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Category:Letter
MONTHYEARML23304A1422024-02-0101 February 2024 Issuance of Environmental Scoping Summary Report Associated with the U.S. Nuclear Regulatory Commission Staffs Review of the Oconee Nuclear Station, Units 1, 2, & 3, Subsequent License Renewal Application ML24005A2492024-01-24024 January 2024 Exemption from Select Requirements of 10 CFR Part 73 (Security Notifications, Reports, and Recordkeeping and Suspicious Activity Reporting) IR 05000269/20243012024-01-11011 January 2024 Notification of Licensed Operator Initial Examination 05000269/2024301, 05000270/2024301, and 05000287/2024301 ML23331A7982023-12-14014 December 2023 Review of the Fall 2022 Steam Generator Tube Inspection Report (01R32) ML23262A9672023-12-13013 December 2023 Alternative to Use RR-22-0174, Risk-Informed Categorization and Treatment for Repair/Replacement Activities in Class 2 and 3 Systems Section XI, Division 1 ML23317A3462023-11-14014 November 2023 Duke Fleet - Correction Letter to License Amendment Nos. 312 & 340 Issuance of Amendments Regarding the Adoption of Technical Specifications Task Force Traveler TSTF-554, Revision 1 IR 05000269/20230032023-11-14014 November 2023 Integrated Inspection Report 05000269/2023003, 05000270/2023003, and 05000287/2023003; and IR 07200040/2023001; and Exercise of Enforcement Discretion ML23219A1402023-10-10010 October 2023 Audit Report Proposed Alternative to Use ASME Code Case N-752, Risk Informed Categorization and Treatment for Repair/Replacement Activities in Class 2 and 3 Systems XI, Division 1 ML23269A1102023-10-0606 October 2023 Letter to Steven Snider-Revised Schedule for the Environmental Review of the Oconee Nuclear Station, Unit 1, 2, and 3, Subsequent License Renewal Application ML23256A0882023-09-25025 September 2023 Issuance of Alternative to Steam Generator Welds ML23195A0782023-08-29029 August 2023 Issuance of Amendments Regarding the Adoption of Technical Specifications Task Force Traveler TSTF-554, Revision 1 IR 05000269/20230112023-08-25025 August 2023 Comprehensive Engineering Team Inspection Report 05000269/2023011 and 05000270/2023011 and 05000287/2023011 IR 05000269/20230052023-08-25025 August 2023 Updated Inspection Plan for Oconee Nuclear Station Units 1, 2 and 3 (Report 05000269/2023005, 05000270/2023005, and 05000287/2023005) IR 05000269/20230022023-07-28028 July 2023 Integrated Inspection Report 05000269/2023002, 05000270/2023002 and 05000287/2023002 ML23208A0972023-07-27027 July 2023 Subsequent License Renewal List of Threatened and Endangered Species That May Occur in Your Proposed Project Location or May Be Affected IR 05000269/20230102023-07-19019 July 2023 Biennial Problem Identification and Resolution Inspection Report 05000269/2023010 and 05000270/2023010 and 05000287/2023010 and Notice of Violation ML23178A0682023-07-0303 July 2023 Audit Plan Proposed Alternative to Use ASME Code Case N-752, Risk-Informed Categorization and Treatment for Repair/Replacement Activities in Class 2 & 3 Systems Section XI, Division 1 ML23132A2392023-06-0101 June 2023 Summary of the April 2023 Remote Environmental Audit Related to the Review of the Subsequent License Renewal Application ML23144A0192023-05-25025 May 2023 Review of the Spring 2022 Steam Generator Tube Inspection Report (O3R31) IR 05000269/20230012023-05-12012 May 2023 Integrated Inspection Report 05000269/2023001 and 05000270/2023001 and 05000287/2023001 ML23121A0552023-05-0303 May 2023 Acknowledgement of Withdrawal Request to Revise TS 