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Category:Letter type:NOC
MONTHYEARNOC-AE-230040, Supplement to Proposed Alternate Frequency to Containment Unbonded Post-Tensioning System Inservice Inspection (Relief Request RR-ENG-4-06)2023-12-14014 December 2023 Supplement to Proposed Alternate Frequency to Containment Unbonded Post-Tensioning System Inservice Inspection (Relief Request RR-ENG-4-06) NOC-AE-230039, Docket Nos. Stn 50-498, Stn 50-499 - Reply to a Notice of Violation, NRC Inspection Report 05000498/2023003 and 05000499/20230032023-12-12012 December 2023 Docket Nos. Stn 50-498, Stn 50-499 - Reply to a Notice of Violation, NRC Inspection Report 05000498/2023003 and 05000499/2023003 NOC-AE-230039, Submittal of Update Foreign Ownership, Control or Influence (FOCI)2023-07-11011 July 2023 Submittal of Update Foreign Ownership, Control or Influence (FOCI) NOC-AE-220039, Physical Security Plan, Training and Qualification Plan, Safeguards Contingency Plan, and Independent Spent Fuel Storage Installation Security Program Revision 252023-02-0606 February 2023 Physical Security Plan, Training and Qualification Plan, Safeguards Contingency Plan, and Independent Spent Fuel Storage Installation Security Program Revision 25 NOC-AE-220038, Independent Spent Fuel Storage Installation Registration of Dry Spent Fuel Storage Cask2022-06-23023 June 2022 Independent Spent Fuel Storage Installation Registration of Dry Spent Fuel Storage Cask NOC-AE-210038, Submittal of Operations Quality Assurance Plan Changes QA-089, QA-091, and Revision 252022-01-0404 January 2022 Submittal of Operations Quality Assurance Plan Changes QA-089, QA-091, and Revision 25 NOC-AE-21003858, 10 CFR 50.46 Thirty-Day Report of Significant ECCS Model Changes2021-12-0606 December 2021 10 CFR 50.46 Thirty-Day Report of Significant ECCS Model Changes NOC-AE-21003853, Revised Response to End of Enforcement Discretion and Request for Approval of Alternate Disposal Procedures for Very Low-Level Radioactive Material2021-12-0303 December 2021 Revised Response to End of Enforcement Discretion and Request for Approval of Alternate Disposal Procedures for Very Low-Level Radioactive Material NOC-AE-21003848, Unit 1 Cycle 24 Core Operating Limits Report2021-11-18018 November 2021 Unit 1 Cycle 24 Core Operating Limits Report NOC-AE-21003846, Response to End of Enforcement Discretion and Request for Approval of Alternate Disposal Procedures for Very Low-Level Radioactive Material2021-11-0404 November 2021 Response to End of Enforcement Discretion and Request for Approval of Alternate Disposal Procedures for Very Low-Level Radioactive Material NOC-AE-21003842, 10 CFR 50.59 Summary Report2021-09-23023 September 2021 10 CFR 50.59 Summary Report NOC-AE-21003841, Request for Relief from ASME Section Xl Code Requirements for Weld Examinations (Relief Request RR-ENG-3-25)2021-09-23023 September 2021 Request for Relief from ASME Section Xl Code Requirements for Weld Examinations (Relief Request RR-ENG-3-25) NOC-AE-21003832, Supplement to License Amendment Request to Adopt TSTF-577, Revised Frequencies for Steam Generator Tube Inspections2021-09-0909 September 2021 Supplement to License Amendment Request to Adopt TSTF-577, Revised Frequencies for Steam Generator Tube Inspections NOC-AE-21003812, Application to Revise Technical Specifications to Adopt TSTF-577, Revised Frequencies for Steam Generator Tube Inspections2021-08-10010 August 2021 Application to Revise Technical Specifications to Adopt TSTF-577, Revised Frequencies for Steam Generator Tube Inspections NOC-AE-21003825, Update of Foreign Ownership, Control, or Influence Information (FOCI)2021-08-0505 August 2021 Update of Foreign Ownership, Control, or Influence Information (FOCI) NOC-AE-21003824, Update Foreign Ownership, Control, or Influence (FOCI)2021-07-29029 July 2021 Update Foreign Ownership, Control, or Influence (FOCI) NOC-AE-21003823, Update Foreign Ownership Control or Influence (FOCI)2021-07-28028 July 2021 Update Foreign Ownership Control or Influence (FOCI) NOC-AE-21003820, Nuclear Insurance Protection2021-07-20020 July 2021 Nuclear Insurance Protection NOC-AE-21003819, Inservice Inspection Summary Report - 2RE212021-07-15015 July 2021 Inservice Inspection Summary Report - 2RE21 NOC-AE-21003816, Commitment Change Summary Report2021-06-30030 June 2021 Commitment Change Summary Report NOC-AE-21003814, Technical Specification Bases Control Program2021-06-24024 June 2021 Technical