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Category:Letter
MONTHYEARML24032A0252024-02-0505 February 2024 NRC Initial Test Program and Operational Programs Integrated Inspection Report 05200026-2023009 ML24010A0712024-01-31031 January 2024 Exemption from Select Requirements of 10 CFR Part 73 (Security Notifications, Reports and Recordkeeping and Suspicious Activity Reporting) ML24031A6102024-01-31031 January 2024 Cyber Security Inspection Report 05200026/2024401 - Public ML24029A0592024-01-30030 January 2024 Request for Withholding Information from Public Disclosure Responses to NRC Request for Additional Information for Refueling Outage 1R24 Steam Generator Tube Inspection Report Enclosure 2, GAE-NRCD-RF-LR-000002 P-Attachment, Rev. 0 ML24016A1132024-01-30030 January 2024 Correction of Unit 1 Amendment Nos. 96 and 190 and Unit 2 Amendment Nos. 74 and 173 Adoption of Standard Technical Specifications Westinghouse Plants NL-24-0031, Inservice Inspection Program Owner'S Activity Report (OAR-1) for Outage 2R232024-01-29029 January 2024 Inservice Inspection Program Owner'S Activity Report (OAR-1) for Outage 2R23 IR 05000424/20244032024-01-26026 January 2024 Information Request for the Cyber-Security Baseline Inspection, Notification to Perform Inspection 05000424/2024403; 05000425/2024403 NL-24-0020, Plan, Unit 1 Responses to NRC Request for Additional Information for Refueling Outage 1R24 Steam Generator Tube Inspection Report2024-01-22022 January 2024 Plan, Unit 1 Responses to NRC Request for Additional Information for Refueling Outage 1R24 Steam Generator Tube Inspection Report ML23347A2092024-01-17017 January 2024 Voluntary Requests for Data, Information, And/Or Observation ML23279A0042024-01-17017 January 2024 Amendment No. 194 to Remove Combined License Appendix C NL-23-0926, Correction of Technical Specification Typographical Error2024-01-12012 January 2024 Correction of Technical Specification Typographical Error ML23341A2042024-01-12012 January 2024 Request for Additional Information Exemption Requests for Physical Barriers (EPID L-2023-LLE-0018 & L-2023-LLE-0021) ML23345A1312024-01-0303 January 2024 Withholding Letter - SNC Fleet - Physical Barriers Exemption (L-2023-LLE-0018 and L-2023-LLE-0021) ML23317A2072023-12-22022 December 2023 Issuance of Amendments 223 and 206 Regarding Revision to Technical Specifications to Adopt TSTF-339-A, Relocate Technical Specification Parameters to the COLR Consistent with WCAP-1448 ML23335A1222023-12-19019 December 2023 Safety Evaluation Regarding Implementation of Mitigating Strategies Related to Order EA-12-049 (EPID L-2023-LRQ-0002) - Letter ML23353A1702023-12-19019 December 2023 LAR-22-002, TS 3.8.3 Inverters Operating Completion Time Extension Letter ML23310A2922023-12-0707 December 2023 Issuance of Amendment for Exception to Regulatory Guide 1.163, LAR 23 007 ML23339A1812023-12-0707 December 2023 Correction Letter Regarding License Amendment Request: More Restrictive Action for Technical Specification 3.1.9 ML23338A2182023-12-0606 December 2023 Project Manager Reassignment NL-23-0878, Request for Exemption from Security Event Notification Implementation2023-11-29029 November 2023 Request for Exemption from Security Event Notification Implementation ML23289A1632023-11-28028 November 2023 Letter and Amendment 195 and 192 LAR-23-006R1 TS 3.1.9 More Restrictive Action NL-23-0827, Response to Requests for Additional Information for a License Amendment Request and a Proposed Alternative Related to TS 3.4.142023-11-17017 November 2023 Response to Requests for Additional Information for a License Amendment Request and a Proposed Alternative Related to TS 3.4.14 ML23318A4582023-11-14014 November 2023 Integrated Inspection Report 05200025/2023003 ML23312A3502023-11-14014 