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Category:Annual Operating Report
MONTHYEARML24003A7212023-11-27027 November 2023 Independent Safety Committee; Diablo Canyon Nuclear Power Plant Operations, Thirty-Third Annual Report on the Safety July 1, 2022-June 30, 2023 ML23318A2092023-09-13013 September 2023 Thirty-Third Annual Report on the Safety of Diablo Canyon Nuclear Power Plant Operations, July I, 2022 - June 30, 2023 - Volume 1 (Main Report) ML23318A2082023-09-13013 September 2023 Thirty-Third Annual Report on the Safety of Diablo Canyon Nuclear Power Plant Operations, July I, 2022 - June 30, 2023 - Volume 2 (Exhibits) DCL-23-041, 10 CFR 50.46 Annual Report of Emergency Core Cooling System Evaluation Model Changes for Peak Cladding Temperature for 20222023-05-22022 May 2023 10 CFR 50.46 Annual Report of Emergency Core Cooling System Evaluation Model Changes for Peak Cladding Temperature for 2022 ML23037A8312022-09-28028 September 2022 Independent Safety Committee; Thirty-Second Annual Report on the Safety July 1, 2021 - June 30, 2022, Volume II - Exhibits ML23037A8302022-09-28028 September 2022 Independent Safety Committee; Thirty-Second Annual Report on the Safety July 1, 2021 - June 30, 2022, Volume I - Main Report ML23041A3772022-06-30030 June 2022 Independent Safety Committee Thirty-Second Annual Report on the Safety of Diablo Canyon Nuclear Power Plant Operations July 1, 2021-June 30, 2022 DCL-22-033, Annual Report of Occupational Radiation Exposure for 20212022-04-26026 April 2022 Annual Report of Occupational Radiation Exposure for 2021 DCL-2021-514, NPDES Receiving Water Monitoring Program: 2020 Annual Report2021-04-27027 April 2021 NPDES Receiving Water Monitoring Program: 2020 Annual Report DCL-19-078, 10 CFR 50.46 Annual Report of Emergency Core Cooling System Evaluation Model Changes for Peak Cladding Temperature for 20182019-10-0303 October 2019 10 CFR 50.46 Annual Report of Emergency Core Cooling System Evaluation Model Changes for Peak Cladding Temperature for 2018 DCL-18-028, Submittal of 2017 Annual Radioactive Effluent Release Report2018-04-24024 April 2018 Submittal of 2017 Annual Radioactive Effluent Release Report DCL-18-032, Summary Report of 10 CFR 50.59. Changes, Tests, and Experiments, for the Period of January 1, 2016, Through December 31, 20172018-04-18018 April 2018 Summary Report of 10 CFR 50.59. Changes, Tests, and Experiments, for the Period of January 1, 2016, Through December 31, 2017 DCL-17-075, Transmittal of 10 CFR 50.46 Annual Report of Emergency Core Cooling System Evaluation Model Changes for Peak Cladding Temperature for 20162017-09-0606 September 2017 Transmittal of 10 CFR 50.46 Annual Report of Emergency Core Cooling System Evaluation Model Changes for Peak Cladding Temperature for 2016 DCL-16-105, 10 CFR 50.46 Annual Report of Emergency Core Cooling System Evaluation Model Changes for Peak Cladding Temperature for 20152016-10-18018 October 2016 10 CFR 50.46 Annual Report of Emergency Core Cooling System Evaluation Model Changes for Peak Cladding Temperature for 2015 DCL-2016-518, NPDES Receiving Water Monitoring Program: 2015 Annual Report2016-04-25025 April 2016 NPDES Receiving Water Monitoring Program: 2015 Annual Report DCL-16-045, Submittal of 2015 Annual Radiological Environmental Operating Report2016-04-21021 April 2016 Submittal of 2015 Annual Radiological Environmental Operating Report DCL-16-046, Summary Report of 10 CFR 50.59, Changes, Tests, and Experiments, for the Period of January 1, 2014, Through December 31, 20152016-04-18018 April 2016 Summary Report of 10 CFR 50.59, Changes, Tests, and Experiments, for the Period of January 1, 2014, Through December 31, 2015 ML15117A6572015-04-27027 April 2015 2014 Annual Radiological Environmental Operating Report for the Year 2014) - Part 3 of 5 ML15117A6622015-04-27027 April 2015 2014 Annual Radiological Environmental Operating Report for the Year 2014) - Part 5 of 5 ML15117A6602015-04-27027 April 2015 2014 Annual Radiological Environmental Operating Report for the Year 