Specification Bases Control Program NOC-AE-21003810, Update Foreign Ownership, Control, or Influence (FOCI)- CPS Energy2021-06-17017 June 2021 Update Foreign Ownership, Control, or Influence (FOCI)- CPS Energy NOC-AE-21003811, Update Foreign Ownership, Control, or Influence (FOCI)- Nrg Energy2021-06-17017 June 2021 Update Foreign Ownership, Control, or Influence (FOCI)- Nrg Energy NOC-AE-21003806, Inservice Inspection Program Plan and Inservice Testing Program Snubber Inservice Test Plan for the Fourth Ten-Year Interval2021-05-20020 May 2021 Inservice Inspection Program Plan and Inservice Testing Program Snubber Inservice Test Plan for the Fourth Ten-Year Interval NOC-AE-21003801, Annual Dose Report for 20202021-04-26026 April 2021 Annual Dose Report for 2020 NOC-AE-21003802, 2020 South Texas Project Electric Generating Station Annual Environmental Operating Report2021-04-26026 April 2021 2020 South Texas Project Electric Generating Station Annual Environmental Operating Report NOC-AE-21003804, Operator Licensing Examination Schedule2021-04-21021 April 2021 Operator Licensing Examination Schedule NOC-AE-21003800, Radioactive Effluent Release Report2021-04-19019 April 2021 Radioactive Effluent Release Report NOC-AE-21003799, Changes to South Texas Project Electric Generating Station (STPEGS) Emergency Plan2021-04-15015 April 2021 Changes to South Texas Project Electric Generating Station (STPEGS) Emergency Plan NOC-AE-21003795, Cycle 22 Core Operating Limits Report2021-04-15015 April 2021 Cycle 22 Core Operating Limits Report NOC-AE-21003796, Update Foreign Ownership, Control, or Influence (FOCI)2021-04-15015 April 2021 Update Foreign Ownership, Control, or Influence (FOCI) NOC-AE-21003791, Financial Assurance for Decommissioning - 2021 Update2021-03-31031 March 2021 Financial Assurance for Decommissioning - 2021 Update NOC-AE-21003790, Response to Apparent Violations in NRC Inspection Report 05000498/2020401 and 05000499/2020401: (EA-20-122) (Letter)2021-03-31031 March 2021 Response to Apparent Violations in NRC Inspection Report 05000498/2020401 and 05000499/2020401: (EA-20-122) (Letter) NOC-AE-210037, STP Fire Hazards Analysis Report, Amendment 26 (Redacted)2021-03-30030 March 2021 STP Fire Hazards Analysis Report, Amendment 26 (Redacted) NOC-AE-21003792, STP Fire Hazards Analysis Report, Amendment 26 (Redacted)2021-03-30030 March 2021 STP Fire Hazards Analysis Report, Amendment 26 (Redacted) NOC-AE-200037, License Amendment Request to Revise Technical Specification 3.6.3 to Append a Note and Remove the Index from Technical Specifications2021-03-11011 March 2021 License Amendment Request to Revise Technical Specification 3.6.3 to Append a Note and Remove the Index from Technical Specifications NOC-AE-21003784, Response to Request for Additional Information Regarding 1RE22 Inspection Summary Report for Steam Generator Tubing2021-03-0808 March 2021 Response to Request for Additional Information Regarding 1RE22 Inspection Summary Report for Steam Generator Tubing NOC-AE-21003786, Annual Fitness for Duty Performance Report for 20202021-03-0101 March 2021 Annual Fitness for Duty Performance Report for 2020 NOC-AE-21003785, Evidence of Financial Protection2021-02-23023 February 2021 Evidence of Financial Protection NOC-AE-21003781, Notice Regarding Withdrawal of Funds from Nuclear Decommissioning Trust Subaccounts2021-01-27027 January 2021 Notice Regarding Withdrawal of Funds from Nuclear Decommissioning Trust Subaccounts NOC-AE-21003780, Submittal of Update Foreign Ownership, Control, or Influence (FOCI)2021-01-0707 January 2021 Submittal of Update Foreign Ownership, Control, or Influence (FOCI) NOC-AE-20003778, Changes to South Texas Project Electric Generating Station Emergency Plan2020-12-17017 December 2020 Changes to South Texas Project Electric Generating Station Emergency Plan NOC-AE-20003777, STPNOC Concerns Regarding the Proposed Change to the Evaluated Force-on-Force Inspection Guidance During the COVID-19 Public Health Emergency2020-12-10010 December 2020 STPNOC Concerns Regarding the Proposed Change to the Evaluated Force-on-Force Inspection Guidance During the COVID-19 Public Health Emergency NOC-AE-20003766, Supplement to Change Implementation Date for License Amendment Request to Revise the STPEGS Emergency Plan2020-12-0202 December 2020 Supplement to Change Implementation Date for License Amendment Request to Revise the STPEGS Emergency Plan NOC-AE-20003767, Request for a One-Time Exemption from 10 CFR 73, Appendix 8, Section VI, Subsection C.3.