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| | number = ML17318A035 | | | number = ML17318A035 |
| | issue date = 11/22/2017 | | | issue date = 11/22/2017 |
| | title = Vogtle Electric Generating Plant, Units 1 and 2 - Request for Additional Information (CAC Nos. MF9685, MF9686, EPID L-2017-TOP-0038) | | | title = Request for Additional Information |
| | author name = Marshall M | | | author name = Marshall M |
| | author affiliation = NRC/NRR/DORL/LPLI | | | author affiliation = NRC/NRR/DORL/LPLI |
| | addressee name = Hutto J J | | | addressee name = Hutto J |
| | addressee affiliation = Southern Nuclear Operating Co, Inc | | | addressee affiliation = Southern Nuclear Operating Co, Inc |
| | docket = 05000424, 05000425 | | | docket = 05000424, 05000425 |
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| =Text= | | =Text= |
| {{#Wiki_filter:UNITED STATES NUCLEAR REGULATORY COMMISSION WASHING TON, D.C. 20555-0001 Mr. James J. Hutto Regulatory Affairs Director Southern Nuclear Operating Co., Inc. P.O. Box 1295, Bin 038 Birmingham, AL 35201-1295 November 22, 2017 | | {{#Wiki_filter:UNITED STATES NUCLEAR REGULATORY COMMISSION WASHINGTON, D.C. 20555-0001 November 22, 2017 Mr. James J. Hutto Regulatory Affairs Director Southern Nuclear Operating Co., Inc. |
| | P.O. Box 1295, Bin 038 Birmingham, AL 35201-1295 |
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| ==SUBJECT:== | | ==SUBJECT:== |
| VOGTLE ELECTRIC GENERATING PLANT, UNITS 1 AND 2 -REQUEST FOR ADDITIONAL INFORMATION (CAC NOS. MF9685 AND MF9686; EPID No. L-2017-TOP-0038) | | VOGTLE ELECTRIC GENERATING PLANT, UNITS 1 AND 2 - REQUEST FOR ADDITIONAL INFORMATION (CAC NOS. MF9685 AND MF9686; EPID No. L-2017-TOP-0038) |
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| ==Dear Mr. Hutto:== | | ==Dear Mr. Hutto:== |
| By letter dated April 21, 2017 (Agencywide Documents Access and Management System (ADAMS) Accession No. ML 17116A096) as supplemented by letters dated July 11, 2017 (ADAMS Accession No. ML 17192A245) and November 9, 2017 (ADAMS Accession No. ML 17314A014), Southern Nuclear Operating Company, Inc. submitted a plant-specific technical report (TR) for Vogtle Electric Generating Plant, Units 1 and 2 , and requested U.S. Nuclear Regulatory Commission (NRC) approval of the methods and inputs described in the TR. The plant-specific TR describes a risk-informed methodology to evaluate debris effects with the exception of in-vessel fiber limits. The NRC staff has reviewed the submittal and has determined that additional information is needed to complete its review. Enclosed is the NRC staff's request for additional information (RAI). The RAls were discussed with your staff on November 13, 2017, and it was agreed that your response would be provided within 45 days from the date of this letter. If you have any questions regarding this request, please contact me at (301) 415-2871 or Michael.Marshall@nrc.gov. Docket Nos. 50-424 and 50-425 | | |
| | By letter dated April 21, 2017 (Agencywide Documents Access and Management System (ADAMS) Accession No. ML17116A096) as supplemented by letters dated July 11, 2017 (ADAMS Accession No. ML17192A245) and November 9, 2017 (ADAMS Accession No. ML17314A014), Southern Nuclear Operating Company, Inc. submitted a plant-specific technical report (TR) for Vogtle Electric Generating Plant, Units 1 and 2 , and requested U.S. Nuclear Regulatory Commission (NRC) approval of the methods and inputs described in the TR. The plant-specific TR describes a risk-informed methodology to evaluate debris effects with the exception of in-vessel fiber limits. |
| | The NRC staff has reviewed the submittal and has determined that additional information is needed to complete its review. Enclosed is the NRC staff's request for additional information (RAI). The RAls were discussed with your staff on November 13, 2017, and it was agreed that your response would be provided within 45 days from the date of this letter. |
| | If you have any questions regarding this request, please contact me at (301) 415-2871 or Michael.Marshall@nrc.gov. |
| | Sincerely, Michael L. Marshall, Jr., Senior Project Manager Plant Licensing Branch I Division of Operating Reactor Licensing Office of Nuclear Reactor Regulation Docket Nos. 50-424 and 50-425 |
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| ==Enclosure:== | | ==Enclosure:== |
| Request for Additional Information Sincerely, Michael L. Marshall, Jr., Senior Project Manager Plant Licensing Branch I Division of Operating Reactor Licensing Office of Nuclear Reactor Regulation REQUEST FOR ADDITIONAL INFORMATION REGARDING SYSTEMATIC RISK-INFORMED ASSESSMENT OF DEBRIS TECHNICAL REPORT 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 April 21, 2017 (Agencywide Documents Access and Management System (ADAMS) Accession No. ML 17116A096) as supplemented by letters dated July 11, 2017 (ADAMS Accession No. ML 17192A245) and November 9, 2017 (ADAMS Accession No. ML 17314A014), Southern Nuclear Operating Company, Inc. submitted a plant-specific technical report (TR) for Vogtle Electric Generating Plant, Units 1 and 2, (VEGP) and requested U.S. Nuclear Regulatory Commission (NRC) approval of the methods and inputs described in the TR. The plant-specific TR describes a risk-informed methodology to evaluate debris effects with the exception of in-vessel fiber limits. The NRC staff reviewed the submittal and has determined that the enclosed additional information is needed to complete its review. The requests for additional information (RAls) listed below are not a complete listing of the additional information needed to complete the NRC staff's review. Additional RAls will be provided via separate correspondence. RAls number 1 through 3 were sent in a separate letter dated October 12, 2017 (ADAMS Accession No. ML 17264A282). RAls number 4 through 1 O were sent in a separate letter dated November 15, 2017 (ADAMS Accession No. ML 17275A026). Unless stated otherwise, all references to enclosures, sections, and page numbers in the RAls are concerning the letter dated April 21, 2017. (11) It is stated in Enclosure 1, Section 7.0, "Quality Assurance" (QA) that: ... most of the analysis and testing for the risk-informed Generic Safety Issue (GSl)-191 evaluation was performed as safety related under vendor QA programs compliant with Title 10 of the Code of Federal Regulations (10 CFR) Part 50 Appendix B. While this section describes exceptions regarding specific equations within the NARWHAL software, explicit discussion of quality assurance measures associated with the software development was not included. a. Please describe quality assurance procedures taken (e.g., validation and verification processes) to ensure the NARWHAL software produces high fidelity results. Enclosure b. Please describe tests of BADGER software performed to verify that the total debris monotonically increases with break size. (12) Enclosure 3, Section 13.1, "NARWHAL Software," states that the plant, at any given time, can be defined by a state vector (i.e., collection of parameters). A series of marching algorithms, constituting the core framework of NARWHAL software, are used to update the state vector by determining the amount of change in each variable given a change in time. While the submittal describes certain assumptions regarding parameters over times (e.g., instantaneous, 7.5 hours, etc.), the computer time step associated with the