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MONTHYEARML17053D4942017-02-27027 February 2017 Closeout Letter Concerning Dissimilar Metal Butt Weld Flaw in Pressurizer Safety Relief Nozzle-to-Safe-End Weld Project stage: Other 2017-02-27
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Category:Letter
MONTHYEARML24222A6772024-08-0909 August 2024 Response to Request for Additional Information for Application to Revise Technical Specifications to Adopt TSTF-591-A, “Revise Risk Informed Completion Time (RICT) Program” Revision 0 and Revise 10 CFR 50.69 License Condition IR 05000317/20240022024-08-0606 August 2024 Integrated Inspection Report 05000317/2024002 and 05000318/2024002 IR 05000317/20240102024-07-31031 July 2024 Age-Related Degradation Inspection Report 05000317/2024010 and 05000318/2024010 ML24179A3262024-07-23023 July 2024 LTR - Constellation - SG Welds and Nozzles (L-2023-LLR-0053, L-2023-LLR-0054, L-2023-LLR-0055, L-2023-LLR-0056) ML24198A0442024-07-16016 July 2024 Inservice Inspection Report IR 05000317/20244012024-07-0909 July 2024 Security Baseline Inspection Report 05000317/2024401 and 05000318/2024401 05000317/LER-2024-001, Submittal of LER 2024-001-01 for Calvert Cliffs Nuclear Power Plant, Unit 1, Condition Prohibited by Technical Specifications Due to Safety Injection Check Valve Not Full Closed2024-07-0202 July 2024 Submittal of LER 2024-001-01 for Calvert Cliffs Nuclear Power Plant, Unit 1, Condition Prohibited by Technical Specifications Due to Safety Injection Check Valve Not Full Closed ML24177A1832024-06-25025 June 2024 Inservice Inspection Report RS-24-061, Constellation Energy Generation, LLC, Response to NRC Regulatory Issue Summary 2024-01, Preparation and Scheduling of Operator Licensing Examinations2024-06-14014 June 2024 Constellation Energy Generation, LLC, Response to NRC Regulatory Issue Summary 2024-01, Preparation and Scheduling of Operator Licensing Examinations ML24161A0012024-06-0909 June 2024 Independent Spent Fuel Storage Installation, Annual Radioactive Effluent Release Report ML24150A0522024-05-29029 May 2024 Operator Licensing Examination Approval ML24079A0762024-05-23023 May 2024 Issuance of Amendments to Adopt TSTF 264 ML24136A1962024-05-15015 May 2024 Independent Spent Fuel Storage Installation - Annual Radiological Environmental Operating Report IR 05000317/20240012024-05-0707 May 2024 Integrated Inspection Report 05000317/2024001 and 05000318/2024001 RS-24-041, Alternative Request to Utilize Code Case OMN-32, Alternative Requirements for Range and Accuracy of Pressure, Flow, and Differential Pressure Instruments Used in Pump Tests2024-04-30030 April 2024 Alternative Request to Utilize Code Case OMN-32, Alternative Requirements for Range and Accuracy of Pressure, Flow, and Differential Pressure Instruments Used in Pump Tests ML24101A1942024-04-22022 April 2024 Closeout Letter for GL 2004-02 ML24114A0182024-04-18018 April 2024 Electronic Reporting of Occupational Exposure Reporting ML24103A2042024-04-12012 April 2024 Constellation Energy Generation, LLC, Application to Revise Technical Specifications to Adopt TSTF-591-A, Revise Risk Informed Completion Time (RICT) Program Revision 0 and Revise 10 CFR 50.69 License Condition IR 05000317/20240402024-04-11011 April 2024 95001 Supplemental Inspection Report 05000317/2024040 and Follow-Up Assessment Letter RS-24-002, Constellation Energy Generation, LLC - Annual Property Insurance Status Report2024-04-0101 April 2024 Constellation Energy Generation, LLC - Annual Property Insurance Status Report ML24082A0082024-03-22022 March 2024 Request for Exemption from Certain Requirements of 10 CFR 72.212 and 10 CFR 72.214 ML24078A1152024-03-18018 March 2024 10 CFR 50.46 Annual Report ML24059A0632024-03-15015 March 2024 Authorization and Safety Evaluation for Alternative Request ISI-05-021 (EPID L-2023-LLR-0006) - Non-Proprietary IR 05000317/20230062024-02-28028 February 2024 Annual Assessment Letter for Calvert Cliffs Nuclear Power Plant, Units 1 and 2, (Reports 05000317/2023006 and 05000318/2023006 ML24052A0072024-02-14014 February 2024 Core Operating Limits Report for Unit 1, Cycle 27, Revision 0 ML24040A1492024-02-0909 February 2024 Response to NRC Request for Additional Information Regarding Final Response to Generic Letter 2004-02 ML24040A0962024-02-0909 February 2024 Notification of Readiness for NRC 95001 Inspection IR 05000317/20230042024-02-0101 February 2024 Integrated Inspection Report 05000317/2023004 and 05000318/2023004 ML24029A0102024-01-29029 January 2024 Request for Information and