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Category:Letter
MONTHYEARML24263A1272024-09-23023 September 2024 – Request for Additional Information (EPID 2023-LLA-0136) - Non-Proprietary BYRON 2024-0046, Cycle 27 Core Operating Limits Report2024-09-19019 September 2024 Cycle 27 Core Operating Limits Report RS-24-088, Relief Requests Associated with the Fifth Inservice Inspection Interval2024-09-13013 September 2024 Relief Requests Associated with the Fifth Inservice Inspection Interval IR 05000456/20240112024-09-12012 September 2024 Biennial Problem Identification and Resolution Inspection Report 05000456/2024011 and 05000457/2024011 ML24164A0032024-09-10010 September 2024 Issuance of Amendment Nos. 235 and 235 Revision of Technical Specifications for the Ultimate Heat Sink ML24250A1182024-09-0606 September 2024 Notification of an NRC Biennial Licensed Operator Requalification Program Inspection and Request for Information 05000454/LER-2024-001, Both Trains of Control Room Ventilation Temperature Control System Inoperable2024-09-0505 September 2024 Both Trains of Control Room Ventilation Temperature Control System Inoperable ML24227A0522024-08-29029 August 2024 Audit Plan for LAR to Remove ATWS Mtc Limit IR 05000456/20240052024-08-29029 August 2024 Updated Inspection Plan and Assessment Follow-Up Letter for Braidwood Station, Units 1 and 2 (Report 05000456/2024005 and 05000457/2024005) IR 05000454/20240052024-08-28028 August 2024 Updated Inspection Plan and Assessment Follow-Up Letter for Byron Station, Units 1 and 2 (Report 05000455/2024005 and 05000454/2024005) ML24225A1112024-08-13013 August 2024 Notification of NRC Fire Protection Team Inspection Request for Information ML24222A6772024-08-0909 August 2024 Response to Request for Additional Information for Application to Revise Technical Specifications to Adopt TSTF-591-A, Revise Risk Informed Completion Time (RICT) Program Revision 0 and Revise 10 CFR 50.69 License Condition IR 05000454/20240112024-08-0808 August 2024 Phase 2 Post- Approval License Renewal Report 05000454/2024011 IR 05000456/20240022024-08-0808 August 2024 Integrated Inspection Report 05000456/2024002 and 05000457/2024002 ML24172A1252024-07-26026 July 2024 Environmental Assessment and Finding of No Significant Impact Related to a Requested Increase in Ultimate Heat Sink Temperature (EPID L-2024-LLA-0075) - Transmittal Letter IR 05000454/20240022024-07-26026 July 2024 Integrated Inspection Report 05000454/2024002 and 05000455/2024002, and Exercise of Enforcement Discretion ML24179A3262024-07-23023 July 2024 LTR - Constellation - SG Welds and Nozzles (L-2023-LLR-0053, L-2023-LLR-0054, L-2023-LLR-0055, L-2023-LLR-0056) 05000456/LER-2024-001, Submittal of LER 2024-001-00 for Braidwood Station, Unit 1, Trip on Low Steam Generator Level Due to Failure to Verify Isolation Valves Were Open2024-07-0303 July 2024 Submittal of LER 2024-001-00 for Braidwood Station, Unit 1, Trip on Low Steam Generator Level Due to Failure to Verify Isolation Valves Were Open RS-24-064, Nuclear Radiological Emergency Plan Document Revisions2024-06-28028 June 2024 Nuclear Radiological Emergency Plan Document Revisions RS-24-066, Inservice Testing Interval Extension for Essential Service Water Valves Due to Required Use of Containment Chiller2024-06-25025 June 2024 Inservice Testing Interval Extension for Essential Service Water Valves Due to Required Use of Containment Chiller ML24163A3922024-06-25025 June 2024 Individual Notice of Consideration of Issuance of Amendments to Renewed Facility Operating Licenses, Proposed No Significant