5.5.2 Containment Leakage Rate Testing Program ML23118A0762023-05-0101 May 2023 Approval for Use of Specific Provision of a Later Edition of the American Society of Mechanical Engineers Boiler and Pressure Vessel Code, Section XI ML23117A0432023-04-20020 April 2023 Framatome, Inc., Part 21 Notification of Existence of a Defect ML23075A0732023-04-0505 April 2023 License Renewal Regulatory Audit Regarding the Environmental Review of the Subsequent License Renewal Application Supplement (EPID Number L-2021-SLE-0002) ML23045A1332023-03-15015 March 2023 Request for Scoping Comments Concerning the Supplemental Environmental Review of Oconee Nuclear Station, Units 1, 2, and 3, Subsequent License Renewal Application - Achp Letter ML23045A1402023-03-15015 March 2023 Request for Scoping Comments Concerning the Supplemental Environmental Review of Oconee Nuclear Station, Units 1, 2, and 3, Subsequent License Renewal Application - Shpo Letter ML23045A1432023-03-15015 March 2023 Request for Scoping Comments Concerning the Supplemental Environmental Review of Oconee Nuclear Station, Units 1, 2, and 3, Subsequent License Renewal Application - State Tribe Letter ML22332A4932023-03-10010 March 2023 William States Lee III 1 and 2 - Issuance of Amendments Regarding the Relocation of the Emergency Operations Facility ML23069A1102023-03-10010 March 2023 Notification of Inspection and Request for Information for NRC Problem Identification and Resolution Inspection ML23061A1772023-03-0303 March 2023 Notification of Oconee Nuclear Station Comprehensive Engineering Team Inspection - NRC Inspection Report 05000269/2023011, 05000270/2023011 and 05000287/2023011 IR 05000269/20220062023-03-0101 March 2023 Annual Assessment Letter for Oconee Nuclear Nuclear Station, Units 1, 2 and 3 (NRC Inspection Report 05000269/2022006, 05000270/2022006, and 05000287/2022006) ML23039A1632023-02-0808 February 2023 Requalification Program Inspection ML23037A0772023-02-0606 February 2023 402 Cyber Notification and RFI Letter Final IR 05000269/20220042023-02-0202 February 2023 Integrated Inspection Report 05000269 2022004 and 05000270/2022004 and 05000287/2022004 ML22363A3942023-01-12012 January 2023 Subsequent License Renewal Environmental Report Supplement - Proposed Review Schedule ML22356A0512022-12-14014 December 2022 Curtiss-Wright Nuclear Division, Letter Regarding Potential Efect in a Configuration of the 11/2 Inch Quick Disconnect Connector Cable Assemblies Supplied to Duke Energy (See Attached Spreadsheet) for a Total of 460 of Connectors Only Suppl ML22321A0492022-12-0808 December 2022 Issuance of Amendment Nos. 426, 428 and 427, Additional Mode Change Limitations Applicable to the Adoption of TSTF- 359, Revision 9, Increase Flexibility in Mode Restraints ML22329A1042022-11-29029 November 2022 Review of the Fall 2021 Steam Generator Tube Inspection Report ML22321A1582022-11-22022 November 2022 Summary of Conference Call Regarding the Fall 2022 Steam Generator Tube Inspections ML22096A0032022-11-18018 November 2022 McGuire Nuclear Station and Shearon Harris Nuclear Power Plant Authorization of RA-19-0352 Regarding Use of Alternative for RPV Head Closure Stud Examinations ML22256A2532022-11-14014 November 2022 Issuance of Amendments Regarding the Adoption of Technical Specifications Task Force Traveler TSTF-541, Rev. 2 IR 05000269/20220032022-11-0707 November 2022 Integrated Inspection Station 05000269/2022003 and 05000270/2022003 and 05000287/2022003 ML22301A0112022-11-0303 November 2022 Request for Withholding Information