2014) - Part 4 of 5 DCL-15-046, 2014 Annual Radiological Environmental Operating Report for the Year 2014) - Part 1 of 52015-04-27027 April 2015 2014 Annual Radiological Environmental Operating Report for the Year 2014) - Part 1 of 5 ML15117A6562015-04-27027 April 2015 2014 Annual Radiological Environmental Operating Report for the Year 2014) - Part 2 of 5 DCL-13-077, CFR 50.46 Annual Report of Emergency Core Cooling System Evaluation Model Changes for Peak Cladding Temperature for 20122013-07-30030 July 2013 CFR 50.46 Annual Report of Emergency Core Cooling System Evaluation Model Changes for Peak Cladding Temperature for 2012 DCL-13-058, Annual Commitment Change Summary Report2013-05-30030 May 2013 Annual Commitment Change Summary Report DCL-13-029, Annual Radiological Environmental Operating Report2013-04-30030 April 2013 Annual Radiological Environmental Operating Report DCL-13-045, Annual Nonradiological Environmental Operating Report2013-04-30030 April 2013 Annual Nonradiological Environmental Operating Report DCL-13-042, Submittal of 2012 Annual Radioactive Effluent Release Report2013-04-30030 April 2013 Submittal of 2012 Annual Radioactive Effluent Release Report DCL-13-022, Annual Report of Occupational Radiation Exposure for 20122013-03-12012 March 2013 Annual Report of Occupational Radiation Exposure for 2012 DCL-12-117, 2011 Annual Commitment Change Summary Report2012-11-20020 November 2012 2011 Annual Commitment Change Summary Report DCL-12-070, 10 CFR 50.46 Annual Report of Emergency Core Cooling System Evaluation Model Changes for Peak Cladding Temperature for 20112012-07-19019 July 2012 10 CFR 50.46 Annual Report of Emergency Core Cooling System Evaluation Model Changes for Peak Cladding Temperature for 2011 DCL-12-040, 2011 Annual Radioactive Effluent Release Report2012-04-30030 April 2012 2011 Annual Radioactive Effluent Release Report ML1120101782011-07-19019 July 2011 Diablo Canyon, 10 CFR 50.46 Annual Report of Emergency Core Cooling System Evaluation Model Changes for 2010 DCL-11-082, Diablo Canyon, 10 CFR 50.46 Annual Report of Emergency Core Cooling System Evaluation Model Changes for 20102011-07-19019 July 2011 Diablo Canyon, 10 CFR 50.46 Annual Report of Emergency Core Cooling System Evaluation Model Changes for 2010 DCL-11-082, CFR 50.46 Annual Report of Emergency Core Cooling System Evaluation Model Changes for 20102011-07-19019 July 2011 CFR 50.46 Annual Report of Emergency Core Cooling System Evaluation Model Changes for 2010 ML11129A0852011-04-28028 April 2011 2010 Annual Radiological Environmental Operating Report DCL-11-049, 2010 Annual Radioactive Effluent Release Report, in Accordance with 10 CFR 50.36a(a)(2) and Section 5.6.32011-04-28028 April 2011 2010 Annual Radioactive Effluent Release Report, in Accordance with 10 CFR 50.36a(a)(2) and Section 5.6.3 DCL-11-051, 2010 Annual Nonradiological Environmental Operating Report2011-04-28028 April 2011 2010 Annual Nonradiological Environmental Operating Report ML1111807472011-04-28028 April 2011 2010 Annual Nonradiological Environmental Operating Report DCL-11-050, Diablo Canyon, Units 1 & 2, 2010 Annual Radiological Environmental Operating Report2011-04-28028 April 2011 Diablo Canyon, Units 1 & 2, 2010 Annual Radiological Environmental Operating Report DCL-10-055, Units, 1 and 2, 2009 Annual Commitment Change Summary Report2010-05-19019 May 2010 Units, 1 and 2, 2009 Annual Commitment Change Summary Report DCL-10-043, Submittal of 2009 Annual Radiological Environmental Operating Report2010-04-28028 April 2010 Submittal of 2009 Annual Radiological Environmental Operating Report DCL-10-039, 10 CFR 50.59 Report of Changes, Tests, and Experiments for the Period January 1, 2008, Through December 31, 20092010-04-19019 April 2010 10 CFR 50.59 Report of Changes, Tests, and Experiments for the Period January 1, 2008, Through December 31, 2009 DCL-10-034, Annual Report of Occupational Radiation Exposure for 20092010-03-26026 March 2010 Annual Report of Occupational Radiation Exposure for 2009 DCL-2009-523, 2008-2009 