(1)(1) Regarding Annual Force-on-Force (FOF) Exercises, Due to Covid 19 Pandemic2020-11-16016 November 2020 Request for a One-Time Exemption from 10 CFR 73, Appendix 8, Section VI, Subsection C.3.(1)(1) Regarding Annual Force-on-Force (FOF) Exercises, Due to Covid 19 Pandemic NOC-AE-20003765, Inservice Testing Program Description for the Fourth Ten-Year Interval2020-10-28028 October 2020 Inservice Testing Program Description for the Fourth Ten-Year Interval NOC-AE-20003764, 1 RE22 Inspection Summary Report for Steam Generator Tubing2020-10-0707 October 2020 1 RE22 Inspection Summary Report for Steam Generator Tubing NOC-AE-20003762, Supplement to License Amendment Request to Revise Technical Specifications to Adopt TSTF-374, Revision 0, Revision to TS 5.5.13 and Associated TS Bases for Diesel Fuel Oil Using the Consolidated Line Item Improvemen2020-09-22022 September 2020 Supplement to License Amendment Request to Revise Technical Specifications to Adopt TSTF-374, Revision 0, Revision to TS 5.5.13 and Associated TS Bases for Diesel Fuel Oil Using the Consolidated Line Item Improvemen NOC-AE-20003761, Supplement to Exemption Request from 10 CFR 50 Appendix E Due to COVID-19 Pandemic2020-09-10010 September 2020 Supplement to Exemption Request from 10 CFR 50 Appendix E Due to COVID-19 Pandemic NOC-AE-20003760, Update Foreign Ownership. Control. or Influence(FOCI)- Transmittal2020-09-0808 September 2020 Update Foreign Ownership. Control. or Influence(FOCI)- Transmittal 2023-07-11
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Nuclear Operating Company South TcsPo/tEkdc Ga11hXngSttan PO. 5282 Mdsrth r=7748J3 March 16, 2004 NOC-AE-04001691 File No. G25 STI: 31708030 U. S. Nuclear Regulatory Commission Attention: Document Control Desk Washington, DC 20555-0001 South Texas Project Units 1 and 2 Docket Nos. STN 50-498, STN 50-499 Clarification of Sensitivity Study Insight Review by Working Group and Expert Panel
Reference:
- 1) SECY-97-229, "Graded Quality Assurance/Probabilistic Risk Assessment Implementation Plan for the South Texas Project Electric Generating Station," dated October 6, 1997
- 2) Letter, J. A. Zwolinski to W. T. Cottle, "South Texas Project Units 1 and 2 - Safety Evaluation on Exemption Requests from Special Treatment Requirements of IOCFR Parts 21, 50, and 100 (TAC Nos. MA6057 and MA6058)," dated August 3, 2001 South Texas Project (STP), as the industry's proto-type pilot for the 10CFR 50.69 effort, is implementing a methodology change on how sensitivity study insights are considered.
This methodology change does not alter the language in the Operations Quality Assurance Program (OQAP) or in UFSAR Section 13.7, nor do we believe the change impacts the intent of the basis for approval of the exemption from certain special treatment requirements. However, STP wishes to keep the NRC staff informed of lessons learned which add efficiency and robustness into the categorization process. Therefore, STP is not seeking NRC approval of this change, but is providing the change to the NRC for information.
The NRC approved the basis for revisions to the STP Operations Quality Assurance Program utilizing a risk-informed approach as stated in the Reference 1 safety evaluation report. In addition, STP was granted an exemption from certain special treatment requirements of IOCFR Parts 21, 50, and 100 as stated in Reference 2. The STP UFSAR contains commitments with respect to the exemption as well as allowances for making changes to UFSAR Section 13.7 without prior NRC approval.
NOC-AE-04001691 Page 2 of 4 During data reviews of the recently approved Revision 4 to the STP Probabilistic Risk Assessment (PRA) Model, STP identified that the approach utilized for considering sensitivity study insights is more conservative than specified in the Graded Quality Assurance (GQA) Safety Evaluation Report (SER) (Reference 1). Section 3.2.2 of the GQA SER specifically states:
The licensee performed a variety of sensitivity studies to provide additional assurance that important SSCs are not inappropriately categorized because of PRA modeling limitations and uncertainties.... All components categorized in the base case as being less significant to plant safety, but categorized as HSS in any of the above sensitivity studies, will be identified and described, and relevant comments prepared for special consideration by the WG and the EP.