from Public Disclosure Regarding the SLR Application - September 2, 2022 ML22298A0752022-10-27027 October 2022 Request for Withholding Information from Public Disclosure Regarding the Subsequent License Renewal Application Duke Energy Letter Dated July 25, 2022 ML22264A0322022-10-20020 October 2022 _Request for Withholding Information from Public Disclosure Regarding the Subsequent License Renewal Application - Duke Energy Letter Dated July 8, 2022 IR 05000269/20220112022-09-26026 September 2022 NRC Inspection Report 05000269/2022011 and 05000270/2022011 and 05000287/2022011 ML22258A0302022-09-15015 September 2022 Evacuation Time Estimate Reports ML22222A0072022-09-14014 September 2022 Request for Withholding Information from Public Disclosure Regarding the Subsequent License Renewal Application ML22231B1362022-09-0101 September 2022 Review of the Draft Environmental Assessment and Findings of No Significant Impact for Catawba Nuclear Station, H.B. Robinson Steam Electric Plant, and Oconee Nuclear Station Independent Spent Fuel Storage Installation Decommissioning Fundi ML22234A0062022-08-30030 August 2022 SLRA - Closed Public Meeting Summary - August 18, 2022 2024-02-01
[Table view] Category:Safety Evaluation
MONTHYEARML23262A9672023-12-13013 December 2023 Alternative to Use RR-22-0174, Risk-Informed Categorization and Treatment for Repair/Replacement Activities in Class 2 and 3 Systems Section XI, Division 1 ML23256A0882023-09-25025 September 2023 Issuance of Alternative to Steam Generator Welds ML23195A0782023-08-29029 August 2023 Issuance of Amendments Regarding the Adoption of Technical Specifications Task Force Traveler TSTF-554, Revision 1 ML23118A0762023-05-0101 May 2023 Approval for Use of Specific Provision of a Later Edition of the American Society of Mechanical Engineers Boiler and Pressure Vessel Code, Section XI ML22332A4932023-03-10010 March 2023 William States Lee III 1 and 2 - Issuance of Amendments Regarding the Relocation of the Emergency Operations Facility ML22349A1452022-12-19019 December 2022 Non-Proprietary Safety Evaluation Related to the SLRA of Oconee Nuclear Station, Units 1, 2, and 3 ML22321A0492022-12-0808 December 2022 Issuance of Amendment Nos. 426, 428 and 427, Additional Mode Change Limitations Applicable to the Adoption of TSTF- 359, Revision 9, Increase Flexibility in Mode Restraints ML22096A0032022-11-18018 November 2022 McGuire Nuclear Station and Shearon Harris Nuclear Power Plant Authorization of RA-19-0352 Regarding Use of Alternative for RPV Head Closure Stud Examinations ML22256A2532022-11-14014 November 2022 Issuance of Amendments Regarding the Adoption of Technical Specifications Task Force Traveler TSTF-541, Rev. 2 ML22096A1872022-07-15015 July 2022 Issuance of Amendment Nos. 424, 426, and 425 Revise TS 3.7.7, Low Pressure Service Water (LPSW) System to Extend the Completion Time for One Required Inoperable LPSW Pump ML22046A0222022-06-14014 June 2022 Issuance of Amendments to Adopt TSTF-439, Eliminate Second Completion Times Limiting Time from Discovery of Failure to Meet an LCO ML22068A0252022-03-15015 March 2022 Code Case OMN-28 - Alternative Valve Position Verification Approach to Satisfy ISTC-3700 for Valves Not Susceptible to Stem-Disk Separation ML22046A2802022-02-23023 February 2022 Relief from ASME Code Paragraph ISTP-3540(b) Related to High Pressure Injection Pumps Vibration Measurements ML22046A2452022-02-18018 February 2022 Regarding Alternative to Implement Code Case OMN-22, Smooth Running Pumps ML22019A1352022-01-21021 January 