Notification of Conduct of IP 71111.21.N.04, Age-Related Degradation, Reference Inspection Report 05000317/2024010 and 05000318/2024010 ML24003A8872024-01-19019 January 2024 Exemption from Select Requirements of 10 CFR Part 73 (EPID L-2023-LLE-0033 (Security Notifications, Reports, and Recordkeeping and Suspicious Activity Reporting)) 05000318/LER-2023-004, Submittal of LER 2023-004-00 for Calvert Cliffs Nuclear Power Plant, Unit 2, Submittal of Automatic Reactor Trip from Reactor Protection System Actuation Due to Loss of Unit Service Transformer2024-01-16016 January 2024 Submittal of LER 2023-004-00 for Calvert Cliffs Nuclear Power Plant, Unit 2, Submittal of Automatic Reactor Trip from Reactor Protection System Actuation Due to Loss of Unit Service Transformer ML24011A0732024-01-11011 January 2024 Proposed Alternative to the Requirements for Repair/Replacement of Saltwater (SW) System Buried Piping 05000318/LER-2023-003, Forward LER 2023-003-00 for Calvert Cliffs Nuclear Power Plant, Unit 2, Manual Actuation of Auxiliary Feedwater System Due to 22 Steam Generator Feedwater Pump Trip2024-01-0808 January 2024 Forward LER 2023-003-00 for Calvert Cliffs Nuclear Power Plant, Unit 2, Manual Actuation of Auxiliary Feedwater System Due to 22 Steam Generator Feedwater Pump Trip 05000318/LER-2023-002, Forward LER 2023-002-00 for Calvert Cliffs Nuclear Power Plant, Unit 2, Automatic Reactor Trip from Reactor Protection System Actuation Due to Loss of Unit Service Transformer2024-01-0808 January 2024 Forward LER 2023-002-00 for Calvert Cliffs Nuclear Power Plant, Unit 2, Automatic Reactor Trip from Reactor Protection System Actuation Due to Loss of Unit Service Transformer ML24005A0222024-01-0505 January 2024 Revised Steam Generator Tube Inspection Reports ML23304A0642024-01-0202 January 2024 Issuance of Amendment No. 349 to Modify the Long-Term Coupon Surveillance Program RS-23-125, Request for Exemption from 10 CFR 2.109(b)2023-12-0707 December 2023 Request for Exemption from 10 CFR 2.109(b) ML23331A2992023-11-27027 November 2023 Submittal of Condition Prohibited by Technical Specifications Due to Failure to Sample Diesel Generator Fuel Oil Storage Tank IR 05000317/20230102023-11-20020 November 2023 Biennial Problem Identification and Resolution Inspection Report 05000317/2023010 and 05000318/2023010 ML23318A4722023-11-14014 November 2023 Supplement to License Amendment Request to Adopt TSTF-59-A ML23317A1192023-11-10010 November 2023 Constellation Energy Generation, LLC - 2023 Annual Report - Guarantees of Payment of Deferred Premiums ML23317A1032023-11-10010 November 2023 Supplemental Information Letter for Part 73 Exemption Request - Responses to Request for Confirmatory Information ML23310A0442023-11-0707 November 2023 Project Manager Assignment IR 05000317/20230402023-11-0202 November 2023 95001 Supplemental Inspection Report 05000317/2023040 and Follow-Up Assessment Letter IR 05000317/20230032023-11-0101 November 2023 Integrated Inspection Report 05000317/2023003 and 05000318/2023003 IR 05000317/20230902023-10-26026 October 2023 Final Significance Determination of a White Finding with Assessment Follow-Up and Notice of Violation; Inspection Report 05000317/2023090 ML23289A1202023-10-16016 October 2023 Request for Exemption from Enhanced Weapons, Firearms Background Checks, and Security Event Notifications Implementation RS-23-097, Constellation Energy Generation, LLC, Advisement of Leadership Changes and Submittal of Updated Standard Practice Procedures Plans2023-10-12012 October 2023 Constellation Energy Generation, LLC, Advisement of Leadership Changes and Submittal of Updated Standard Practice Procedures Plans RS-23-108, Proposed Alternative for Examinations of Examination Categories B-B, B-D, and C-A Steam Generator Pressure Retaining Welds and Full Penetration Welded Nozzles2023-10-11011 October 2023 Proposed Alternative for Examinations of Examination Categories B-B, B-D, and C-A Steam Generator Pressure Retaining Welds and Full Penetration Welded Nozzles RS-23-105, Proposed Alternative for Examinations of Examination Category C-B Steam Generator Nozzle-to-Shell Welds and Nozzle Inside Radius Sections2023-10-10010 October 2023 Proposed Alternative for Examinations of Examination Category C-B Steam Generator Nozzle-to-Shell Welds and Nozzle Inside Radius Sections 2024-08-09