marching algorithms is not stated, nor is the dependence of the results on computer time-stepping. Please describe the time step(s) used in executing the marching algorithms and whether those time steps are sufficient to ensure convergence of the results to capture the pertinent GSl-191 phenomena modeled properly (e.g., time evolution of head loss and core fiber penetration). (13) Table 3-5 of Enclosure 3, Section 14.1, "VEGP NARWHAL CFP Evaluaion," provides NARWHAL software conditional failure probability (CFP) values for Strainer A and B, Strainer A only, and Strainer B only. Given that asymmetric transport may actually occur, but is not modeled in NARWHAL (page E2-51, Enclosure 5) demonstrate that NARWHAL calculations of CFP yield conservative values of (or have a negligible impact on) delta Core Damage Frequency (CDF) (i.e., ~CDF) and Large Early Release Frequency (LEAF). (14) It is described in Enclosure 3, Section 14.2, "NARWHAL Uncertainty and Sensitivity," that competing factors affecting delta CDF (i.e., ~CDF), as summarized in the tornado diagram in Figure 3-9 and in Tables 3-13 and 3-14. Please explain the competing physical processes that determine the "bounding direction" for the following entries:
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| * Tables 3-13-pool volume, pool temperature, secure containment spray time, pH.
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| * Table 3-14-pool volume, pool temperature, emergency core cooling system flow rate, pH. (15) Enclosure 1, Attachment 3, "Resolution of the VEGP Seismic PRA Peer Review Findings," provides a description of peer review facts and observations (F&Os) and their disposition to support the application of the seismic probabilistic risk assessment (SPRA) to informed systematic assessment of debris. a. The VEGP SPRA peer review was performed using the process defined in Nuclear Energy Institute (NEI) 12-13, August 2012, "External Hazards PRA Peer Review Process Guidelines," (ADAMS Accession No. ML 12240A027). While NEI 12-13 follows a process, which is similar to NRC endorsed peer review processes, NEI 12-13 has not been endorsed by the NRC. The NRC staff provided comments on NEI 12-13 via a letter dated November 16, 2012 (ADAMS Accession No. ML 12321 A280). Further, the letter stated that the NRC staff's comments on NEI 12-13: ... could impact the integrity and quality of the peer-review process, which could also affect the confidence the NRC has in establishing the technical adequacy of licensee probabilistic risk assessments (PRAs) using this guidance ... Please provide the following additional information to justify the use of NEI 12-13: i. Please describe how the qualifications of the VEGP SPRA peer review team comply with the peer review requirements in Sections 1-6.2 and 5-3.2 of the American Society of Mechanical Engineers (ASME)/American Nuclear Society (ANS) PAA Standard (RA-Sa-2009) as endorsed in Regulatory Guide (RG) 1.200, Revision 2, "An Approach for Determining the Technical Adequacy of Probabilistic Risk Assessment Results for Risk-Informed Activities" (ADAMS Accession No. ML090410014). ii. Please identify the unreviewed analysis methods (UAMs) used in the VEGP SPRA as determined by the peer review team and describe each UAM, including bases and any supporting analyses. iii. Please describe if the VEGP SPRA relies on expert judgement to meet any supporting requirement (SR) and if so, demonstrate conformance to the expert judgment requirements of Section 1-4.3 of the 2009 ASME/ANS PAA Standard (RA-Sa-2009). Cite any information from the peer review report related to the evaluation of the use of expert judgment by the peer review team and whether the peer review team found the use of expert judgment to be appropriate. iv. Please clarify whether VEGP SPRA was reviewed against Capability Category (CC) I for any SR. Provide a list of all SRs that were reviewed against CC I or found to meet only CC I without an associated finding. For each such SR, justify why not meeting the SR at CC II does not impact this application of VEGP SPRA to the risk-informed systematic assessment of debris. v. Please clarify whether an "in-process" peer review was performed for the VEGP SPRA. If an "in-process" peer review was utilized, confirm that: 1. The approach met the requirements for an independent peer review as stated in ASME/ANS PAA Standard (RA-Sa-2009) and as endorsed in RG 1.200, Revision 2, and the process described in NEI 12-13. 2. A final review by the entire peer review team occurred after the completion of the SPRA. 3. Peer reviewers remained independent throughout the PAA development activity. b. In RG 1.200, Revision 2, the NRC states: For each application that calls upon this regulatory guide, the applicant identifies the key assumptions and approximations relevant to that application. This will be used to identify sensitivity studies as input to the decision-making associated with the application. Enclosure 3, Section 14.3, describes the SPRA models assumptions and sources of uncertainty. Table 3-19 in Enclosure 3 does not describe any specific uncertainty that was considered for the application of the SPRA to support the risk-informed systematic assessment of debris or the impact on this application. Please describe the key assumptions and sources of uncertainties associated with the VEGP SPRA that were considered for this application and how their impact on the GSl-191 results was addressed. c. In Attachment 3 of Enclosure 1, F&O 16-11, states that the review of the potential for additional dependencies introduced by the SPRA model is missing. The resolution states that the dependency analysis has been performed using the Electric Power Research Institute (EPRI) human reliability analysis (HRA) Calculator. The "Suggested Finding Resolution" states that the licensee plans to transition to a different dependency analysis method based on the EPRI HRA calculator. The 2009 ASME/ANS PRA Standard (RA-Sa-2009) defines a PRA upgrade as: ... incorporation into a PRA model of a new methodology or significant changes in scope or capability that impact the significant accident sequences or the significant accident progression sequences. Non-mandatory Appendix 1-A of ASME/ANS PRA Standard (RA-Sa-2009) identifies "a different HRA approach to human error analysis ... " as a potential PRA upgrade. Based on Section 1-5, "PRA Configuration Control," of ASME/ANS PRA Standard (RA-Sa-2009) and RG 1.200, Revision 2, Regulatory Position 1.4, "PRA Development, Maintenance, and Upgrade," performance of a peer review of a PRA upgrade is identified as one of the characteristics and attributes of an acceptable process for maintaining and upgrading a PRA. i. Please justify why the use of the EPRI HRA Calculator in the VEGP SPRA is not considered a PRA upgrade requiring a focused-scope peer review. In the justification, include a comparison of the implemented methods and base values for the top 25 human error probabilities (HEPs), as well as HRA dependencies. ii. If not part of the top 25 HEPs, pre-and post-Calculator, please demonstrate that the same methods, steps, and sequence that had been used in the existing, manual HRA calculations were exactly mirrored when adopting the HRA Calculator. iii. If this change qualifies as an upgrade, please provide the results from of the focused-scope peer review addressing the associated F&Os and their resolutions.