Annual Report for Storm Water Discharges Associated with Industrial Activities, Diablo Canyon Power Plant (Dcpp), Facility Wdid No. 340I0182482009-06-11011 June 2009 2008-2009 Annual Report for Storm Water Discharges Associated with Industrial Activities, Diablo Canyon Power Plant (Dcpp), Facility Wdid No. 340I018248 DCL-09-031, Submittal of 2008 Annual Commitment Change Summary Report2009-05-0707 May 2009 Submittal of 2008 Annual Commitment Change Summary Report DCL-09-029, 2008 Annual Radiological Environmental Operating Report2009-04-24024 April 2009 2008 Annual Radiological Environmental Operating Report DCL-08-061, CFR 50.46 Annual Report of Emergency Core Cooling System Evaluation Model Changes for 2007, Affect Peak Cladding Temperature (PCT) Calculations2008-07-23023 July 2008 CFR 50.46 Annual Report of Emergency Core Cooling System Evaluation Model Changes for 2007, Affect Peak Cladding Temperature (PCT) Calculations DCL-08-031, Transmittal of 10 CFR 50.59 Report of Changes, Tests, and Experiments for the Period of January 1, 2006, Through December 31, 20072008-04-17017 April 2008 Transmittal of 10 CFR 50.59 Report of Changes, Tests, and Experiments for the Period of January 1, 2006, Through December 31, 2007 ML0729107542007-10-22022 October 2007 2006 Rulemaking Annual Report DCL-07-071, CFR 50.46 Annual Report of Emergency Core Cooling System Evaluation Model Changes for 20062007-07-23023 July 2007 CFR 50.46 Annual Report of Emergency Core Cooling System Evaluation Model Changes for 2006 2023-09-13
[Table view] Category:Letter
MONTHYEARIR 05000275/20230042024-02-0909 February 2024 Integrated Inspection Report 05000275/2023004 and 05000323/2023004 ML24002B1802024-01-29029 January 2024 LRA Audit Plan DCL-24-010, Nuclear Material Transaction Report for New Fuel2024-01-29029 January 2024 Nuclear Material Transaction Report for New Fuel ML24018A0152024-01-29029 January 2024 License Renewal Application Review Schedule Letter ML24017A2492024-01-24024 January 2024 Letter to Neil Peyron, Chairman, Tule River Tribe, Re. Diablo Canyon ML24024A1752024-01-24024 January 2024 Letter to Tribal Council San Luis Obispo County Chumash Indians on Section 106 Consultation and Scoping Process for the Environmental Review of Diablo Canyon Nuclear Plant, Unit 1 and 2 License Renewal Application ML24003A8902024-01-24024 January 2024 Letter to P. Gerfen - Diablo Canyon Notice of Intent to Conduct Scoping and Prepare an Environmental Impact Statement ML24012A1582024-01-24024 January 2024 Letter to Hon. Violet Sage Walker, Chairwoman Northern Chumash Tribal Council on Section 106 Consultation and Scoping Process for the Environmental Review of Diablo Canyon Nuclear Plant, Unit 1 and 2 License Renewal Application ML24012A0062024-01-24024 January 2024 Achp Scoping Letter for Diablo Canyon License Renewal ML24012A0552024-01-24024 January 2024 Letter to J. Polanco, Shpo, on Request to Initiate Section 106 Consultation and Scooping Process for the Environmental Review of Diablo Canyon Nuclear Plant, Unit 1 and 2 License Renewal Application ML24024A1562024-01-24024 January 2024 Letter to Hon. Gabe Frausto, Coastal Band of Chumash Indians on Section 106 Consultation and Scoping Process for the Environmental Review of Diablo Canyon Nuclear Plant, Unit 1 and 2 License Renewal Application ML24024A1652024-01-24024 January 2024 Letter to Hon. Mona Olivas Tucker, Yak Tityu Tityu Yak Tilhini Northern Chumas Indians on Section 106 Consultation and Scoping Process for the Environmental Review of Diablo Canyon Nuclear Plant, Unit 1 and 2 License Renewal Application ML24024A1612024-01-24024 January 2024 Letter Hon. Gary Pierce, Salian Tribe of Monterey and San Luis Obispo Counties on Section 106 Consultation and Scoping Process for the Environmental Review of Diablo Canyon Nuclear Plant, Unit 1 and 2 License Renewal Application ML24012A0362024-01-24024 January 2024 Request to Initiate Section 106 Consultation and Scoping Process for the Environmental Review License Renewal Application DCL-24-009, Nuclear Material