2022 Proposed Alternative to Implement ASME Code Case OMN-24 ML21347A0102021-12-20020 December 2021 Proposed Alternative to Implement ASME Code Case OMN-26 ML21335A1062021-12-0707 December 2021 Proposed Alternative to ASME Code W, Section XI, Subsection Iwl Regarding Containment Post-Tensioning System Inservice Inspection Requirements ML21281A1412021-11-19019 November 2021 Authorization and Safety Evaluation for Alternative Reactor Pressure Vessel Inservice Inspection Intervals ML21155A2132021-08-26026 August 2021 Plant ML21113A0132021-05-0606 May 2021 Request for Use of a Later Edition of ASME Boiler and Pressure Vessel Code, Section XI for Repair and Replacement Activities ML21006A0982021-03-15015 March 2021 Issuance of Amendment Nos. 421, 423, and 422 Revision of Licensing Basis for High Energy Line Breaks Outside of Containment (EPID L-2019-LLA-0184) (Public Version) ML21029A3352021-02-16016 February 2021 Request to Use a Provision of a Later Edition of the American Society of Mechanical Engineers Boiler and Pressure Vessel Code, Section XI ML20335A0012021-01-26026 January 2021 Issuance of Amendment Nos. 420, 422, and 421 Measurement Uncertainty Recapture Power Uprate ML20303A0242020-12-0909 December 2020 Issuance of Amendments 419, 421, 420 TSTF-272, Refueling Boron Concentration Clarification ML20296A2812020-11-25025 November 2020 Issuance of Amendment Nos. 418, 420 and 419 TSTF-421, Revision to RCP Flywheel Inspection Program ML20300A2062020-11-0909 November 2020 Duke Fleet - Request to Use a Provision of a Later Edition of the American Society of Mechanical Engineers Boiler and Pressure Vessel Code, Section XI ML20258A2712020-09-21021 September 2020 Correction Letter to Amendment Nos. 301, 329, 307, 303, 178, 317, 296, 416, 418, 417, and 268 ML20237F4352020-09-0404 September 2020 Issuance of Amendments Regarding the Technical Specification Requirements Pertaining to Mode Change Limitations ML20083F9272020-08-12012 August 2020 Issuance of Amendments to Relocate the Unit/Facility/Plant Staff Qualification Requirements to the Duke Energy Quality Assurance Program Description ML20055F5712020-02-26026 February 2020 Proposed Alternative Request 19-ON-001 to Use Modified American Society of Mechanical Engineer'S Boiler and Pressure Vessel Code Case N-853 ML20042D7142020-02-13013 February 2020 Relief Request 19-ON-002 for Proposed Alternative to Reactor Vessel Nozzle Weld Examination Frequency Requirements in ASME Code Case N-770-2 ML19260E0842019-10-31031 October 2019 Issuance of Amendments 415, 417, and 416, Regarding the Updated Final Safety Analysis Report Description of Tornado Mitigation ML19056A0862019-09-30030 September 2019 Issuance of Amendments Nos. 414, 416 and 415 Regarding the Physical Security Plan ML19254A6202019-09-17017 September 2019 Duke Energy Fleet (Brunswick, Catawba, Robinson, McGuire, Oconee, and Shearon Harris) - Alternative to Use Encoded Phased Array Ultrasonic Examination in Lieu of Radiography ML19183A3172019-07-17017 July 2019 Issuance of Amendments Regarding the Updated Final Safety Analysis Report Section for Fission Gas Gap Release Rates ML19058A6322019-07-0101 July 2019 Issuance of Amendments to Revise Emergency Action Level Schemes to Incorporate Clarifications Provided by Emergency Preparedness FAQs ML19128A3262019-06-20020 June 2019 Alternative to Depth Sizing Qualification Examination of Welds ML18311A1342018-12-17017 December 2018 Non Proprietary - Issuance of Amendments Regarding the Updated Final Safety Analysis Report Section for the Standby