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| ML 17318A035 OFFICE NRR/DORL/LPL 1/PM NRR/DORL/LPL2-1/PM NAME MMarshall MOrenak DATE 11/16/2017 11/20/2017 OFFICE NRR/DORL/LPL2-1/BC NRR/DORL/LPL 1/PM NAME MMarkley MMarshall DATE 11/22/2017 11/22/2017
| | Request for Additional Information |
| * via email NRR/DORL/LPL2-1 /LA NRR/DSS/APLB/TL(A)* KGoldstein Slyons 11/16/17 10/12/2017}}
| | |
| | REQUEST FOR ADDITIONAL INFORMATION REGARDING SYSTEMATIC RISK-INFORMED ASSESSMENT OF DEBRIS TECHNICAL REPORT 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 April 21, 2017 (Agencywide Documents Access and Management System (ADAMS) Accession No. ML17116A096) as supplemented by letters dated July 11, 2017 (ADAMS Accession No. ML17192A245) and November 9, 2017 (ADAMS Accession No. ML17314A014), Southern Nuclear Operating Company, Inc. submitted a plant-specific technical report (TR) for Vogtle Electric Generating Plant, Units 1 and 2, (VEGP) and requested U.S. Nuclear Regulatory Commission (NRC) approval of the methods and inputs described in the TR. The plant-specific TR describes a risk-informed methodology to evaluate debris effects with the exception of in-vessel fiber limits. |
| | The NRC staff reviewed the submittal and has determined that the enclosed additional information is needed to complete its review. The requests for additional information (RAls) listed below are not a complete listing of the additional information needed to complete the NRC staff's review. Additional RAls will be provided via separate correspondence. RAls number 1 through 3 were sent in a separate letter dated October 12, 2017 (ADAMS Accession No. ML17264A282). RAls number 4 through 1O were sent in a separate letter dated November 15, 2017 (ADAMS Accession No. ML17275A026). |
| | Unless stated otherwise, all references to enclosures, sections, and page numbers in the RAls are concerning the letter dated April 21, 2017. |
| | (11) It is stated in Enclosure 1, Section 7.0, "Quality Assurance" (QA) that: |
| | ... most of the analysis and testing for the risk-informed Generic Safety Issue (GSl)-191 evaluation was performed as safety related under vendor QA programs compliant with Title 10 of the Code of Federal Regulations (10 CFR) Part 50 Appendix B. |
| | While this section describes exceptions regarding specific equations within the NARWHAL software, explicit discussion of quality assurance measures associated with the software development was not included. |
| | : a. Please describe quality assurance procedures taken (e.g., validation and verification processes) to ensure the NARWHAL software produces high fidelity results. |
| | Enclosure |
| | : b. Please describe tests of BADGER software performed to verify that the total debris monotonically increases with break size. |
| | (12) Enclosure 3, Section 13.1, "NARWHAL Software," states that the plant, at any given time, can be defined by a state vector (i.e., collection of parameters). A series of marching algorithms, constituting the core framework of NARWHAL software, are used to update the state vector by determining the amount of change in each variable given a change in time. While the submittal describes certain assumptions regarding parameters over times (e.g., instantaneous, 7.5 hours, etc.), the computer time step associated with the marching algorithms is not stated, nor is the dependence of the results on computer time-stepping. |
| | Please describe the time step(s) used in executing the marching algorithms and whether those time steps are sufficient to ensure convergence of the results to capture the pertinent GSl-191 phenomena modeled properly (e.g., time evolution of head loss and in-core fiber penetration). |
| | (13) Table 3-5 of Enclosure 3, Section 14.1, "VEGP NARWHAL CFP Evaluaion," provides NARWHAL software conditional failure probability (CFP) values for Strainer A and B, Strainer A only, and Strainer B only. Given that asymmetric transport may actually occur, but is not modeled in NARWHAL (page E2-51, Enclosure 5) demonstrate that NARWHAL calculations of CFP yield conservative values of (or have a negligible impact on) delta Core Damage Frequency (CDF) (i.e., ~CDF) and Large Early Release Frequency (LEAF). |
| | (14) It is described in Enclosure 3, Section 14.2, "NARWHAL Uncertainty and Sensitivity," that competing factors affecting delta CDF (i.e., ~CDF), as summarized in the tornado diagram in Figure 3-9 and in Tables 3-13 and 3-14. |
| | Please explain the competing physical processes that determine the "bounding direction" for the following entries: |
| | * Tables 3 pool volume, pool temperature, secure containment spray time, pH. |
| | * Table 3 pool volume, pool temperature, emergency core cooling system flow rate, pH. |
| | (15) Enclosure 1, Attachment 3, "Resolution of the VEGP Seismic PRA Peer Review Findings," |
| | provides a description of peer review facts and observations (F&Os) and their disposition to support the application of the seismic probabilistic risk assessment (SPRA) to risk-informed systematic assessment of debris. |
| | : a. The VEGP SPRA peer review was performed using the process defined in Nuclear Energy Institute (NEI) 12-13, August 2012, "External Hazards PRA Peer Review Process Guidelines," (ADAMS Accession No. ML12240A027). While NEI 12-13 follows a process, which is similar to NRC endorsed peer review processes, NEI 12-13 has not been endorsed by the NRC. The NRC staff provided comments on NEI 12-13 via a letter dated November 16, 2012 (ADAMS Accession No. ML12321A280). Further, the letter stated that the NRC staff's comments on NEI 12-13: |
| | ... could impact the integrity and quality of the peer-review process, which could also affect the confidence the NRC has in establishing the technical |
| | |
| | adequacy of licensee probabilistic risk assessments (PRAs) using this guidance ... |
| | Please provide the following additional information to justify the use of NEI 12-13: |
| | : i. Please describe how the qualifications of the VEGP SPRA peer review team comply with the peer review requirements in Sections 1-6.2 and 5-3.2 of the American Society of Mechanical Engineers (ASME)/American Nuclear Society (ANS) PAA Standard (RA-Sa-2009) as endorsed in Regulatory Guide (RG) 1.200, Revision 2, "An Approach for Determining the Technical Adequacy of Probabilistic Risk Assessment Results for Risk-Informed Activities" (ADAMS Accession No. ML090410014). |