November 2023 Integrated Inspection Report 05200026/2023003 ML23306A3552023-11-0808 November 2023 NRC Initial Test Program and Operational Programs Integrated Inspection Report 052000/262023008 ML23268A0572023-11-0707 November 2023 Issuance of Amendments 194 & 191 Request for License Amendment Relocation of Technical Specification 3.7.9, Spent Fuel Pool Makeup Water Sources (LAR-23-003) IR 05000424/20234022023-11-0606 November 2023 Security Baseline Inspection Report 05000424/2023402 and 05000425/2023402 IR 05000424/20230032023-10-27027 October 2023 Integrated Inspection Report 05000424/2023003 and 05000425/2023003 ML23291A1512023-10-18018 October 2023 Information Request for the Cyber Security Baseline Inspection, Notification to Perform Inspection 0520026/2024401 ML23263A9852023-10-12012 October 2023 Issuance of Amendments Nos. 221 and 204, Regarding Technical Specification 5.5.11.C, Acceptance Criteria for Charcoal Filter Testing ML23283A0472023-10-0808 October 2023 Neop Letter Dated October 8, 2023 - Vogtle 3 & 4 - TS 3.7.6 License Amendment Request NL-23-0750, Response to Second Request for Additional Information Regarding License Amendment Request: Technical Specification Revision to Adopt TSTF-339-A, Relocate Technical Specification Parameters to the Colr2023-10-0404 October 2023 Response to Second Request for Additional Information Regarding License Amendment Request: Technical Specification Revision to Adopt TSTF-339-A, Relocate Technical Specification Parameters to the Colr NL-23-0745, Refueling Outage 1R24 Steam Generator Tube Inspection Report2023-09-22022 September 2023 Refueling Outage 1R24 Steam Generator Tube Inspection Report ML23254A2032023-09-13013 September 2023 Initial Test Program and Operational Programs Inspection Report 05200025/2023013 ML23241B0212023-09-12012 September 2023 Review of Quality Assurance Topical Report ML23234A2352023-09-0808 September 2023 Request for Withholding Information from Public Disclosure Notification of Full Compliance of Required Action for NRC Order EA-12-049 Mitigation Strategies for Beyond-Design-Basis External Events IR 05000424/20230912023-09-0505 September 2023 Plan Units 1 and 2 - NRC Investigation Report 2-2022-006 and Notice of Violation - NRC Inspection Report 05000424/2023091 and 05000425/2023091 ML23234A3002023-09-0101 September 2023 NRC Integrated Inspection Report 05200026/2023003 ML23243A0092023-08-31031 August 2023 Updated Inspection Plan for Vogtle Electric Generating Plant, Units 3 & 4 (Report 05200025 2023005 & 05200026 2023005) NL-23-0695, Response to Round 2 Request for Additional Information Regarding License Amendment Request for Technical Specification 3.8.3, Inverters Operating, Completion Time Extension (LAR-22-002S2)2023-08-31031 August 2023 Response to Round 2 Request for Additional Information Regarding License Amendment Request for Technical Specification 3.8.3, Inverters Operating, Completion Time Extension (LAR-22-002S2) ML23243B0252023-08-30030 August 2023 Exam Corporate Notification Letter (210 Day) IR 05000424/20230052023-08-29029 August 2023 Updated Inspection Plan for Vogtle Electric Generating Plant, Units 1 & 2 - Report 05000424/2023005 and 05000425/2023005 NL-23-0666, License Amendment Request: Remove Combined License Appendix C (LAR 23-008)2023-08-28028 August 2023 License Amendment Request: Remove Combined License Appendix C (LAR 23-008) 2024-02-05
[Table view] Category:Request for Additional Information (RAI)