Shutdown Facility ML18172A1722018-08-15015 August 2018 Issuance of Amendments to Adopt TSTF-545, Revision 3, TS Inservice Testing Program Removal & Clarify SR Usage Rule Application ML18040A1942018-04-12012 April 2018 Issuance of Amendments Regarding the Technical Specifications for Control Room Habitability (CAC Nos. MF9555, MF9556, and MF9557; EPID L-2017-LLA-0219) ML18051B2572018-02-28028 February 2018 Safety Evaluation for Alternative to Codes and Standards Requirements Associated with Bronze Tape Wrapped Emergency Power Cables (CAC Nos. MF7365, MF7366, and MF7367; EPID L-2016-LLR-0001) ML17331A0862017-12-26026 December 2017 Alternative to Inservice Inspection Regarding Reactor Pressure Vessel Threads ML17335A0252017-12-0505 December 2017 Correction to Safety Evaluation for Amendment Nos. 406, 408, and 407 (CAC Nos. MF7417, MF7418, and MF7419; EPID L-2016-LLA-0002) ML17124A6082017-11-20020 November 2017 Issuance of Amendments Regarding the Technical Specifications for Electrical Power Systems (CAC Nos. MF7417, MF7418, and MF7419; EPID L-2016-LLA-0002) ML17202U7912017-08-30030 August 2017 Safety Evaluation Regarding Implementation of Mitigating Strategies and Reliable Spent Fuel Pool Instrumentation Related to Orders EA-12-049 and EA-12-051 ML17188A3872017-08-21021 August 2017 Issuance of Amendments Regarding Application to Consolidate Emergency Operations Facilities and Associated Emergency Plan Changes (CAC Nos. MF7650 Through MF7660) ML17167A2652017-07-12012 July 2017 Issuance of Amendments Regarding the Technical Specifications for Dry Spent Fuel Storage Cask Loading and Unloading (CAC Nos. MF8161, MF8162, and MF8163) ML17103A5092017-05-11011 May 2017 Issuance of Amendments Allowing the Use of the Copernic Fuel Performance Code ML17066A3742017-04-26026 April 2017 Issuance of Amendments Re. Application to Revise TSs to Adopt TSTF-427, Rev. 2, Using the Consolidated Line Item Improvement Process (CAC Nos. MF8039 Through MF8049) ML16197A0112016-07-22022 July 2016 Relief Request Nos. 15-ON-002 and 15-ON-003, Fourth 10-Year Inservice Inspection Interval 2023-09-25
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UNITED STATES NUCLEAR REGULATORY COMMISSION WASHINGTON, D.C. 20555-0001 October 7, 2015
SUBJECT:
OCONEE NUCLEAR STATION, UNITS 1, 2, AND 3 - STAFF EVALUATION RE:
REPORT PURSUANT TO 10 CFR 50.46 REQUIREMENTS RELATED TO THERMAL CONDUCTIVITY DEGRADATION (CAC NOS. MF5572, MF5573, AND MF5574)
Dear Mr. Batson:
By letter dated December 17, 2014, Duke Energy Carolinas, LLC (the licensee), submitted a report describing a significant error identified in the emergency core cooling system evaluation model, and an estimate of the effect of the error on the predicted peak cladding temperature for Oconee Nuclear Station, Units 1, 2 and 3. This report was submitted pursuant to Title 10 of the Code of Federal Regulations (10 CFR), Part 50, Section 46 (1 O CFR 50.46), paragraph (a)(3).
The U.S. Nuclear Regulatory Commission (NRC) staff has evaluated the report, along with its supplemental information submitted by letter dated March 31, 2015. Based on its evaluation, the NRC staff determined that the report, as supplemented, satisfies the reporting requirements of 10 CFR 50.46(a)(3). A staff evaluation describing the technical and regulatory basis for the NRC staff's conclusion is enclosed. This letter concludes the NRC staff's review associated with CAC Nos. MF5572, MF5573, and MF5574.
If you have any questions, please contact me at (301) 415-4090 or via e-mail at Jeffrey. Whited@nrc.gov.
