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MONTHYEARML14070A5892014-04-0909 April 2014 Request for Additional Information Regarding Fukushima Lessons Learned - Flood Hazard Reevaluation Report Project stage: RAI ML15072A0072015-03-31031 March 2015 Staff Assessment of Response to 10 CFR 50.54(f) Information Request - Flood-Causing Mechanism Reevaluation Project stage: Acceptance Review ML15307A0562015-11-0404 November 2015 Supplement to Staff Assessment of Response to 10 CFR 50.54(f) Information Request - Flood Causing Mechanisms Reevaluation Project stage: Other RS-16-100, Mitigating Strategies Flood Hazard Assessment (Msfha) Submittal2016-06-30030 June 2016 Mitigating Strategies Flood Hazard Assessment (Msfha) Submittal Project stage: Other RS-17-088, Response to March 12, 2012, Request for Information Enclosure 2, Recommendation 2.1, Flooding, Required Response 3, Flooding Integrated Assessment Submittal2017-09-0808 September 2017 Response to March 12, 2012, Request for Information Enclosure 2, Recommendation 2.1, Flooding, Required Response 3, Flooding Integrated Assessment Submittal Project stage: Request 2015-03-31
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Category:Letter
MONTHYEARIR 05000237/20240022024-08-14014 August 2024 Integrated Inspection Report 05000237/2024002 and 05000249/2024002 IR 05000237/20240102024-08-0909 August 2024 NRC Age-Related Degradation Inspection Report 05000237/2024010 and 05000249/2024010 IR 05000237/20230112024-08-0707 August 2024 Reissue - Dresden Nuclear Power Station, Units 2 and 3 Comprehensive Engineering Team Inspection Report 05000237/2023011 and 05000249/2023011 IR 05000237/20200012024-08-0606 August 2024 Reissue - Dresden Nuclear Power Station, Units 2 and 3 - Integrated Inspection Report 05000237/2020001 and 05000249/2020001 ML24184A1712024-08-0202 August 2024 SLRA Schedule Letter RS-24-073, Alternative Schedule to Complete Decommissioning Beyond 60 Years of Permanent Cessation of Operations – Additional Information Supporting Request to Withhold Security-Related Information2024-07-31031 July 2024 Alternative Schedule to Complete Decommissioning Beyond 60 Years of Permanent Cessation of Operations – Additional Information Supporting Request to Withhold Security-Related Information ML24136A1322024-07-30030 July 2024 Transmittal Letter for Renewed License ML24208A0962024-07-25025 July 2024 57243-EN 57243 - Rssc Wire & Cable LLC, Dba Marmon - Part 21 Notification ML24193A0882024-07-24024 July 2024 Request for Withholding Information from Public Disclosure for Dresden Nuclear Power Station, Unit 1 Alternative Schedule to Complete Decommissioning Beyond 60-Years of Permanent Cessation of Operations (Docket 50-10) ML24204A1862024-07-24024 July 2024 – Regulatory Audit in Support of License Amendment Requests to Adopt TSTF 505, Revision 2; TSTF-591, Revision 0; and 10 CFR 50.69 IR 05000237/20243012024-06-27027 June 2024 NRC Initial License Examination Report 05000237/2024301; 05000249/2024301 ML24138A0572024-06-26026 June 2024 – Issuance of Amendment Nos. 285 and 278 Application to Adopt TSTF-564, “Safety Limit Mcpr” ML24138A1812024-06-18018 June 2024 Aging Management Audit Plan Regarding the Subsequent License Renewal Application Review RS-24-063, Response to Request for Additional Information for 10 CFR 50.55a Request No. I5R-222024-06-14014 June 2024 Response to Request for Additional Information for 10 CFR 50.55a Request No. I5R-22 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 ML24128A2742024-06-14014 June 2024 Notice of Acceptance and Opportunity for Hearing - Letter ML24156A2332024-06-11011 June 2024 Letter Supplemental Information for Alternative Schedule to Complete Decommissioning Beyond 60-Years of Permanent Cessation of Operations ML24151A6482024-06-0303 June 2024 Changes in Reactor Decommissioning Branch Project Management Assignments for Some Decommissioning Facilities ML24183A2752024-05-30030 May 2024 Registration of Use of Casks to Store Spent Fuel SVPLTR 24-0020, Registration of Use of Casks to Store Spent Fuel2024-05-30030 May 2024 Registration of Use of Casks to Store Spent Fuel RS-24-056, Application to Adopt 10 CFR 50.69, Risk-Informed Categorization and Treatment of Structures, Systems, and Components for Nuclear Power Reactors2024-05-28028 May 2024 Application to Adopt 10 CFR 50.69, Risk-Informed Categorization and Treatment of Structures, Systems, and Components for Nuclear Power Reactors ML24145A0432024-05-23023 May 2024 Registration of Use of Casks to Store Spent Fuel 10 CFR 72.212 SVPLTR 24-0019, Registration of Use of Casks to Store Spent Fuel2024-05-23023 May 2024 Registration of Use of Casks to Store Spent Fuel ML24158A0012024-05-22022 May 2024 License Amendment Request to Adopt TSTF-564 (EPID L-2023-LLA-0120) Illinois State Concurrence ML24142A3352024-05-21021 May 2024 Quad Cities—Information Request to Support the NRC Annual Baseline Emergency Action Level and Emergency Plan Changes RS-24-055, 2023 Corporate Regulatory Commitment Change Summary Report2024-05-17017 May 2024 2023 Corporate Regulatory Commitment Change Summary Report ML24135A0722024-05-10010 May 2024 Submittal of 2023 Annual Radiological Environmental Operating Report ML24129A1352024-05-0808 May 2024 License Amendment Request to Revise Technical Specifications to Adopt Risk Informed Completion Times TSTF-505, Revision 2, Provide Risk-Informed Extended Completion Times - RITSTF Initiative 4b, and TSTF-59 ML24128A1212024-05-0707 May 2024 Response to Braidwood and Dresden FOF Dates Change Request (2025) IR 05000237/20240012024-05-0101 May 2024 Integrated Inspection Report 05000237/2024001 & 05000249/2024001 ML24127A0982024-04-30030 April 2024 Radioactive Effluent Release Report 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 ML24120A2032024-04-29029 April 2024 Operator Licensing Exam Approval - Dresden Nuclear Power Station, May 2024 IR 05000237/20244012024-04-18018 April 2024 – Security Baseline Inspection Report 05000237/2024401 and 05000249/2024401 ML24108A0082024-04-17017 April 2024 Application for Renewed Operating License ML24179A2232024-02-12012 February 2024 ILT 23-1 (2024-301) SVP Letter - 24-007 ILT Exam Submittal IR 05000237/20230042024-02-0202 February 2024 Integrated Inspection Report 05000237/2023004 and 05000249/2023004 IR 05000010/20230012024-01-17017 January 2024 NRC Inspection Report 05000010/2023001 (Drss) ML23354A2812024-01-0404 January 2024 Exemption from Select Requirements of 10 CFR Part 73 (EPID L-2023-LLE-0031 (Security Notifications, Reports, and Recordkeeping and Suspicious Activity Reporting)) ML23305A1402023-12-13013 December 2023 Units 1 & 2; Nine Mile Point, Unit 2; Peach Bottom, Units 2 & 3; and Quad Cities, Units 1 and 2 - Issuance of