| | ii. Please identify the unreviewed analysis methods (UAMs) used in the VEGP SPRA as determined by the peer review team and describe each UAM, including bases and any supporting analyses. |
| | iii. Please describe if the VEGP SPRA relies on expert judgement to meet any supporting requirement (SR) and if so, demonstrate conformance to the expert judgment requirements of Section 1-4.3 of the 2009 ASME/ANS PAA Standard (RA-Sa-2009). Cite any information from the peer review report related to the evaluation of the use of expert judgment by the peer review team and whether the peer review team found the use of expert judgment to be appropriate. |
| | iv. Please clarify whether VEGP SPRA was reviewed against Capability Category (CC) I for any SR. Provide a list of all SRs that were reviewed against CC I or found to meet only CC I without an associated finding. For each such SR, justify why not meeting the SR at CC II does not impact this application of VEGP SPRA to the risk-informed systematic assessment of debris. |
| | : v. Please clarify whether an "in-process" peer review was performed for the VEGP SPRA. If an "in-process" peer review was utilized, confirm that: |
| | : 1. The approach met the requirements for an independent peer review as stated in ASME/ANS PAA Standard (RA-Sa-2009) and as endorsed in RG 1.200, Revision 2, and the process described in NEI 12-13. |
| | : 2. A final review by the entire peer review team occurred after the completion of the SPRA. |
| | : 3. Peer reviewers remained independent throughout the PAA development activity. |
| | : b. In RG 1.200, Revision 2, the NRC states: |
| | For each application that calls upon this regulatory guide, the applicant identifies the key assumptions and approximations relevant to that |
| | |
| | application. This will be used to identify sensitivity studies as input to the decision-making associated with the application. |
| | Enclosure 3, Section 14.3, describes the SPRA models assumptions and sources of uncertainty. Table 3-19 in Enclosure 3 does not describe any specific uncertainty that was considered for the application of the SPRA to support the risk-informed systematic assessment of debris or the impact on this application. |
| | Please describe the key assumptions and sources of uncertainties associated with the VEGP SPRA that were considered for this application and how their impact on the GSl-191 results was addressed. |
| | : c. In Attachment 3 of Enclosure 1, F&O 16-11, states that the review of the potential for additional dependencies introduced by the SPRA model is missing. The resolution states that the dependency analysis has been performed using the Electric Power Research Institute (EPRI) human reliability analysis (HRA) Calculator. The "Suggested Finding Resolution" states that the licensee plans to transition to a different dependency analysis method based on the EPRI HRA calculator. The 2009 ASME/ANS PRA Standard (RA-Sa-2009) defines a PRA upgrade as: |
| | ... incorporation into a PRA model of a new methodology or significant changes in scope or capability that impact the significant accident sequences or the significant accident progression sequences. |
| | Non-mandatory Appendix 1-A of ASME/ANS PRA Standard (RA-Sa-2009) identifies "a different HRA approach to human error analysis ... " as a potential PRA upgrade. Based on Section 1-5, "PRA Configuration Control," of ASME/ANS PRA Standard (RA-Sa-2009) and RG 1.200, Revision 2, Regulatory Position 1.4, "PRA Development, Maintenance, and Upgrade," performance of a peer review of a PRA upgrade is identified as one of the characteristics and attributes of an acceptable process for maintaining and upgrading a PRA. |
| | : i. Please justify why the use of the EPRI HRA Calculator in the VEGP SPRA is not considered a PRA upgrade requiring a focused-scope peer review. In the justification, include a comparison of the implemented methods and base values for the top 25 human error probabilities (HEPs), as well as HRA dependencies. |
| | ii. If not part of the top 25 HEPs, pre- and post-Calculator, please demonstrate that the same methods, steps, and sequence that had been used in the pre-existing, manual HRA calculations were exactly mirrored when adopting the HRA Calculator. |
| | iii. If this change qualifies as an upgrade, please provide the results from of the focused-scope peer review addressing the associated F&Os and their resolutions. |
| | |
| | ML17318A035 |
| | * via email OFFICE NRR/DORL/LPL 1/PM NRR/DORL/LPL2-1/PM NRR/DORL/LPL2-1 /LA NRR/DSS/APLB/TL(A)* |
| | NAME MMarshall MOrenak KGoldstein Slyons DATE 11/16/2017 11/20/2017 11/16/17 10/12/2017 OFFICE NRR/DORL/LPL2-1/BC NRR/DORL/LPL 1/PM NAME MMarkley MMarshall DATE 11/22/2017 11/22/2017}} |
Letter Sequence RAI |
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MONTHYEARNL-16-2002, Supplemental Response to NRC Generic Letter 2004-022017-04-21021 April 2017
Supplemental Response to NRC Generic Letter 2004-02
Project stage: Request
ML17166A4332017-06-26026 June 2017
Supplemental Information Needed for Acceptance of Systematic Risk-Informed Assessment of Debris Technical Report
Project stage: Acceptance Review
NL-17-1201, Response to Supplemental Information Needed for Acceptance of Systematic Risk-Informed Assessment of Debris Technical Report2017-07-11011 July 2017
Response to Supplemental Information Needed for Acceptance of Systematic Risk-Informed Assessment of Debris Technical Report
Project stage: Request
ML17191A8332017-07-24024 July 2017
Request for Withholding Information from Public Disclosure for Vogtle Electric Generating Plant, Units 1 and 2
Project stage: Withholding Request Acceptance
ML17191A5702017-07-24024 July 2017
Request for Withholding Information from Public Disclosure
Project stage: Withholding Request Acceptance
ML17191A6912017-07-24024 July 2017
Request for Withholding Information from Public Disclosure for Vogtle Electric Generating Plant, Units 1 and 2
Project stage: Withholding Request Acceptance