Sincerely, 4P~
Jeffrey A. Whited, Project Manager Plant Licensing Branch 11-1 Division of Operating Reactor Licensing Office of Nuclear Reactor Regulation Docket No. 50-269, 50-270, and 50-287
Enclosure:
Staff Evaluation cc w/encl: Distribution via ListServ
UNITED STATES NUCLEAR REGULATORY COMMISSION WASHINGTON, D.C. 20555-0001 STAFF EVALUATION BY THE OFFICE OF NUCLEAR REACTOR REGULATION RELATED TO REPORT PURSUANT TO 10 CFR 50.46 DUKE ENERGY CAROLINAS, LLC OCONEE NUCLEAR STATION, UNITS 1, 2 AND 3 DOCKET NOS. 50-269, 50-270, 50-287
1.0 INTRODUCTION
By letter dated December 17, 2014, 1 as supplemented by letter dated March 31, 2015, 2 Duke Energy Carolinas, LLC, (Duke, the licensee), submitted a report describing a significant error identified in the emergency core cooling system (ECCS) evaluation model (EM) and an estimate of the effect of the error on the predicted peak cladding temperature (PCT) for the Oconee Nuclear Station, Units 1, 2 and 3 (ONS). This report was submitted pursuant to Section 50.46(a)(3) of Title 10 of the Code of Federal Regulations (1 O CFR).
The U.S. Nuclear Regulatory Commission (NRC) staff has completed its review of the submittals and determined, as discussed below, that Duke has satisfied the reporting requirements of 10 CFR 50.46(a)(3).
2.0 REGULATORY EVALUATION
2.1 Regulatory Requirements Acceptance criteria for ECCS for light-water nuclear power reactors are found in 10 CFR 50.46.
Among other things, 10 CFR 50.46(a)(1 )(i) requires that ECCS cooling performance must be calculated in accordance with an acceptable evaluation model. Paragraph (b) of 10 CFR 50.46 provides the acceptance criteria for ECCS evaluation. In particular, 10 CFR 50.46(b)(1 ), "Peak Cladding Temperature," states, "The calculated maximum fuel element cladding temperature shall not exceed 2200 °F [degrees Fahrenheit]."
Paragraph (a)(3)(i) of 10 CFR 50.46 requires licensees to estimate the effect of any change to or error in an acceptable evaluation model, or in the application of such a model, to determine if 1 Agencywide Documents Access and Management System (ADAMS) Accession No. ML14353A214.
2 ADAMS Accession No. ML15090A303. .
Enclosure
the change or error is significant. For the purpose of 10 CFR 50.46, a significant change or error is one which results in a calculated peak fuel cladding temperature difference of more than 50 °F from the temperature calculated for the limiting transient using the last acceptable model, or is a cumulation of changes and errors such that the sum of the absolute magnitudes of the respective temperature changes is greater than 50 °F. For each change to or error discovered in an acceptable EM, or in the application of such a model, 10 CFR 50.46(a)(3)(ii) requires the affected licensee to report the nature of the change or error and its estimated effect on the limiting ECCS analysis to the NRC at least annually. If the change or error is significant, the licensee is required to provide this report within 30 days and include with the report a proposed schedule for providing a reanalysis or taking other action as may be needed to show compliance with 10 CFR 50.46 requirements.
2.2 Background The AREVA Inc. (AREVA) proprietary topical report BAW-10192P-A, "BWNT (Babcock and Wilcox (B&W) Nuclear Technologies) Loss-of-Coolant Accident (LOCA) Evaluation Model (EM) for Once-Through Steam Generator Plants" (BWNT LOCA EM), 3 is the acceptable EM used to evaluate ECCS cooling performance at ONS. In accordance with 10 CFR Part 21, "Reporting of Defects and Noncompliance," AREVA reported an error in its LOCA analysis for plants with a B&W design, including ONS, by letter to the NRC dated December 16, 2014. 4 In its report, AREVA stated that the current fuel "thermal conductivity model does not adequately represent the change in conductivity with burnup for the fuel." This defect relates to the uranium fuel thermal conductivity models in the fuel thermal-mechanical codes T AC03 5 and GDTAC0, 6 which are part of the BWNT LOCA EM. The defect resulted in an under-prediction of the large-break PCT at ONS. To compensate for the under-prediction of PCT, AREVA stated that each affected plant, including ONS, was advised to reduce fuel linear heat rate (LHR) by 2 kilowatts per foot (kW/ft).
