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MONTHYEARML16032A1702016-02-22022 February 2016 Supplemental Information Needed for Acceptance of License Amendment Request for Implementation of WCAP-15376-P-A, Rev. 1 Project stage: Acceptance Review RC-16-0036, License Amendment Request - LAR-15-01424 - Implementation of WCAP-15376-P-A, Revision 1, Response to Request for Supplemental Information2016-03-0707 March 2016 License Amendment Request - LAR-15-01424 - Implementation of WCAP-15376-P-A, Revision 1, Response to Request for Supplemental Information Project stage: Supplement ML16302A1252016-11-0808 November 2016 Request for Additional Information License Amendment Request for Implementation of TSTF-411 and WCAP-15376-P-A, Revision 1 Project stage: RAI RC-17-0019, Response to Request for Additional Information Regarding License Amendment Request LAR-15-01424, Implementation of WCAP-15376-P-A, Revision 12017-02-0606 February 2017 Response to Request for Additional Information Regarding License Amendment Request LAR-15-01424, Implementation of WCAP-15376-P-A, Revision 1 Project stage: Response to RAI ML17095A2842017-05-11011 May 2017 Request for Additional Information License Amendment Request for Implementation of TSTF-411 (WCAP-15376-P-A), Revision 1 Project stage: RAI RC-17-0088, Implementation of WCAP-15376-P-A, Revision 1 - Risk-Informed Assessment of the RTS and ESFAS Surveillance Test Intervals and Reactor Trip Breaker Test and Completion Times - Response to Request for Additional Information2017-06-22022 June 2017 Implementation of WCAP-15376-P-A, Revision 1 - Risk-Informed Assessment of the RTS and ESFAS Surveillance Test Intervals and Reactor Trip Breaker Test and Completion Times - Response to Request for Additional Information Project stage: Response to RAI RC-17-0093, License Amendment Request - LAR-15-01424 Implementation of WCAP-15376-P-A, Revision 1 - Risk-Informed Assessment of the RTS and ESFAS Surveillance Test Intervals and Reactor Trip Breaker Test and Completion Times, Response To.2017-07-0606 July 2017 License Amendment Request - LAR-15-01424 Implementation of WCAP-15376-P-A, Revision 1 - Risk-Informed Assessment of the RTS and ESFAS Surveillance Test Intervals and Reactor Trip Breaker Test and Completion Times, Response To. Project stage: Request RC-17-0134, Response to Request for Supplemental Information, License Amendment Request - LAR-15-01424; Implementation of WCAP-15376-P-A, Revision 12017-09-27027 September 2017 Response to Request for Supplemental Information, License Amendment Request - LAR-15-01424; Implementation of WCAP-15376-P-A, Revision 1 Project stage: Supplement ML17206A4122017-10-0404 October 2017 Issuance of Amendment TSTF-411, Revision 1, Surveillance Test Interval Extensions for Components of the Reactor Protection System (WCAP-15376-P-A). Project stage: Approval 2017-02-06
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Category:Letter
MONTHYEARML24038A0322024-02-0707 February 2024 (Vcsns), Unit 1, 10 CFR 21 Report - Emergency Diesel Generator Flash Contactor Relay IR 05000395/20230042024-01-31031 January 2024 Integrated Inspection Report 05000395/2023004 ML24022A1582024-01-22022 January 2024 (Vcsns), Unit 1 - Reply to a Notice of Violation: EA-23-093 ML24022A1202024-01-22022 January 2024 Notification of Target Set Inspection and Request for Information (NRC Inspection Report 05000395/2024403) ML24018A0112024-01-18018 January 2024 CFR 21 Report Emergency Diesel Generator Fuel Oil Piping IR 05000395/20240112024-01-17017 January 2024 Notification of VC Summer Station Comprehensive Engineering Team Inspection - U.S. Nuclear Regulatory Commission Inspection Report 05000395/2024011 ML23361A1042023-12-21021 December 2023 Inservice Testing Program for Pumps and Valves Fifth Interval Update and Associated Relief and Alternative Requests IR 05000395/20230912023-12-21021 December 2023 Final Significance Determination of a White Finding and Notice of Violation and Assessment Followup Letternrc Inspection Report 05000395/2023091 ML23354A1802023-12-20020 December 2023 301 Examination Report with Cover