Letter Sequence Draft RAI |
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CAC:MF2400, Control Room Habitability (Approved, Closed) CAC:MF2401, Control Room Habitability (Approved, Closed) CAC:MF2402, Control Room Habitability (Approved, Closed) CAC:MF2403, Control Room Habitability (Approved, Closed) CAC:MF2404, Control Room Habitability (Approved, Closed) CAC:MF2405, Control Room Habitability (Approved, Closed) CAC:MF2406, Control Room Habitability (Approved, Closed) CAC:MF2407, Control Room Habitability (Approved, Closed) CAC:MF2408, Control Room Habitability (Approved, Closed) CAC:MF2409, Control Room Habitability (Approved, Closed) |
Administration
- Meeting, Meeting, Meeting, Meeting, Meeting, Meeting, Meeting, Meeting, Meeting, Meeting, Meeting
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MONTHYEARML15274A5992015-10-0101 October 2015 10-01-15 Public Phone Call Project stage: Request ML16011A0612016-02-0202 February 2016 Summary of 10/1/15 Meeting with STP Nuclear Operating Company to Discuss Revised Pilot Submittal and Request for Exemptions for a Risk-Informed Approach to Resolve Generic Safety Issue (GSI)-191 at South Texas Project, Units 1 and 2 (CAC MF Project stage: Meeting ML16028A1522016-02-18018 February 2016 1/14/2016 Summary of Public Meeting with STP Nuclear Operating Company Regarding Modifications to the Licensee'S Risk-Informed Generic Safety Issue (GSI) 191 Application and Supplements for South Texas Project, Units 1 and 2 Project stage: Meeting ML16088A2432016-04-0101 April 2016 2/18/2016, Summary of Public Meeting with STP Nuclear Operating Company Regarding Open Items, Risk-Informed Generic Safety Issue (GSI) 191 Application and Supplements for South Texas Project, Units 1 and 2 (CAC Nos. MF2400-MF2409) Project stage: Meeting ML16092A0442016-04-11011 April 2016 Summary of 3/3/2016 Public Meeting with STP Nuclear Operating Company Regarding Open Items, Risk-Informed Generic Safety Issue (GSI) 191 Application and Supplements for South Texas Project, Units 1 and 2 (CAC Nos. MF2400-MF2409) Project stage: Meeting ML16082A5072016-04-11011 April 2016 Request for Additional Information, Phased Response Requested, Exemption and License Amendment Request for a Risk-Informed Approach to Resolve Generic Safety Issue (GSI)-191 (CAC Nos. MF2400-MF2409) Project stage: RAI ML16095A0102016-04-13013 April 2016 Summary of November 17-19, 2015 Thermal-Hydraulic Review at Texas A&M University; Pilot Submittal and Request for Exemptions for a Risk-Informed Approach to Resolve Generic Safety Issue (GSI)-191 (CAC MF2400-MF2409) Project stage: Other ML16092A0852016-04-13013 April 2016 3/17/2016 Summary of Public Meeting with STP Nuclear Operating Company Regarding Open Items, Risk-Informed Generic Safety Issue (GSI) 191 Application and Supplements for South Texas Project, Units 1 and 2 (CAC Nos. MF2401-MF2409) Project stage: Meeting ML16096A0652016-04-13013 April 2016 Summary of February 4 and 16, 2016, Regulatory Audit at Westinghouse in Rockville, MD, Boric Acid Precipitation, Exemption and License Amendment Request, Risk-Informed Approach to Resolve Generic Safety Issue 191 Project stage: Other ML16111A0272016-04-18018 April 2016 STP Nuclear Operating Company Slideshow for Public Meeting on April 21, 2016 for GSI-191 Resolution (CAC No. MF2400-01) Project stage: Meeting ML16103A3442016-04-26026 April 2016 Summary of February 24-26, 2016 Audit, Debris Transport Review at Alion Science and Technology Corporation, Albuquerque, Nm; Pilot Submittal and Exemption Request, Risk-Informed Approach to Resolve GSI 191 Project stage: Other ML16032A4032016-04-26026 April 2016 FRN, Draft Environmental Assessment and Finding of No Significant Impact, Revise Licensing Basis as Documented in the UFSAR and Request for Exemptions, Risk-Informed Approach to Address GSI-191 (CAC MF2400-MF2409) Project stage: Draft Other ML16032A3872016-04-26026 April 2016 Draft Environmental Assessment and Finding of No Significant Impact, Revise Licensing Basis as Documented in the UFSAR and Request for Exemptions, Risk-Informed Approach to Address GSI-191 (CAC MF2400-MF2409) Project stage: Draft Other ML16127A4002016-05-11011 May 2016 Audit Summary, Thermal-Hydraulic Review on February 23-25, 2016 at Texas A&M University; Pilot Submittal and Request for Exemptions for a Risk-Informed Approach to Resolve Generic Safety Issue 191 (CAC MF2400-MF2409) Project stage: Other ML16125A2902016-05-26026 May 2016 Request for Additional Information, Risk Review, Exemption and License Amendment Request for a Risk-Informed Approach to Resolve Generic Safety Issue (GSI)-191 (CAC Nos. MF2400-MF2409) Project stage: RAI ML16141B0812016-05-31031 May 2016 Audit Summary, Risk Audit on April 12-13, 2016, at Alumni Center at the University of Texas, Austin, Tx; Pilot Generic Safety Issue 191 Submittal and Exemption Request, and Draft Request for Additional Information Project stage: Draft RAI ML16175A1082016-06-24024 June 2016 Summary of 4/21/2016 Public Meeting with STP Nuclear Operating Company Regarding Open Items, Risk-Informed Generic Safety Issue (GSI) 191 Application and Supplements for South Texas Project, Units 1 and 2 Project stage: Meeting ML16190A0082016-07-13013 July 2016 Summary of 6/22/2016 Public Meeting with STP Nuclear Operating Company Regarding Open Items, Risk-Informed Generic Safety Issue (GSI) 191 Application and Supplements for South Texas Project, Units 1 and 2 (CAC Nos. MF2400-MF2409) Project stage: Meeting ML16194A2342016-07-21021 July 2016 Request for Withholding Information from Public Disclosure - 5/6/16 Affidavit Executed by D. Munoz and M. Rozboril, Alion Science and Technology, Response to Follow-up RAIs 18, 38, and 44 Project stage: RAI ML16242A0102016-08-23023 August 2016 NRR E-mail Capture - (External_Sender) FW: South Texas Project GSI-191 Draft Risk Responses to Questions for Public Meeting on August 29, 2016 Project stage: Request ML16242A0092016-08-25025 August 2016 NRR E-mail Capture - (External_Sender) South Texas Project GSI-191 Draft thermal-hydraulic Responses to Questions for Public Meeting on August 29, 2016 Project stage: Request ML16238A5272016-09-0101 September 2016 Summary of 7/28/16, Public Meeting with STP Nuclear Operating Company to Discuss the License Amendment and Exemption Requests to Use a Risk-Informed Approach to the Resolution of GSI-191 (CAC Nos. MF2400 - MF2409) Project stage: Meeting ML16258A3672016-09-0606 September 2016 NRR E-mail Capture - (External_Sender) South Texas Project Generic Safety Issue 191 Resolution SNPB-3-2, Bullet 4 16 -inch Bounding Break Clarification for September 14, 2016 Public Meeting Project stage: Request ML16258A1002016-09-12012 September 2016 NRR E-mail Capture - (External_Sender) South Texas Project Generic Safety Issue 191 Resolution RAI APLA-3-2 Clarification for September 14, 2016 Public Meeting Project stage: Request ML16258A1042016-09-12012 September 