ML17199A1032017-07-25025 July 2017
Acceptance of Requested Plant-Specific Technical Report Review Systematic Risk-Informed Assessment of Debris
Project stage: Acceptance Review
ML17264A2822017-10-12012 October 2017
Request for Additional Information Re Systematic Risk-Informed Assessment of Debris Technical Report
Project stage: RAI
ML17277A4892017-10-18018 October 2017
Audit Plan Re Systematic Risk-Informed Assessment of Debris Technical Report (CAC Nos. MF9685 and MF9686)
Project stage: Other
ML17275A0262017-11-15015 November 2017
Request for Additional Information (CAC Nos. MF9685 and MF9686; EPID L-2017-TOP-0038)
Project stage: RAI
ML17318A0352017-11-22022 November 2017
Request for Additional Information
Project stage: RAI
ML17355A1012018-01-11011 January 2018
Request for Additional Information (CAC Nos. MF9685 and MF9686; EPID L-2017-TOP-0038)
Project stage: RAI
NL-18-0102, Incorporate Seismic Probabilistic Risk Assessment Into the 10 CFR 50.69 Categorization Process, Response to Request for Additional Information (RAIs 1,2,3, & 12)2018-02-0606 February 2018
Incorporate Seismic Probabilistic Risk Assessment Into the 10 CFR 50.69 Categorization Process, Response to Request for Additional Information (RAIs 1,2,3, & 12)
Project stage: Response to RAI
ML18051A3172018-03-16016 March 2018
Audit Plan for Second Audit Concerning Systematic Risk-Informed Assessment of Debris Technical Report (CAC Nos. MF9685 and MF9686; EPID L-2017-TOP-0038)
Project stage: Other
ML18109A1152018-05-0101 May 2018
Request for Additional Information
Project stage: RAI
ML18193B1622018-07-10010 July 2018
Units 1 & 2 - Supplemental Response to NRC Generic Letter 2004-02
Project stage: Request
ML18275A0402018-10-31031 October 2018
Technical Evaluation Report: Use of BADGER and Narwhal to Compute Strainer Failure Probability - Vogtle Units 1 and 2 Nuclear Power Plant
Project stage: Other
ML18306A5752018-11-0808 November 2018
Summary of Public Telephone Conference with Southern Nuclear Operating Company Regarding Proposed Limitations and Conditions Related to the Review of Vogtle Systematic Risk Informed Assessment of Debris Technical Report
Project stage: Approval
ML19120A4692019-09-30030 September 2019
Final Safety Evaluation for Vogtle Electric Generating Plant, Units 1 and 2 Systematic Risk-Informed Assessment of Debris Technical Report
Project stage: Approval
2017-07-25
[Table View] |
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Category:Letter
MONTHYEARML24297A6482024-10-23023 October 2024
5 to the Updated Final Safety Analysis Report, Technical Specification Bases Changes, Technical Requirements Manual Changes, Summary Report and Revised NRC Commitments Report
ML24269A2502024-09-26026 September 2024
Acknowledgement of the Withdrawal of the Requested Exemption and License Amendment Request to Remove Tier 1 and Tier 2* Requirements
NL-24-0350, Core Operating Limits Report, Cycle 24, Version 22024-09-25025 September 2024
Core Operating Limits Report, Cycle 24, Version 2
NL-24-0369, Withdrawal of License Amendment Request and Exemption Request: Remove Tier 1 and Tier 2 Requirements2024-09-25025 September 2024
Withdrawal of License Amendment Request and Exemption Request: Remove Tier 1 and Tier 2 Requirements
ML24243A0072024-09-10010 September 2024
– Correction of Amendment Nos. 223 and 206 Regarding Revision to Technical Specifications to Adopt TSTF-339-A, Relocate Technical Specification Parameters to the COLR Consistent with WCAP-14483
NL-24-0337, Interim 10 CFR 21.21(a)(2) Report Regarding Operation Technology, Inc., ETAP Software Error in Transient Stability Program2024-09-0909 September 2024
Interim 10 CFR 21.21(a)(2) Report Regarding Operation Technology, Inc., ETAP Software Error in Transient Stability Program
ML24102A2642024-09-0909 September 2024
– Exemption Request Regarding Final Safety Analysis Report Update Schedule (EPID L-2024-LLE-0013) - Letter
ML24249A2942024-09-0606 September 2024
Correction of Amendment Nos. 218 and 201 Regarding Revision to Technical Specifications to Use Online Monitoring Methodology
05200025/LER-2024-002, Manual Reactor Protection System and Automatic Safeguards Actuation Due to an Unexpected Change in Position of a Main Feedwater Pump Minimum Flow Control Valve2024-09-0505 September 2024
Manual Reactor Protection System and Automatic Safeguards Actuation Due to an Unexpected Change in Position of a Main Feedwater Pump Minimum Flow Control Valve
IR 05000424/20240052024-08-26026 August 2024
Updated Inspection Plan for Vogtle Electric Generating Plant, Units 1 and 2 - Report 05000424/2024005 and 05000425/2024005
ML24235A1952024-08-22022 August 2024
Updated Inspection Plan for Vogtle Electric Generating Plant, Units 3 and 4 - Report 05200025/2024005 and 05200026/2024005
IR 05000424/20244012024-08-15015 August 2024
4 - Security Baseline Inspection Report 05000424-2024401, 05000425-2024401, 05200025-2024402, and 05200026-2024403 - Cover Letter
NL-24-0299, Exemption Request: Final Safety Analysis Report Update Schedule, Response to Request for Additional Information2024-08-14014 August 2024
Exemption Request: Final Safety Analysis Report Update Schedule, Response to Request for Additional Information
05000425/LER-2024-001, Manual Actuation of the Reactor Protection System Due to a Rod Control Fuse Opening Causing a Misaligned Shutdown Rod2024-08-0909 August 2024
Manual Actuation of the Reactor Protection System Due to a Rod Control Fuse Opening Causing a Misaligned Shutdown Rod
ML24218A1842024-08-0707 August 2024
Examination Report and Cover Letter
05200026/LER-2024-001, Manual Reactor Protection System Actuation Due to Procedure Not Optimally Sequenced to Reset the Rapid Power Reduction Signal2024-08-0606 August 2024
Manual Reactor Protection System Actuation Due to Procedure Not Optimally Sequenced to Reset the Rapid Power Reduction Signal
ML24212A1442024-08-0101 August 2024
Integrated Inspection Report 05200025/2024002 and 05200026/2024002
IR 05000424/20240022024-07-29029 July 2024
Integrated Inspection Report 05000424/2024002 and 05000425/2024002
IR 05000424/20244042024-07-26026 July 2024
Material Control and Accounting Program Inspection Report 05000424/2024404 and 05000425/2024404 (Cover Letter)