Letter ML23347A0492023-12-12012 December 2023 Technical Specification Bases Changes Updated Through November 2023 ML23334A2462023-11-30030 November 2023 Request for Exemption from Enhanced Weapons, Firearms Background Checks, and Security Event Notifications Implementation ML23334A2372023-11-30030 November 2023 (Vvsns), Unit 1 - Annual Commitment Change Summary Report ML23332A1942023-11-28028 November 2023 (Vcsns), Unit 1, Correction of Typographical Error in License Amendment Request - Inverter Allowed Outage Time (AOT) Extension ML23317A2242023-11-0909 November 2023 (Vcsns), Unit 1 - License Amendment Request - Inverter Allowed Outage Time (AOT) Extension ML23289A1172023-11-0303 November 2023 Tribal Request for Scoping Comments Concerning the Environmental Review of the V.C. Summer SLRA ML23289A1152023-11-0303 November 2023 Ltr to R. Nelson - Request for Scoping Comments Concerning the Environmental Review of the V.C. Summer SLRA ML23289A1162023-11-0303 November 2023 Ltr to W. Emerson - Request for Scoping Comments Concerning the Environmental Review of the V.C. Summer SLRA IR 05000395/20234032023-11-0101 November 2023 Material Control and Accounting Program Inspection Report 05000395/2023403 Cover IR 05000395/20230032023-11-0101 November 2023 Integrated Inspection Report 05000395/2023003 ML23284A1792023-10-16016 October 2023 Subsequent License Renewal Application Online Reference Portal ML23275A0142023-10-11011 October 2023 SLRA - Acceptance and Opportunity for Hearing - Letter ML23284A1662023-10-10010 October 2023 (Vcsns), Unit 1 - Request for Regulatory Conference; (EA-23-093) IR 05000395/20230902023-10-0404 October 2023 NRC Inspection Report 05000395/2023090 and Preliminary Yellow Finding and Apparent Violation IR 05000395/20230112023-09-27027 September 2023 Focused Engineering Inspection Report 05000395/2023011 ML23250A3112023-09-20020 September 2023 Request to Revise Reactor Vessel Material Surveillance Capsule Withdrawal Schedules ML23244A2352023-09-18018 September 2023 Request to Use a Subsequent Edition of the ASME Code, Section XI ML23230A0012023-09-15015 September 2023 Request to Use a Provision of a Previous Edition of the ASME Boiler and Pressure Vessel Code, Section XI, for Non-Destructive Examinations ML23235A0432023-09-0505 September 2023 Receipt and Availability of the Subsequent License Renewal Application IR 05000395/20234012023-08-30030 August 2023 Security Baseline Inspection Report 05000395/2023401 ML23242A1192023-08-29029 August 2023 (Vcsns), Unit 1 - Inservice Inspection (ISI) Owner'S Activity Report (OAR) for Refueling Outage 27 ML23243B0362023-08-25025 August 2023 Request for FEMA Consultation on the Dominion Energy Proposal to Consolidate the Emergency Operations Facility for the Virgil C. Summer Nuclear Station Unit 1 IR 05000395/20230052023-08-23023 August 2023 Updated Inspection Plan for Virgil C. Summer Nuclear Station (Report 05000395 2023005) ML23233A1752023-08-17017 August 2023 Application for Subsequent Renewed Operating License IR 05000395/20230022023-08-14014 August 2023 Integrated Inspection Report - Integrated Inspection Report 05000395/2023002 and Apparent Violation IR 05000395/20230102023-08-12012 August 2023 Biennial Problem Identification and Resolution Inspection Report 05000395/2023010 ML23207A1102023-07-26026 July 2023 NRC Regulatory Issues Summary 2023-01 Preparation and Scheduling of Operator Licensing Examinations IR 05000395/20234412023-07-17017 July 2023 95001 Supplemental Inspection Report 05000395/2023441 and Follow Up Assessment Letter ML23190A0012023-07-0909 July 2023 Special Report 2023-003 Inoperable Radiation Monitoring Instrumentation Channel ML23187A5092023-07-0606 July 2023 Request for Federal Emergency Management Agency Consultation on the Dominion Energy Proposal to Consolidate the Emergency Operations Facility for the Virgil C. Summer Nuclear Station Unit 1 ML23178A1682023-06-26026 June 2023 2022 Annual Report of Emergency Core Cooling System (ECCS) Model Changes Pursuant to the Requirements of 10 CFR 50.46 ML23173A1052023-06-22022 June 2023 Special Report 2023-002 Inoperable Loose-Part Monitoring System Channel ML23163A2352023-06-12012 June 2023 Request to Use a Later Edition of the ASME Boiler and Pressure Vessel Code, Section XI, for the SPS Sixth Inservice Inspection (Isi) Intervals and VCSNS Fifth ISI Interval ML23159A2332023-06-0808 June 2023 License Amendment Request - Emergency Response Organization Augmentation Time Change, Emergency Operations Facility Relocation and Other Emergency Plan Changes ML23156A3092023-06-0505 June 2023 Requalification Program Inspection Virgil C. Summer Nuclear Station Unit 1 - 05000395/2023003 2024-02-07