2016 NRR E-mail Capture - (External_Sender) South Texas Project Generic Safety Issue 191 Resolution RAI SNPB-3-13 Clarification for September 14, 2016 Public Meeting Project stage: Request ML16258A0962016-09-13013 September 2016 NRR E-mail Capture - (External_Sender) South Texas Project Generic Safety Issue 191 Resolution RAI SSIB-3-4 Clarification for September 14, 2016 Public Meeting Project stage: Request ML16258A0982016-09-13013 September 2016 NRR E-mail Capture - (External_Sender) South Texas Project Generic Safety Issue 191 Resolution RAI 33 Clarification for September 14, 2016 Public Meeting Project stage: Request ML16258A2072016-09-14014 September 2016 NRR E-mail Capture - (External_Sender) South Texas Project Generic Safety Issue 191 Resolution RAI 37 Clarification for September 14, 2016 Public Meeting Project stage: Request ML16258A2082016-09-14014 September 2016 NRR E-mail Capture - (External_Sender) South Texas Project Generic Safety Issue 191 Resolution RAI 34 Clarification for September 14, 2016 Public Meeting Project stage: Request ML16246A0222016-10-0505 October 2016 Summary of Public Meeting with STP Nuclear Operating Company Regarding Open Items Related to Risk-Informed Generic Safety Issue (GSI) 191 Application and Supplements for South Texas Project, Units 1 and 2 (CAC Nos. MF2400 - MF2409) Project stage: Meeting ML16279A3312016-10-27027 October 2016 Summary of Public Meeting with STP Nuclear Operating Company Regarding Open Items, Risk-Informed Generic Safety Issue (GSI) 191 Application and Supplements for South Texas Project, Units 1 and 2 (CAC Nos. MF2400-MF2409) Project stage: Meeting ML16302A4532016-12-12012 December 2016 Closeout of Request for Additional Information Questions That Are No Longer Applicable, Resolution of Generic Safety Issue (GSI) 191 (CAC Nos. MF2400-MF2409) Project stage: RAI ML16351A1502016-12-16016 December 2016 Correction Letter Closeout of Request for Information Questions That Are No Longer Applicable Associated with the Resolution of Generic Safety Issue 191 (CAC Nos. MF2400 - MF2409) Project stage: RAI ML16278A5982017-05-0202 May 2017 Letter, Environmental Assessment and Finding of No Significant Impact, Revise Licensing Basis as Documented in the UFSAR and Request for Exemptions, Risk-Informed Approach to Address GSI-191 (CAC MF2400 to MF2409) Project stage: Other ML16278A5992017-05-0202 May 2017 Environmental Assessment and Finding of No Significant Impact, Revise Licensing Basis as Documented in the UFSAR and Request for Exemptions, Risk-Informed Approach to Address GSI-191 (CAC MF2400 to MF2409) Project stage: Other ML17137A3252017-05-17017 May 2017 Safety Evaluation of LAR by South Texas Project Nuclear Operating Company to Adopt a Risk-Informed Resolution of Generic Safety Issue-191 Project stage: Approval ML17151A8432017-06-16016 June 2017 OEDO-17-00326 - EDO Response to ACRS Chairman, Safety Evaluation of License Amendment Request by STP Nuclear Operating Company to Adopt a Risk-Informed Resolution of Generic Safety Issue-191 Project stage: Approval NRC-2016-0092, South Texas Project, Units 1 and 2 - FRN: Exemption from the Requirements of 10 CFR 50.46 and 10 CFR Part 50, Appendix a, General Design Criteria 35, 38, 41 (CAC Nos. MF2402-MF2409)2017-07-11011 July 2017 South Texas Project, Units 1 and 2 - FRN: Exemption from the Requirements of 10 CFR 50.46 and 10 CFR Part 50, Appendix a, General Design Criteria 35, 38, 41 (CAC Nos. MF2402-MF2409) Project stage: Approval ML17037C8712017-07-11011 July 2017 Letter, Exemption from the Requirements of 10 CFR Part 50, Section 50.46 (CAC Nos. MF2402-MF2409) Project stage: Approval ML17037C8762017-07-11011 July 2017 FRN: Exemption from the Requirements of 10 CFR 50.46 and 10 CFR Part 50, Appendix a, General Design Criteria 35, 38, 41 (CAC Nos. MF2402-MF2409) Project stage: Approval ML17055A5002017-07-11011 July 2017 Enclosure 4 to Amendment Nos. 212 and 198, Resolution of Licensee Comments on Safety Evaluation - Risk-Informed Approach to Resolve Generic Safety Issue 191 Project stage: Approval ML17019A0032017-07-11011 July 2017 Attachment 2 to Safety Evaluation - In-Vessel Thermal-Hydraulic Analysis, Issuance of Amendment Nos. 212 and 198 - Risk-Informed Approach to Resolve Generic Safety Issue 191 Project stage: Approval ML17038A2232017-07-11011 July 2017 Issuance of Amendment Nos. 212 and 198 - Risk-Informed Approach to Resolve Generic Safety Issue 191 Project stage: Approval ML17019A0022017-07-11011 July 2017 Safety Evaluation, Enclosure 3 to Amendment Nos. 212 and 198 - Risk-Informed Approach to Resolve Generic Safety Issue 191 Project stage: Approval 2016-05-31
[Table View] |
Audit Summary, Risk Audit on April 12-13, 2016, at Alumni Center at the University of Texas, Austin, Tx; Pilot Generic Safety Issue 191 Submittal and Exemption Request, and Draft Request for Additional InformationML16141B081 |
Person / Time |
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Site: |
South Texas ![STP Nuclear Operating Company icon.png](/w/images/9/9c/STP_Nuclear_Operating_Company_icon.png) |
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Issue date: |
05/31/2016 |
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From: |
Lisa Regner Plant Licensing Branch IV |
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To: |
Koehl D South Texas |
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Regner L |
References |
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CAC MF2400, CAC MF2401, CAC MF2402, CAC MF2403, CAC MF2404, CAC MF2405, CAC MF2406, CAC MF2407, CAC MF2408, CAC MF2409 |
Download: ML16141B081 (11) |
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Category:Audit Report
MONTHYEARML21236A3082021-09-10010 September 2021 Regulatory Audit Summary Regarding License Amendment Request to Revise Moderator Temperature Coefficient Surveillance Requirements ML20142A2792020-05-27027 May 2020 Regulatory Audit Summary Regarding Exigent License Amendment Request to Revise the Safety Injection Accumulators Pressures ML17107A3192017-05-16016 May 2017 Aluminum Bronze Selective Leaching Aging Management Program Audit Report Regarding the South Texas Project, Units 1 and 2, License Renewal Application (CAC Nos. ME4936 and ME4937) ML16218A2562016-08-30030 August 2016 Aluminum Bronze Selective Leaching Aging Management Program and PWR Reactor Internals Program Inspection Plan Audit Report Regarding the South Texas Project, Units 1 and 2 ML16214A2912016-08-26026 August 2016 Summary of June 28-30, 2016, Regulatory Audit at Westinghouse in Rockville, MD, License Amendment Request to Revise Technical Specification 5.3.2 to Allow Operation with 56 Full-Length Control Rod Assemblies ML16141B0812016-05-31031 May 2016 Audit Summary, Risk Audit on April 12-13, 2016, at Alumni Center at the University of Texas, Austin, Tx; Pilot Generic Safety Issue 191 Submittal and Exemption Request, and Draft Request for