Amendments to Adopt Traveler TSTF-580 RS-23-121, Sixth Ten-Year Interval Inservice Testing Program2023-11-30030 November 2023 Sixth Ten-Year Interval Inservice Testing Program SVPLTR 23-0037, Core Operating Limits Report for Cycle 292023-11-29029 November 2023 Core Operating Limits Report for Cycle 29 RS-23-119, Supplemental Information Letter for Part 73 Exemption Request - Responses to Request for Confirmatory Information2023-11-10010 November 2023 Supplemental Information Letter for Part 73 Exemption Request - Responses to Request for Confirmatory Information ML23317A1192023-11-10010 November 2023 Constellation Energy Generation, LLC - 2023 Annual Report - Guarantees of Payment of Deferred Premiums RS-23-107, Relief Request I5R-22, Inservice Inspection Program Relief Request Regarding Examination Coverage for the Fifth Inservice Inspection Interval2023-11-0808 November 2023 Relief Request I5R-22, Inservice Inspection Program Relief Request Regarding Examination Coverage for the Fifth Inservice Inspection Interval RS-23-102, Request for Exemption from Enhanced Weapons, Firearms Background Checks, and Security Event Notifications Implementation2023-10-16016 October 2023 Request for Exemption from Enhanced Weapons, Firearms Background Checks, and Security Event Notifications Implementation ML23285A2342023-10-13013 October 2023 Confirmation of Initial License Examination 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 ML23279A0712023-10-0606 October 2023 Response to NRC Dresden Nuclear Power Station, Units 2 and 3 - Comprehensive Engineering Team Inspection Report 05000237/2023011 and 05000249/2023011 ML23269A0662023-09-28028 September 2023 Proposed Alternative Request RV-23H Associated with the Sixth 10-Year Inservice Testing Interval 2024-08-09
[Table view] Category:Report
MONTHYEARNMP1L3469, Constellation Energy Company, LLC, Request for Use of Honeywell Mururoa V4F1 R Supplied Air Suits2022-06-30030 June 2022 Constellation Energy Company, LLC, Request for Use of Honeywell Mururoa V4F1 R Supplied Air Suits RS-22-082, Defueled Safety Analysis Report Update, Revision 112022-06-22022 June 2022 Defueled Safety Analysis Report Update, Revision 11 ML22047A1322022-02-15015 February 2022 Owner'S Activity Report Submittal Fifth 10-Year Interval 2021 Refueling Outage Activities RS-21-086, Supplement to Request for Exemptions from Portions of 10 CFR 50.47 and 10 CFR 50, Appendix E2021-08-23023 August 2021 Supplement to Request for Exemptions from Portions of 10 CFR 50.47 and 10 CFR 50, Appendix E RS-21-001, Revised Proposed Alternative to Utilize Code Cases N-878 and N-880 for Carbon Steel Piping2021-01-0404 January 2021 Revised Proposed Alternative to Utilize Code Cases N-878 and N-880 for Carbon Steel Piping ML20300A2352020-11-17017 November 2020 Documentation of the Completion of Required Actions Taken in Response to the Lessons Learned from the Fukushima Dai Ichi Accident ML20303A1752020-10-23023 October 2020 Proposed Relief Request from Section XI Repair/Replacement Documentation for Bolting Replacement of Pressure Retaining Bolting RS-20-070, Defueled Safety Analysis Report Update, Revision 102020-06-22022 June 2020 Defueled Safety Analysis Report Update, Revision 10 RS-19-093, Secondary Containment Drawdown Analysis2019-10-17017 October 2019 Secondary Containment Drawdown Analysis ML18138A3852019-03-0606 March 2019 Staff Assessment of Flood Hazard Integrated Assessment (CAC Nos. MG0221 and MG0222; EPID L-2017-JLD-0050) SVPLTR 19-0005, Owner'S Activity Report Submittal Fifth 10-Year Interval 2018 Refueling Outage Activities2019-02-0808 February 2019 Owner'S Activity Report Submittal Fifth 10-Year Interval 2018 Refueling Outage Activities RS-18-077, Defueled Safety Analysis Report Update, Revision 92018-06-20020 June 2018 Defueled Safety Analysis Report Update, Revision 9 ML18082A0812018-03-13013 March 2018 Request to Extend Enforcement Discretion Provided in Enforcement Guidance Memorandum 15-002 for Tornado-Generated Missile Protection Non-conformances Identified in Response to Regulatory Issues Summary 2015-06, Tornado Missile... RS-18-003, Report of Full Compliance with Phase 1 and Phase 2 of June 6, 2013 Commission Order Modifying Licenses with Regard to Reliable Hardened Containment Vents Capable of Operation Under Severe Accident Conditions2018-01-12012 January 2018 Report of Full Compliance with Phase 1 and Phase 2 of June 6, 2013 Commission Order Modifying Licenses with Regard to Reliable Hardened Containment Vents Capable of Operation Under Severe Accident Conditions ML18052A4862017-02-12012 February 2017 Owner'S Activity Report Submittal; Fifth 10-Year Interval 2017 Refueling Outage Activities ML16291A0212016-11-0808 November 2016 Staff Review of Spent Fuel Pool Evaluation Associated with Reevaluated Seismic Hazard Implementing Near-Term Task Force Recommendation 2.1 RS-16-124, Spent Fuel Pool Evaluation Supplemental Report, Response to NRC Request for Information Pursuant to 10 CFR 50.54(f) Regarding Recommendation 2.1 of the Near-Term Task Force Review of Insights from the Fukushima Dai-ichi Accident2016-08-31031 August 2016 Spent Fuel Pool Evaluation Supplemental Report, Response to NRC Request for Information Pursuant to 10 CFR 50.54(f) Regarding Recommendation 2.1 of the Near-Term Task Force Review of Insights from the Fukushima Dai-ichi Accident ML16190A1162016-07-0606 July 2016 2015 Regulatory Commitment Change Summary Report RS-16-100, Mitigating Strategies Flood Hazard Assessment (Msfha) Submittal2016-06-30030 June 2016 Mitigating Strategies Flood Hazard Assessment (Msfha) Submittal SVPLTR 16-0017, Submittal of Post Accident Monitoring Report Instrumentation2016-04-0808 April 2016 Submittal of Post Accident Monitoring Report Instrumentation ML15307A0562015-11-0404 November 2015 Supplement to Staff Assessment of Response to 10 CFR 50.54(f) Information Request - Flood Causing Mechanisms Reevaluation RS-15-265, Annual Report of Emergency Core Cooling System Evaluation Model Changes and Errors2015-10-23023 October 2015 Annual Report of Emergency Core Cooling System Evaluation Model Changes and Errors ML15251A3842015-08-31031 August 2015 Attachment 9 - NP-3305NP, Revision 1, Mechanical Design Report for Quad Cities and Dresden Atrium 10XN Fuel Assemblies - Licensing Report. (Non-Proprietary) ML15215A3372015-07-30030 July 2015 Holtec International Report No. HI-2146153, Revision 2, Licensing Report for the Criticality Analysis of the Dresden Unit 2 and 3 SEP for Atrium 10XM Fuel Design ML15097A5192015-04-27027 April 2015 Staff Assessment of Information Provided Pursuant to Title 10 of the Code of Federal Regulations Relating to Recommendation 2.1 of the Near-Term Task Force Review of Insights from the Fukushima