[Table view] Category:Request for Additional Information (RAI)
MONTHYEARML23270B8712023-09-27027 September 2023 NRR E-mail Capture - Draft RAIs for License Amendment Request (LAR) to Revise the Virgil C. Summer Nuclear Station (VCSNS) Unit 1 Emergency Plan (L-2023-LLA-0083) ML22263A0502022-09-19019 September 2022 NRR E-mail Capture - Draft Request for Additional Information for Proposed Alternative Request RR-4-26 Extension of Steam Generator Primary Inlet Nozzle Dissimilar Metal Weld Inspection Interval V.C. Summer Unit 1 ML22194A9422022-07-13013 July 2022 NRC 50.59 Inspection (IP 71111.17T) Information Request ML22075A0482022-03-16016 March 2022 V.C. Summer Nuclear Station - Information Request for the Cyber-Security Baseline Inspection, Notification to Perform Inspection 05000395/2022401 ML21333A1892021-11-29029 November 2021 NRR E-mail Capture - Draft RAI for Summer LAR Relocate Surveillance Frequencies to Licensee Control - RITSTF Initiative 5b, (TSTF-425) ML21253A1352021-09-0808 September 2021 Document Request for VC Summer Nuclear Station - Radiation Protection Inspection - Inspection Report 2021-04 ML21154A2792021-06-0303 June 2021 Requalification Program Inspection 05000395/2021003 - Virgil C. Summer Nuclear Station, Unit 1, ML21145A0222021-05-24024 May 2021 003 Radiation Safety Baseline Inspection Information Request ML21131A0402021-05-11011 May 2021 NRR E-mail Capture - V.C. Summer, Unit 1 - Final RAI for the Spring 2020 RFO Sgtir Review ML21020A0562021-01-20020 January 2021 Email Capture Upcoming V.C. Summer POV Inspection (IP71111.21N.02) Information Request ML20342A1822020-12-0707 December 2020 NRR E-mail Capture - Final RAI for Summer LAR - TS 3.6.4 ML20342A3822020-12-0707 December 2020 NRR E-mail Capture - Final RAIs for Summer Fs LOCA LAR ML20321A2112020-11-16016 November 2020 NRR E-mail Capture - Summer, Unit 1 - Final RAIs for the SG Tube Inspection Report Review ML20196L7782020-07-13013 July 2020 Notification of Virgil C. Summer Nuclear Station Design Bases Assurance Inspection U.S. Nuclear Regulatory Commission Inspection Report 05000395/2020010 ML20106E8902020-04-15015 April 2020 Program Inspection RFI ML20056E3042020-02-25025 February 2020 VC Summer 2020-002 Radiation Safety Baseline Inspection Information Request ML19211D5102019-07-30030 July 2019 NRR E-mail Capture - Virgil C. Summer Nuclear Station, Unit No. 1 - Request for Additional Information LAR-16-01490 NFPA-805 (Supplement to PRA RAI 03) ML19179A1262019-06-27027 June 2019 NRR E-mail Capture - Virgil C. Summer Nuclear Station, Unit No. 1 - Request for Additional Information LAR-16-01490 NFPA-805 Program Revisions ML19095A6532019-04-0404 April 2019 NRR E-mail Capture - Virgil C. Summer Nuclear Station, Unit No. 1 - Request for Additional Information NFPA-805 Program Revisions LAR ML19072A1442019-03-13013 March 2019 NRR E-mail Capture - Virgil C. Summer Nuclear Station, Unit No. 1 - Request for Additional Information LAR-16-01490 NFPA-805 Program Revisions ML19009A1052019-01-0909 January 2019 NRR E-mail Capture - Virgil C. Summer Nuclear Station, Unit No. 1 - Request for Additional Information LAR-10-02395, TS 3.8.2, D.C. Sources - Operating ML18249A1932018-09-0505 September 2018 TS 4.3.3.6 SR LAR - Request for Additional Information ML18225A0932018-08-13013 August 2018 Notification of Inspection and Request for Information ML18218A2622018-08-0101 August 2018 Emergency Preparedness Program Inspection Request for Information ML18066A0002018-03-0808 March 2018 Request for Additional Information Integrated