MONTHYEARIR 05000424/20244032024-01-26026 January 2024 Information Request for the Cyber-Security Baseline Inspection, Notification to Perform Inspection 05000424/2024403; 05000425/2024403 ML23341A2042024-01-12012 January 2024 Request for Additional Information Exemption Requests for Physical Barriers (EPID L-2023-LLE-0018 & L-2023-LLE-0021) ML23342A0802023-12-0808 December 2023 NRR E-mail Capture - Request for Additional Information (RAI) - Vogtle, Unit 1 - Review of SG Tube Inspection Report for Refueling Outage 24 (L-2023-LRO-0067) ML23279A2082023-10-0505 October 2023 Issuance of Formal RAIs - Vogtle, Units 1 and 2 - Proposed LAR and Proposed Alternative Request to Revise TS 3.4.14.1 and IST ALT-VR-02 (EPIDs L-2023-LLA-0061 and L-2023-LLR-0023) ML23257A2092023-09-14014 September 2023 NRR E-mail Capture - Formal Issuance of 2nd Round RAIs for Surry Units 1&2 and North Anna Units 1&2 Emergency Plans LAR ML23248A3482023-09-0505 September 2023 NRR E-mail Capture - for Your Action - Request for Additional Information (RAI) 6 - Vogtle - TSTF-339 LAR (L-2023-LLA-0053) ML23243A9862023-08-31031 August 2023 NRR E-mail Capture - Draft RAIs for EP Staff Augmentation Times LAR (L-2022-LLA-0166) ML23188A1512023-08-0909 August 2023 Round 2 RAIs for LAR 22-002 TS 3.8.3 Inverters-Operating, Completion Time Extension ML23200A0112023-07-18018 July 2023 Document Request for Vogtle Unit 3 RP Inspection ML23198A1552023-07-17017 July 2023 NRR E-mail Capture - for Your Action - Request for Additional Information (RAI) - Hatch, Farley, and Vogtle, Units 1 and 2 Quality Assurance Topical Report (QATR) Submittal Dated June 15, 2023 ML23193A7832023-07-12012 July 2023 NRR E-mail Capture - for Your Action - Request for Additional Information (RAI) - Vogtle - TSTF-339 LAR (L-2023-LLA-0053) ML23065A0612023-03-0303 March 2023 NRR E-mail Capture - for Your Action - Request for Additional Information (RAI) 14 - Vogtle - AST, TSTF-51, TSTF-471, and TSTF-490 LAR (L-2022-LLA-0096) ML23006A0882023-01-0606 January 2023 NRR E-mail Capture - for Your Action - Request for Additional Information (RAI) - Vogtle - Accident Source Term (Ast), TSTF-51, TSTF-471, and TSTF-490 LAR (L-2022-LLA-0096) ML22348A0332022-12-13013 December 2022 NRR E-mail Capture - for Your Action - RAI - Vogtle, Unit 2 - Steam Generator Tube Inspection Report (L-2022-LRO-0120) ML22192A1042022-08-0101 August 2022 Acceptance of Requested Licensing Action Amendment Request Application to Allow Use of Lead Test Assemblies for Accident Tolerant Fuel with Request for Additional Information ML22157A0902022-06-0606 June 2022 NRR E-mail Capture - RAIs - Vogtle, Unit 1 - Refueling Outage (RFO) 1R23 Steam Generator (SG) Tube Inspection Report ML22104A1312022-04-14014 April 2022 NRR E-mail Capture - Request for Additional Information - Farley and Vogtle - Relocate Piping Inspection License Amendment Request (L-2021-LLA-0235) ML22026A3942022-01-26026 January 2022 NRR E-mail Capture - Request for Additional Information - Vogtle, Units 1 and 2, TS 3.7.2 LAR ML21350A1032021-12-16016 December 2021 NRR E-mail Capture - Request for Additional Information - Vogtle, Units 1 and 2, TS 3.7.2 LAR ML21321A3762021-11-15015 November 2021 NRR E-mail Capture - Request for Additional Information - Vogtle, Units 1 and 2, TS 3.7.2 LAR ML21075A0032021-03-12012 March 2021 Emergency Preparedness Exercise Inspection Request for Information for - Brunswick, Catawba, North Anna, Oconee, Vogtle 1 & 2 ML21033B1072021-02-0202 February 2021 NRR E-mail Capture - RAI - Vogtle Unit 1 - SG Report (L-2020-LRO-0059) ML20338A1512020-12-0303 December 2020 NRR E-mail Capture - RAIs for Vogtle GSI-191 LAR (L-2020-LLA-0182) ML20325A0432020-11-20020 November 2020 NRR E-mail Capture - for Your Review - Draft RAIs for Vogtle GSI-191 LAR (L-2020-LLA-0182) ML20297A3052020-10-22022 October 2020 NRR E-mail Capture - RAIs for Vogtle Relief Request - EPRI Report (L-2020-LLR-0109) ML20293A0752020-10-14014 October 2020 NRR E-mail Capture - RAIs for SNC Fleet EP LAR (L-2020-LLA-0150 and L-2020-LLA-0151) ML20149K6252020-05-27027 May 2020 NRR E-mail