Dai-Ichi ML15007A4912015-02-11011 February 2015 Interim Staff Evaluation Relating to Overall Integrated Plan in Response to Order EA-13-109 (Severe Accident Capable Hardened Vents) SVPLTR 15-0014, Owner'S Activity Report Submittal Fifth 10-Year Interval 2014 Refueling Outage Activities2015-02-11011 February 2015 Owner'S Activity Report Submittal Fifth 10-Year Interval 2014 Refueling Outage Activities RS-14-310, License Amendment Request Regarding Spent Fuel Storage Pool Criticality Methodology and Proposed Change to Technical Specification 4.3.1, Criticality2014-12-30030 December 2014 License Amendment Request Regarding Spent Fuel Storage Pool Criticality Methodology and Proposed Change to Technical Specification 4.3.1, Criticality RS-14-277, Proposed Alternative to Utilize Code Case N-513-4, Evaluation Criteria for Temporary Acceptance of Flaws in Moderate Energy Class 2 or 3 Piping Section XI, Division 12014-09-24024 September 2014 Proposed Alternative to Utilize Code Case N-513-4, Evaluation Criteria for Temporary Acceptance of Flaws in Moderate Energy Class 2 or 3 Piping Section XI, Division 1 RS-14-208, Third Six-Month Status Report in Response to March 12, 2012 Commission Order Modifying Licenses with Regard to Requirements for Mitigation Strategies for Beyond-Design-Basis External Events (Order Number EA-12-049)2014-08-28028 August 2014 Third Six-Month Status Report in Response to March 12, 2012 Commission Order Modifying Licenses with Regard to Requirements for Mitigation Strategies for Beyond-Design-Basis External Events (Order Number EA-12-049) ML14176A9612014-06-24024 June 2014 Submittal of Non-Proprietary BWROG Technical Product, BWROGTP-11-006 - ECCS Containment Walkdown Procedure, Rev 1 (January 2011), as Formally Requested During the Public Meeting Held on April 30, 2014 ML14115A2692014-05-30030 May 2014 Staff Assessment of the Seismic Walkdown Report Supporting Implementation of Near-Term Task Force Recommendation 2.3 Related to the Fukushima Dai-Ichi Nuclear Power Plant Accident RS-14-122, Response to Request for Additional Information Regarding Fukushima Lessons Learned - Flooding Hazard Reevaluation Report - Redacted2014-05-19019 May 2014 Response to Request for Additional Information Regarding Fukushima Lessons Learned - Flooding Hazard Reevaluation Report - Redacted ML14153A0062014-04-29029 April 2014 Revision 4 to Local Intense Precipitation Evaluation Report RS-14-067, Seismic Hazard and Screening Report (Central and Eastern United States (CEUS Sites), Response to NRC Request for Information Pursuant to 10 CFR 50.54(f) Re Recommendation 2.1 of The..2014-03-31031 March 2014 Seismic Hazard and Screening Report (Central and Eastern United States (CEUS Sites), Response to NRC Request for Information Pursuant to 10 CFR 50.54(f) Re Recommendation 2.1 of The.. SVPLTR 14-0013, Owner'S Activity Report Submittal Fifth 10-Year Interval 2013 Refueling Outage Activities2014-02-28028 February 2014 Owner'S Activity Report Submittal Fifth 10-Year Interval 2013 Refueling Outage Activities RS-13-288, Request for License Amendment to Technical Specifications Section 5.6.5. Core Operating Limits Report.2013-12-19019 December 2013 Request for License Amendment to Technical Specifications Section 5.6.5. Core Operating Limits Report. ML13220A2382013-11-22022 November 2013 Interim Staff Evaluation Relating to Overall Integrated Plan in Response to Order EA-12-049 - Mitigation Strategies ML13317A8292013-11-20020 November 2013 Mega-Tech Services, LLC Technical Evaluation Report Regarding the Overall Integrated Plan for Dresden Nuclear Power Station Units 2 and 3, TAC Nos.: MF1046 and MF1047 ML13126A1792013-03-28028 March 2013 Seismic Walkdown Report in Response to 50.54(f) Information Request Re Fukushima Near-Term Task Force Recommendation 2.3: Seismic, Updated Transmittal #1 (Annex a) for Dresden, Unit 3, Report No. RS-13-06, Part 1 of 13 ML13126A1802013-03-28028 March 2013 Seismic Walkdown Report in Response to 50.54(f) Information Request Re Fukushima Near-Term Task Force Recommendation 2.3: Seismic, Updated Transmittal #1 (Annex a) for Dresden, Unit 3, Report No. RS-13-06, Part 13 of 13 ML13126A1812013-03-28028 March 2013 Seismic Walkdown Report in Response to 50.54(f) Information Request Re Fukushima Near-Term Task Force Recommendation 2.3: Seismic, Updated Transmittal #1 (Annex a) for Dresden, Unit 3, Report No. RS-13-06, Part 2 of 13 ML13126A1832013-03-28028 March 2013 Seismic Walkdown Report in Response to 50.54(f) Information Request Re Fukushima Near-Term Task Force Recommendation 2.3: Seismic, Updated Transmittal #1 (Annex a) for Dresden, Unit 3, Report No. RS-13-06, Part 3 of 13 ML13126A1842013-03-28028 March 2013 Seismic Walkdown Report in Response to 50.54(f) Information Request Re Fukushima Near-Term Task Force Recommendation 2.3: Seismic, Updated Transmittal #1 (Annex a) for Dresden, Unit 3, Report No. RS-13-06, Part 4 of 13 ML13126A1852013-03-28028 March 2013 Seismic Walkdown Report in Response to 50.54(f) Information Request Re Fukushima Near-Term Task Force Recommendation 2.3: Seismic, Updated Transmittal #1 (Annex a) for Dresden, Unit 3, Report No. RS-13-06, Part 5 of 13 ML13126A1862013-03-28028 March 2013 Seismic Walkdown Report in Response to 50.54(f) Information Request Re Fukushima Near-Term Task Force Recommendation 2.3: Seismic, Updated Transmittal #1 (Annex a) for Dresden, Unit 3, Report No. RS-13-06, Part 6 of 13 ML13126A1872013-03-28028 March 2013 Seismic Walkdown Report in Response to 50.54(f) Information Request Re Fukushima Near-Term Task Force Recommendation 2.3: Seismic, Updated Transmittal #1 (Annex a) for Dresden, Unit 3, Report No. RS-13-06, Part 7 of 13 ML13126A1882013-03-28028 March 2013 Seismic Walkdown Report in Response to 50.54(f) Information Request Re Fukushima Near-Term Task Force Recommendation 2.3: Seismic, Updated Transmittal #1 (Annex a) for Dresden, Unit 3, Report No. RS-13-06, Part 8 of 13 ML13126A1892013-03-28028 March 2013 Seismic Walkdown Report in Response to 50.54(f) Information Request Re Fukushima Near-Term Task Force Recommendation 2.3: Seismic, Updated Transmittal #1 (Annex a) for Dresden, Unit 3, Report No. RS-13-06, Part 9 of 13 ML13126A1902013-03-28028 March 2013 Seismic Walkdown Report in Response to 50.54(f) Information Request Re Fukushima Near-Term Task Force Recommendation 2.3: Seismic, Updated Transmittal #1 (Annex a) for Dresden, Unit 3, Report No. RS-13-06, Part 10 of 13 2022-06-30
[Table view] Category:Miscellaneous