Additional Information ML16127A4002016-05-11011 May 2016 Audit Summary, Thermal-Hydraulic Review on February 23-25, 2016 at Texas A&M University; Pilot Submittal and Request for Exemptions for a Risk-Informed Approach to Resolve Generic Safety Issue 191 (CAC MF2400-MF2409) ML16103A3442016-04-26026 April 2016 Summary of February 24-26, 2016 Audit, Debris Transport Review at Alion Science and Technology Corporation, Albuquerque, Nm; Pilot Submittal and Exemption Request, Risk-Informed Approach to Resolve GSI 191 ML16095A0102016-04-13013 April 2016 Summary of November 17-19, 2015 Thermal-Hydraulic Review at Texas A&M University; Pilot Submittal and Request for Exemptions for a Risk-Informed Approach to Resolve Generic Safety Issue (GSI)-191 (CAC MF2400-MF2409) ML16096A0652016-04-13013 April 2016 Summary of February 4 and 16, 2016, Regulatory Audit at Westinghouse in Rockville, MD, Boric Acid Precipitation, Exemption and License Amendment Request, Risk-Informed Approach to Resolve Generic Safety Issue 191 ML16029A2722016-03-15015 March 2016 12/7-8/2015 Audit Summary, Audit Conducted to Support License Amendment Request to Revise TS 5.3.2 to Allow Operation with 56 Full-Length Control Rod Assemblies for Unit 1 Cycle 20 (Emergency Circumstances) ML15175A0242015-07-29029 July 2015 Audit Summary for May 12-14, 2015 Audit of Roverd Methodology Pilot Submittal and Request for Exemptions for a Risk-Informed Approach to Resolve Generic Safety Issue (GSI)-191 (TAC Nos. MF2400 Through MF2409) ML15183A0072015-07-15015 July 2015 Audit Summary, 3/31 to 4/2/15 Audit of Systems, Structures and Equipment at STP Facility; Pilot Submittal and Request for Exemptions for a Risk-Informed Approach to Resolve Generic Safety Issue (GSI)-191 ML15131A1452015-06-0404 June 2015 Audit Report for the 2015 Supplemental Audit STP License Renewal ML15111A4652015-05-0606 May 2015 Report for the Onsite Audit Regarding Implementation of Mitigating Strategies and Reliable Spent Fuel Instrumentation Related to Orders EA-12-049 and EA-12-051 ML15183A0092015-04-0202 April 2015 Photos, Audit Summary, 3/31 to 4/2/15 Audit of Systems, Structures and Equipment at STP Facility; Pilot Submittal and Request for Exemptions for a Risk-Informed Approach to Resolve Generic Safety Issue (GSI)-191 ML14321A6772015-01-15015 January 2015 Audit Report for 9/16-17/2014 Audit at University of New Mexico Pilot Submittal and Request for Exemptions for a Risk-Informed Approach to Resolve Generic Safety Issue (GSI)-191 (TAC MF2400 Through and MF2409) ML13339A7362014-01-29029 January 2014 Interim Staff Evaluation and Audit Report Relating to Overall Integrated Plan in Response to Order EA-12-049 - Mitigation Strategies ML12165A2392012-06-15015 June 2012 Report Regarding the Follow-up Audit of the Selective Leaching of Aluminum Bronze Aging Management Program for the South Texas Project, Units 1 and 2, License Renewal Application (TAC ME4936 and ME4937) ML11224A2652011-09-22022 September 2011 Aging Management Programs Audit Report Regarding the South Texas Project, Units 1 and 2, Station License Renewal Application (TAC Nos. ME4936 and ME4937) ML1122106582011-09-0707 September 2011 Audit of the Licensee Regulatory Commitment Management Program, Audit Performed July 19-20, 2011 ML11230A0032011-09-0606 September 2011 Scoping and Screening Audit Report Regarding the South Texas Project, Units 1 and 2 (TAC Nos. ME4936 and ME4937) ML11173A3042011-07-18018 July 2011 Audit Report Regarding South Texas Project License Renewal Application - Cultural Resource ML11145A0642011-06-21021 June 2011 Plan for the Environmental Related Regulatory Audit Regarding the South Texas Project, Units 1 and 2, License Renewal Application Review (TAC Nos. ME4938 and ME4939) ML0834501622008-12-24024 December 2008 Audit Report of Licensee Regulatory Commitment Management Program for Audit Performed August 19, 2008 ML0721101192007-08-16016 August 2007 Us NRC Audit Report for South Texas Project Combined License Application Review ML0426702502004-09-22022 September 2004 Audit of the Licensees Management of Regulatory Commitments NOC-AE-04001712, Appendix a Cameco Corporation 2003 Consolidated Audited Financial Statements2004-02-27027 February 2004 Appendix a Cameco Corporation 2003 Consolidated Audited Financial Statements 2021-09-10
[Table view] Category:Letter
MONTHYEARML24029A2752024-01-29029 January 2024 Request to Reschedule Evaluated Force-on-Force Drill IR 05000498/20230042024-01-29029 January 2024 Integrated Inspection Report 05000498/2023004 and 05000499/2023004 ML24024A1162024-01-24024 January 2024 STP Unit 2 Request for Information IR 05000498/20244042024-01-18018 January 2024 Information Request for the Cyber-Security Baseline Inspection, Notification to Perform Inspection 05000498/2024404; 05000499/2024404 IR 05000498/20230032023-12-28028 December 2023 Acknowledgment of Reply to a Notice of Violation (NRC Inspection Report 05000498/2023003 and 05000499/2023003) ML23360A1692023-12-26026 December 2023 FEMA, Submittal of Radiological Emergency Preparedness Final Report for the South Texas Project Medical Services Drill Evaluated on August 31, 2023 NOC-AE-230040, Supplement to Proposed Alternate Frequency to Containment Unbonded Post-Tensioning System Inservice Inspection (Relief Request RR-ENG-4-06)2023-12-14014 December 2023 Supplement to Proposed Alternate Frequency to Containment Unbonded Post-Tensioning System Inservice Inspection (Relief Request RR-ENG-4-06) NOC-AE-230039, Docket Nos. Stn 50-498, Stn 50-499 - Reply to a Notice of Violation, NRC Inspection Report 05000498/2023003 and 05000499/20230032023-12-12012 December 2023 Docket Nos. Stn 50-498, Stn 50-499 - Reply to a Notice of Violation, NRC Inspection Report 05000498/2023003 and 05000499/2023003 ML23326A2592023-12-0505 December 2023 Review of the Fall 2022 Steam Generator Tube Inspection Report ML23339A1902023-12-0505 December 2023 Update Foreign Ownership, Control, or Influence (FOCI) IR 05000498/20234012023-12-0404 December 2023 Security Baseline Inspection Report 05000498/2023401 and 05000499/2023401 ML23324A0102023-11-16016 November 2023 Request for Exemption from Enhanced Weapons, Firearms Background Checks, and Security Event Notifications Implementation ML23310A2282023-11-13013 November 2023 Integrated Inspection Report 05000498/2023003 and 05000499/2023003, and Notice of Violation ML23311A2082023-11-0909 November 2023 Reassignment of U.S. Nuclear Regulatory Commission Branch Chief in the Division of Operating Reactor Licensing for Plant Licensing Branch IV ML23298A0002023-11-0101 November 2023 the Associated Independent Spent Fuel Storage Installation - Issuance of Amendment Nos. 226 and 211 Related to Order Approving Indirect Transfer of Licenses and Conforming License Amendments ML23303A0782023-10-30030 October 2023 Submittal of Supplemental Information in Response to Order Consenting to License Transfers and Approval of