Capture - RAIs for SNC Fleet Fire Protection Exemption Requests ML19263A6432019-09-19019 September 2019 NRR E-mail Capture - RAI - Vogtle End State License Amendment Request (LAR) to Revise the Technical Specifications (Tss) for Vogtle, Units 1 and 2 (L-2019-LLA-0148) ML19156A1872019-06-0505 June 2019 NRR E-mail Capture - Request for Additional Information (RAI) for Vogtle Unit 2 Core Operating Limits Report, Cycle 21 ML19105B1632019-04-15015 April 2019 NRR E-mail Capture - Request for Additional Information (RAI) for Voglte TSTF-412 Adoption LAR (L-2018-LLA-0731) ML18355A4772019-01-0404 January 2019 Request for Additional Information Revise TS 5.2.2.g and Update Emergency Plan Minimum On-Shift Staff Tables ML18337A4032018-12-0606 December 2018 Request for Additional Information Revise Technical Specification 5.2.2.G and Updating Emergency Plan Minimum On-Shift Staff Tables ML18236A4452018-08-30030 August 2018 Review of Response to RAI License Amendment Request for Approval to Utilize the Tornado Missile Risk Evaluator to Analyze Tornado Missile Protection Non-Conformances ML18227A0222018-08-15015 August 2018 Notification of Inspection and Request for Information ML18225A3362018-08-13013 August 2018 NRR E-mail Capture - Request for Additional Information Regarding Relief Request VEGP-ISI-RR-03 ML18197A0602018-07-13013 July 2018 Us NRC Final RAI No. 1 for Vogtle 3 and 4 LAR-18-015, Fire Protection System Non-Safety Cable Spray Removal ML18197A1882018-07-13013 July 2018 Us NRC Final Request for Additional Information (Final RAI) No. 4 on Vogtle LAR-17-024, Technical Specification Updates for Reactivity Controls and Other Miscellaneous Changes ML18197A1052018-07-13013 July 2018 Us NRC Final Request for Additional Information (Final RAI) No. 1 on Vogtle 3 and 4 LAR-17-043, Containment Pressure Analysis ML18192C0782018-07-11011 July 2018 RAI (LAR 18-009) - Vogtle Electric Generating Plant, Unit 3 and 4 ML18192B7692018-07-11011 July 2018 Us NRC Draft Request for Additional Information (Draft RAI) No. 4 on Vogtle LAR-17-024, Technical Specification Updates for Reactivity Controls and Other Miscellaneous Changes ML18136A4972018-06-0101 June 2018 Request for Additional Information, License Amendment Request to Incorporate Tornado Missile Risk Evaluator Methodology Into Licensing Basis ML18109A1152018-05-0101 May 2018 Request for Additional Information ML18079A9572018-03-28028 March 2018 Request for Additional Information Incorporate Seismic Probabilistic Risk Assessment Into the 10 CFR 50.69 Categorization Process (CAC Nos. MF9861 and MF9862; EPID L-2017-LLA-0248) ML18058A0812018-02-27027 February 2018 Enclosurequest for Additional Information(Rai for Review of Southern Nuclear Operating Company'S Decommissioning Funding Plan Updates for Joseph M. Farley,Unit 1 and 2;Edwin I. Hatch,Units 1 and 2; and Vogtle Electric Generating Plant, Unit ML18030B0622018-02-0808 February 2018 Request for Additional Information Reverse Technical Specification 5.5.17 for Permanent Extension of Type a and Type C Leak Rate Test Frequencies (CAC Nos. MG0240, MG0241; EPID L-2017-LLA-0295) ML17355A1012018-01-11011 January 2018 Request for Additional Information (CAC Nos. MF9685 and MF9686; EPID L-2017-TOP-0038) ML17354A7822018-01-0505 January 2018 Request for Additional Information Incorporate Seismic Probabilistic Risk Assessment Into the 10 CFR 50.69 Categorization Process (CAC Nos. MF9861 and MF9862; EPID L-2017-LLA-0248) ML17318A0352017-11-22022 November 2017 Request for Additional Information 2024-01-26
[Table view] |
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UNITED STATES NUCLEAR REGULATORY COMMISSION WASHINGTON, D.C. 20555-0001 February 8, 2018 Mr. James J. Hutto Regulatory Affairs Director Southern Nuclear Operating Co., Inc.