Transaction Report for New Fuel2024-01-17017 January 2024 Nuclear Material Transaction Report for New Fuel DCL-24-008, Schedule Considerations for Review of the DCPP License Renewal Application2024-01-17017 January 2024 Schedule Considerations for Review of the DCPP License Renewal Application DCL-24-004, Supplement to License Amendment Request 23-01 Revision to Technical Specifications to Adopt Risk-Informed Completion Times TSTF-505, Revision 2, Provide Risk-Informed Extended Completion Times - RITSTF Initiative 4b2024-01-15015 January 2024 Supplement to License Amendment Request 23-01 Revision to Technical Specifications to Adopt Risk-Informed Completion Times TSTF-505, Revision 2, Provide Risk-Informed Extended Completion Times - RITSTF Initiative 4b IR 05000275/20230112024-01-12012 January 2024 NRC License Renewal Phase 1 Inspection Report 05000275/2023011 DCL-23-129, Nuclear Material Transaction Report for New Fuel2023-12-27027 December 2023 Nuclear Material Transaction Report for New Fuel ML23326A0122023-12-21021 December 2023 12-21-23 Letter to the Honorable Byron Donalds from Chair Hanson Responds to Letter Regarding 2.206 Petition to Close Diablo Canyon Nuclear Power Plant, Unit 1 ML23341A0042023-12-19019 December 2023 LRA Acceptance Letter ML23352A2342023-12-18018 December 2023 Notification of Age-Related Degradation Inspection (05000275/2024014 and 05000323/2024014) and Request for Information DCL-23-122, Request for Exemption from Enhanced Weapons, Firearms Background Checks, and Security Event Notifications Implementation2023-12-14014 December 2023 Request for Exemption from Enhanced Weapons, Firearms Background Checks, and Security Event Notifications Implementation DCL-23-128, Emergency Plan Update2023-12-13013 December 2023 Emergency Plan Update ML23355A0952023-12-0808 December 2023 License Renewal Application Online Reference Portal DCL-23-125, Core Operating Limits Report for Unit 1 Cycle 252023-12-0606 December 2023 Core Operating Limits Report for Unit 1 Cycle 25 ML23291A2702023-11-28028 November 2023 Letter to Nakia Zavalla, Shpo, the Santa Ynez Band of Chumash Indians; Re., Diablo Canyon ISFSI Initiating Section 106 Consultation ML23320A2442023-11-28028 November 2023 Letter to Kerri Vera, Director of Department of Environmental Protection, Tule River Tribe; Re., Diablo Canyon ISFSI Initiating Section 106 Consultation ML23325A1382023-11-27027 November 2023 ISFSI Tribal Letter to San Luis Obispo County Chumash Indians ML23325A1322023-11-27027 November 2023 ISFSI Tribal Letter to Salian Tribe of Montgomery, San Luis Obispo ML23325A1332023-11-27027 November 2023 ISFSI Tribal Letter to Yak Tityu Tityu Northern Chumash Indians ML23307A0062023-11-27027 November 2023 ISFSI Tribal Letter to Northern Chumash Tribal Council ML24003A7242023-11-27027 November 2023 Independent Safety Committee; Diab Lo Canyon Nuclear Power Plant Operations, Thirty-Third Annual Report on the Safety ML23325A1292023-11-27027 November 2023 ISFSI Tribal Letter to Coastal Band of Chumash ML23320A1502023-11-17017 November 2023 Individual Notice of Consideration of Issuance of Amendment to Facility Operating License, Proposed No Significant Hazards Consideration Determination, & Opportunity for Hearing (Exigent Circumstances) (EPID L-2023-LLA-0155) - LTR DCL-23-121, Supplement to License Amendment Request 23-03, Revision to Technical Specification3.7.8, Auxiliary Saltwater System2023-11-16016 November 2023 Supplement to License Amendment Request 23-03, Revision to Technical Specification3.7.8, Auxiliary Saltwater System ML23296A0982023-11-15015 November 2023 Notification and Request for Consultation Regarding Pacific Gas and Electric Diablo Canyon Independent Spent Fuel Storage Installation Material License Renewal Request (Docket Number: 72-26) DCL-23-120, License Amendment Request 23-03 Revision to Technical Specification 3.7.8, Auxiliary Saltwater (Asw) System2023-11-14014 November 2023 License Amendment Request 23-03 Revision to Technical Specification 3.7.8, Auxiliary Saltwater (Asw) System