MONTHYEARML22047A1322022-02-15015 February 2022 Owner'S Activity Report Submittal Fifth 10-Year Interval 2021 Refueling Outage Activities ML20303A1752020-10-23023 October 2020 Proposed Relief Request from Section XI Repair/Replacement Documentation for Bolting Replacement of Pressure Retaining Bolting ML18138A3852019-03-0606 March 2019 Staff Assessment of Flood Hazard Integrated Assessment (CAC Nos. MG0221 and MG0222; EPID L-2017-JLD-0050) SVPLTR 19-0005, Owner'S Activity Report Submittal Fifth 10-Year Interval 2018 Refueling Outage Activities2019-02-0808 February 2019 Owner'S Activity Report Submittal Fifth 10-Year Interval 2018 Refueling Outage Activities ML18082A0812018-03-13013 March 2018 Request to Extend Enforcement Discretion Provided in Enforcement Guidance Memorandum 15-002 for Tornado-Generated Missile Protection Non-conformances Identified in Response to Regulatory Issues Summary 2015-06, Tornado Missile... ML18052A4862017-02-12012 February 2017 Owner'S Activity Report Submittal; Fifth 10-Year Interval 2017 Refueling Outage Activities ML16291A0212016-11-0808 November 2016 Staff Review of Spent Fuel Pool Evaluation Associated with Reevaluated Seismic Hazard Implementing Near-Term Task Force Recommendation 2.1 RS-16-124, Spent Fuel Pool Evaluation Supplemental Report, Response to NRC Request for Information Pursuant to 10 CFR 50.54(f) Regarding Recommendation 2.1 of the Near-Term Task Force Review of Insights from the Fukushima Dai-ichi Accident2016-08-31031 August 2016 Spent Fuel Pool Evaluation Supplemental Report, Response to NRC Request for Information Pursuant to 10 CFR 50.54(f) Regarding Recommendation 2.1 of the Near-Term Task Force Review of Insights from the Fukushima Dai-ichi Accident ML16190A1162016-07-0606 July 2016 2015 Regulatory Commitment Change Summary Report RS-16-100, Mitigating Strategies Flood Hazard Assessment (Msfha) Submittal2016-06-30030 June 2016 Mitigating Strategies Flood Hazard Assessment (Msfha) Submittal SVPLTR 16-0017, Submittal of Post Accident Monitoring Report Instrumentation2016-04-0808 April 2016 Submittal of Post Accident Monitoring Report Instrumentation ML15307A0562015-11-0404 November 2015 Supplement to Staff Assessment of Response to 10 CFR 50.54(f) Information Request - Flood Causing Mechanisms Reevaluation RS-15-265, Annual Report of Emergency Core Cooling System Evaluation Model Changes and Errors2015-10-23023 October 2015 Annual Report of Emergency Core Cooling System Evaluation Model Changes and Errors ML15097A5192015-04-27027 April 2015 Staff Assessment of Information Provided Pursuant to Title 10 of the Code of Federal Regulations Relating to Recommendation 2.1 of the Near-Term Task Force Review of Insights from the Fukushima Dai-Ichi ML15007A4912015-02-11011 February 2015 Interim Staff Evaluation Relating to Overall Integrated Plan in Response to Order EA-13-109 (Severe Accident Capable Hardened Vents) SVPLTR 15-0014, Owner'S Activity Report Submittal Fifth 10-Year Interval 2014 Refueling Outage Activities2015-02-11011 February 2015 Owner'S Activity Report Submittal Fifth 10-Year Interval 2014 Refueling Outage Activities RS-14-208, Third Six-Month Status Report in Response to March 12, 2012 Commission Order Modifying Licenses with Regard to Requirements for Mitigation Strategies for Beyond-Design-Basis External Events (Order Number EA-12-049)2014-08-28028 August 2014 Third Six-Month Status Report in Response to March 12, 2012 Commission Order Modifying Licenses with Regard to Requirements for Mitigation Strategies for Beyond-Design-Basis External Events (Order Number EA-12-049) RS-14-122, Response to Request for Additional Information Regarding Fukushima Lessons Learned - Flooding Hazard Reevaluation Report - Redacted2014-05-19019 May 2014 Response to Request for Additional Information Regarding Fukushima Lessons Learned - Flooding Hazard Reevaluation Report - Redacted ML14153A0062014-04-29029 April 2014 Revision 4 to Local Intense Precipitation Evaluation Report RS-14-067, Seismic Hazard and Screening Report (Central and Eastern United States (CEUS Sites), Response to NRC Request for Information Pursuant to 10 CFR 50.54(f) Re Recommendation 2.1 of The..2014-03-31031 March 2014 Seismic Hazard and Screening Report (Central and Eastern United States (CEUS Sites), Response to NRC Request for Information Pursuant to 10 CFR 50.54(f) Re Recommendation 2.1 of The.. SVPLTR 14-0013, Owner'S Activity Report Submittal Fifth 10-Year Interval 2013 Refueling Outage Activities2014-02-28028 February 2014 Owner'S Activity Report Submittal Fifth 10-Year Interval 2013 Refueling Outage Activities IR 05000272/20132012013-01-31031 January 2013 Exelon Generation Co., LLC, U.S. Nuclear Regulatory Commission (NRC) Office of Investigations (01) Investigation; Summary of 01 Report No. 3-2010-034; NRC Inspection Report Conference Letter - Licensee IR 05000456/20132022013-01-31031 January 2013 Exelon Generation Co., LLC, U.S. Nuclear Regulatory Commission (NRC) Office of Investigations (01) Investigation; Summary of 01 Report No. 3-2010-034; NRC Inspection Report Conference Letter - Licensee ML13008A2192013-01-31031 January 2013 U.S. Nuclear Regulatory Commission (NRC) Office of Investigations (01) Investigation; Summary of 01 Report No. 3-2010-034; NRC Inspection Report Conference Letter - Licensee IR 05000454/20132022013-01-31031 January 2013 Exelon Generation Co., LLC, U.S. Nuclear Regulatory Commission (NRC) Office of Investigations (01) Investigation; Summary of 01 Report No. 3-2010-034; NRC Inspection Report Conference Letter - Licensee IR 05000461/20132012013-01-31031 January 2013 Exelon Generation Co., LLC, U.S. Nuclear Regulatory Commission (NRC) Office of Investigations (01) Investigation; Summary of 01 Report No. 3-2010-034; NRC Inspection Report Conference Letter - Licensee IR 05000237/20132022013-01-31031 January 2013 Exelon Generation Co., LLC, U.S. Nuclear Regulatory Commission (NRC) Office of Investigations (01) Investigation; Summary of 01 Report No. 3-2010-034; NRC Inspection Report Conference Letter - Licensee IR 05000289/20132012013-01-31031 January 2013 Exelon Generation Co., LLC, U.S. Nuclear Regulatory Commission (NRC) Office of Investigations (01) Investigation; Summary of 01 Report No. 3-2010-034; NRC Inspection Report Conference Letter - Licensee IR 05000254/20132012013-01-31031 January 2013 Exelon Generation Co., LLC, U.S. Nuclear Regulatory Commission (NRC) Office of Investigations (01) Investigation; Summary of 01 Report No. 3-2010-034; NRC Inspection Report Conference Letter - Licensee IR 05000277/20132012013-01-31031 January 2013 Exelon Generation Co., LLC, U.S. Nuclear Regulatory Commission (NRC) Office of Investigations (01) Investigation; Summary of 01 Report No. 3-2010-034; NRC Inspection Report Conference Letter - Licensee IR 05000219/20132012013-01-31031 January 2013 Exelon Generation Co., LLC, U.S. Nuclear Regulatory Commission (NRC) Office of Investigations (01) Investigation; Summary of 01 Report No. 