-31031 October 2022 Request to Resume Review of the License Renewal Application or, Alternatively, for an Exemption from 10 CFR 2.109(b), Concerning a Timely Renewal Application DCL-22-041, Site-Specific Decommissioning Cost Estimate, Revision 12022-10-12012 October 2022 Site-Specific Decommissioning Cost Estimate, Revision 1 DCL-22-042, Post-Shutdown Decommissioning Activities Report, Revision 12022-10-12012 October 2022 Post-Shutdown Decommissioning Activities Report, Revision 1 2024-01-29
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Pacific Gas and Electric Company Barry S. Allen Diablo Canyon Power Plant Site Vice President Mail Code 104/6 P. O. Box 56 Avila Beach, CA 93424 805.545.4888 August 6,2013 Internal: 691 .4888 Fax: 805.545.6445 PG&E Letter DCL-13-078 U.S. Nuclear Regulatory Commission 10 CFR 50.55a ATTN: Docu ment Control Desk Washington, DC 20555-0001 Docket No. 50-275, OL-DPR-80 Diablo Canyon Power Plant Unit 1 Response to NRC Request for Additional Information Regarding Request for Relief NDE-RCS-SE-1 R18 to Allow Use of Alternative Depth Sizing Criteria
Reference:
- 1. PG&E Letter DCL-13-038, "ASME Section XI Inservice Inspection Program Relief Request NDE-RCS-SE-1 R18 to Allow Use of Alternative Depth Sizing Criteria," dated April 11, 2013 In Reference 1, Pacific Gas and Electric Company (PG&E) submitted a request for relief to use an alternate root mean square error criteria for sizing flaws that are greater than the requirements of American Society of Mechanical Engineers Code (ASME Code) Case N-695, "Qualification Requirements for Dissimilar Metal Piping Welds," and ASME Code Case N-696, "Qualification Requirements for Appendix VIII Piping Examinations Conducted From the Inside Surface" at Diablo Canyon Power Plant, Unit 1.
The NRC Staff provided a request for additional information (RAI) via e-mail, dated July 9, 2013. The Enclosure to this letter provides PG&E's response to the NRC RAI.
PG&E makes no regulatory commitments (as defined by NEI 99-04) in this letter.
If you have any questions or require additional information, please contact Mr. Tom Baldwin at (805) 545-4720.
A member of the STARS (Strategic Teaming and Resource Sharing) Alliance Callaway
Document Control Desk PG&E Letter DCL-13-078 August 6, 2013 Page 2 RNTT/4231/SAPN 50033145-74 Enclosure cc: Diablo Distribution cc/encl: Thomas R. Hipschman, NRC Senior Resident Inspector James T. Polickoski, NRR Project Manager Steven A. Reynolds, Acting NRC Region IV State of California, Department of Occupational Safety and Health, Pressure Vessel Unit A member of the STARS (Strategic Teaming and Resource Sharing) Alliance Callaway . Comanche Peak . Diablo Canyon
Enclosure PG&E Letter OCL-13-078 PG&E Response to NRC Request for Additional Information Regarding Request for Relief NOE-RCS-SE-1 R18 to Allow Use of Alternative Depth Sizing Criteria NRC Question 1:
No procedures or personnel are able to depth-size cracks with an RMS error of O. 125 inches or less from the inner diameter for dissimilar metal or austenitic welds; however, there are procedures and personnel qualified to examine and depth-size these welds from the outer diameter. Please describe the difficulties (if any) in inspecting the subject welds from the outer diameter of the welds.
PG&E Response:
Access and General Considerations The outside diameter (00) of the Diablo Canyon Power Plant Unit 1 reactor safe-end welds can only be accessed through removable covers in the refueling cavity floor that lead to an annulus that surrounds the reactor vessel. The annulus is a relatively confined area and does not allow unrestricted work access to the welds. Attempts to reduce dose levels by shielding are impractical due to the essentially omnidirectional source from the reactor and coolant piping.
00 examination of the reactor nozzle to safe-end welds and safe-end to reactor coolant system (RCS) piping welds are addressed separately below.
Reactor Nozzle to Safe-End Welds Automated Examination The 8 nozzle to safe-end dissimilar metal welds are accessible for 00 examination.
The American Society of Mechanical Engineers (ASME)Section XI, Appendix VIII, Supplement 10 qualified vendor has estimated that automated 00 examination of the nozzle to safe-end welds would require 6 man-hours of duration for each of the 8 welds, in the annulus area. The 6 hour6.944444e-5 days <br />0.00167 hours <br />9.920635e-6 weeks <br />2.283e-6 months <br /> duration includes various inspection-related activities, including installation and removal of scanner tracks, search unit tending and change out, and calibrations.
Review of previous reactor annulus work activities indicates that the average dose accrual rate to be approximately 0.050 rem per hour. Based on the 6 man-hour annulus time per weld estimate, the accumulated dose for automated examinations of the eight welds would be 2.4 rem.
When the related support activities such as access cover removal/restoration, insulation removal/restoration, radiation protection support, etc. are included, the total dose estimate for automated examination of reactor nozzle to safe-end welds is 3.45 rem.
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Enclosure PG&E Letter DCL-13-078 Manual Examination Qualified manual examination of the reactor nozzle to safe-end dissimilar welds from the 00 is possible; the dose estimate based on historical data exceeds 4.25 rem for examination and related support activities for these eight welds.
Safe-End to RCS Piping Welds Automated Examination The four hot leg safe-end to RCS pipe welds are accessible from the 00 for examination. PG&E estimates that automated examination of these four welds would accrue dose at a rate similar to the nozzle to safe-end welds for a total dose of 1.2 rem.
The four cold leg safe-end to RCS pipe welds join to cast elbows; the 00 configuration of the welds and elbows are not suitable for 00 examination. Furthermore, no ASME XI, Appendix VIII ultrasonic examination techniques have been qualified for 00 detection or sizing through cast austenitic material. Examination of these welds would therefore be limited to the axial direction from the safe-end side only. PG&E estimates that accumulated dose for 00 automated examination of these four welds would be 0.8 rem since examination is limited to a single side.
When including the related support activities such as insulation removallrestoration, radiation protection support, etc., the total dose estimate for automated examination of safe-end to RCS piping welds is 2.15 rem.
Manual Examination Qualified manual examination of the hot leg safe-end and one side of the cold leg safe-end welds from the 00 is possible although cold leg examinations are limited for the same reasons as automated examinations. PG&E estimates a total exposure of 2.55 rem for manual 00 examination of these eight safe-end to RCS piping welds.
Generic Examination Related Issues Safe-end 00 examinations result in added risk to plant equipment. The small diameter annulus personnel access portals also house the ex-core nuclear instrumentation cabling which is vulnerable to damage from contact with personnel or equipment. The multiple entries/exits with tracks, scanners, and related equipment pose an incremental damage threat to safety related equipment that is likely to be required to be in-service during examinations.
Conclusion The estimates of 5.6 rem total exposure associated with automated 00 examinations and the 6.8 rem for manual 00 examination of the 16 subject welds far exceeds the very small incremental exposure increase associated with automated inside diameter examinations (estimated by PG&E to be 0.1 rem) when included with the end of interval reactor vessel examination.
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Enclosure PG&E Letter DCL-13-078 Limited examination coverage of the safe-end to cast elbow welds and increased risk to plant equipment are also significant considerations, in addition to as low as is reasonably achievable concerns that are described in this request for additional information response.
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