Draft Conforming License Amendments ML23279A0342023-10-30030 October 2023 Associated Independent Spent Fuel Storage Installation - Order Approving Indirect Transfer of Licenses and Draft Conforming License Amendments (EPID L-2023-LLM-0004) (Letter) IR 05000498/20234032023-10-26026 October 2023 Material Control and Accounting Program Inspection Report 05000498/2023403 and 05000499/2023403 (Cover Letter) ML23317A1262023-10-12012 October 2023 South. Texas Project Physical Security Plan, Training and Qualification Plan, Safeguards Contingency Plan, and Independent Spent Fuel Storage Installation Security Program Revision 26 ML23279A1382023-10-0505 October 2023 Responses to Requests for Additional Information Related to Application for Order Approving Indirect Transfer of Control of Licenses ML23271A1942023-10-0303 October 2023 Notification of Commercial Grade Dedication Inspection (05000498/2024013 and 05000499/2024013) and Request for Information ML23270B2592023-09-27027 September 2023 Update Foreign Ownership, Control, or Influence ML23263B1132023-09-20020 September 2023 Operator Licensing Examination Schedule Revision 1 IR 05000498/20243012023-09-0707 September 2023 Notification of NRC Initial Operator Licensing Examination 05000498/2024301; 05000499/2024301 IR 05000498/20233012023-09-0101 September 2023 NRC Examination Report 05000498/2023301 and 05000499/2023301 ML23243B0562023-08-31031 August 2023 Supplemental Information to Application for Order Approving Indirect Transfer of Control of Licenses ML23236A6042023-08-24024 August 2023 Annual Dose Report for 2022 IR 05000498/20230052023-08-22022 August 2023 Updated Inspection Plan for South Texas Project Electric Generating Station, Units 1 and 2 (Report 05000498/2023005 and 05000499/2023005) - Mid Cycle Letter ML23229A5262023-08-17017 August 2023 Inservice Inspection Summary Report - 1 RE24, ML23229A5892023-08-17017 August 2023 Voluntary Response to Regulatory Issue Summary (RIS) 2023-02, Scheduling Information for the Licensing of Accident Tolerant, Increased Enrichment, and Higher Burnup Fuels ML23229A4992023-08-17017 August 2023 Supplement to Proposed Alternate Frequency to Containment Unbonded Post-Tensioning System Inservice Inspection (Relief Request RR-ENG-4-06) ML23228A2102023-08-15015 August 2023 Closure of Investigation (OI 4-22-19) ML23222A0322023-08-10010 August 2023 Report of Changes Made to Quality Assurance Program for Radioactive Material Packages ML23221A3002023-08-0909 August 2023 RE22 Inspection Summary Report for Steam Generator Tubinq, Rev. 1 (Epld L-2023-LRO-0029) ML23222A2792023-08-0909 August 2023 Submittal of Update Foreign Ownership, Control, or Influence (FOCI) IR 05000498/20230022023-07-28028 July 2023 Integrated Inspection Report 05000498/2023002 and 05000499/2023002 ML23198A0532023-07-24024 July 2023 Request for Withholding Information from Public Disclosure ML23188A1612023-07-14014 July 2023 the Associated ISFSI - Notice of Consideration of Approval of Indirect Transfer of Licenses and Conforming Amendments and Opportunity to Request a Hearing (EPID L-2023-LLM-0004) - Letter ML23193A9932023-07-11011 July 2023 Submittal of Update Foreign Ownership, Control or Influence (FOCI) ML23192A0482023-07-11011 July 2023 NRC Initial Operator Licensing Examination Approval 05000498/2023301; 05000499/2023301 NOC-AE-230039, Submittal of Update Foreign Ownership, Control or Influence (FOCI)2023-07-11011 July 2023 Submittal of Update Foreign Ownership, Control or Influence (FOCI) ML23180A2822023-06-29029 June 2023 Operator Licensing Examination Schedule ML23177A2522023-06-26026 June 2023 Units 1, 2 & Independent Spent Fuel Storage Installation - Biennial Submittal of Technical Specification Bases Changes, Commitment Changes, 10 CFR 50.59 Evaluation Summary, and 10 CFR 72.48 Evaluation Summary ML23166B0802023-06-14014 June 2023 Update Foreign Ownership, Control, or Influence (FOCI) ML23163A1762023-06-12012 June 2023 Application for Order Approving Indirect Transfer of Control of Licenses 2024-01-29
[Table view] Category:Request for Additional Information (RAI)
MONTHYEARML24024A1162024-01-24024 January 2024 STP Unit 2 Request for Information ML23334A0062023-11-29029 November 2023 NRR E-mail Capture - South Texas Project - Request for Additional Information - Proposed Alternative to ASME BPV Code Requirements ML23319A4442023-11-15015 November 2023 NRR E-mail Capture - South Texas Project - Draft Request for Additional Information - Proposed Alternative to ASME BPV Code Requirements ML23278A1532023-10-0505 October 2023 NRR E-mail Capture - South Texas Project Request for Additional Information - Request for Indirect Transfer of Licenses and Conforming Amendments (L-2023-LLM-0004) ML23264A0972023-09-21021 September 2023 NRR E-mail Capture - South Texas Project - Request for Additional Information - License Amendment Request to Revise the Alternate Source Term Dose Calculation (L-2023-LLA-0047) ML23255A2862023-09-12012 September 2023 NRR E-mail Capture - South Texas Project Draft Request for Additional Information License Amendment Request to Revise the Alternate Source Term Dose Calculation (L-2023-LLA-0047) ML23145A1872023-05-24024 May 2023 July 2023 Emergency Preparedness Program Inspection - Request for Information ML22255A1542022-09-13013 September 2022 Operating Company Information Request for the Cyber Security Baseline Inspection 05000498/2022401 and 05000499/2022401 ML22206A0142022-07-20020 July 2022 NRR E-mail Capture - South Texas Project - Request for Additional Information - 10 CFR 20.2002 Alternate Disposal Request ML22194A0502022-07-0707 July 2022 NRR E-mail Capture - South Texas Project - Updated Draft Request for Additional Information - 10 CFR 20.2002 Alternate Disposal Request ML22194A0492022-06-0808 June 2022 NRR E-mail Capture - South Texas Project - Draft Request for Additional Information - 10 CFR 20.2002 Alternate Disposal Request ML22123A3272022-05-0303 May 2022 STP EP Exercise Inspection July 2022 RFI ML22084A0762022-04-0404 April 2022 Notification of NRC Design Bases Assurance Inspection (Team) (05000498/2022012 and 05000499/2022012) and Request for Information ML21286A5732021-10-18018 October 2021 Notification of NRC Design Bases Assurance Inspection (Programs) (05000498/2022011 and 05000499/2022011) and Request for Information ML21166A2392021-06-16016 June 2021 Notification of Inspection (NRC Inspection Report 05000498/2021003 and 05000499/2021003) and Request for Information ML21160A1522021-06-0909 June 2021 Request for Information NRC Inspection 2021-003 Public Radiation Safety ML21133A2372021-05-0505 May 2021 Request for Additional Information: STP EP Exercise Inspection - July 2021 ML21039A8902021-02-0808 February 2021 NRR E-mail Capture - South Texas Project - Request for Additional Information - 1RE22 Inspection Summary Report for Steam Generator Tubing ML21029A3312021-01-29029 January 2021 NRR E-mail Capture - South Texas Project - Draft Request for Additional Information - 1RE22 Inspection Summary Report for Steam Generator Tubing ML20280A5452020-08-17017 August 2020 STP 2020 PIR Request for Information ML20111A0052020-04-17017 April 2020 NRR E-mail Capture - South Texas Project - Request for Additional Information - Proposed Alternative to ASME OM Code 2012 Edition - Relief Request PRR-01 ML20070N0222020-03-10010 March 2020 NRC Selection for Onsite Review ML20057G4612020-02-26026 February 2020 05000498/499 Request for Information - Occupational Radiation Safety Inspection ML20045E2172020-02-13013 February 2020 Licensed Operator Positive Fitness-For-Duty Test ML20036F5862020-02-0404 February 2020 Request for Additional Information - Proposed Alternative to ASME Code Requirements for the Repair of Essential Cooling Water System Class 3 Buried Piping (EPID L-2019-LLR-0096)Redacted ML19165A1032019-06-14014 June 2019 NRR E-mail Capture - Draft RAI for STP TS 3.8.1.1 Sbdg SR Change ML19081A1512019-03-21021 March 2019 NRR E-mail Capture - Draft Round 2 RAI - Sbdg Voltage and Frequency LAR (L-2018-LLA-0078) ML18283B9522018-10-10010 October 2018 NRR E-mail Capture - Final RAI - South Texas Standby DG TS Change (L-2018-LLA-0078) ML18263A1432018-09-12012 September 2018 NRR E-mail Capture - Final RAI for South Texas Project RR-ENG-E-16 (L-2018-LLR-0097) ML18197A4172018-07-17017 July 2018 Notification of NRC Triennial Heat Sink Performance Inspection (05000498/2018003 and 05000499/2018003) and Request for Information ML18003B4222018-01-0303 January 2018 NRR E-mail Capture - Final Request for Additional Information Amendment Request to Modify the Emergency Response Organization for South Texas Project ML17229B4672017-08-16016 August 2017 Notification of NRC Inspection 05000499/2017008 and Request for Information ML17132A0712017-05-15015 May 2017 Information Request the Cyber Security Baseline Inspection, Notification to Perform Inspection 05000498/2017407; 05000499/2017407 ML17103A6272017-04-13013 April 2017 Notification of Evaluations of Changes, Tests, and Experiments Inspection (05000498/2017007 and 05000499/2017007) and Request for Information ML16351A1502016-12-16016 December 2016 Correction Letter Closeout of Request for Information Questions That Are No Longer Applicable Associated with the Resolution of Generic Safety Issue 191 (CAC Nos. MF2400 - MF2409) ML16302A4532016-12-12012 December 2016 Closeout of Request for Additional Information Questions That Are No Longer Applicable, Resolution of Generic Safety Issue (GSI) 191 (CAC Nos. MF2400-MF2409) ML16343A0422016-12-0808 December 2016 Request for Additional Information for the Review of the South Texas Project, Units 1 and 2 License Renewal Application (CAC NOS. ME4936, ME4937) ML16340A1022016-12-0505 December 2016 Requests for Additional Information for the Review of the South Texas Project License Renewal Application (CAC Nos. ME4936 and ME4937) ML16246A0952016-09-15015 September 2016 Correction to 8/26/16 Request for Additional Information Enclosure, License Amendment Request to Revise Technical Specification 5.3.2 to Allow Operation with 56 Full-Length Control Rod Assemblies ML16214A2912016-08-26026 August 2016 Summary of June 28-30, 2016, Regulatory Audit at Westinghouse in Rockville, MD, License Amendment Request to Revise Technical Specification 5.3.2 to Allow Operation with 56 Full-Length Control Rod Assemblies ML16187A0522016-07-0707 July 2016 Request for Additional Information Regarding License Renewal Application ML16141B0812016-05-31031 May 2016 Audit Summary, Risk Audit on April 12-13, 2016, at Alumni Center at the University of Texas, Austin, Tx; Pilot Generic Safety Issue 191 Submittal and Exemption Request, and Draft Request for Additional Information ML16125A2902016-05-26026 May 2016 Request for Additional Information, Risk Review, Exemption and License Amendment Request for a Risk-Informed Approach to Resolve Generic Safety Issue (GSI)-191 (CAC Nos. MF2400-MF2409) ML16127A4522016-05-12012 May 2016 Supplemental Information Needed for Acceptance of Requested Licensing Action, Amendment Request to Revise Technical Specification 5.3.2 to Allow Operation with 56 Full-Length Control Rod Assemblies ML16104A3522016-04-22022 April 2016 Requests for Additional Information Set 35 for the Review of the South Texas Project License Renewal Application (Tac Nos. ME4936, ME4937) ML16082A5072016-04-11011 April 2016 Request for Additional Information, Phased Response Requested, Exemption and License Amendment Request for a Risk-Informed Approach to Resolve Generic Safety Issue (GSI)-191 (CAC Nos. MF2400-MF2409) ML16082A4842016-03-22022 March 2016 NRR E-mail Capture - South Texas Project Units 1 & 2, Draft Request for Additional Information for Risk Review for GSI-191 ML16081A0042016-03-18018 March 2016 NRR E-mail Capture - South Texas Project Units 1 & 2, Draft Request for Additional Information for Thermal-hydraulic Review for GSI-191 ML16053A1872016-03-0101 March 2016 Request for Additional Information, Request to Revise Technical Specification 6.8.3.j, Containment Leakage Rate Testing Program, to Extend Integrated Leak Rate Test Interval from 10 to 15 Years (CAC MF6176-MF6177) ML16060A2872016-02-29029 February 2016 NRR E-mail Capture - Request for Additional Information - STP LRA Safety Review 2024-01-24
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UNITED STATES NUCLEAR REGULATORY COMMISSION WASHINGTON, D.C. 20555-0001 May 31, 2016 Mr. Dennis L. Koehl President and CEO/CNO STP Nuclear Operating Company South Texas Project P.O. Box 289 VVadsworth, TX 77483
SUBJECT:
SOUTH TEXAS PROJECT, UNITS 1 AND 2 - AUDIT
SUMMARY
RELATED TO APRIL 12-13, 2016, REGULATORY AUDIT FOR THE REVIEVV OF THE RISK-INFORMED SOLUTION TO GENERIC SAFETY ISSUE 191 AND DRAFT REQUEST FOR ADDITIONAL INFORMATION (CAC NOS. MF2400 THROUGH MF2409)
Dear Mr. Koehl:
By letter dated June 19, 2013 (Agencywide Documents Access and Management System (ADAMS) Accession No. ML131750250), as supplemented by letters dated October 3, October 31, November 13, November 21 and December 23, 2013 (two letters); January 9, February 13, February 27, March 17, March 18, May 15 (two letters), May 22, June 25, and July 15, 2014; March 10, March 25, and August 20, 2015; and April 13, 2016 (ADAMS Accession Nos. ML13295A222, ML13323A673, ML13323A128, ML13338A165, ML14015A312, ML14015A311, ML14029A533, ML14052A110, ML14072A075, ML14086A383, ML14087A126, ML14149A353, ML14149A354, ML14149A439, ML14178A467, ML14202A045, ML15072A092, ML15091A440, ML15246A125, and ML16111B204, respectively), STP Nuclear Operating Company (STPNOC, the licensee) submitted exemption requests accompanied by a license amendment request (LAR) for a risk-informed approach to resolve Generic Safety Issue (GSl)-191, "Assessment of Debris Accumulation on PVVR [Pressurized-VVater Reactor] Sump Performance," at South Texas Project, Units 1 and 2.
