Letter Sequence Request |
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TAC:MC4570, Revise Containment Requirements During Handling Irradiated Fuel and Core Alterations (Approved, Closed) |
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Category:Letter type:GO
MONTHYEARGO2-24-004, License Amendment Request to Revise Emergency Plan2024-01-30030 January 2024 License Amendment Request to Revise Emergency Plan GO2-24-003, Relief Requests for the Columbia Generating Station Fifth Ten-Year Interval Inservice Testing2024-01-29029 January 2024 Relief Requests for the Columbia Generating Station Fifth Ten-Year Interval Inservice Testing GO2-24-005, Docket No. 50-397 Supplement to Reply to a Notice of Violation; EA-21-1702024-01-0808 January 2024 Docket No. 50-397 Supplement to Reply to a Notice of Violation; EA-21-170 GO2-23-136, Guarantee of Payment of Deferred Premium2023-12-20020 December 2023 Guarantee of Payment of Deferred Premium GO2-23-135, Notice of Readiness for Supplemental Inspection2023-12-14014 December 2023 Notice of Readiness for Supplemental Inspection GO2-23-130, Reply to a Notice of Violation; EA-23-0542023-12-14014 December 2023 Reply to a Notice of Violation; EA-23-054 GO2-23-105, Licensing Basis Document Update and Biennial Commitment Change Report2023-12-12012 December 2023 Licensing Basis Document Update and Biennial Commitment Change Report GO2-23-107, Application to Revise Technical Specifications to Adopt TSTS-584, Eliminate Automatic RWCU System Isolation on SLC Initiation2023-12-0505 December 2023 Application to Revise Technical Specifications to Adopt TSTS-584, Eliminate Automatic RWCU System Isolation on SLC Initiation GO2-23-126, Docket No. 50-397 Voluntary Response to Regulatory Issue Summary 2023-012023-11-28028 November 2023 Docket No. 50-397 Voluntary Response to Regulatory Issue Summary 2023-01 GO2-23-121, Request for Exemption from Enhanced Weapons, Firearms Background Checks, and Security Event Notifications Implementation2023-11-27027 November 2023 Request for Exemption from Enhanced Weapons, Firearms Background Checks, and Security Event Notifications Implementation GO2-23-097, In-Service Inspection Summary Report for the Twenty-Sixth Refueling Outage (R26)2023-09-0606 September 2023 In-Service Inspection Summary Report for the Twenty-Sixth Refueling Outage (R26) GO2-23-100, Technical Specification Section 5.6.4 Post Accident Monitoring Instrumentation 14-Day Report for Inoperable Suppression Pool Level Indication2023-08-31031 August 2023 Technical Specification Section 5.6.4 Post Accident Monitoring Instrumentation 14-Day Report for Inoperable Suppression Pool Level Indication GO2-23-056, Application to Revise Technical Specifications to Adopt TSTF-230, Add New Condition B to LCO 3.6.2.3, RHR Suppression Pool Cooling2023-08-29029 August 2023 Application to Revise Technical Specifications to Adopt TSTF-230, Add New Condition B to LCO 3.6.2.3, RHR Suppression Pool Cooling GO2-23-093, Supplement to Reply to a Notice of Violation: EA-21-1702023-07-27027 July 2023 Supplement to Reply to a Notice of Violation: EA-21-170 GO2-23-068, Notification of Completion of Commitments Required Prior to Entry Into the Period of Extended Operation2023-07-19019 July 2023 Notification of Completion of Commitments Required Prior to Entry Into the Period of Extended Operation GO2-23-090, Reply to a Notice of Violation2023-07-12012 July 2023 Reply to a Notice of Violation GO2-23-073, Notification of NPDES Permit Issuance2023-06-26026 June 2023 Notification of NPDES Permit Issuance GO2-23-072, Cycle 27 Core Operating Limits Report2023-06-0505 June 2023 Cycle 27 Core Operating Limits Report GO2-23-055, Independent Spent Fuel Storage Installation, 2022 Annual Radiological Environmental Operating Report2023-05-15015 May 2023 Independent Spent Fuel Storage Installation, 2022 Annual Radiological Environmental Operating Report GO2-23-006, License Amendment Request to Clean-Up Operating License and Appendix a Technical Specifications2023-05-0101 May 2023 License Amendment Request to Clean-Up Operating License and Appendix a Technical Specifications GO2-23-053, 2022 Annual Environmental Operating Report2023-04-26026 April 2023 2022 Annual Environmental Operating Report GO2-23-057, 2022 Annual Radioactive Effluent Release Report2023-04-25025 April 2023 2022 Annual