ML23293A1052023-11-14014 November 2023 Receipt and Availability of License Renewal Application IR 05000275/20230032023-11-13013 November 2023 Integrated Inspection Report 05000275/2023003 and 05000323/2023003 ML23311A2082023-11-0909 November 2023 Reassignment of U.S. Nuclear Regulatory Commission Branch Chief in the Division of Operating Reactor Licensing for Plant Licensing Branch IV DCL-23-118, License Renewal Application2023-11-0707 November 2023 License Renewal Application ML23318A2102023-10-31031 October 2023 Independent Safety Committee; Thirty-Third Annual Report on the Safety of Diablo Canyon Nuclear Power Plant Operations DCL-2023-520, Discharge Self-Monitoring at Diablo Canyon Power Plant (DCPP)2023-10-19019 October 2023 Discharge Self-Monitoring at Diablo Canyon Power Plant (DCPP) DCL-23-103, Independent Spent Fuel Storage Installation - Withdrawal of License Amendment Request 22-01, Request for Approval of Alternative Security Measures for Early Warning System2023-10-13013 October 2023 Independent Spent Fuel Storage Installation - Withdrawal of License Amendment Request 22-01, Request for Approval of Alternative Security Measures for Early Warning System IR 05000275/20240152023-10-10010 October 2023 Information Request for the Cybersecurity Baseline Inspection, Notification to Perform Inspection (050002752024015 and 050003232024015) 2024-02-09
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Pacific Gas and Electric Company . July 19, 2011 PG&E Letter DCL-11-082 U.S. Nuclear Regulatory Commission ATTN: Document Control Desk Washington, DC 20555-0001 Docket No. 50-275, OL-DPR-80 Docket No. 50-323, OL-DPR-82 Diablo Canyon Units 1 and 2 James R. B ecker Site Vice President Diablo Canyon Power Plant Mail Code 104/5/601
- p. O. Box 56 Avila Beach, CA 93424 805.545.3462 Internal:
691.3462 Fax: 805.545.6445 10 CFR 50.46 10 CFR 50.46 Annual Report of Emergency Core Cooling System Evaluation Model Changes for 2010 Dear Commissioners and Staff: Pursuant to 10 CFR 50.46, this letter provides an annual report of changes in the Westinghouse emergency core cooling system (ECCS) evaluation models that affect peak cladding temperature (PCT) calculations for Pacific Gas and Electric Company (PG&E) Diablo Canyon Power Plant (DCPP), Units 1 and 2. There have been no changes in the small-break loss-of-coolant accident (SBLOCA) PCT results for either Unit 1 or Unit 2 since the last annual update. The last update was provided in PG&E Letter DCL-10-080, "10 CFR 50.46 Annual Report of Emergency Core Cooling System Evaluation Model Changes for 2009," dated July 19, 2010. In support of a prompt operability assessment (POA), the best estimate large-break loss-of-coolant accident (BELOCA) PCT results for both Unit 1 and Unit 2 have assessed a PCT margin allocation since the last update. A summary of the PCT margin allocations and their bases are provided in the enclosure.
The Unit 1 SBLOCA and BELOCA PCT Margin Utilization sheets are provided in Attachment A to the enclosure.
The Unit 2 SBLOCA and BELOCA PCT Margin Utilization Sheets are provided in Attachment B to the enclosure.
The ECCS evaluation model changes and PCT margin allocations that have occurred since the last annual report are summarized in Attachment C to the enclosure.
The PCT values remain well within the 2200°F limit specified in 10 CFR 50.46. However, since the Unit 1 BELOCA has a total PCT margin allocation that is currently greater than 50°F, PG&E is proposing a schedule for reanalysis, per 10 CFR 50.46(a)(3)(ii).
PG&E has recently initiated a long term* project to implement a transition to a standard fuel design that will require a reanalysis of the Unit 1 BELOCA PCT results. In addition, it is anticipated that BELOCA analysis model changes requiring NRC approval will be required to address the regulation changes A member of the STARS (Strategic Teaming and Resource Sharing) Alliance Callaway
- Wolf Creek Document Control Desk July 19, 2011 Page 2 PG&E Letter DCL-11-0B2 related to 10 CFR 50.46 that are still in development.