P.O. Box 1295, Bin 038 Birmingham, AL 35201-1295
SUBJECT:
VOGTLE ELECTRIC GENERATING PLANT, UNITS 1 AND 2 - REQUEST FOR ADDITIONAL INFORMATION RE: REVISE TECHNICAL SPECIFICATION 5.5.17 FOR PERMANENT EXTENSION OF TYPE A AND TYPE C LEAK RATE TEST FREQUENCIES (CAC NOS. MG0240, MG0241; EPID L-2017-LLA-0295)
Dear Mr. Hutto:
By letter dated September 12, 2017, Southern Nuclear Operating Company (SNC) submitted a license amendment request to revise Vogtle Electric Generating Plant, Units 1 and 2 (VEGP),
Technical Specifications (TS). The licensee proposed to revise TS 5.5.17 "Containment Leakage Rate Testing Program."
The U.S. Nuclear Regulatory Commission (NRC) staff has determined that additional information is needed for the NRC to complete its review as discussed in the Enclosure. During a clarification call on February 8, 2018, Mr. Bates agreed that SNC respond within 45 days of the date of this letter. Please note that the NRC staff's review is continuing and further requests for information may be developed.
Sincerely, Shawn Williams, Project Manager Plant Licensing Branch, 11-1 Division of Operating Reactor Licensing Office of Nuclear Reactor Regulation Docket Nos. 50-424 and 50-425
Enclosure:
Request for Additional Information cc w/enclosure: Listserv
REQUEST FOR ADDITIONAL INFORMATION TS 5.5.17 CONTAINMENT LEAKAGE RATE TESTING PROGRAM SOUTHERN NUCLEAR OPERATING COMPANY, INC.
VOGTLE ELECTRIC GENERATING PLANT, UNITS 1 AND 2 SOUTHERN NUCLEAR OPERATING COMPANY DOCKET NOS. 50-424 AND 50-425 By letter dated September 12, 2017 (Agencywide Documents Access and Management System (ADAMS) Accession No. ML17257A177),Southern Nuclear Operating Company (SNC) submitted a license amendment request to revise Vogtle Electric Generating Plant, Units 1 and 2 (VEGP), Technical Specifications (TS). The licensee proposed to revise TS 5.5.17 "Containment Leakage Rate Testing Program."
The U.S. Nuclear Regulatory Commission (NRC) staff is reviewing the submittal and has determined that the following additional information is needed to complete its review.
RAI No. 1 Section 2.5.3 of Regulatory Guide (RG) 1.174, Revision 2 (ADAMS Accession No. ML100910006), states:
The development of the PRA [probabilistic risk assessment] model is supported by the use of models for specific events or phenomena. In many cases, the industry's state of knowledge is incomplete, and there may be different opinions on how the models should be formulated. Examples include approaches to modeling human performance, common-cause failures, and reactor coolant pump seal behavior upon loss of seal cooling. This gives rise to model uncertainty.
Regarding model uncertainty, Section 2.5.3 of RG 1.174, Revision 2, states:
... The impact of using alternative assumptions or models may be addressed by performing appropriate sensitivity studies or by using qualitative arguments, based on an understanding of the contributors to the results and how they are impacted by the change in assumptions or models.
In addition, Section 2.5.5 states:
[l]n general, the results of the sensitivity studies should confirm that the guidelines are still met even under the alternative assumptions (i.e., change generally remains in the appropriate region)."