Leak Rate Test Peak Calculated Containment Internal Pressure Change ML18023B0692018-02-15015 February 2018 Request for Additional Information Relief Request (RR-4-13), Use of Risk-Informed Process as an Alternative for the Selection of Class 1 and Class 2 Piping Welds ML17095A2842017-05-11011 May 2017 Request for Additional Information License Amendment Request for Implementation of TSTF-411 (WCAP-15376-P-A), Revision 1 ML17067A5322017-03-0808 March 2017 Notification of Radiation Protection Baseline Inspection and Request for Information ML17059C5382017-02-23023 February 2017 Notification of Inspection and Request for Information ML16302A1252016-11-0808 November 2016 Request for Additional Information License Amendment Request for Implementation of TSTF-411 and WCAP-15376-P-A, Revision 1 RC-16-0112, NRC Request Information Baseline Radiation Safety Inspection2016-07-0707 July 2016 NRC Request Information Baseline Radiation Safety Inspection ML16111A0912016-05-0303 May 2016 Request for Additional Information Regarding the Station Physical Security Plan, Revision 14 ML16097A0812016-04-0808 April 2016 Request for Additional Information ML16064A0332016-03-0303 March 2016 NRR E-mail Capture - Request for Additional Information Related to the March 1, 2016, Exigent Amendment Request ML16042A4712016-02-18018 February 2016 Request for Additional Information ML15320A3382015-12-0101 December 2015 Request for Additional Information Regarding License Basis Changes in Steam Generator Tube Rupture Analysis RC-15-0177, Submits LAR-12-04269, License Basis Changes in Steam Generator Tube Rupture Analysis Response to Response for Additional Information2015-11-0505 November 2015 Submits LAR-12-04269, License Basis Changes in Steam Generator Tube Rupture Analysis Response to Response for Additional Information ML15261A0512015-09-22022 September 2015 Request for Additional Information Regarding License Basis Changes in Steam Generator Tube Rupture Analysis ML15118A4592015-05-19019 May 2015 Request for Additional Information Regarding Alternative Request ML15118A3802015-05-0505 May 2015 Request for Additional Information Regarding Snubber Program Alternative Request ML15076A1182015-04-13013 April 2015 Request for Additional Information Regarding License Basis Changes in Steam Generator Tube Rupture Analysis ML15079A0992015-03-26026 March 2015 Request for Additional Information ML14339A0302015-01-0909 January 2015 Request for Additional Information Regarding License Basis Changes in Steam Generator Tube Rupture Analysis ML14268A5162014-10-23023 October 2014 Request for Additional Information Associated with Near-Term Task Force Recommendation 2.1, Seismic Re-evaluation Related to Southeastern Catalog Changes ML14226A2552014-08-29029 August 2014 Request for Additional Information ML14182A4732014-07-11011 July 2014 Request for Additional Information Regarding License Amendment Request to Adopt National Fire Protection Association Standard 805 ML14071A1692014-03-24024 March 2014 Request for Additional Information ML14023A7402014-01-30030 January 2014 (VCSNS) - Request for Additional Information ML13347B0492013-12-19019 December 2013 (VCSNS) - Request for Additional Information ML13340A3772013-12-11011 December 2013 (VCSNS) - Request for Additional Information 2023-09-27
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UNITED STATES NUCLEAR REGULATORY COMMISSION WASHINGTON, D.C. 20555-0001 May 11, 2017 Mr. George A. Lippard, Ill Vice President, Nuclear Operations South Carolina Electric & Gas Company Virgil C. Summer Nuclear Station Post Office Box 88, Mail Code 800 Jenkinsville, SC 29065
SUBJECT:
VIRGIL C. SUMMER NUCLEAR STATION, UNIT NO. 1 - REQUEST FOR ADDITIONAL INFORMATION RE: LICENSE AMENDMENT REQUEST FOR IMPLEMENTATION OF TSTF-411 (WCAP-15376-P-A), REVISION 1 (CAC NO. MF7196)
Dear Mr. Lippard:
By letter dated December 16, 2015, as supplemented by letters dated March 7, 2016, and February 6, 2017, South Carolina Electric & Gas Company (SCE&G, the licensee) requested changes to the Technical Specifications for the Virgil C. Summer Nuclear Station, Unit No. 1.