Based on AREVA's notification, Duke submitted its December 17, 2014, letter to notify the NRC that the defect constituted an error in the ECCS EM for ONS. The licensee's letter provided:
(1) a description of the nature of the error and its estimated effect on the PCT, (2) a summary of actions taken to ensure compliance with 10 CFR 50.46 requirements, including implementing the 2 kW/ft LHR reduction, and (3) a commitment that a large break LOCA (LBLOCA) reanalysis, accounting for the effects of thermal conductivity degradation (TCD) for the highest PCT case, would be performed for ONS by September 15, 2015. This commitment date was revised to 15 months after NRC approval of a supplement to BAW-10192P-A, by the supplemental letter dated March 31, 2015.
3 BAW-10192P-A describes the ECCS EM; however, the EM requires use of input from approved thermal-mechanical models. Plant-specific application is described in further detail in BAW-10179P-A, "Safety Criteria and Methodology for Acceptable Cycle Reload Analyses."
4 ADAMS Accession No. ML14351A308.
5 AREVA NP Licensing Topical Report BAW-10162P-A, "TAC03- Fuel Pin Thermal Analysis Code."
6 AREVA NP Licensing Topical Report BAW-10184P-A, "GDTACO- Urania Gadolinia Fuel Pin Thermal Analysis Code."
The December 17, 2014, letter stated that the TCD-related defect was estimated to cause the PCT at ONS to increase 428 °f. The licensee's implementation of a 2 kW/ft LHR reduction was estimated to offset the TCD effect by a compensating amount. Therefore, the predicted PCT for ONS remains 1852 °f, which is less than the regulatory limit of 2200 °f.
3.0 TECHNICAL EVALUATION
3.1 Use of an Acceptable Evaluation Model for Reanalysis The December 17, 2014, letter indicated Duke would complete a reanalysis incorporating the effects of TCD by September 17, 2015. Section 4.3.2.3 of the BWNT LOCA EM requires licensees to use NRG-approved fuel thermal-mechanical models to be consistent with the topical report. The fuel temperature uncertainty values used in TAC03 and GDTACO are specified in the NRG-approved fuel performance methodology documented in BAW-10162P-A and BAW-10184P-A. The AREVA report identified that these uncertainty values need to be modified in order to account for TCD.
In its March 31, 2015 letter, the licensee stated that AREVA will develop a supplement to its BWNT LOCA EM and submit it for NRC review and approval. The licensee stated the supplement will describe the modifications to the BWNT LOCA EM necessary to correct for the TCD issue. Based on this information, the NRC staff determined that the licensee has adequately described how it will ensure ECCS cooling performance is calculated using an acceptable EM. The March 31, 2015, letter also revised the fulfillment date of the reanalysis commitment to 15 months following receipt of NRC approval of the BWNT LOCA EM update.
3.2 Adequacy of Reanalysis Scope As discussed above, the licensee stated that the TCD-related model changes will be incorporated as a supplement to the BWNT LOCA EM. The December 17, 2014, letter stated that the reanalysis would be performed for the highest PCT case at middle-of-life (MOL) conditions. Based on the magnitude of the estimated effect of a TCD correction on the ONS ECCS evaluation, the NRC staff determined that these model revisions would significantly change the predicted ECCS performance for ONS.