NL-24-0282, License Amendment Request and Exemption Request: Remove Tier 1 and Tier 2* Requirements2024-07-25025 July 2024
License Amendment Request and Exemption Request: Remove Tier 1 and Tier 2* Requirements
NL-24-0126, – Units 3 and 4, License Amendment Request: Changes to Technical Specification 3.7.6, Main Control Room Emergency Habitability System (Ves) Action a and SR 3.7.6.62024-07-25025 July 2024
– Units 3 and 4, License Amendment Request: Changes to Technical Specification 3.7.6, Main Control Room Emergency Habitability System (Ves) Action a and SR 3.7.6.6
ML24204A0722024-07-23023 July 2024
Issuance of Amendment No. 225, Regarding LAR to Revise TS 3.7.9 for a one-time Change to Support Nuclear Service Cooling Water Transfer Pump Repairs - Emergency Circumstances
NL-24-0286, Emergency Request to Revise Technical Specification 3.7.9 for a One-Time Change to Support a Unit 1 Nuclear Service Cooling Water Transfer Pump Repair2024-07-20020 July 2024
Emergency Request to Revise Technical Specification 3.7.9 for a One-Time Change to Support a Unit 1 Nuclear Service Cooling Water Transfer Pump Repair
ML24191A4562024-07-19019 July 2024
Request for Relief and Alternative Requirements for Squib (Explosively Actuated) Valves First Test Interval
NL-24-0261, 10 CFR 50.46 ECCS Evaluation Model Annual Report for 20232024-07-19019 July 2024
10 CFR 50.46 ECCS Evaluation Model Annual Report for 2023
ML24194A0342024-07-12012 July 2024
Review of the Refueling Outage 1R24 Steam Generator Tube Inspection Report
ML24191A3792024-07-10010 July 2024
– Initial Test Program and Operational Programs Inspection Report 05200026/2024011
NL-24-0227, Proposed Inservice Inspection Alternative GEN-ISI-AL T-2024-03 for Pressurizer Welds in Accordance with 10 CFR 50.55a(z)(1)2024-07-0303 July 2024
Proposed Inservice Inspection Alternative GEN-ISI-AL T-2024-03 for Pressurizer Welds in Accordance with 10 CFR 50.55a(z)(1)
NL-24-0234, Application to Revise Technical Specifications to Adopt TSTF-589, Eliminate Automatic Diesel Generator Start During Shutdown2024-06-28028 June 2024
Application to Revise Technical Specifications to Adopt TSTF-589, Eliminate Automatic Diesel Generator Start During Shutdown
NL-24-0143, Proposed Alternative to Use ASME Code Case N-752, Risk-Informed Categorization and Treatment for Repair/ Replacement Activities in2024-06-27027 June 2024
Proposed Alternative to Use ASME Code Case N-752, Risk-Informed Categorization and Treatment for Repair/ Replacement Activities in
NL-24-0087, License Amendment Request: Changes to Technical Specification 3.7.6, Main Control Room Emergency Habitability System (Ves) Air Storage Tanks2024-06-21021 June 2024
License Amendment Request: Changes to Technical Specification 3.7.6, Main Control Room Emergency Habitability System (Ves) Air Storage Tanks
NL-24-0201, Proposed Inservice Inspection Alternative GEN-ISI-ALT-2024-002 for Steam Generator Welds in Accordance with 10 CFR 50.55a(z)(1)2024-06-18018 June 2024
Proposed Inservice Inspection Alternative GEN-ISI-ALT-2024-002 for Steam Generator Welds in Accordance with 10 CFR 50.55a(z)(1)
NL-24-0243, Registration of Spent Fuel Cask Use2024-06-18018 June 2024
Registration of Spent Fuel Cask Use
ML24163A0632024-06-12012 June 2024
2024 Licensed Operator Re-qualification Inspection Notification Letter Vogtle, Units 3 & 4
ML24155A1772024-06-0505 June 2024
Regulatory Audit in Support of Review of the LAR to Revise Emergency Diesel Generator Frequency and Voltage Ranges for Technical Specification 3.8.1, Surveillance Requirements
NL-24-0202, SNC Response to Regulatory Issue Summary 2024-01: Preparation and Scheduling of Operator Licensing Examinations2024-05-24024 May 2024
SNC Response to Regulatory Issue Summary 2024-01: Preparation and Scheduling of Operator Licensing Examinations
ML24141A0482024-05-17017 May 2024
EN 56958_1 Ametek Solidstate Controls, Inc
ML24094A1402024-05-16016 May 2024
Staff Response to Request for Revision to NRC Staff Assessment of Updated Seismic Hazard Information and Latest Understanding of Seismic Hazards at the Vogtle Plant Site Following the NRC Process for the Ongoing Assessment of Natural Hazard
ML24130A2412024-05-13013 May 2024
Integrated Inspection Report 05200025/2024001 and 05200026/2024001
ML24120A1812024-05-13013 May 2024
Request for Withholding Information from Public Disclosure Responses to NRC Request for Additional Information for Refueling Outage IR24 Steam Generator Tube Inspection Report – Enclosure 2
ML24101A2112024-05-11011 May 2024
Expedited Issuance of Amendment No. 198 Change to Technical Specification 5.5.13, Ventilation Filter Testing Program (VFTP)
NL-24-0191, Annual Radiological Environmental Operating Reports for 20232024-05-10010 May 2024
Annual Radiological Environmental Operating Reports for 2023
ML24127A2372024-05-0909 May 2024
Initial Test Program and Operational Programs Inspection Report 05200026/2024010
NL-24-0194, Revised Request for Relief and Alternative Requirements for Squib Valves First Test Interval (V34-IST-ALT-03-R1)2024-05-0707 May 2024
Revised Request for Relief and Alternative Requirements for Squib Valves First Test Interval (V34-IST-ALT-03-R1)
IR 05000424/20244032024-05-0101 May 2024
Cyber Security Inspection Report 05000424/2024403 and 05000425/2024403 Public
ML24120A2832024-04-30030 April 2024
Project Manager Reassignment
NL-24-0170, Responses to Second Round NRC Request for Additional Information for Refueling Outage 1 R24 Steam Generator Tube Inspection Report2024-04-25025 April 2024
Responses to Second Round NRC Request for Additional Information for Refueling Outage 1 R24 Steam Generator Tube Inspection Report
NL-24-0165, Annual Non-Radiological Environmental Operating Reports and Annual Radioactive Effluent Release Reports for 20232024-04-25025 April 2024
Annual Non-Radiological Environmental Operating Reports and Annual Radioactive Effluent Release Reports for 2023
IR 05000424/20240012024-04-23023 April 2024
–Integrated Inspection Report 05000424/2024001 and 05000425/2024001
NL-24-0154, Preservice Inspection Progam Owners Activity Report2024-04-16016 April 2024
Preservice Inspection Progam Owners Activity Report
2024-09-09
[Table view]