The proposed license amendment changes are based on Technical Specification Task Force (TSTF) Traveler TSTF-411, Revision 1, "Surveillance Test Interval Extensions for Components of the Reactor Protection System (WCAP-15376-P)."
The U.S. Nuclear Regulatory Commission (NRC) staff has reviewed the licensee's submittal and determined that additional information is needed to continue its review. During a clarification call on May 9, 2017, Mr. Thompson of SCE&G requested 45 days of the date of this letter to respond to the NRC request for additional information. The NRC staff agreed to this request but notes that the NRC staff's review is continuing, and further requests for information may be developed.
If you have any questions, please contact me at 301-415-1009 or Shawn.Williams@nrc.gov.
Sincerely, Shawn A. Williams, Senior Project Manager Plant Licensing Branch 11-1 Division of Operating Reactor Licensing Office of Nuclear Reactor Regulation Docket No. 50-395
Enclosure:
Request for Additional Information cc w/enclosure: Distribution via Listserv
REQUEST FOR ADDITIONAL INFORMATION LICENSE AMENDMENT REQUEST FOR IMPLEMENTATION OF WCAP-15376-P-A, REVISION 1 SOUTH CAROLINA ELECTRIC & GAS COMPANY VIRGIL C. SUMMER NUCLEAR STATION, UNIT NO. 1 DOCKET NO. 50-395 By letter dated December 16, 2015 (Agencywide Documents Access and Management System (ADAMS) Accession No. ML15356A048), as supplemented by letter dated March 7, 2016 (ADAMS Accession No. ML16069A021 ), and February 6, 2017 (ADAMS Accession No.
ML17037D369), South Carolina Electric & Gas Company (SCE&G, the licensee), submitted a license amendment request (LAR) for the Virgil C. Summer Nuclear Station, Unit No. 1 (VCSNS). The licensee proposes to revise Technical Specification (TS) 3/4.3.1, "Reactor Trip System Instrumentation," and TS 3/4.3.2, "Engineered Safety Feature Actuation System Instrumentation," to implement the allowed outage time, bypass test time, and surveillance frequency changes approved by the U.S. Nuclear Regulatory Commission (NRC) in Technical Specification Task Force (TSTF) Traveler TSTF-411, Revision 1, "Surveillance Test Interval Extensions for Components of the Reactor Protection System (WCAP-15376-P)" (ADAMS Accession No. ML022470164).
The NRC staff has reviewed the February 6, 2017, response to a request for additional information (RAI), and has determined follow-up RAls are needed to complete NRC staff review.
Follow up RAI 1:
In the cover letter to the February 6, 2017, supplement, the licensee stated that the probabilistic risk assessment (PRA) model was peer reviewed in June 2016 and that the final version of the Peer Review Report has not yet been received by VCSNS. As such, the facts and observations (F&Os) from this peer review were not included in the LAR, as supplemented. In addition, the response to RAI 1 noted some open F&Os from a previous peer review. Therefore, the NRC staff requests the following additional information.
- a. Please confirm what impact, if any, the June 2016 peer review had on the PRA model of record used to support the LAR, and as supplemented, by RAI responses.