The U.S. Nuclear Regulatory Commission (NRC) staff conducted a regulatory audit at the University of Texas in Austin, Texas, on April 12-13, 2016, to review remaining open items associated with the licensee's risk-informed analysis of debris as provided in the LAR. of this letter describes the results of the NRC staff's audit and some of the key technical issues highlighted by the NRC staff during the audit. The draft request for additional information questions 1 are included in Enclosure 2.
1 Draft requests for additional information were sent by e-mail to the licensee on March 22 and May 4, 2016 (ADAMS Accession Nos. ML16082A484 and ML16125A239, respectively). The May document updated the March document and added one question (question APLA-4-6).
D. Koehl If you have any questions, please contact me at 301-415-1906 or via e-mail at Lisa. Regner@nrc.gov.
isa M. Regner, Senior Project Manager Plant Licensing Branch IV-1 Division of Operating Reactor Licensing Office of Nuclear Reactor Regulation Docket Nos. 50-498 and 50-499
Enclosures:
- 1. Audit Summary
- 2. Draft Request for Additional Information cc w/encls: Distribution via Listserv
AUDIT
SUMMARY
-APRIL 12-13, 2016 REVIEW OF PROBABILISTIC RISK ASSESSMENT ASSOCIATED WITH THE RISK-INFORMED SOLUTION TO GENERIC SAFETY ISSUE 191 STP NUCLEAR OPERATING COMPANY SOUTH TEXAS PROJECT, UNITS 1 AND 2 DOCKET NOS. 50-498 AND 50-499
1.0 BACKGROUND
By letter dated June 19, 2013 (Agencywide Documents Access and Management System (ADAMS) Accession No. ML131750250), as supplemented by letters dated October 3, October 31, November 13, November 21 and December 23, 2013 (two letters); January 9, February 13, February 27, March 17, March 18, May 15 (two letters}, May 22, June 25, and July 15, 2014; March 10, March 25, and August 20, 2015; and April 13, 2016 (ADAMS Accession Nos. ML13295A222, ML13323A673, ML13323A128, ML13338A165, ML14015A312, ML14015A311, ML14029A533, ML14052A110, ML14072A075, ML14086A383, ML14087A126, ML14149A353, ML14149A354, ML14149A439, ML14178A467, ML14202A045, ML15072A092, ML15091A440, ML15246A125, and ML16111B204, respectively}, STP Nuclear Operating Company (STPNOC, the licensee) submitted exemption requests accompanied by a license amendment request (LAR) for a risk-informed approach to resolve Generic Safety Issue (GSl)-191, "Assessment of Debris Accumulation on PWR [Pressurized-Water Reactor] Sump Performance," at South Texas Project, Units 1 and 2 (STP).
In order to complete its review, the NRC staff needed a better understanding of the licensee's probabilistic risk assessment (PRA) of the effects of debris on core cooling following a design-basis loss-of-coolant accident (LOCA). The NRC staff provided requests for additional information (RAls) in draft documents dated March 22 and May 4, 2016 (ADAMS Accession Nos. ML16125A239 and ML16082A484, respectively). Due to the complexity of this analysis, to more efficiently complete its review of this subject, the NRC staff determined that a regulatory audit was necessary.
2.0 SCOPE AND PURPOSE The NRC staff audited STPNOC's PRA for GSl-191 at the University of Texas in Austin on April 12-13, 2016. The purpose of the audit was to determine the remaining open items for the risk review of the submittals, and ensure that the RAI included questions to close these open items. The NRC staff conducted the audit in accordance with the draft audit plan e-mailed to STPNOC staff on March 29, 2016 (ADAMS Accession No. ML16090A132). The final draft questions are included in this document as Enclosure 2. These questions will be issued as a formal RAI.
Enclosure 1
The following NRC staff and contractors participated in the audit:
- CJ Fong, Team Leader, Risk-Informed Licensing Initiatives
- Steve Laur, Senior Reliability and Risk Analyst
- Osvaldo Pensado, NRC contractor The following STPNOC staff and contractors participated in the audit:
- Zahra Mohaghegn, STPNOC contractor
- Seyed Reihani, STPNOC contractor
- David Johnson, STPNOC contractor
- Jeremy Tejada, STPNOC contractor
- Bruce Letellier, STPNOC contractor
- John Hasenbein, STPNOC contractor 3.0 AUDIT REPORT The audit plan outlined a series of technical areas for the NRC staff and licensee to discuss.
The audit team met the objective of the audit plan and obtained the following insights:
- With respect to monitoring and corrective action, the licensee suggested a change to its Updated Final Safety Analysis Report rather than a license condition to provide the regulatory control the NRC staff is seeking. The licensee stated that this approach was used to implement its risk-informed Quality Assurance Program.
- The licensee stated that it would provide additional information to resolve a discrepancy between the double-ended guillotine break-only core damage frequency value (reported in the August 20, 2015, submittal) and the independent calculation performed by the NRC's Southwest Research Institute contractors.
- The licensee provided information on its current programs (e.g., design control) and how these would be used to prevent future introduction of problematic debris sources.