Category:Request for Additional Information (RAI)
MONTHYEARML24290A1572024-10-16016 October 2024
NRR E-mail Capture - for Your Action - RAI - Farley and Vogtle 1 and 2 - Alternative Request for Pressurizer Welds (L-2024-LLR-0047)
ML24290A1552024-10-16016 October 2024
NRR E-mail Capture - for Your Action - RAI - Farley, Hatch, and Vogtle 1 and 2 - Proposed Alternative Request for Code Case N-572
ML24289A2002024-10-15015 October 2024
NRR E-mail Capture - for Your Action - RAI - Proposed License Amendment Request (LAR) for Vogtle Electric Generating Plant, Units 3 and 4 TS 3.7.6 Action E and SR 3.7.6.5 (L-2024-LLA-0083)
ML24199A1592024-07-17017 July 2024
NRR E-mail Capture - Request for Additional Information - Vogtle 3 and 4 - Exemption for the Requirements in 10 CFR 50.71 Pertaining to the Submittal of Updated Final Safety Analysis Report
ML24100A7842024-04-0909 April 2024
NRR E-mail Capture - for Your Action - Request for Additional Information (RAI) - Vogtle, Units 3 and 4 - Alternative Request for Explosively Actuated Valves (L-2023-LLR-0016)
ML24072A3982024-03-12012 March 2024
NRR E-mail Capture - for Your Action - Second Round Request for Additional Information (RAI) - Vogtle, Unit 1 - SG Tube Inspection Report - 1R24 (L-2023-LRO-0067)
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)
2024-07-17
[Table view] |
Text
UNITED STATES NUCLEAR REGULATORY COMMISSION WASHINGTON, D.C. 20555-0001 November 22, 2017 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 (CAC NOS. MF9685 AND MF9686; EPID No. L-2017-TOP-0038)
Dear Mr. Hutto:
By letter dated April 21, 2017 (Agencywide Documents Access and Management System (ADAMS) Accession No. ML17116A096) as supplemented by letters dated July 11, 2017 (ADAMS Accession No. ML17192A245) and November 9, 2017 (ADAMS Accession No. ML17314A014), Southern Nuclear Operating Company, Inc. submitted a plant-specific technical report (TR) for Vogtle Electric Generating Plant, Units 1 and 2 , and requested U.S. Nuclear Regulatory Commission (NRC) approval of the methods and inputs described in the TR. The plant-specific TR describes a risk-informed methodology to evaluate debris effects with the exception of in-vessel fiber limits.
The NRC staff has reviewed the submittal and has determined that additional information is needed to complete its review. Enclosed is the NRC staff's request for additional information (RAI). The RAls were discussed with your staff on November 13, 2017, and it was agreed that your response would be provided within 45 days from the date of this letter.
If you have any questions regarding this request, please contact me at (301) 415-2871 or Michael.Marshall@nrc.gov.
Sincerely, Michael L. Marshall, Jr., Senior Project Manager Plant Licensing Branch I Division of Operating Reactor Licensing Office of Nuclear Reactor Regulation Docket Nos. 50-424 and 50-425
Enclosure:
Request for Additional Information
REQUEST FOR ADDITIONAL INFORMATION REGARDING SYSTEMATIC RISK-INFORMED ASSESSMENT OF DEBRIS TECHNICAL REPORT 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 April 21, 2017 (Agencywide Documents Access and Management System (ADAMS) Accession No. ML17116A096) as supplemented by letters dated July 11, 2017 (ADAMS Accession No. ML17192A245) and November 9, 2017 (ADAMS Accession No. ML17314A014), Southern Nuclear Operating Company, Inc. submitted a plant-specific technical report (TR) for Vogtle Electric Generating Plant, Units 1 and 2, (VEGP) and requested U.S. Nuclear Regulatory Commission (NRC) approval of the methods and inputs described in the TR. The plant-specific TR describes a risk-informed methodology to evaluate debris effects with the exception of in-vessel fiber limits.
The NRC staff reviewed the submittal and has determined that the enclosed additional information is needed to complete its review. The requests for additional information (RAls) listed below are not a complete listing of the additional information needed to complete the NRC staff's review. Additional RAls will be provided via separate correspondence. RAls number 1 through 3 were sent in a separate letter dated October 12, 2017 (ADAMS Accession No. ML17264A282). RAls number 4 through 1O were sent in a separate letter dated November 15, 2017 (ADAMS Accession No. ML17275A026).
Unless stated otherwise, all references to enclosures, sections, and page numbers in the RAls are concerning the letter dated April 21, 2017.
(11) It is stated in Enclosure 1, Section 7.0, "Quality Assurance" (QA) that:
... most of the analysis and testing for the risk-informed Generic Safety Issue (GSl)-191 evaluation was performed as safety related under vendor QA programs compliant with Title 10 of the Code of Federal Regulations (10 CFR) Part 50 Appendix B.
While this section describes exceptions regarding specific equations within the NARWHAL software, explicit discussion of quality assurance measures associated with the software development was not included.
- a. Please describe quality assurance procedures taken (e.g., validation and verification processes) to ensure the NARWHAL software produces high fidelity results.
Enclosure
- b. Please describe tests of BADGER software performed to verify that the total debris monotonically increases with break size.
(12) Enclosure 3, Section 13.1, "NARWHAL Software," states that the plant, at any given time, can be defined by a state vector (i.e., collection of parameters). A series of marching algorithms, constituting the core framework of NARWHAL software, are used to update the state vector by determining the amount of change in each variable given a change in time. While the submittal describes certain assumptions regarding parameters over times (e.g., instantaneous, 7.5 hours5.787037e-5 days <br />0.00139 hours <br />8.267196e-6 weeks <br />1.9025e-6 months <br />, etc.), the computer time step associated with the marching algorithms is not stated, nor is the dependence of the results on computer time-stepping.
Please describe the time step(s) used in executing the marching algorithms and whether those time steps are sufficient to ensure convergence of the results to capture the pertinent GSl-191 phenomena modeled properly (e.g., time evolution of head loss and in-core fiber penetration).