3-2010-034; NRC Inspection Report Conference Letter - Licensee IR 05000352/20132012013-01-31031 January 2013 Exelon Generation Co., LLC, U.S. Nuclear Regulatory Commission (NRC) Office of Investigations (01) Investigation; Summary of 01 Report No. 3-2010-034; NRC Inspection Report Conference Letter - Licensee IR 05000373/20132012013-01-31031 January 2013 Exelon Generation Co., LLC, U.S. Nuclear Regulatory Commission (NRC) Office of Investigations (01) Investigation; Summary of 01 Report No. 3-2010-034; NRC Inspection Report Conference Letter - Licensee ML12348A2602012-11-15015 November 2012 12Q0106.30-R-002, Rev. 2, Seismic Walkdown Report in Response to the 50.54(f) Information Request Regarding Fukushima Near-Term Task Force Recommendation 2.3: Seismic for the Dresden Nuclear Power Station, Unit 3, Part 6 of 11 ML12348A2562012-11-15015 November 2012 12Q0106.30-R-002, Rev. 2, Seismic Walkdown Report in Response to the 50.54(f) Information Request Regarding Fukushima Near-Term Task Force Recommendation 2.3: Seismic for the Dresden Nuclear Power Station, Unit 3, Part 2 of 11 ML12348A2572012-11-15015 November 2012 12Q0106.30-R-002, Rev. 2, Seismic Walkdown Report in Response to the 50.54(f) Information Request Regarding Fukushima Near-Term Task Force Recommendation 2.3: Seismic for the Dresden Nuclear Power Station, Unit 3, Part 3 of 11 ML12348A2582012-11-15015 November 2012 12Q0106.30-R-002, Rev. 2, Seismic Walkdown Report in Response to the 50.54(f) Information Request Regarding Fukushima Near-Term Task Force Recommendation 2.3: Seismic for the Dresden Nuclear Power Station, Unit 3, Part 4 of 11 ML12348A2592012-11-15015 November 2012 12Q0106.30-R-002, Rev. 2, Seismic Walkdown Report in Response to the 50.54(f) Information Request Regarding Fukushima Near-Term Task Force Recommendation 2.3: Seismic for the Dresden Nuclear Power Station, Unit 3, Part 5 of 11 ML12348A2612012-11-15015 November 2012 12Q0106.30-R-002, Rev. 2, Seismic Walkdown Report in Response to the 50.54(f) Information Request Regarding Fukushima Near-Term Task Force Recommendation 2.3: Seismic for the Dresden Nuclear Power Station, Unit 3, Part 7 of 11 ML12348A2632012-11-15015 November 2012 12Q0106.30-R-002, Rev. 2, Seismic Walkdown Report in Response to the 50.54(f) Information Request Regarding Fukushima Near-Term Task Force Recommendation 2.3: Seismic for the Dresden Nuclear Power Station, Unit 3, Part 9 of 11 ML12348A2642012-11-15015 November 2012 12Q0106.30-R-002, Rev. 2, Seismic Walkdown Report in Response to the 50.54(f) Information Request Regarding Fukushima Near-Term Task Force Recommendation 2.3: Seismic for the Dresden Nuclear Power Station, Unit 3, Part 10 of 11 ML12348A2662012-11-15015 November 2012 12Q0108.30-R-001, Rev. 1, Seismic Walkdown Report in Response to the 50.54(f) Information Request Regarding Fukushima Near-Term Task Force Recommendation 2.3: Seismic for the Dresden Nuclear Power Station, Unit 2, Part 1 of 7 ML12348A2672012-11-15015 November 2012 12Q0108.30-R-001, Rev. 1, Seismic Walkdown Report in Response to the 50.54(f) Information Request Regarding Fukushima Near-Term Task Force Recommendation 2.3: Seismic for the Dresden Nuclear Power Station, Unit 2, Part 2 of 7 ML12348A2682012-11-15015 November 2012 12Q0108.30-R-001, Rev. 1, Seismic Walkdown Report in Response to the 50.54(f) Information Request Regarding Fukushima Near-Term Task Force Recommendation 2.3: Seismic for the Dresden Nuclear Power Station, Unit 2, Part 3 of 7 ML12348A2692012-11-15015 November 2012 12Q0108.30-R-001, Rev. 1, Seismic Walkdown Report in Response to the 50.54(f) Information Request Regarding Fukushima Near-Term Task Force Recommendation 2.3: Seismic for the Dresden Nuclear Power Station, Unit 2, Part 4 of 7 ML12348A2622012-11-15015 November 2012 12Q0106.30-R-002, Rev. 2, Seismic Walkdown Report in Response to the 50.54(f) Information Request Regarding Fukushima Near-Term Task Force Recommendation 2.3: Seismic for the Dresden Nuclear Power Station, Unit 3, Part 8 of 11 ML12348A2732012-11-15015 November 2012 12Q0106.30-R-002, Rev. 2, Seismic Walkdown Report in Response to the 50.54(f) Information Request Regarding Fukushima Near-Term Task Force Recommendation 2.3: Seismic for the Dresden Nuclear Power Station, Unit 3, Part 1 of 11 ML12348A2722012-11-15015 November 2012 12Q0108.30-R-001, Rev. 1, Seismic Walkdown Report in Response to the 50.54(f) Information Request Regarding Fukushima Near-Term Task Force Recommendation 2.3: Seismic for the Dresden Nuclear Power Station, Unit 2, Part 7 of 7 ML12348A2712012-11-15015 November 2012 12Q0108.30-R-001, Rev. 1, Seismic Walkdown Report in Response to the 50.54(f) Information Request Regarding Fukushima Near-Term Task Force Recommendation 2.3: Seismic for the Dresden Nuclear Power Station, Unit 2, Part 6 of 7 ML12348A2702012-11-15015 November 2012 12Q0108.30-R-001, Rev. 1, Seismic Walkdown Report in Response to the 50.54(f) Information Request Regarding Fukushima Near-Term Task Force Recommendation 2.3: Seismic for the Dresden Nuclear Power Station, Unit 2, Part 5 of 7 2022-02-15
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UNITED STATES NUCLEAR REGULATORY COMMISSION WASHINGTON, D.C. 20555-0001 Mr. Bryan C. Hanson Senior Vice President Exelon Generation Company, LLC 4300 Winfield Rd Warrenville, IL 60555 November 4, 2015
SUBJECT:
DRESDEN NUCLEAR POWER STATION, UNITS 2 AND 3-SUPPLEMENT TO STAFF ASSESSMENT OF RESPONSE TO 10 CFR 50.54(f) INFORMATION REQUEST -FLOOD-CAUSING MECHANISMS REEVALUATION (TAC NOS. MF1795 AND MF1796)
Dear Mr. Hanson:
The purpose of this letter is to transmit the supplement to the U.S. Nuclear Regulatory Commission (NRC) staff's assessment of Dresden Nuclear Power Station, Units 2 and 3 (Dresden) reevaluated flood hazard information that was issued to you by a letter dated March 31, 2015 (Agencywide Documents Access and Management System (ADAMS) Accession No. ML 15072A007).
The supplement updates the original staff assessment to address changes in the NRC's approach to next steps following the review of the flood hazard reevaluations as directed by the Commission.
The letter also addresses the next steps associated with the mitigation strategies assessment with respect to the reevaluated flood hazards. By letter dated March 12, 2012 (ADAMS Accession No. ML 12053A340), the NRC issued a request for information pursuant to Title 10 of the Code of Federal Regulations, Section 50.54(f) (hereafter referred to as the 50.54(f) letter). The request was issued as part of implementing lessons learned from the accident at the Fukushima Dai-ichi nuclear power plant. Enclosure 2 to the 50.54(f) letter requested licensees to reevaluate flood-causing mechanisms using present-day methodologies and guidance.