- The licensee clarified the basis for screening certain sequences from the analysis.
- The NRC staff and licensee discussed reasonable approaches to quantify the risk from a seismically induced LOCA (both direct and indirect).
- The licensee provided information on how the risk from water hammer has been addressed.
- The NRC staff and licensee discussed which LOCA break sizes (for breaks in the reactor cavity) could be treated using risk and which would be treated deterministically through RELAP5-3D analysis.
Open and positive communications occurred throughout the audit, and there were no deviations from the draft audit plan. Consistent with the NRR guidance on audits (LIC-111, ADAMS Accession No. ML082900195), the audit team reminded participants that no regulatory decisions are made during audits.
At the conclusion, the audit team stated that answers to open items in other disciplines (e.g.,
deterministic analysis for long-term core cooling and treatment of epoxy debris in the reactor cavity) could change the PRA results. The NRC staff stated that this needs to be factored into the RAI responses.
4.0 CONCLUSION
The NRC staff found that the audit provided a better understanding of the licensee's PRA activities associated with the resolution of GSl-191. These audit activities helped to clarify for the audit team members the licensee's expected responses to the remaining NRC open items associated with the risk analysis.
DRAFT REQUEST FOR ADDITIONAL INFORMATION EXEMPTION REQUESTS AND LICENSE AMENDMENT REQUEST RISK-INFORMED APPROACH TO RESOLVE THE ISSUE OF POTENTIAL IMPACT OF DEBRIS BLOCKAGE ON EMERGENCY RECIRCULATION DURING DESIGN-BASIS ACCIDENTS AT PRESSURIZED-WATER REACTORS STP NUCLEAR OPERATING COMPANY SOUTH TEXAS PROJECT. UNITS 1 AND 2 DOCKET NOS. 50-498 AND 50-499 By letter dated June 19, 2013 (Agencywide Documents Access and Management System (ADAMS) Accession No. ML131750250), as supplemented by letters dated October 3, October 31, November 13, November 21 and December 23, 2013 (two letters); January 9, February 13, February 27, March 17, March 18, May 15 (two letters), May 22, June 25, and July 15, 2014; March 10, March 25, and August 20, 2015; and April 13, 2016 (ADAMS Accession Nos. ML13295A222, ML13323A673, ML13323A128, ML13338A165, ML14015A312, ML14015A311, ML14029A533, ML14052A110, ML14072A075, ML14086A383, ML14087A126, ML14149A353, ML14149A354, ML14149A439, ML14178A467, ML14202A045, ML15072A092, ML15091A440, ML15246A125, and ML16111B204, respectively), STP Nuclear Operating Company (STPNOC) submitted exemption requests accompanied by a license amendment request (LAR) for a risk-informed approach to resolve Generic Safety Issue (GSl)-191, "Assessment of Debris Accumulation on PWR [Pressurized-Water Reactor] Sump Performance," at South Texas Project, Units 1 and 2.
The U.S. Nuclear Regulatory Commission (NRC) staff has reviewed the information provided in your application and your responses to NRC staff requests for additional information (RAI) related specifically to the probabilistic risk analysis portions of these documents, and determined that the following additional information is required to complete its review.
REQUEST FOR ADDITIONAL INFORMATION Note: The questions below use the numbering system established in the RAJ issued to STPNOC on April 11, 2016 (ADAMS Accession No. ML16082A507). The system consists of the Office of Nuclear Reactor Regulation (NRR) Branch acronym (i.e., Probabilistic Risk Assessment Licensing Branch or APLA), the NRG RAJ Round No., then a sequential number starting with 1.
APLA-4-1: NRC Regulatory Guide (RG) 1.174, Revision 2, "An Approach for Using Probabilistic Risk Assessment in Risk-Informed Decisions on Plant-Specific Changes to the Licensing Basis," May 2011 (ADAMS Accession No. ML100900006), states, in part, that, "the
[probabilistic risk assessment (PRA)] should realistically reflect the actual design, construction, Enclosure 2
operational practices, and operational experience of the plant." Therefore, whether a particular accident sequence (e.g., secondary side break followed by sump recirculation) is part of a plant's licensing basis is immaterial when performing a risk analysis. For example, accident sequences involving common cause failures are not part of a plant's licensing basis since the Updated Final Safety Analysis Report (UFSAR) Chapter 15 accident analyses require consideration of only a single active failure. Yet operational experience shows that these types of accidents can occur and they therefore must be modeled by the plant's PRA. Consistent with this guidance, the risk assessment of debris should consider all hazards, initiating events, and plant operating modes. It should not be limited to design-basis accidents, licensing basis events, specific plant operating modes, or specific initiating events such as a loss-of-coolant accident (LOCA).
In the licensee's submittal dated October 13, 2013, Enclosure 4-2, "South Texas Project Risk-Informed Closure of GSl-191, Volume 2, Probabilistic Risk Analysis" (Reference 1), provides the screening rationale and concluded in Section 12.3 that "Medium and large LOCAs from internal events only are retained for further consideration with respect to core damage resulting from GSl-191 phenomena." The Volume 2 document also stated that the full-power analysis bounds consequences of other plant states.
A supplemental analysis (Risk-Over-Deterministic or RoverD) was submitted in STPNOC's letter dated August 20, 2015 (Attachment 1-3; Reference 2), which did not supersede previous submittals but purported to be "stand-alone." This raises the question regarding the applicability of the earlier information.
Please confirm that the conclusion in Section 12.3 in the earlier submittal (Reference 1) applies to the Rovero supplemental analysis (Reference 3); that is, confirm that all hazards, initiating events, and plant operating modes were screened out of consideration except medium and large LOCAs and that full-power operation is the only operating mode that merits consideration in the detailed Rovero analyses.
APLA-4-2: NUREG-1829, "Estimating Loss-of-Coolant Accident (LOCA) Frequencies Through the Elicitation Process," April 2008 (ADAMS Accession No. ML082250436), includes only breaks caused by long-term material degradation. Other potential contributors to LOCA frequency such as seismically induced LOCA (both direct and indirect) should be evaluated separately. A "direct" seismically induced LOCA involves rupture of a piping or non-piping component caused by the seismic event itself. An "indirect" seismically induced LOCA is caused by, for example, failure of piping or component supports that leads to the consequential failure of the piping or non-piping component.
In its May 22, 2014, response to an NRC RAI dated April 14, 2014 (ADAMS Accession No. ML14087A075), STP provided an estimate of the frequency of seismically induced LOCA (Attachment 1, p. 24/86; Reference 4). However, the response did not appear to consider indirect seismically induced LOCAs. One acceptable approach for evaluating indirect seismically induced LOCAs is for the analyst to use the method described by NUREG-1903, "Seismic Considerations for the Transition Break Size," Section 4.6, "Indirectly Induced Piping Failures," February 2008 (ADAMS Accession No. ML080880140). "Representative" values in the NUREG could be replaced with site-specific fragility and hazard information that, as appropriate, accounts for any effects of material degradation or aging. Alternatively, it may
demonstrated that the representative values are bounding for the site with consideration of effects due to material degradation or aging.