Hazards Consideration Determination, & Opportunity for a Hearing (EPID L-2024-LLA-0075)- Letter ML24170A7652024-06-19019 June 2024 Confirmation of Initial License Examination RS-24-061, Constellation Energy Generation, LLC, Response to NRC Regulatory Issue Summary 2024-01, Preparation and Scheduling of Operator Licensing Examinations2024-06-14014 June 2024 Constellation Energy Generation, LLC, Response to NRC Regulatory Issue Summary 2024-01, Preparation and Scheduling of Operator Licensing Examinations ML24164A2132024-06-13013 June 2024 Information Request to Support Upcoming Problem Identification and Resolution (Pi&R) Inspection at Braidwood Nuclear Plant RS-24-057, License Amendment to Technical Specification 3.7.9, Ultimate Heat Sink2024-06-0404 June 2024 License Amendment to Technical Specification 3.7.9, Ultimate Heat Sink IR 05000456/20240102024-05-31031 May 2024 License Renewal Phase 1 Report 05000456/2024010 RS-24-044, License Amendment to Transition to Framatome Gaia Fuel and Exemptions to 10 CFR 50.46 and 10 CFR 50 Appendix K. Attachments 1 to 11 Enclosed2024-05-28028 May 2024 License Amendment to Transition to Framatome Gaia Fuel and Exemptions to 10 CFR 50.46 and 10 CFR 50 Appendix K. Attachments 1 to 11 Enclosed RS-24-043, Application to Remove Power Distribution Monitoring System (Pdms) Details from Technical Specifications2024-05-24024 May 2024 Application to Remove Power Distribution Monitoring System (Pdms) Details from Technical Specifications ML24079A0762024-05-23023 May 2024 Issuance of Amendments to Adopt TSTF 264 ML24142A3352024-05-21021 May 2024 Quad Cities—Information Request to Support the NRC Annual Baseline Emergency Action Level and Emergency Plan Changes RS-24-055, 2023 Corporate Regulatory Commitment Change Summary Report2024-05-17017 May 2024 2023 Corporate Regulatory Commitment Change Summary Report BYRON 2024-0031, Completion of License Renewal Activities Prior to Entering the Period of Extended Operation2024-05-16016 May 2024 Completion of License Renewal Activities Prior to Entering the Period of Extended Operation ML24136A0132024-05-15015 May 2024 2023 Annual Radiological Environmental Operating Report ML24136A2452024-05-15015 May 2024 Notification of NRC Baseline Inspection and Request for Information; Inspection Report 05000457/2024004 IR 05000454/20240012024-05-10010 May 2024 Integrated Inspection Report 05000454/2024001; 05000455/2024001 and 07200068/2024001 BYRON 2024-0028, Annual Radiological Environmental Operating Report (AREOR)2024-05-0909 May 2024 Annual Radiological Environmental Operating Report (AREOR) ML24128A1212024-05-0707 May 2024 Response to Braidwood and Dresden FOF Dates Change Request (2025) BYRON 2024-0022, 2023 Regulatory Commitment Change Summary Report2024-05-0202 May 2024 2023 Regulatory Commitment Change Summary Report ML24122A6522024-05-0101 May 2024 Submittal of 2023 Annual Radioactive Effluent Release Report RS-24-041, Alternative Request to Utilize Code Case OMN-32, Alternative Requirements for Range and Accuracy of Pressure, Flow, and Differential Pressure Instruments Used in Pump Tests2024-04-30030 April 2024 Alternative Request to Utilize Code Case OMN-32, Alternative Requirements for Range and Accuracy of Pressure, Flow, and Differential Pressure Instruments Used in Pump Tests IR 05000456/20243012024-04-29029 April 2024 NRC Initial License Examination Report 05000456/2024301; 05000457/2024301 ML24116A0052024-04-25025 April 2024 Transmittal of Braidwood Station, Unit 1, Core Operating Limits Report, Braidwood Unit 1 Cycle 25 ML24116A1192024-04-25025 April 2024 2023 