By letter dated March *10, 2013 (ADAMS Accession No. ML 13135A120), Exelon Generation Company, LLC (the ilcensee) responded to this request for Dresden. In response to NRC staff questions, this response was supplemented by letter dated May 19, 2014 (ADAMS Accession No. ML 15092A821).
- The NRC staff has completed its review of the information provided, as documented in the staff assessment and the enclosed supplement to the staff assessment.
This closes out the NRC's efforts associated with TAC Nos. MF1795 and MF1796. . The enclosed supplement to the staff assessment updates the NRC staff's conclusions in accordance with the flood hazard reevaluation approach described in NRC letter dated September 1, 2015 (ADAMS Accession No. ML 15174A257), 'concerning the coordination of requests for information regarding flooding hazard reevaluations and mitigating strategies for beyond-design-basis external events. This letter describes the changes in the NRC's approach to the flood hazard reevaluations that were approved by the Commission in its Staff
B. Hanson As documented in the NRC staff assessment and the enclosed supplement, the NRC staff has concluded that the licensee's reevaluated flood hazard information is suitable for the assessment of mitigation strategies developed in response to Order EA-12-049 (i.e., defines the mitigating strategies flood hazard information described in guidance documents currently being finalized by the industry and NRC staff) for Dresden. Further, the NRC staff continues to assert that the licensee's reevaluated flood hazard information is suitable for other assessments associated with Near-Term Task Force Recommendation 2.1 "Flooding." The reevaluated flood hazard results for local intense precipitation and upstream dam failures were not bounded by the current design-basis flood hazard. In order to complete its response to Enclosure 2 to the 50.54(f) letter, the licensee is expected to submit a revised integrated
- assessment or focused evaluation(s), as appropriate, to address these reevaluated flood hazards, as described in the NRC's September 1, 2015 letter. If you have any questions, please contact me at (301) 415-6197 or e-mail at Tekia.Govan@nrc.gov.
Docket Nos. 50-237 and 50-249
Enclosure:
Supplement to Staff Assessment of Flood Hazard Reevaluation Report cc w/encl: Distribution via Listserv Tekia Govan, Project Manager Hazards Management Branch Japan Lessons-Learned Division Office of Nuclear Reactor Regulation SUPPLEMENT TO STAFF ASSESSMENT BY THE OFFICE OF NUCLEAR REACTOR REGULATION RELATED TO FLOODING HAZARD REEVALUATION REPORT NEAR-TERM TASK FORCE RECOMMENDATION
2.1 RELATED
TO THE FUKUSHIMA DAl-ICHI NUCLEAR POWER PLANT ACCIDENT DRESDEN NUCLEAR POWER STATION, UNITS 2 AND 3 DOCKET NOS. 50-237 AND 50-249
1.0 INTRODUCTION
This document is a supplement to the U.S. Nuclear Regulatory Commission (NRC) staff assessment that was transmitted by letter dated March 31, 2015 (NRC, 2015a), to Exelon Generation Company, LLC (the licensee) for Dresden Nuclear Power Station, Units 2 and 3 (Dresden, DNPS). With the exceptions of the Table 3.1.2-1 and the Reference section, this supplement only contains the sections that were changed to resolve the open items and reflect the changes in the NRC's approach to the flood hazard reevaluations that were approved by the Commission in its Staff Requirements Memorandum (SRM) (NRC, 2015b) to COMSECY 0019 (NRC, 2015c), which described the NRC's mitigating strategies and flooding hazard reevaluation action plan. Table 3.1.2-1 at the end of the supplement is copied from the staff assessment for convenience.
Instead of repeating the Reference section in its entirety, only the additions to the list of references are included in the supplement.
2.0 REGULATORY
BACKGROUND
2.1 Applicable
Regulatory Requirements There are no changes or updates to this section of the NRC staff assessment.
2.2 Enclosure
2 to the 50.54(f) Letter By letter dated March 12, 2012 (NRC, 2012a) the NRC issued a request for information Pursuant to Title 1 O of the Code of Federal Regulations (10 CFR), Section 50.54(f) (hereafter referred to as the 50.54(f) letter). The 50.54(f) letter requests all power reactor licensees and construction permit holders reevaluate all external flooding-causing mechanisms at each site. The reevaluation should apply present-day methods and regulatory guidance that are used by the NRC staff to conduct early site permit (ESP) and combined license (COL) reviews. This includes current techniques, software, and methods used in present-day standard engineering practice.
If the reevaluated flood-causing mechanisms are not bounded by the current plant design-basis flood hazard, an integrated assessment may be necessary.
Enclosure 2.2.1 Flood-Causing Mechanisms There are no changes or updates to this section of the NRC staff assessment.
2.2.2 Associated
Effects There are no changes or updates to this section of the NRC staff assessment.
2.2.3 Combined
Effects Flood There are no changes or updates to this section of the NRC staff assessment.
2.2.4 Flood
Event Duration There are no changes or updates to this section of the NRC staff assessment.
2.2.5 Actions
Following the Flooding Hazard Reevaluation Report (FHRR) For the sites where the reevaluated probable maximum flood elevation is not bounded by the current design-basis probable maximum flood elevation for all flood-causing mechanisms, the 50.54(f) letter requests licensees and construction permit holders to:
- Submit an Interim Action Plan with the FHRR documenting actions planned or already taken to address the reevaluated hazard.
- Perform an integrated assessment subsequent to the FHRR to (a) evaluate the effectiveness of the current licensing basis (i.e., flood protection and mitigation systems), (b) identify plant-specific vulnerabilities, and (c) assess the effectiveness of existing or planned systems and procedures for protecting against and mitigating consequences of flooding for the flood event duration.
After issuance of the 50.54(f) letter, the NRC changed the approach to the steps following the review of the flood hazard reevaluations, as directed by the Commission, to permit use of focused evaluations as an alternative to an integrated assessment.
The NRC letter dated September 1, 2015 (NRC, 2015d) describes the changes in the NRC's approach to the flood hazard reevaluations.
If the reevaluated flood hazard is bounded by the current design-basis flood hazard for all causing mechanisms at the site, licensees are not required to perform an integrated assessment or focused evaluation(s) at this time. 3.0 TECHNICAL EVALUATION There are no changes or updates to this section of the NRC staff assessment. 3.1 Site Information There are no changes or updates to this section of the NRC staff assessment.
3.2 LIP and Associated Site Drainage There are no changes or updates to this section of the NRC staff assessment.
3.2.1 Model
Inputs and Assumptions There are no changes or updates to this section of the NRC staff assessment.
3.2.2 Probable
Maximum Precipitation The licensee's analysis developed the 1-hour, 1-square mile probable maximum precipitation (PMP) event distribution using Hydrometerological Reports (HMRs) 51 and 52 (National Oceanic and Atmospheric Administration (NOAA), 1978 and 1982). The licensee stated that the local intense precipitation (LIP) event is defined by NUREG/CR-7046 (NRC, 2011 d) as the 1-hour, 1-square mile PMP event. The licensee extrapolated from the PMP depth contour map provided in HMR 52. The licensee developed the distribution of the 1-hour PMP from the 5-, 15-, 30-and 60-minute time intervals from HMR 52. The licensee computed a cumulative depth of the 1-hour, 1-square mile PMP of 17.97 inches (45.28 cm). The NRC staff verified the HMR 51 and HMR 52 computations based on the location of the DNPS, and concluded the PMP depths are appropriate.