In order to accommodate these anticipated changes, PG&E proposes to complete the Unit 1 BELOCA reanalysis and provide the updated PCT results to the NRC by December 2016. If you have questions regarding this submittal please contact Mr. Steve Baker at B05-545-6742.
c=?U . , Becker Site Vice President and Station Director dngd/4955/64041516-0200 Enclosure cc/enc: Elmo E. Collins, NRC Region IV Michael S. Peck, NRC Senior Resident Inspector Alan B. Wang, NRR Project Manager James T. Polickoski, NRR Project Manager Diablo Distribution A member of the STARS (Strategic Teaming and Resource Sharing) Alliance Callaway
- Wolf Creek Enclosure PG&E Letter DCL-11-082 ANNUAL REPORT OF EMERGENCY CORE COOLING SYSTEM EVALUATION MODEL CHANGES FOR PEAK CLADDING TEMPERATURE Pursuant to 10 CFR 50.46, this enclosure provides an annual report of changes in the Westinghouse emergency core cooling system (ECCS) evaluation models that affect peak cladding temperature (PCT) calculations for Pacific Gas and Electric Company (PG&E) Diablo Canyon Power Plant (DCPP), Units 1 and 2. This report is based on changes described in the following Westinghouse 10 CFR 50.46 notification letter: Westinghouse Letter LTR-LlS-11-43, "Diablo Canyon Units 1 and 2 10 CFR 50.46 Annual Notification and Reporting for 2010," dated January 27, 2011. Attachment A to this enclosure provides DCPP Unit 1 small-break loss-of-coolant accident (SBLOCA) and best estimate large-break loss-of-coolant accident (BELOCA) PCT Margin Utilization Sheets. Attachment B to this enclosure provides DCPP Unit 2 SBLOCA and BELOCA PCT Margin Utilization Sheets. Attachment C to this enclosure summarizes the ECCS evaluation model changes and PCT margin allocations that have occurred since the last annual report. There have been no changes in the SBLOCA PCT results for either Unit 1 or Unit 2 since the last annual update. The last update was provided in PG&E Letter DCL-10-080, "10 CFR 50.46 Annual Report of Emergency Core Cooling System Evaluation Model Changes for 2009" dated July 19, 2010. In support of a prompt operability assessment (POA), the BELOCA PCT results for both Unit 1 and Unit 2 have assessed a PCT margin allocation since the last update. A summary of the PCT margin allocations and their bases are provided in the attachments.
The final net PCT values are listed below for each unit. It should be noted that two PCT values are reported for the Unit 1 BELOCA results. The two BELOCA PCT values are labeled Reflood 1 and Reflood 2, as they represent the two distinctive PCT peaks that occur during the reflood phase for the Unit 1 BELOCA Code Qualification Document (CQD) methodology.
The Unit 2 BELOCA reports only one PCT value consistent with the BELOCA Automated Statistical Treatment of Uncertainty Method (ASTRUM) methodology.
Small-Break LOCA Unit 1: 1391°F (no change) Unit 2: 1288°F (no change) Best Estimate Large-Break LOCA Reflood 1 1990°F (no change) Reflood 2 1975°F The PCT values remain well within the 2200°F limit specified in 10 CFR 50.46. However, since the Unit 1 BELOCA has a total PCT margin allocation that is currently greater than 50°F, PG&E is proposing a schedule for reanalysis, per 1 Enclosure PG&E Letter DCL-11-082 10 CFR 50.46(a)(3)(ii).
PG&E has recently initiated a long term project to implement a transition to a standard fuel design that will require a reanalysis of the Unit 1 BELOCA PCT results. In addition, it is anticipated that BELOCA analysis model changes requiring NRC approval will be required to address the regulation changes related to 10 CFR 50.46 that are still in development.
In order to accommodate these anticipated changes, PG&E proposes to complete the Unit 1 BELOCA reanalysis and provide the updated PCT results to the NRC by December 2016. 2 Attachment A PG&E Letter DCL-11-082 DCPP UNIT 1 PEAK CLADDING TEMPERATURE (PCT) MARGIN UTILIZATION SMALL-BREAK LOCA PG&E Letter 1 A. ANAL YSIS OF RECORD PCT= 1391°F DCL-09-057 B. PRIOR 10 CFR 50.46 ECCS MODEL ASSESSMENTS 2 1. None llPCT = OaF C. 10 CFR 50.46 ECCS MODEL ASSESSMENTS THIS YEAR 1. None llPCT = OaF D. SUM OF 10 CFR 50.46 CHANGES 1. Net Sum of 10 CFR 50.46 PCT Changes llPCT = OaF 2. Absolute Sum of 10 CFR 50.46 PCT Changes llPCT = OaF E. Analysis of Record PCT -Line A + Line D.1 Net Sum of 10 1391°F CFR 50.46 PCT Changes The sum of the PCT from the most recent analysis of record using an acceptable evaluation model and the estimates of the net PCT effect for changes and errors identified since this analysis remain less than 2200°F. 2 For those issues that have been previously reported under 10 CFR 50.46, a PG&E letter number is listed. Only permanent assessments of PCT margin are included.