Annual Radioactive Effluent Release Report (ARERR) RS-24-026, License Amendment to Braidwood Station, Units 1 and 2, and Byron Station, Units 1 and 2, Technical Specifications 5.6.5, Core Operating Limits Report (COLR)2024-04-25025 April 2024 License Amendment to Braidwood Station, Units 1 and 2, and Byron Station, Units 1 and 2, Technical Specifications 5.6.5, Core Operating Limits Report (COLR) IR 05000456/20240012024-04-24024 April 2024 Integrated Inspection Report 05000456/2024001 and 05000457/2024001 ML24113A1272024-04-22022 April 2024 Audit Plan in Support of Review of LAR Revision of TS 3.7.15, 3.7.16, and 4.3.1 (EPID: L-2023-LLA-0136) (Non-Proprietary) ML24113A2892024-04-22022 April 2024 Notification of NRC Baseline Inspection and Request for Information IR 05000457/20240902024-04-19019 April 2024 Final Significance Determination for 2b Auxiliary Feedwater Pump Diesel Engine Fuel Oil Dilution Issue - NRC Inspection Report 05000457/2024090 BYRON 2024-0020, Annual Dose Report for 20232024-04-18018 April 2024 Annual Dose Report for 2023 ML24103A2042024-04-12012 April 2024 Constellation Energy Generation, LLC, Application to Revise Technical Specifications to Adopt TSTF-591-A, Revise Risk Informed Completion Time (RICT) Program Revision 0 and Revise 10 CFR 50.69 License Condition 2024-09-06
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August 12, 2020 Mr. Bryan C. Hanson Senior Vice President Exelon Generation Company, LLC President and Chief Nuclear Officer (CNO)
Exelon Nuclear Braidwood and Byron Station 4300 Winfield Road Warrenville, IL 60555
SUBJECT:
BRAIDWOOD STATION, UNITS 1 AND 2 AND BYRON STATION, UNIT NOS. 1 AND 2 - RESOLUTION OF ISSUES PERTAINING TO BORIC ACID PRECIPITATION RELATED TO THE CLOSEOUT OF GENERIC LETTER, 2004-02, POTENTIAL IMPACT OF DEBRIS BLOCKAGE ON EMERGENCY RECIRCULATION DURING DESIGN BASIS ACCIDENTS AT PRESSURIZED-WATER REACTORS
Dear Mr. Hanson:
In letter dated May 19, 2016 Agencywide Documents Access and Management System (ADAMS) Accession No. ML15296A358), the U.S. Nuclear Regulatory Commission (NRC) documented that Braidwood Station, Units 1 and 2, (Braidwood), and Byron Station, Units 1 and 2, (Byron), had provided all information required to close Generic Letter (GL) 2004 02.
Documentation for closure of the in-vessel portion of GL 2004 02 was performed by demonstrating that Braidwood and Byron met the requirements of topical report (TR) WCAP 16793 NP A, Revision 2, and the associated NRC staff safety evaluation (SE) (ADAMS Accession No. ML13239A114). In its SE, the staff concluded that plants with relatively low fiber amounts reaching the core could use the TR methodology to show that core cooling would not be adversely affected by debris. However, the SE stated that the potential for debris to change flow patterns or inhibit the mixing of boric acid in the core that might result in earlier boric acid precipitation (BAP) had not been evaluated. This left the question of the effects of debris on the plant licensing basis for BAP open.
In its response to GL 2004 02, Braidwood and Byron demonstrated that they have a very small amount of fiber that may arrive at the core inlet. The NRC staff has determined that this amount of debris will not adversely affect BAP timing and Braidwood and Byron can maintain their current licensing basis. (See staff technical evaluation report (ADAMS Accession No. ML19178A252) and staff guidance (ADAMS Accession No. ML19228A011) for more information.) The staff has no further questions related to potential effects of post-accident debris on the reactor vessel.