The NRC staff notes that a reasonable estimate of the site's LIP PMP is the application of an appropriate NOAA HMR estimate for any rainfall duration used in NUREG/CR-7046, regardless of temporal distribution of the rainfall.
The licensee obtained 1-sq. mile PMP depths for durations ranging between 5-minutes to 1-hour using HMR-51 and HMR-52. Therefore, the NRC staff confirmed that the licensee selected appropriate rainfall rate values to satisfy the 50.54(f) information request. Based on the NRC staff's reviews of FHRRs to date, the NRC staff observed that, when using transient rainfall runoff models, PMP events having longer than 1-hour durations may result in higher LIP flood elevations and longer periods of inundation than the 1-hour event. NRC staff also noted that LIP events deriving from PMPs having relatively short durations may result in limiting warning time and may likewise result in consequential LIP flood elevation (e.g., flood elevations above the openings to plant structures).
3.2.3 Site Topography There are no changes or updates to this section of the NRC staff assessment.
3.2.4 Site Land Cover There are no changes or updates to this section of the NRC staff assessment. 3.2.5 FL0-20 Results The licensee computed the water surface elevations, maximum flooding depths, maximum velocity, maximum resultant impact loading (forces due to moving water), and maximum resultant static load (height of water) using the FL0-20 model. The maximum flood elevation of 518.1 ft (157.9 m) occurs at several Category 1 structures.
The flooding depths range between 0.1 ft (0.03 m) (Reactor Building, Unit 3) to 1. 7 ft (0.5 m) (Turbine Building, Unit 2), which produce a maximum static load of 85.0 lbs. per ft (126.5 kg-force perm). The velocities are generally less than 1 foot per second (ft/s; 0.3 meters per second (m/s)), with resultant impact loads of 5 lbs. per ft (7.5 kg-force perm) or less. The licensee noted that based on the sensitivity analysis of the grid size and Manning's n values (n-values), an accuracy of+/-0.1 ft (0.03 m) should be taken when considering the flood elevations.
The NRC staff reviewed the FL0-20 model input and output files provided by the licensee.
In the course of the review, NRC staff performed a mass balance verification and concluded that the runoff amount passing through the model boundary is less than the amount of rainfall.
The difference in mass could result in a potential underestimation of the maximum water levels around the site. The licensee is requested to resolve numerical modeling issue associated with the LIP flood analyses, specifically the reduction of volume of outflow runoff as compared to the inflow precipitation, accounting for infiltration.
This issue may relate to runoff from rooftops being removed from the numerical model domain rather than discharging to the ground surface near the structure or an adjacent area. 3.2.6 Site-Specific Probable Maximum Precipitation There are no changes or updates to this section of the NRC staff assessment.
3.2. 7 NRC Staff Conclusion The NRC staff confirmed the licensee's conclusion that the reevaluated flood hazard for LIP and associated site drainage is not bounded by the current design-basis flood hazard. Therefore, the licensee is expected to submit a focused evaluation for LIP and associated site drainage consistent with the process outlined in COMSECY-15-0019 (NRC, 2015b) and associated guidance that will be issued. Under this approach, the NRC staff anticipates that licensees will perform and document a focused evaluation for LIP and associated site drainage that evaluates the impact of the LIP hazard on the site and implements any necessary programmatic, procedural or plant modifications to address this hazard exceedance.
The modelling issues that are discussed in Section 3.2.5 should be addressed in the focused evaluation, if the licensee uses the same FL0-20 model in its focused evaluation.
The NRC staff anticipates that licensees will submit letters providing a summary of the evaluation and, if needed, regulatory commitments to implement and maintain appropriate programmatic, procedural or plant modifications to protect against the LIP hazard. 3.3 Streams and Rivers There are no changes or updates to this section of the NRG staff assessment.
3.4 Failure
of Dams and Onsite Water Control/Storage Structures There are no changes or updates to this section of the NRG staff assessment.
3.4.1 Critical
Dam Evaluation and Selection There are no changes or updates to this section of the NRG staff assessment.
3.4.2 Upstream
Dam Failure Mechanism Summary There are no changes or updates to this section of the NRG staff assessment.
3.4.3 Hydrologic
Dam Failure Analysis There are no changes or updates to this section of the NRG staff assessment.
3.4.4 Seismic
Upstream Dam Failure There are no changes or updates to this section of the NRG staff assessment.
3.4.5 Upstream
Dam Failure Timing and Duration There are no changes or updates to this section of the NRG staff assessment.
3.4.6 Other
Associated Effects of Upstream Dam Failure 3.4. 7 NRG Staff Conclusion The NRC staff reviewed the assumptions and approach used in the flooding from upstream dams analysis, and concluded the approach appropriate and assumptions to be reasonable.
The NRG staff verified that the models were consistent with results presented in the FHRR and that in cases where the one model output was used as an input to another model, the two data sets were exactly the same. The NRG staff verified the references used, to ensure that they met standard engineering practices and NRG guidance.
The NRG staff confirmed the licensee's conclusion that the reevaluated flood hazard for failure of dams and onsite water control or storage structures is not bounded by the current design-basis flood hazard. Therefore, the treatment of the upstream dam failures should be addressed in the integrated assessment or focused evaluation consistent with the process and guidance discussed in COMSECY-15-0019 (NRG, 2015c). 3.5 Storm Surge There are no changes or updates to this section of the NRC staff assessment.
3.6 Seiche
There are no changes or updates to this section of the NRC staff assessment.
3.7 Tsunami
There are no changes or updates to this section of the NRC staff assessment.
3.8 Ice-Induced Flooding There are no changes or updates to this section of the NRC staff assessment.
3.9 Channel
Migrations or Diversions There are no changes or updates to this section of the NRC staff assessment.
4.0 REEVALUATED
FLOOD HEIGHT. EVENT DURATION AND ASSOCIATED EFFECTS FOR HAZARDS NOT BOUNDED BY THE COB The NRC staff confirms that the reevaluated hazard results for LIP and dam failures are not bounded by the current design-basis flood hazard. Therefore, the NRC staff anticipates that the licensee will perform additional assessments (i.e., integrated assessment or focused evaluation) of plant response for DNPS, as described in NRC letter dated September 1, 2015 (NRC, 2015d). The NRC staff reviewed the following flood hazard parameters needed to perform the additional assessments or evaluations of plant response:
- Flood event duration, including warning time and intermediate water surface elevations that trigger actions by plant personnel, as defined in Japan Lessons-Learned Directorate (JLD) Interim Staff Guidance (ISG) JLD-ISG-2012-05.
Flood event durations for the flood-causing mechanisms identified above are shown in Table 4.0-1.
Flood height and associated effects for the flood-causing mechanisms identified above are shown in Table 4.0-2. Based upon the preceding analysis, the NRC staff confirmed that the reevaluated flood hazard information is appropriate input to other assessments or evaluations associated with Near-Term Task Force Recommendations, including the assessment of mitigation strategies developed in response to Order EA-12-049 (i.e., defines the mitigating strategies flood hazard information described in guidance documents currently being finalized by the industry and NRC staff).