Radioactive Effluent Release Report GO2-23-012, Application to Revise Technical Specifications to Adopt Tstf-541, Add Exceptions to Surveillance Requirements for Valves and Dampers Locked in the Actuated Position2023-03-27027 March 2023 Application to Revise Technical Specifications to Adopt Tstf-541, Add Exceptions to Surveillance Requirements for Valves and Dampers Locked in the Actuated Position GO2-23-041, Generation Station - Level of Financial Protection - Annual Reporting Requirement2023-03-15015 March 2023 Generation Station - Level of Financial Protection - Annual Reporting Requirement GO2-23-038, Plant Decommissioning Fund Status Report2023-03-15015 March 2023 Plant Decommissioning Fund Status Report GO2-23-034, Report of Changes or Errors in Emergency Core Cooling System Loss of Coolant Accident Analysis Models Pursuant to 10 CFR 50.462023-03-13013 March 2023 Report of Changes or Errors in Emergency Core Cooling System Loss of Coolant Accident Analysis Models Pursuant to 10 CFR 50.46 GO2-23-035, Supplement to License Amendment Request to Adopt TSTF-580, Provide Exception from Entering Mode 4 with No Operable RHR Shutdown Cooling2023-03-0909 March 2023 Supplement to License Amendment Request to Adopt TSTF-580, Provide Exception from Entering Mode 4 with No Operable RHR Shutdown Cooling GO2-23-019, Emergency Plan - Summary of Changes and Analysis for Revision 68 of the EP-012023-02-0808 February 2023 Emergency Plan - Summary of Changes and Analysis for Revision 68 of the EP-01 GO2-22-131, Guarantee of Payment of Deferred Premium2022-12-19019 December 2022 Guarantee of Payment of Deferred Premium GO2-22-122, Response to Request for Additional Information Related to License Amendment Request to Adopt TSTF-505, Revision 2, Provide Risk-Informed Extended Completion Times - RITSTF Initiative 4b2022-11-28028 November 2022 Response to Request for Additional Information Related to License Amendment Request to Adopt TSTF-505, Revision 2, Provide Risk-Informed Extended Completion Times - RITSTF Initiative 4b GO2-22-076, Status of License Renewal Commitments2022-10-31031 October 2022 Status of License Renewal Commitments GO2-22-110, Supplement to License Amendment Request to Adopt 10 CFR 50.69, Risk-Informed Categorization and Treatment of Structures, Systems and Components for Nuclear Power Reactor2022-10-17017 October 2022 Supplement to License Amendment Request to Adopt 10 CFR 50.69, Risk-Informed Categorization and Treatment of Structures, Systems and Components for Nuclear Power Reactor GO2-22-096, Supplement to License Amendment Request to Adopt TSTF-505, Revision 2, Provide Risk-Informed Extended Completion Times - RITSTF Initiative 4b2022-10-0404 October 2022 Supplement to License Amendment Request to Adopt TSTF-505, Revision 2, Provide Risk-Informed Extended Completion Times - RITSTF Initiative 4b GO2-22-085, Docket No. 50-397, Evacuation Time Estimate Analysis2022-08-30030 August 2022 Docket No. 50-397, Evacuation Time Estimate Analysis GO2-22-075, Response to Request for Additional Information Related to Revised Pressure-Temperature Limit Curves2022-07-11011 July 2022 Response to Request for Additional Information Related to Revised Pressure-Temperature Limit Curves GO2-22-072, Summary of Changes and Analysis for Revision 57 of PPM 13.14.4 - Emergency Equipment Maintenance and Testing2022-07-11011 July 2022 Summary of Changes and Analysis for Revision 57 of PPM 13.14.4 - Emergency Equipment Maintenance and Testing GO2-22-042, Application to Revise Technical Specifications to Adopt TSTF-580, Provide Exception from Entering Mode 4 with No Operable RHR Shutdown Colling Using the Consolidated Line Item Improvement Process2022-05-25025 May 2022 Application to Revise Technical Specifications to Adopt TSTF-580, Provide Exception from Entering Mode 4 with No Operable RHR Shutdown Colling Using the Consolidated Line Item Improvement Process GO2-22-062, Registration of Spent Fuel Cask Use2022-05-19019 May 2022 Registration of Spent Fuel Cask Use GO2-22-049, Supplement to Licensing Amendment Request to Adopt 10CFR50.69, Risk-Informed Categorization and Treatment of Structures, Systems and Components for Nuclear Power Rectors2022-05-10010 May 2022 Supplement to Licensing Amendment Request to Adopt 10CFR50.69, Risk-Informed Categorization and Treatment of Structures, Systems and Components