If you have any questions, please contact me at 301-415-6606 or via e-mail at Joel.Wiebe@nrc.gov Sincerely,
/RA/
Joel S. Wiebe, Senior Project Manager Plant Licensing Branch III Division of Operating Reactor Licensing Office of Nuclear Reactor Regulation Docket Nos. STN 50-456 and STN 50-457 STN 50-454 and STN 50-455
Enclosure:
Staff Documentation of issues related to Generic Letter 2004-02 cc: Listserv
U.S. NUCLEAR REGULATORY COMMISSION STAFF DOCUMENTATION OF BORIC ACID PRECIPITATION CONCERNING GENERIC LETTER 2004-02, POTENTIAL IMPACT OF DEBRIS BLOCKAGE ON EMERGENCY RECIRCULATION DURING DESIGN BASIS ACCIDENTS AT PRESSURIZED-WATER REACTORS EXELON GENERATION COMPANY, LLC BRAIDWOOD STATION, UNITS 1 AND 2, AND BYRON STATION, UNIT NOS. 1 AND 2 DOCKET NOS. STN 50-456 AND STN 50-457; STN 50-454 AND STN 50-455 In September 2004, the U.S. Nuclear Regulatory Commission (NRC) issued Generic Letter 2004-02, Potential Impact of Debris Blockage on Emergency Recirculation During Design Basis Accidents at Pressurized-Water Reactors, (Agencywide Documents Access and Management System (ADAMS) Accession No. ML042360586) to holders of operating licenses for pressurized-water reactors. In Generic Letter (GL) 2004-02, the NRC staff requested that licensees perform an evaluation of their emergency core cooling system (ECCS) and containment spray system (CSS) recirculation functions, considering the potential for debris-laden coolant to be circulated by the ECCS and the CSS after a loss-of-coolant accident or high-energy line break inside containment, and, if appropriate, take additional action to ensure system function. GL 2004-02 required, per Title 10 of the Code of Federal Regulations (10 CFR) Section 50.54(f), that licensees provide the NRC a written response describing the results of their evaluation and any modifications made, or planned, to ensure ECCS and CSS system function during recirculation following a design-basis event, or any alternate action proposed and the basis for its acceptability.
In a letter dated May 19, 2016 (ADAMS Accession No. ML15296A358), the NRC documented that Braidwood Station, Units 1 and 2, (Braidwood), and Byron Station, Units 1 and 2, (Byron),
had provided all information required to close GL 2004-02. Documentation for closure of the in-vessel portion of GL 2004-02 was performed by demonstrating that Braidwood and Byron met the requirements of topical report (TR) WCAP-16793-NP-A, Revision 2, and the associated NRC staff safety evaluation (SE) (ADAMS Accession No. ML13239A114). In its SE, the NRC staff concluded that plants with relatively low fiber amounts reaching the core could use the TR methodology to show that core cooling would not be adversely affected by debris. However, the SE stated that the potential for debris to change flow patterns or inhibit the mixing of boric acid in the core that might result in earlier boric acid precipitation (BAP) had not been evaluated.
This left the question of the effects of debris on the plant licensing basis for BAP open.
Enclosure
The Pressurized Water Reactors Owners Group continued to evaluate the effects of larger amounts of debris on long-term core cooling. This work is documented in TR WCAP-17788, Revision 1 (ADAMS Package Accession No. ML20010F181). The NRC staff performed a thorough review of this TR but was unable to conclude that the methodology used for evaluating reactor core debris limits was acceptable for licensing basis calculations.
However, the NRC staff found that the TR methodology provided meaningful safety and regulatory insights regarding the treatment of BAP. The staffs technical review of the TR methodology is documented in its technical evaluation report (ADAMS Accession No. ML19178A252). WCAP-17788, Revision 1, evaluated the potential for debris to affect current BAP analyses and found that BAP timing would not be adversely affected. The NRC performed sensitivity studies during its review of WCAP-17788, Revision 1. These analyses explicitly modeled the physical phenomena that affect the potential for BAP and were conducted for reactor designs considered to be the most limiting with respect to BAP. The analyses found that debris collecting at the core inlet would not adversely affect BAP timing under conditions that conservatively modeled the effects of debris. The NRC staff determined that licensees that demonstrate that their plants fall within specific bounds can maintain their current licensing basis for BAP (Refer to Staff Guidance in ADAMS Accession No. ML19228A011), even with debris amounts greater than those approved in WCAP-16793-NP-A, Revision 2.
In its response to GL 2004-02, Braidwood and Byron demonstrated that they have a very small amount of fiber that may arrive at the core inlet. The NRC staff has determined that this amount of debris will not adversely affect BAP timing and Braidwood and Byron can maintain their current licensing basis for BAP. The staff has no further questions related to potential effects of post-accident debris on the reactor vessel.
ML20174A482 via e-mail OFFICE NRR/DORL/LPL3/PM* NRR/DORL/LPL3/LA* NRR/DSS/STSB/BC*
NAME JWiebe SRohrer VCusumano DATE 07/07/2020 06/23/2020 05/22/2020 OFFICE NRR/DORL/LPL3/BC* NRR/DORL/LPL3/PM*
NAME NSalgado JWiebe DATE 08/12/2020 08/12/2020