5.0 CONCLUSION
The NRC staff has reviewed the information provided for the reevaluated flood-causing mechanisms of DNPS, Units. 2 and 3. Based on its review, the NRC staff concludes that the licensee conducted the hazard reevaluation using present-day methodologies and regulatory guidance used by the NRC staff in connection with ESP and COL reviews. Based on the preceding analysis, the NRC staff confirmed that the licensee responded appropriately to Enclosure 2, Required Response 2, of the 50.54(f) letter. In reaching this determination, the NRC staff confirmed the licensee's conclusions that (a) the reevaluated flood hazard results for LIP and upstream dam failure are not bounded by the current design-basis flood hazard, (b) additional assessments of plant response will be performed for the local intense precipitation and upstream dam failure flood-causing mechanisms, and (c) the reevaluated flood-causing mechanism information is appropriate input to additional assessments or evaluations of plant response, as described in the 50.54(f) letter and COMSECY-15-0019 (NRC, 2015b), including the assessment of mitigation strategies developed in response to Order EA-12-049 (i.e., defines the mitigating strategies flood hazard information described in guidance documents currently being finalized by the industry and NRC staff). The NRC staff has no additional information needs at this time with respect to the FHRR.
6.0 REFERENCES
6.1 U.S. Nuclear Regulatory Commission (NRC) Documents and Publications:
NRC (U.S. Nuclear Regulatory Commission), 2015a, letter from Victor Hall (NRC), to Bryan Hanson, Senior Vice President, Exelon Generation Company, LLC, " Dresden Nuclear Power Station, Units 2 and 3 -Staff Assessment of Response to 10 CFR 50.54(f) Information Request-Flood-Causing Mechanism Reevaluation" (TAC Nos. MF1795 AND MF1796) March 31, 2015, ADAMS Accession No. ML 15072A007.
NRC (U.S. Nuclear Regulatory Commission), 2015b, "SRM -COMSECY-15-0019
-Closure Plan for the Reevaluation Of Flooding Hazards for Operating Nuclear Power Plants,
COMSECY-15-0019, July 28, 2015, ADAMS Accession No. ML 15209A682.
NRC (U.S. Nuclear Regulatory Commission), 2015c, "Closure Plan for the Reevaluation of Flooding Hazards For Operating Nuclear Power Plants," COMSECY-15-0019, June 30, 2015, ADAMS Accession No. ML 15153A104.
NRC (U.S. Nuclear Regulatory Commission), 2015d, letter from William M. Dean, Director, to Power Reactor Licensees, "Coordination of Requests for Information Regarding Flooding Hazard Reevaluations and Mitigating Strategies for Beyond-Design-Basis External Events", ADAMS Accession No. ML 15174A257.
6.2 Codes
and Standards There are no additions to the references in this section. 6.3 Other
References:
There are no additions to the references in this section. T bl 3121 C t D . B . Fl d H d a e .. -urren es1gn as1s 00 azar s Stillwater Current Design Flooding Elevation Associated Basis Flood Effects Elevation Reference Mechanism ft {m) ft {m) NGVD29 NGVD29 LIP and Associated 517.5 Exelon, Drainage (157.7) Not discussed 517.5 (157.7) 2013b Section 5 Streams and Rivers 525.0 3.0 ft (0.9 m) 528.0 (160.9) FHRR, (160.0) (wind wave) Section 2.a Failure of Dams and Onsite Water 508.2 Not discussed 508.2 (154.9) FHRR, Control/Storage (154.9) Section 2.a Structures Storm Surge Not applicable to DNPS site. FHRR, Section 2.a Seiche Not applicable to DNPS site. FHRR, Section 2.a Tsunami Not applicable to DNPS site. FHRR, Section 2.a Ice-Induced No elevation provided in UFSAR. FHRR, Section 2.a Channel Migrations No elevation provided in UFSAR; discussed in FHRR, or Diversions reference to control of locks and dams by USAGE. Section 2.a Table 4.0-1: Flood Event Duration for Flood-Causing Mechanisms Not Bounded by COB Hazard Flood-Causing Time Available Duration of Time for Water to for Preparation Mechanism for Flood Event Inundation of Site Recede from Site LIP and Associated See Section 3.2 See Section 3.2 See Sections 3.2 Drainage Failure of Dams 1 day, 12 hours1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br />, 6 days, 15 hours1.736111e-4 days <br />0.00417 hours <br />2.480159e-5 weeks <br />5.7075e-6 months <br /> and Onsite Water 11 days, 8 hours9.259259e-5 days <br />0.00222 hours <br />1.322751e-5 weeks <br />3.044e-6 months <br /> (Table Control/Storage and 45 minutes (Table 6.1, 6.1, Barstow, 2014b) Structures (Kaegi, 2013) Barstow, 2014b) Table 4.0-2: Reevaluated Flood Hazards for Flood-Causing Mechanisms Not Bounded by COB Hazard Stillwater Reevaluated Flood-Causing Elevation, Associated Effects Flood Reference Mechanism ft (m) Hazard, ft NGVD29 (m) NGVD29 LIP and Varies with None Varies with Exelon, 2013b, Associated maximum of maximum of Section 4 Drainage 518.1 518.1 (157.9) (157.9) Failure of Dams Varies with Varies with a maximum Varies with a FHRR, Section and Onsite Water a maximum of 4.2 (1.3) (Wind wave maximum of 3, Table 1, and Control/Storage of 524.8 Section 4, Structures (160.0) and wave runup) 529.0 (161.2) Table 6 Table 4.0-3 Associated Effects Inputs Not Bounded by COB Hazard Flooding Mechanism Failure of Dams and Associated Effects Local Intense Onsite Water Factor Precipitation Control/Storage Structures Hydrodynamic loading at Minimal, not bounding 117 .2 psf (572.2 kg-plant grade (FHRR, Section. 4.2) force/m 2) (FHRR, Table 4) Debris loading at plant None Varies with maximum of grade 3,387 lbs (1,536 kg) at Unit 2 Turbine Building (Barstow, 2014b) Sediment loading at plant None Minimal effect (Barstow, grade 2014b) Sediment deposition and None Minimal effect (Barstow, erosion 2014b) Concurrent conditions, None Hail, strong winds, and including adverse weather tornadoes (Barstow, 2014b) Groundwater ingress None Bounded (Barstow, 2014b) Other pertinent factors None Examined barge collision (e.g., waterborne (Barstow, 2014b) projectiles) Table 5.0-1: Integrated Assessment Open Items Deleted B. Hanson As documented in the NRC staff assessment and the enclosed supplement, the NRC staff has concluded that the licensee's reevaluated flood hazard information is suitable for the assessment of mitigation strategies developed in response to Order EA-12-049 (i.e., defines the mitigating strategies flood hazard information described in guidance documents currently being finalized by the industry and NRC staff) for Dresden. Further, the NRC staff continues to assert that the licensee's reevaluated flood hazard information is suitable for other assessments associated with Near-Term Task Force Recommendation 2.1 "Flooding." The reevaluated flood hazard results for local intense precipitation and upstream dam failures were not bounded by the current design-basis flood hazard. In order to complete its response to Enclosure 2 to the 50.54(f) letter, the licensee is expected to submit a revised integrated assessment or focused evaluation(s), as appropriate, to address these reevaluated flood hazards, as described in the NRC's September 1, 2015 letter. If you have any questions, please contact me at (301) 415-6197 or e-mail at Tekia. Govan@nrc.gov.
Sincerely, IRA/ Tekia Govan, Project Manager Hazards Management Branch Japan Lessons-Learned Division Office of Nuclear Reactor Regulation Docket Nos. 50-237 and 50-249
Enclosure:
Supplement to Staff Assessment of Flood Hazard Reevaluation Report cc w/encl: Distribution via Listserv DISTRIBUTION:
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