- b. In 2011, the licensee performed a Capability Category II gap self-assessment for the PRA model against the Regulatory Guide 1.200, Revision 2, and the ASME/ANS PRA Model Internal Events Standard as a follow-up to a 2007 review against Regulatory Guide 1.200, Revision 1. The response to RAI 1 identified that some open suggestions/findings had not been resolved. Finding 6_9 involved system-related screenings from the PRA model as specified in system supporting requirements. The licensee's resolution states that re-screening of all of the systems is not yet complete.
Enclosure
Please complete the resolution of finding 6_9, and provide an updated resolution of this finding and an assessment of its significance to the application. Alternatively, please justify why resolution of this Finding will not affect this application.
Follow-up RAI 7d, 7f, 7g, 7i, 7j, and 12 The NRC staff has reviewed the response to RAI 7 for the plant-specific analysis of the Engineered Safety Features Actuation System (ESFAS) signals 8.a and 6.h, and has determined that additional information is necessary regarding the risk evaluation associated with extending their surveillance test intervals (STls). Therefore, please address the following:
- a. The proposed TS STls apply to analog channels, logic cabinets, and master relays. Based on the response to RAI 7.j, the risk calculation provided in the March 7, 2016, supplement evaluated the STI extension for analog channels.
For these two signals, logic cabinets and the master relays do not appear to be quantified in the risk evaluation. The WCAP-15376-P-A analysis for the logic cabinet discussed in the response does not appear to be applicable for these two signals since the TSTF-411, Revision 1, stipulates the plant specific functions not evaluated generically for WCAP-15376-P-A orWCAP-10271-P-A must have a plant-specific analysis. In addition, the response to RAI 7.i describes a test in which more than one of the LAR-related instrumentation and control (l&C) components are tested, and indicates that the proposed STI extensions apply to this test. However, the response did not specify if the risk associated with this test is included in the risk assessment.
Please clarify whether logic cabinet and master relays for those two signals and the test described in response to RAI 7.i were included in plant-specific risk evaluation. If the approach taken in the response to the RAls to evaluate only the analog channels is sufficient, please provide justification. If not, then, consistent with TSTF-411, Revision 1 guidance, complete a plant-specific risk evaluation for these two signals for all proposed STI extensions to l&C components (analog channels, logic cabinet, master relays) and applicable tests involving these components. Please describe how this updated STI extension risk analysis is performed. Please include what was evaluated (e.g., components, tests) for the proposed TS changes; method used to evaluate their STI extension (e.g.,
increasing failure rates, etc.); as well as other assumptions such as test unavailability. If an updated risk assessment is performed to include the logic cabinet and master relays, provide updated results for the LAR following RG 1.177, RG 1.174, and TSTF-411, Revision 1 guidance, and provide updated results of the response to RAI 12 regarding cumulative risk as appropriate.
- b. The response to RAI 7.d requested a description of the method used to evaluate the common cause failure (CCF) for the STI extension. The response stated that the software generates the appropriate common cause basic events using Multiple Greek Letter common cause factors. However, there was no discussion on how the CCF probabilities are adjusted for extending the STI.
Please explain how the change in the CCF was evaluated for the STI extension for each of the l&C components in the proposed TS changes, and include an example of how the CCF probability was adjusted.
- c. The response to the RAI 7.f stated that doubling the failure rate for the unavailability of the STI extension of analog channels was conservative, but did not provide a basis for this conclusion. Since the STI unavailability depends on the testing scheme (e.g., staggered),
please explain what testing scheme was used for calculating the analog channels STI unavailability and why the method described in the RAI response is conservative for this testing scheme. Also, clarify what the fault exposure time was taken to be (e.g., STl/2).
The response to RAI 7.f does not appear to address components not included in the WCAP-10271-P-A STI extensions, as requested. Because neither of the logic cabinet nor the master relays for these two signals were included in the WCAP-10271 STI extensions, according to WCAP-15376-P-A, please explain the testing scheme used for calculating their STI unavailability and the fault exposure time used.
- d. The RAI 7.g.i stated: "Explain why the increase in CDF/LERF [Core Damage Frequency/Large Early Release Frequency] for the new signals given in the supplementary information response is low."