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UNITED STATES NUCLEAR REGULATORY COMMISSION WASHINGTON, D.C. 20555-0001 Mr. Bryan C. Hanson President and Chief Nuclear Officer Exelon Nuclear 4300 Winfield Road Warrenville, IL 60555 February 27, 2017 SUBJECT: CALVERT CLIFFS NUCLEAR POWER PLANT, UNIT 1 -CLOSEOUT LETTER CONCERNING DISSIMILAR METAL BUTT WELD FLAW IN PRESSURIZER SAFETY RELIEF NOZZLE-TO-SAFE-END WELD (CAC NO. MF7409) Dear Mr. Hanson: By letter dated February 25, 2016 (Agencywide Documents Access and Management System Accession No. ML 16057A002), Exelon Generation Company, LLC (the licensee) submitted a report in accordance with Title 10 of the Code of Federal Regulations (10 CFR) 50.55a(g)(6)(ii)(F)(6) for the Calvert Cliffs Nuclear Power Plant, Unit 1 (CCNPP1 ). The report summarized the evaluation, along with inputs, methodologies, assumptions, and the preliminary causes for the identification of a change in size of a previous axial flaw in the pressurizer safety relief nozzle-to-safe-end dissimilar metal butt weld (ISi Weld 4-SR-1006-1) that was mitigated by the Mechanical Stress Improvement Process (MSIP) in 2006. Under 10 CFR 50.55a(g)(6)(ii)(F)(6), for any mitigated weld whose volumetric examination detects growth of existing flaws in the required examination volume that exceeds the previous IWB-3600 flaw evaluations or new flaws, a report summarizing the evaluation, along with inputs, methodologies, assumptions, and causes of the new flaw or flaw growth is required to be provided to the U.S. Nuclear Regulatory Commission (NRC) prior to the weld being placed in service other than modes 5 or 6. The NRC staff has completed its assessment of the subject report and finds that it meets the regulatory requirements of 10 CFR 50.55a(g)(6)(ii)(F)(6), and no additional followup regulatory action is required at this time. As stated in the report, during the February 2016 refueling outage (CC1 R23), the licensee performed a full structural weld overlay of ISi Weld 4-SR-1006-1 to ensure future structural integrity of the weld for the remaining life of the plant. The licensee also examined all 27 dissimilar metal butt welds within the scope of the American Society of Mechanical Engineers (ASME) Code Case N-770-1 during the refueling outage. No other new flaws or changes in existing flaws were found. The NRC staff finds that the licensee's actions address any uncertainties concerning the leak-tightness or structural integrity of ISi Weld 4-SR-1006-1, and there are no immediate safety concerns regarding the subject weld or any other dissimilar metal butt welds under the scope of ASME Code Case N-770-1 at CCNPP1. The NRC staff also reviewed the licensee's report for the generic impact of potential growth of an existing flaw in an MSIP mitigated weld. The NRC staff evaluated both the stress effect of the applied MSIP and the non-destructive examinations performed by the licensee in 2006, B. Hanson -2 -2010, and 2016. Based on the non-destructive examination information provided to the NRC, the staff was unable to reach an independent conclusion regarding the change in the reported axial flaw through-wall extent from the licensee's data between 2006 and 2016. Additionally, the NRC identified an issue of generic interest regarding the modeling of post-MSIP stresses; the NRC staff's continued assessment of this generic issue will be coordinated via the Electric Power Research lnstitute's Materials Reliability Program. Based on the above, the NRC staff concludes that the regulatory requirements of 10 CFR 50.55a(g)(6)(ii)(F)(6) are satisfied, and no further action is requested from the licensee at this time. The NRC staff activities on the subject report have been concluded, and the associated Cost Activity Code MF7409 has been closed. If you have any questions regarding this matter, please contact me at 301-415-1030 or Richard.Guzman@nrc.gov. Docket No. 50-317 cc: Distribution via Listserv Sincerely, Richard V. Guzman, Senior Project Manager Plant Licensing Branch I Division of Operating Reactor Licensing Office of Nuclear Reactor Regulation B. Hanson -3 -SUBJECT: CALVERT CLIFFS NUCLEAR POWER PLANT, UNIT 1 -CLOSEOUT LETTER CONCERNING DISSIMILAR METAL BUTT WELD FLAW IN PRESSURIZER SAFETY RELIEF NOZZLE-TO-SAFE-END WELD (CAC NO. MF7409) DATED FEBRUARY 27, 2017 DISTRIBUTION: Public LPL 1 R/F RidsNrrDeEpnb Resource RidsNrrPMMillstone Resource RidsRgn1 MailCenter Resource RidsNrrDorlLpl1 Resource RidsACRS_MailCTR Resource JCollins, NRR RidsNrrLALRonewicz Resource ADAMS A ccess1on N b ML 17053D494 um er: *b >Y e-ma1 OFFICE DORL/LPL 1 /PM DORL/LPL 1/LA DE/EPNB/BC* DORL/LPL 1/BC(A) NAME RGuzman LRonewicz DAiiey SKoenick DATE 02/24/2017 02/24/2017 02/22/2017 02/27/2017 OFFICIAL RECORD COPY DORL/LPL 1 /PM RGuzman 02/27/2017