Enclosure
In Section 3.3.2 of the license amendment request (LAR), the licensee stated:
The Westinghouse reactor coolant pump (RCP) shutdown seals have been installed at
[Vogtle Electric Generating Plant] VEGP, and are credited in the PRA.
Please provide the following information to validate and confirm the PRA technical acceptability for use in the risk evaluation performed to support the requested permanent 15-year integrated leak rate test (ILRT) extension.
- a. Provide a summary of the PRA modeling of the RCP shutdown seals, addressing the following aspects:
- 1. Specify the PRA models (e.g., internal events, fire, seismic) that credit the RCP shutdown seals.
- 2. Describe the PRA modeling of the RCP shutdown seals. Demonstrate how any limitations and conditions delineated in the NRG-approved guidance are being met [e.g., those in Section 3 of Topical Report PWROG-14001-P, Revision 1, "PRA Model for the Generation Ill Westinghouse Shutdown Seal,"
and Section 5 of NRC safety evaluation (SE) for PWROG-14001-P (ADAMS Accession Number ML17200A116)).
- 3. Indicate, and provide justification, whether the incorporation of the RCP shutdown seals into the PRA model is PRA maintenance or PRA upgrade, as defined in Section 1-5.4 of the American Society of Mechanical Engineers/
American Nuclear Society, ASME/ANS RA-Sa-2009, as qualified by RG 1.200, Revision 2 (ADAMS Accession No. ML090410014). This discussion should be of sufficient detail to allow NRC staff to independently assess whether this change is a PRA maintenance or PRA upgrade (e.g.,
summarize the original method in the PRA and the new method, summarize the impact that this change has on significant accident sequences or the significant accident progression sequences).
- b. If PRA modeling of the RCP shutdown seals is considered a PRA upgrade and a peer review(s) was performed for this upgrade, then discuss this peer review(s). In this discussion, describe the peer review process applied to the shutdown seal model; identify the guidance used to perform this peer review(s) (e.g., ASME/ANS RA-Sa-2009, Nuclear Energy Institute NEI 05-04, RG 1.200, Revision 2); include any necessary gap- or self-assessments if current guidance/standards were not used in the peer review(s); provide all facts and observations (F&Os) characterized as findings from the peer review(s) and the associated dispositions as it pertains to this application.
- c. If PRA modeling of the RCP shutdown seals is considered a PRA upgrade and a peer review was not performed for this upgrade, then perform an appropriate sensitivity and/or bounding analysis for the RCP shutdown seals (e.g., remove credit for RCP shutdown seals) that assesses the contribution of risk for permanently extending the ILRT to 15 years. This analysis should also address the below consideration on the regulatory guides related to fire PRA (FPRA). Discuss this sensitivity/bounding analysis and provide updated risk values that include the increase in total large early release frequency (LERF), change in LERF (ilLERF), population dose rate (PDR), and conditional containment failure probability (CCFP) for each unit to assess the risk
impact. Confirm that the results of this analysis still meet the acceptance guidelines in RG 1.174, Revision 2, and Electric Power Research Institute EPRI Technical Report 1009325, Revision 2-A. If the acceptance guidelines are exceeded, then provide qualitative or quantitative arguments, based on an understanding of the contributors to the results and how they are impacted by the change in assumptions or models, to support the conclusion of the LAR. This discussion should include which metrics are exceeded and the conservatisms in the analysis and the risk significance of these conservatisms.
If the FPRA applied in the sensitivity/bounding analysis does not incorporate the recently approved FPRA methodologies below, provide a detailed justification for why the integration of these NRG-approved FPRA methods and studies would not change the conclusions of the LAR.
- The NRC issued a letter dated June 21, 2012, "Recent Fire PRA Methods Review Panel Decisions and EPRI 1022993, 'Evaluation of Peak Heat Release Rates in Electrical Cabinet Fires"' (ADAMS Accession No. ML12171A583), providing staff positions on (1) frequencies for cable fires initiated by welding and cutting, (2) clarifications for transient fires, (3) alignment factor for pump oil fires, (4) electrical cabinet fire treatment refinement details, and (5) the EPRI 1022993 report.