Temporary PCT allocations that address current loss-of-coolant accident (LOCA) model issues are not considered with respect to 10 CFR 50.46 reporting requirements.
A-1 Attachment A PG&E Letter DCL-11-082 DCPP UNIT 1 PEAK CLADDING TEMPERATURE (PCT) MARGIN UTILIZATION BEST ESTIMATE LARGE-BREAK LOCA A. ANAL YSIS OF RECORD B. PRIOR 10 CFR 50.46 ECCS MODEL ASSESSMENTS 2 1. Revised blowdown heatup uncertainty distribution.
- 2. HOTSPOT Fuel Relocation Error. 3. Replacement Steam Generators C. 10 CFR 50.46 ECCS MODEL ASSESSMENTS THIS YEAR 1. 230 kV Degraded Voltage Event Evaluation D. SUM OF 10 CFR 50.46 CHANGES 1. Net Sum of 10 CFR 50.46 PCT Changes 2. Absolute Sum of 10 CFR 50.46 PCT Changes E. Analysis of Record PCT -Line A + Line D.1 Net Sum of 10 CFR 50.46 PCT Changes Reflood 1 1900°F 5°F 10°F 75°F OaF 90°F 90°F PG&E Letter 1 Reflood 2 1860°F DCL-05-146 5°F DCL-05-086 OaF DCL-07-071 71°F DCL-09-057 39°F This letter in Attachment C 115°F 115°F The sum of the PCT from the most recent analysis of record using an acceptable evaluation model and the estimates of the net PCT effect for changes and errors identified since this analysis remain less than 2200°F. For those issues that have been previously reported under 10 CFR 50.46, a PG&E letter number is listed. A-2 2 Attachment A PG&E Letter DCL-11-082 Only permanent assessments of PCT margin are included.
Temporary PCT allocations that address current LOCA model issues are not considered with respect to 10 CFR 50.46 reporting requirements.
A-3 Attachment 8 PG&E Letter DCL-11-082 DCPP UNIT 2 PEAK CLADDING TEMPERATURE (PCT) MARGIN UTILIZATION SMALL-BREAK LOCA PG&E Letter 1 A. ANAL YSIS OF RECORD PCT= 1288°F DCL-08-061
- 8. PRIOR 10 CFR 50.46 ECCS MODEL ASSESSMENTS 2 1. None O°F C. 10 CFR 50.46 ECCS MODEL ASSESSMENTS THIS YEAR 2. None O°F D. SUM OF 10 CFR 50.46 CHANGES 3. Net Sum of 10 CFR 50.46 PCT Changes O°F 4. Absolute Sum of 10 CFR 50.46 PCT Changes O°F E. Analysis of Record PCT -Line A + Line D.1 Net Sum of 10 1288°F CFR 50.46 PCT Changes The sum of the PCT from the most recent analysis of record using an acceptable evaluation model and the estimates of the net PCT effect for changes and errors identified since this analysis remain less than 2200°F. 2 For those issues that have been previously reported under 10 CFR 50.46, a PG&E Letter number is listed. Only permanent assessments of PCT margin are included.
Temporary PCT allocations that address current loss-of-coolant-accident (LOCA) model issues are not considered with respect to 10 CFR 50.46 reporting requirements.