If an updated plant-specific risk assessment for each of these two signals in a, above is performed, and if the updated analysis does not retain the conclusion of "small" risk per RG 1.177, explain why the risk is not "small." Please explain, consistent with RG 1.174 guidance that the change in risk is in an acceptable range. Please provide justification, if applicable. In addition, if the risk assessment was updated and resulted in any new Tier 2 measures, please provide Tier 2 results consistent with RG 1.177 guidance. Include demonstration that there are appropriate restrictions on dominant risk-significant configurations associated with the change, and Tier 2 documentation, as discussed in Section 4.
Follow-up RAI 7.k.ii:
Limitation and Condition number 4 from the NRC staff's SE on the WCAP-15376 topical report states: "To ensure consistency with the reference plant, the model assumptions for human reliability in WCAP-15376-P, Rev. 0 should be confirmed to be applicable to the plant-specific configuration." The response to RAI 7.k.ii identified that limitation and condition number 4 is confirmed because the operator actions modeled in the WCAP-15376-P-A analysis are not applicable for these two plant-specific signals. A review of WCAP-15376-P-A indicates that these operator actions in the response are back-up actuation signals.
The response does not appear to fully address the limitation and condition because the human reliability modeling should be confirmed to be applicable to the plant-specific configuration for these two signals not evaluated in the topical report. The response to RAI 7.k.iii identified that there are operator actions to back-up both automatic functions. Since these operator actions are not evaluated in WCAP 15376-P-A, and, therefore, model assumptions in WCAP-15376-P-A are not applicable to V.C. Summer plant-specific signals, please confirm that these operator actions for the two signals are in the PRA model and explain what they are.
Follow-up RAI 9:
The response to RAI 9 describes how the configuration risk management program (CRMP) tool uses surrogates for signals not modeled in the PRA. (Surrogates are not used for the signals 6.h. or 8.a, according to the response to RAI 7.c.iv.). However, the response to RAI 9 did not provide sufficient information for the surrogates described.
The NRC staff requests the following additional information regarding l&C surrogates for non-modeled signals in the CRMP tool.
- a. The response to RAI 9.ii describes surrogates for analog channels as doubling the "initiating event frequencies (reactor trip or safety injection)". Reactor trip and safety injection signals are applicable to a wide range of initiating events and accident sequences. Please discuss whether all initiating events are increased, or if only some initiating events are increased, please confirm that the initiating event frequencies which are increased (i.e., doubled) as a surrogate cover the possible initiators for the non-modeled signals.
- b. The unavailability of a logic cabinet may have a different plant and risk impact than the unavailability of an analog channel, therefore, doubling the initiating event frequency may not be applicable. Please confirm that the PRA modeling of the logic cabinet unavailability accounts for the plant response impact of the non-modeled signals (as well as associated relevant modeled signals).
- c. The response to RAI 9 does not include master relays, which are also part of the proposed TS changes. The unavailability of a master relay may also have a different risk significance than an analog channel, and the doubling of the initiating event frequency may not be appropriate. Please describe and justify surrogates, if used, for master relays associated with the functions in the LAR. Please confirm that the PRA modeling of the master relays unavailability accounts for the impact on the plant response.
SUBJECT:
VIRGIL C. SUMMER NUCLEAR STATION, UNIT NO. 1 - REQUEST FOR ADDITIONAL INFORMATION RE: LICENSE AMENDMENT REQUEST FOR IMPLEMENTATION OF TSTF-411 (WCAP-15376-P-A), REVISION 1 (CAC NO. MF7196) DATE: MAY 11, 2017.
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PUBLIC LPL2-1 R/F RidsACRS_MailCTR Resource RidsNrrDorllpl2-1 Resource RidsRgn2MailCenter Resource RidsNrrDraApla Resource RidsNrrLAKGoldstein Resource RidsNrrPMSummer Resource DONeal, NRR MReisi Fard, NRR ADAMS A ccess1on No.: ML17095A284 *b>Y M emo OFFICE DORL/LPL2-1/PM DORL/LPL2-1/LA DRA/APLA/BC* DORL/LPL2-1/BC DORL/LPL2-1/PM NAME SWilliams KGoldstein SRosenberq MMarkley SWilliams DATE 5/4/2017 5/4/2017 4/25/2017 5/11/2017 5/11/2017 OFFICIAL RECORD COPY