(13) Table 3-5 of Enclosure 3, Section 14.1, "VEGP NARWHAL CFP Evaluaion," provides NARWHAL software conditional failure probability (CFP) values for Strainer A and B, Strainer A only, and Strainer B only. Given that asymmetric transport may actually occur, but is not modeled in NARWHAL (page E2-51, Enclosure 5) demonstrate that NARWHAL calculations of CFP yield conservative values of (or have a negligible impact on) delta Core Damage Frequency (CDF) (i.e., ~CDF) and Large Early Release Frequency (LEAF).
(14) It is described in Enclosure 3, Section 14.2, "NARWHAL Uncertainty and Sensitivity," that competing factors affecting delta CDF (i.e., ~CDF), as summarized in the tornado diagram in Figure 3-9 and in Tables 3-13 and 3-14.
Please explain the competing physical processes that determine the "bounding direction" for the following entries:
(15) Enclosure 1, Attachment 3, "Resolution of the VEGP Seismic PRA Peer Review Findings,"
provides a description of peer review facts and observations (F&Os) and their disposition to support the application of the seismic probabilistic risk assessment (SPRA) to risk-informed systematic assessment of debris.
- a. The VEGP SPRA peer review was performed using the process defined in Nuclear Energy Institute (NEI) 12-13, August 2012, "External Hazards PRA Peer Review Process Guidelines," (ADAMS Accession No. ML12240A027). While NEI 12-13 follows a process, which is similar to NRC endorsed peer review processes, NEI 12-13 has not been endorsed by the NRC. The NRC staff provided comments on NEI 12-13 via a letter dated November 16, 2012 (ADAMS Accession No. ML12321A280). Further, the letter stated that the NRC staff's comments on NEI 12-13:
... could impact the integrity and quality of the peer-review process, which could also affect the confidence the NRC has in establishing the technical
adequacy of licensee probabilistic risk assessments (PRAs) using this guidance ...
Please provide the following additional information to justify the use of NEI 12-13:
- i. Please describe how the qualifications of the VEGP SPRA peer review team comply with the peer review requirements in Sections 1-6.2 and 5-3.2 of the American Society of Mechanical Engineers (ASME)/American Nuclear Society (ANS) PAA Standard (RA-Sa-2009) as endorsed in Regulatory Guide (RG) 1.200, Revision 2, "An Approach for Determining the Technical Adequacy of Probabilistic Risk Assessment Results for Risk-Informed Activities" (ADAMS Accession No. ML090410014).
ii. Please identify the unreviewed analysis methods (UAMs) used in the VEGP SPRA as determined by the peer review team and describe each UAM, including bases and any supporting analyses.
iii. Please describe if the VEGP SPRA relies on expert judgement to meet any supporting requirement (SR) and if so, demonstrate conformance to the expert judgment requirements of Section 1-4.3 of the 2009 ASME/ANS PAA Standard (RA-Sa-2009). Cite any information from the peer review report related to the evaluation of the use of expert judgment by the peer review team and whether the peer review team found the use of expert judgment to be appropriate.
iv. Please clarify whether VEGP SPRA was reviewed against Capability Category (CC) I for any SR. Provide a list of all SRs that were reviewed against CC I or found to meet only CC I without an associated finding. For each such SR, justify why not meeting the SR at CC II does not impact this application of VEGP SPRA to the risk-informed systematic assessment of debris.
- v. Please clarify whether an "in-process" peer review was performed for the VEGP SPRA. If an "in-process" peer review was utilized, confirm that:
- 1. The approach met the requirements for an independent peer review as stated in ASME/ANS PAA Standard (RA-Sa-2009) and as endorsed in RG 1.200, Revision 2, and the process described in NEI 12-13.
- 2. A final review by the entire peer review team occurred after the completion of the SPRA.
- 3. Peer reviewers remained independent throughout the PAA development activity.
- b. In RG 1.200, Revision 2, the NRC states:
For each application that calls upon this regulatory guide, the applicant identifies the key assumptions and approximations relevant to that
application. This will be used to identify sensitivity studies as input to the decision-making associated with the application.
Enclosure 3, Section 14.3, describes the SPRA models assumptions and sources of uncertainty. Table 3-19 in Enclosure 3 does not describe any specific uncertainty that was considered for the application of the SPRA to support the risk-informed systematic assessment of debris or the impact on this application.
Please describe the key assumptions and sources of uncertainties associated with the VEGP SPRA that were considered for this application and how their impact on the GSl-191 results was addressed.
- c. In Attachment 3 of Enclosure 1, F&O 16-11, states that the review of the potential for additional dependencies introduced by the SPRA model is missing. The resolution states that the dependency analysis has been performed using the Electric Power Research Institute (EPRI) human reliability analysis (HRA) Calculator. The "Suggested Finding Resolution" states that the licensee plans to transition to a different dependency analysis method based on the EPRI HRA calculator. The 2009 ASME/ANS PRA Standard (RA-Sa-2009) defines a PRA upgrade as:
... incorporation into a PRA model of a new methodology or significant changes in scope or capability that impact the significant accident sequences or the significant accident progression sequences.
Non-mandatory Appendix 1-A of ASME/ANS PRA Standard (RA-Sa-2009) identifies "a different HRA approach to human error analysis ... " as a potential PRA upgrade. Based on Section 1-5, "PRA Configuration Control," of ASME/ANS PRA Standard (RA-Sa-2009) and RG 1.200, Revision 2, Regulatory Position 1.4, "PRA Development, Maintenance, and Upgrade," performance of a peer review of a PRA upgrade is identified as one of the characteristics and attributes of an acceptable process for maintaining and upgrading a PRA.
- i. Please justify why the use of the EPRI HRA Calculator in the VEGP SPRA is not considered a PRA upgrade requiring a focused-scope peer review. In the justification, include a comparison of the implemented methods and base values for the top 25 human error probabilities (HEPs), as well as HRA dependencies.
ii. If not part of the top 25 HEPs, pre- and post-Calculator, please demonstrate that the same methods, steps, and sequence that had been used in the pre-existing, manual HRA calculations were exactly mirrored when adopting the HRA Calculator.
iii. If this change qualifies as an upgrade, please provide the results from of the focused-scope peer review addressing the associated F&Os and their resolutions.
ML17318A035
- via email OFFICE NRR/DORL/LPL 1/PM NRR/DORL/LPL2-1/PM NRR/DORL/LPL2-1 /LA NRR/DSS/APLB/TL(A)*
NAME MMarshall MOrenak KGoldstein Slyons DATE 11/16/2017 11/20/2017 11/16/17 10/12/2017 OFFICE NRR/DORL/LPL2-1/BC NRR/DORL/LPL 1/PM NAME MMarkley MMarshall DATE 11/22/2017 11/22/2017