Regarding the evaluation of ECCS performance, 1O CfR 50.46(a)(1 )(i) states, in part, that ECCS cooling performance "must be calculated for a number of postulated loss-of-coolant accidents of different sizes, locations, and other properties sufficient to provide assurance that the most severe postulated loss-of-coolant accidents are calculated." In its March 31, 2015, letter, the licensee stated, in part, that:
As part of the supplement to BAW-10192P-A, AREVA intends to confirm that the TCD error correction does not alter the conclusion of existing sensitivity studies
[that confirm the limiting break size and location for ONS]. AREVA also intends to perform demonstration analyses to show how the revised evaluation model would be used in a licensing analysis. AREVA has indicated that the demonstration analysis to be included in the supplement to BAW-10192P-A will utilize the Oconee LBLOCA model.
For the Oconee TCD reanalysis effort, the middle-of-life (MOL) time in life is expected to remain limiting with respect to PCT, since TCD is not expected to affect the beginning-of-life (BOL) cases. For the Oconee reanalysis, the number of MOL cases to be analyzed, at particular axial core elevations, will be sufficient to ensure that the limiting break scenario has been calculated with an acceptable evaluation model, which includes the TCD error corrections to be described in the supplement to BAW-10192P-A. Also, an end-of-life (EOL) case at the 2.506 foot core elevation will be evaluated to ensure that EOL remains non-limiting with respect to PCT.
In the NRG staff experience, various issues associated with EGGS evaluation may be addressed using an evaluation of a spectrum of break sizes, locations, and other properties, and this evaluation may be performed on a more general, simplified basis. Once a set of generally limiting properties is identified, a more detailed, plant-specific analysis identifies the exact limiting properties and determines the results for comparison against the 10 CFR 50.46(b) acceptance criteria. The licensee's statement above is consistent with this practice, since the AREVA supplement to BAW-10192P-A will be based on sensitivity studies and demonstration calculations using the Oconee plant model.
Should, during the NRG staff review of the BAW-10192P-A supplement, issues be identified that indicate that the sensitivity studies and demonstration analyses are insufficient to ensure that the Oconee analysis continues to provide assurance that the most severe hypothetical LOCAs are calculated, conditions or limitations could be placed on the staff approval of the BAW-10192P-A supplement requiring further Oconee-specific analysis prior to implementation.
Based on the discussion above, the NRG staff determined that the licensee adequately described how it will provide assurance that the most severe postulated LOCAs are calculated.
3.3 Technical Specification (TS) Impacts ONS TS 5.6.5, "Core Operating Limits Report," requires, in part, that:
The analytical methods used to determine the core operating limits shall be those previously reviewed and approved by the NRG [for use at ONS], specifically those described in the following documents: (6) BAW-10192P-A, BWNT LOCA-BWNT Loss of Coolant Accident Evaluation Model for Once-Through Steam Generator Plants.
In its letter dated March 31, 2015, Duke stated that the Oconee Large Break LOCA reanalysis would be performed incorporating a TCD error correction, once the NRG has approved a supplement to BAW-10192P-A. The licensee also stated that any subsequent Core Operating Limits Report (COLR) would provide a complete citation to the updated method, consistent with the ONS TS requirements for the COLR.
Based on the information provided by the licensee, the NRG staff determined that the reanalysis will be performed using NRG-approved methods, consistent with the ONS TS COLR requirements.
4.0 CONCLUSION
Based on its review, the NRC staff concluded that Duke's report, as supplemented, satisfies the reporting requirements of 10 CFR 50.46(a)(3). The report described the nature of the TCD-related error and provided its estimated effect on the PCT for the limiting ECCS evaluation. The report also indicated that the licensee took action to reduce LHR limits to compensate for the effect of TCD and showed that the predicted PCT would remain below 2200 °F. The report, as supplemented, included a proposed schedule for performing reanalysis and taking other actions, as needed, to comply with 10 CFR 50.46 requirements.
Principal Contributor: Benjamin Parks Date: October 7, 2015
ML15272A340 *via memo dated OFFICE LPL2-1/PM LPL2-1/LA DSS/SNPB* LPL2-1/BC LPL2-1/PM NAME JWhited SFigueroa JDean RPascarelli JWhited DATE 10/06/2015 10/06/2015 09/03/2015 10/06/2015 10/07/2015