Previously, the STP implementing procedures have conservatively treated all PRA sensitivity study insights. This methodology required that if three or more of the Scheduled Maintenance Case studies, or if any of the other sensitivity studies (e.g.,
Operator Recovery, Common Cause Failures, Induced Steam Generator Tube Rupture, and Increased Failure Rate of LSS Components), reflected a higher risk ranking than the PRA base case ranking, the associated component PRA risk ranking was automatically increased to the higher risk ranking. This higher risk ranking was presented to the Working Group as the PRA ranking, and the Working Group was not procedurally allowed to alter the PRA ranking.
Therefore, the previous methodology was more restrictive than the approach stated in the GQA SER. Per the GQA SER, if a component were PRA risk ranked lower than HSS, but ranked as HSS in any of the sensitivity studies, this information would be presented to the Working Group and to the Expert Panel for special consideration. The Working Group would then deliberate the technical merits of the component's sensitivity study insight, and determine if the SSC final categorization should be a higher value than the PRA base case. The Working Group consideration would also factor in other available deterministic information to aid in its final conclusions. Once the final conclusion is reached, the documented information would be forwarded to the Expert Panel for their independent assessment of the Working Group's results.
The STP UFSAR, Section 13.7.2.3, makes reference to aggregate PRA sensitivity studies (not component sensitivity studies), and does not specify the detail or methodology on how the aggregate sensitivity study insights are to be considered. The UFSAR currently states:
To determine the impact of a potential change in reliability of the LSS components on the overall plant risk, a sensitivity study is performed as part of the periodic updates to the PRA to determine the cumulative impact on CDF and LERF from postulating a factor of 10 increase in the failure rates for all modeled LSS components and non-categorized low ranking PRA components.
NOC-AE-04001691 Page 3 of 4 The increases in CDF and LERF are determined to be acceptable using the guidelines for changes as outlined in Regulatory Guide 1.174.
To address defense-in-depth issues related to Late Containment Failures, a similar sensitivity analysis is performed as part of the periodic updates to the PRA. This study postulates an increase in component failure rates by a factor of 10 for all modeled LSS components and non-categorized low ranking PRA components.
STP compares the resulting late containment failure frequency with its nominal frequency to assure that the delta increase in the late containment failure frequency is small, in support of adhering to the defense-in-depth philosophy stated in Regulatory Guide 1.174.
Based on the STP Working Group and Expert Panel experience to date, it was concluded that the approach to sensitivity study consideration should be adjusted to closer align with the approach stated in the GQA SER. This approach, as changed, includes separating the PRA base case ranking from the PRA sensitivity study insights. The Working Group is presented with both the PRA base case risk ranking (which the Working Group cannot alter) and any sensitivity study results which indicate a higher risk rank than the PRA base case (applies to all higher risk ranks; not for HSS only as specified in the GQA SER). The Working Group deliberates the technical merits of the sensitivity study insights along with other available deterministic information. The results of the sensitivity study evaluation is then documented and presented to the Expert Panel for independent assessment and approval. STP believes that this methodology adds realism and robustness to SSC categorizations when considering sensitivity studies, and thus improves the effectiveness of the categorization process.
This methodology change does not impact the basis for NRC approval of the risk-informed Operations Quality Assurance Program or the exemption from certain special treatment requirements. In addition, the language in UFSAR Section 13.7 is not altered.
STP, as the industry's proto-type pilot for 10CER 50.69 activities, is communicating this change to keep the NRC staff informed of lessons learned which add efficiency and robustness into the categorization process If there are any questions regarding this change, please contact me at (361) 972-7136.
Scott M. Head Manager, Licensing
NOC-AE-04001691 Page 4 of 4 cc:
(paper copy) (electronic copy)
Bruce S. Mallett A. H. Gutterman, Esquire Regional Administrator, Region IV Morgan, Lewis & Bockius LLP U. S. Nuclear Regulatory Commission 611 Ryan Plaza Drive, Suite 400 L. D. Blaylock Arlington, Texas 76011-8064 City Public Service U. S. Nuclear Regulatory Commission David H. Jaffe Attention: Document Control Desk U. S. Nuclear Regulatory Commission One White Flint North 11555 Rockville Pike R. L. Balcom Rockville, MD 20852 Texas Genco, LP Richard A. Ratliff A. Ramirez Bureau of Radiation Control City of Austin Texas Department of Health 1100 West 49th Street C. A. Johnson Austin, TX 78756-3189 AEP Texas Central Company Jeffrey Cruz Jon C. Wood U. S. Nuclear Regulatory Commission Matthews & Branscomb P. O. Box 289, Mail Code: MN116 Wadsworth, TX 77483 C. M. Canady City of Austin Electric Utility Department 721 Barton Springs Road Austin, TX 78704