8-1 Attachment B PG&E Letter DCL-11-082 DCPP UNIT 2 PEAK CLADDING TEMPERATURE (PCT) MARGIN UTILIZATION BEST ESTIMATE LARGE-BREAK LOCA PG&E Letter 1 A. ANALYSIS OF RECORD PCT= 1872°F DCL-07-071 B. PRIOR 10 CFR 50.46 ECCS MODEL ASSESSMENTS 2 1. HOTSPOT Fuel Relocation Error. C. 10 CFR 50.46 ECCS MODEL ASSESSMENTS THIS YEAR 1. 230 kV Degraded Voltage Event Evaluation D. SUM OF 10 CFR 50.46 CHANGES 1. Net Sum of 10 CFR 50.46 PCT Changes 2. Absolute Sum of 10 CFR 50.46 PCT Changes E. Analysis of Record PCT -Line A + Line D.1 Net Sum of 10 CFR 50.46 PCT Changes DCL-07-071 This letter in Attachment C The sum of the PCT from the most recent analysis of record using an acceptable evaluation model and the estimates of the net PCT effect for changes and errors identified since this analysis remain less than 2200°F. 2 For those issues that have been previously reported under 10 CFR 50.46, a PG&E letter number is listed. Only permanent assessments of PCT margin are included.
Temporary PCT allocations that address current LOCA model issues are not considered with respect to 10 CFR 50.46 reporting requirements.
B-2 Attachment C PG&E Letter DCL-11-082 CURRENT EMERGENCY CORE COOLING SYSTEM MODEL CHANGES AND ERRORS 230 kV Degraded Voltage Event Evaluation During an NRC Component Design Basis Inspection it was identified that, contrary to license basis requirements, the 230 kV undervoltage relay delay setpoints are not bound by the current Diablo Canyon Power Plant (DCPP) FSAR safety analysis.
Postulating a sustained 230 kV degraded voltage results in increasing engineered safety feature (ESF) component delay times beyond what has previously been evaluated.
The DCPP small-break loss-of-coolant accident (SBLOCA) and best estimate large-break loss-of-coolant accident (BELOCA) safety analyses of record have been evaluated for increased ESF delay times of 5 seconds for the auxiliary feedwater (AFW) and 15 seconds for the emergency core cooling system (ECCS) injection flow as summarized below. The increased ESF delay times represent a malfunction of a structure, system, or component (SSC) important to safety with a different result than previously evaluated in the Final safety Analysis Report Update (FSARU) per 10 CFR 50.59 and is being submitted for prior NRC approval in License Amendment Request 11-06 as documented in PG&E Letter DCL-11-072.
SBLOCA The core uncovery and peak cladding temperature (PCT) for the limiting Unit 1 and Unit 2 SBLOCA cases occurs at 12 to 15 minutes into the event. The 15 second increase in ECCS flow due delay time was determined to represent a small reduction in the total amount of ECCS injection flow that has entered the reactor coolant system (RCS) up to the time of core uncovery.
Similarly, the 5 second increase in the AFW actuation time was determined to have a negligible impact on the thermal hydraulic results since the major source of decay heat removal is due to the RCS flow out of the break. Therefore, it was concluded that there was a O°F impact on the current SBLOCA Unit 1 and Unit 2 PCT results. Large-Break Loss-of-Coolant Accident (LBLOCA) Both Diablo Canyon Unit 1 and Unit 2 use a BELOCA evaluation methodology for the analysis of record. The LBLOCA evaluation considered an increase in ECCS injection flow delay time from 27 seconds to 42 seconds. The primary effect of increasing the ECCS delay time is that it can lead to increased duration of fuel heatup periods during the refill and reflood periods. The blowdown remains unaffected since this phase is over before the ECCS injection flow begins. Depending on the break size and the accumulator pressure and volume, the end of the refill and periods and the accumulator injection can vary and create periods with significantly different and/or reduced ECCS injection flow. C -1 Attachment C PG&E Letter DCL-11-082 For Unit 1, the evaluation was based on global model runs with an effective break size area greater than the reference transient.
These greater break areas will depressurize the RCS faster leading to a more rapid accumulator blowdown and are more likely to result in a delay between the accumulator injection and the start of ECCS injection flow. The cases were selected to evaluate the relative effects of accumulator volume, accumulator pressure, and break size. The limiting evaluation case resulted in a O°F penalty for the early Reflood 1 period and an estimated 39°F penalty for the Reflood 2 period. Unit 2 uses the newer Automated Statistical Treatment of Uncertainty Method (ASTRUM) BELOCA methodology which does not track the individual Reflood 1 and Reflood 2 penalties but only reports one overall reflood penalty. For Unit 2, the evaluation was also based on selecting cases with higher break sizes that depressurize faster and lead to a faster accumulator blowdown that create a greater potential for a delay between accumulator injection and ECCS injection.
The evaluation also considered cases with high accumulator pressure or low accumulator volume which could also lead to a faster accumulator blowdown.
The evaluation for the limiting case concluded that there is a net PCT penalty of 16 OF due to the increased ECCS injection flow delay time. C -2