- The NRC published NUREG/CR-7150, "Joint Assessment of Cable Damage and Quantification of Effects from Fire (JACQUE-FIRE)," Volume 2 (ADAMS Accession No. ML14141A129), which is supported by a letter from the NRC to NEI, "Supplemental Interim Technical Guidance on Fire-Induced Circuit Failure Mode Likelihood Analysis," and supplemented in April 2014 (ADAMS Accession Nos. ML14017A135 and ML14086A165).
- The NRC published NUREG-2169, "Nuclear Power Plant Fire Ignition Frequency and Non-Suppression Probability Estimation Using the Updated Fire Events Database: United States Fire Event Experience Through 2009" (ADAMS Accession No. ML15016A069).
ML16343A058). The guidance provided in FAQ 08-0046, "Closure of National Fire Protection Association 805 Frequently Asked Question 08-0046 Incipient Fire Detection Systems" (ADAMS Accession No. ML093220426), has been rescinded.
RAI No. 2 Table 6-2, "Vogtle Units 1 and 2 Internal and External Events Summary," provided LERF values for Units 1 and 2. The LERF values for the Units 1 and 2 internal events PRA (IEPRA) are both 6.45E-09/year. For fire events, the LERF values for Units 1 and 2 are 1.39E-06/year and 1.56E-06/year, respectively. The LERF values across the IEPRA and FPRA hazards are approximately two orders of magnitude (i.e., 10-2) in difference, while that for core damage frequency (CDF) is one order of magnitude. Confirm the LERF values across the IEPRA and FPRA hazards.
RAI No. 3 In the section of the LAR entitled, "Assessment of PRA Model Technical Adequacy," the licensee stated that in 2013 "[a] significant upgrade in [Modular Accident Analysis Program]
MAAP capabilities was initiated" for the IEPRA. Further review of the technical adequacy of the VEGP IEPRA does not readily identify whether a peer review in accordance with the ASME/ANS RA-Sa-2009 PRA standard, as qualified by RG 1.200, Revision 2, was performed to assess the upgrade in MAAP capabilities.
Provide a summary of the upgrade in MAAP capabilities and justify whether the "significant upgrade" constitutes a PRA upgrade in accordance with ASME/ANS RA-Sa-2009, as qualified by RG 1.200, Revision 2. If the significant upgrade in MAAP capabilities constitutes a PRA upgrade, provide the results from the focused-scope peer review, including the associated F&Os and their dispositions for any impact to the ILRT application; otherwise, provide a quantitative evaluation (e.g., sensitivity or bounding analysis) of its effect until a focused-scope peer review can be completed. For this quantitative evaluation, confirm that the results of this analysis still meet the acceptance guidelines in RG 1.174, Revision 2, and EPRI Technical Report 1009325, Revision 2-A. If the acceptance guidelines are exceeded, then provide qualitative or quantitative arguments, based on an understanding of the contributors to the results and how they are impacted by the change in assumptions or models, to support the conclusion of the LAR. This discussion should include which metrics are exceeded and the conservatisms in the analysis and the risk significance of these conservatisms.
RAI No. 4 In Table 6-2 of the LAR, a CDF value of 2.52E-06/year and a LERF value of 6.45E-09/year for Units 1 and 2, respectively, are provided for the internal events hazard. These CDF and LERF values are identical for each unit. Typically, differences in CDF and LERF results exist for multiple-unit plants, even if the differences are not significant. Accordingly, it is not clear whether the risk values reported in the LAR are the results of separate PRAs performed for each unit or whether PRAs were performed only for a given unit and assumed to represent both units.
- a. If the PRAs were performed only for a given unit and assumed to represent both units, then for the internal events hazard justify that the PRA model is an adequate representation of Units 1 and 2. Include a discussion of systems, structures, and components that are shared between units and how these were implicitly or explicitly modeled.
- b. If the PRAs were performed for each unit separately, briefly explain why the risk results are identical.
ML180308062 *Via e-mail OFFICE D0RULPL2-1 /PM D0RULPL2-1 /LA DRA/APLA/BC* D0RULPL2-1 /BC D0RULPL2-1 /PM NAME SWilliams KGoldstein SRosenberg MMarkley SWilliams DATE 02/02/18 02/01/18 01/29/18 02/02/18 02/08/18