Please clarify whether the analysis documented in the RAI response considered indirect seismic LOCAs. If not, provide an analysis accounting for indirect damage mechanics eventually leading to rupture of piping and non-piping systems and LOCA events. For both direct and indirect seismically induced LOCAs, estimate, bound or screen any increase in seismic risk due to debris.
APLA-4-3: NUREG-1829 LOCA frequencies include only breaks caused by long-term material degradation. Other potential contributors to LOCA frequency, such as water hammer, should be evaluated separately.
One acceptable approach for evaluating water hammer is to verify that the potential for water hammer is not likely to cause pipe rupture in the break locations that can produce and transport problematic debris. Water hammer includes various unanticipated high-frequency hydrodynamic events, such as steam hammer and water slugging. To demonstrate that component failure risk due to water hammer is acceptably low, the analyst could take the following actions:
- Assess historical frequencies of water hammer events affecting break locations (piping and non-piping) that could generate and transport debris.
- Evaluate operating procedures and conditions and demonstrate that they are effective in precluding water hammer.
- Alternatively, the analyst can demonstrate the following:
o Plant changes, such as the use of J-tubes, vacuum breakers, and jockey pumps, coupled with improved operating procedures, have been used to successfully mitigate water hammer events.
o Measures used to abate water hammer frequency and magnitude have been effective over the licensing period of the plant.
Please evaluate the relevance of water hammer events in the context of GSl-191 and estimate, bound, or screen any increase in risk due to water hammer events.
APLA-4-4: Please provide values of total risk estimates (also including water hammer and seismically induced LOCA) for the plant expressed as core damage frequency (CDF) and large early release frequency (LERF). Those values are not available in the recent Rovero analysis (Reference 2). This information is needed to compare pairs {CDF, ~CDF} and {LERF, ~LERF}
to risk acceptance guidelines in RG 1.174.
APLA-4-5: Title 10 to the Code of Federal Regulations (10 CFR), Subsection 50.46(b)(5),
Long-term cooling, and Appendix A to 10 CFR Part 50, General Design Criterion 35, Emergency core cooling, state, in part, that the emergency core cooling system (ECCS) must provide core cooling for extended periods following postulated LOCAs. Licensing basis analyses used to
demonstrate compliance with these regulations have historically analyzed the effects of debris in a deterministic manner. STPNOC has submitted a pilot LAR and a series of exemptions that, if approved, would change its licensing basis by using a risk-informed treatment of debris (Reference 3). RG 1.174 contains five key principles for performing risk-informed changes to a plant's licensing basis. Principle 5 states that an implementation and monitoring program should be utilized to ensure that the conclusions reached by the staff (e.g., that the increase in risk is small) remain valid after the change is implemented.
The NRC staff has determined that it does not yet have adequate assurance that principle 5 of RG 1.174 is met and that there are sufficient regulatory controls of the key elements of the STP risk-informed assessment of debris.
Specifically, the NRC requires regulatory assurance of the continued applicability of the results of the risk-informed approach for consideration of debris in order to issue the requested license amendments and grand the associated exemptions. In order to obtain this regulatory assurance, certain aspects of the risk-informed approach must (1) be subject to an ongoing monitoring program consistent with principle 5 of RG 1.174; (2) be periodically updated; (3) continue to use methods acceptable to the NRC; and (4) be subject to reporting and corrective action when the risk-informed acceptance criteria are not met. The NRC also requires regulatory assurance that the risk-informed approach will not be employed for plant design changes that would increase the problematic debris source term without prior NRC review and approval.
Please provide assurance of appropriate regulatory considerations:
- a. Prior to changing the key methods, approaches, and data of the risk-informed analysis set forth in (reference).
- b. Prior to using the risk-informed approach to justify future plant design changes that would increase the problematic debris source term compared to the level that existed as of (date).
- c. STPNOC will implement and maintain a program to monitor key assumptions and data used in the risk assessment and the evaluation of defense-in-depth and safety margins. The monitoring program must assess the effects of design or plant modifications, procedure changes, as-found conditions, identified changes or errors in the analysis, industry operating experience, and any other information that could result in increased risk, or decreased defense-in-depth or safety margins, under the alternative risk-informed approach. The results of the monitoring program should be retained onsite for inspection.
- d. STPNOC will update the risk-informed evaluation no later than 48 months after initial NRC approval or the latest update and compare the risk results, CDF, LERF, ~CDF, and ~LERF, to the acceptance criteria in the safety evaluation that accompanies the requested LAR (reference).
- e. In the event that the acceptance criteria for the risk-informed analysis are not met:
- 1. STPNOC will notify the NRC in accordance with 10 CFR § 50. 72 or 50. 73 to notify the NRC that the acceptance criteria has been exceeded; and,
- 2. STPNOC will take timely action to ensure that the acceptance criteria are met.
These requirements are in addition to (and separate from) the reporting requirements in 10 CFR 50.46(a).
APLA-4-6: Please confirm the accuracy of the computation of the b.CDF for the double-ended guillotine break (DEGB)-only model that was provided (References 2 and 3). It appears that the current approach assumes, for example, that a 12.8-in DEGB could occur in larger diameter pipes (e.g., 27.5-in, 29-in, and 31-in diameter pipes). Include arithmetic and geometric mean approaches.
REFERENCES:
- 1. STP Nuclear Operating Company, "Enclosure 4-2, 'South Texas Project Risk-Informed Closure of GSl-191, Volume 2, Probabilistic Risk Analysis,"' Revision 2, dated October 22, 2013 (ADAMS Accession No. ML13323A189).
- 2. Powell, G. T., STP Nuclear Operating Company, letter to U.S. Nuclear Regulatory Commission, "South Texas Project Units 1 and 2 - Supplement 2 to STP Pilot Submittal and Requests for Exemptions and License Amendment for a Risk-Informed Approach to Address Generic Safety Issue (GSl)-191 and Respond to Generic Letter (GL) 2004-02,"
dated August 20, 2015 (ADAMS Accession No. ML15246A126).
- 3. Powell, G. T., STP Nuclear Operating Company, letter to U.S. Nuclear Regulatory Commission, "Description of Revised Risk-Informed Methodology and Responses to Round 2 Requests for Additional Information Regarding STP Risk-Informed GSl-191 Licensing Application," dated March 25, 2015 (ADAMS Accession No. ML15091A440).
- 4. Powell, G. T., STP Nuclear Operating Company, letter to U.S. Nuclear Regulatory Commission, "South Texas Project Units 1 and 2 -First Set of Responses to April, 2014, Requests for Additional Information Regarding STP Risk-Informed GSl-191 Licensing Application Revised," dated May 22, 2014 (ADAMS Accession No. ML14149A434).
D. Koehl If you have any questions, please contact me at 301-415-1906 or via e-mail at Lisa.Reqner@nrc.gov.
Sincerely, IRA/
Lisa M. Regner, Senior Project Manager Plant Licensing Branch IV-1 Division of Operating Reactor Licensing Office of Nuclear Reactor Regulation Docket Nos. 50-498 and 50-499
Enclosures:
- 1. Audit Summary
- 2. Draft Request for Additional Information cc w/encls: Distribution via Listserv DISTRIBUTION:
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