for Nuclear Power Rectors GO2-22-054, Independent Spent Fuel Storage Installation, 2021 Annual Radiological Environmental Operating Report2022-05-0909 May 2022 Independent Spent Fuel Storage Installation, 2021 Annual Radiological Environmental Operating Report GO2-22-056, Registration of Spent Fuel Cask Use2022-04-21021 April 2022 Registration of Spent Fuel Cask Use GO2-22-055, 2021 Annual Environmental Operating Report2022-04-20020 April 2022 2021 Annual Environmental Operating Report GO2-22-048, 2021 Annual Radioactive Effluent Release Report2022-04-15015 April 2022 2021 Annual Radioactive Effluent Release Report GO2-22-045, Registration of Spent Fuel Cask Use2022-04-0606 April 2022 Registration of Spent Fuel Cask Use GO2-22-044, Level of Financial Protection - Annual Reporting Requirement2022-03-21021 March 2022 Level of Financial Protection - Annual Reporting Requirement GO2-22-038, Docket No. 50-397, Report of Changes or Errors in Emergency Core Cooling System Loss of Coolant Accident Analysis Models Pursuant to 10 CFR 50.462022-03-0909 March 2022 Docket No. 50-397, Report of Changes or Errors in Emergency Core Cooling System Loss of Coolant Accident Analysis Models Pursuant to 10 CFR 50.46 GO2-22-031, Response to Audit Plan and Online Reference Portal Request2022-02-15015 February 2022 Response to Audit Plan and Online Reference Portal Request GO2-22-011, Docket No. 72-35; Independent Spent Fuel Storage Installation, 2021 Annual Effluent Release Report2022-02-0808 February 2022 Docket No. 72-35; Independent Spent Fuel Storage Installation, 2021 Annual Effluent Release Report GO2-22-001, License Amendment Request to Adopt TSTF-505, Revision 2, Provide Risk-Informed Extended Completion Times - RITSTF Initiative 4b2022-02-0303 February 2022 License Amendment Request to Adopt TSTF-505, Revision 2, Provide Risk-Informed Extended Completion Times - RITSTF Initiative 4b GO2-22-012, Independent Spent Fuel Storage Installation - Biennial 50.59/72.48 Report2022-01-24024 January 2022 Independent Spent Fuel Storage Installation - Biennial 50.59/72.48 Report 2024-01-08
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ENERGY William G. Hettel Columbia Generating Station P.O. Box 968, PE23 NORTHWEST Richland, WA 99352-0968 Ph. 509-377-8311 IF. 509-377-4150 wghettel@energy-northwest.com January 31, 2018 G02-18-005 U.S. Nuclear Regulatory Commission ATTN: Document Control Desk Washington, D.C. 20555-0001
Subject:
COLUMBIA GENERATING STATION, DOCKET NO. 50-397 REQUEST FOR CLARIFICATION OF AST SER
Reference:
Letter from 8. J. Benney (NRG) to J. V. Parrish (Energy Northwest),
"Columbia Generating Station - Issuance of Amendment RE: Alternative Source Term (TAC No. MC4570)", dated November 27, 2006
Dear Sir or Madam:
As discussed during a telephone call on August 15, 2017, Energy Northwest would like to request a clarification to Columbia Generating Station's Alternate Source Term Safety Evaluation Report. During a 2016 inspection, two issues were brought up concerning the verbiage in the evaluation and how the actions are implemented at Columbia Generating Station.
There are no commitments being made to the Nuclear Regulatory Commission herein. If you have any questions, or require additional information, please contact Ms. D. M.
Wolfgramm, Regulatory Compliance Supervisor, at (509) 377-4792.
Executed on this ~\~ day of January, 2018 Respectfully, rJ~~
W. G. Hettel Vice President, Operations
Enclosure:
Columbia Generating Station Safety Evaluation Clarification Request cc: NRC Region IV Administrator CD Sonoda - BPA/1399 NRG NRR Project Manager WA Horin - Winston & Strawn NRG Senior Resident lnspector/988C
GO2-18-005 Enclosure Page 1 of 3 Columbia Generating Station Safety Evaluation Clarification Request During the 2016 Component Design Basis Inspection, wording in a safety evaluation received by the station in 2006 in response to the Alternate Source Term License Amendment Request was questioned, as wording used in the evaluation could be interpreted differently than intended. Specifically, language regarding activation of the Standby Liquid Control (SLC) System for buffering suppression pool pH, and continuous spray versus intermittent spray for aerosol removal was heavily discussed.
Activation of SLC During an Event Amendment No. 199 to Columbias Facility Operating License replaced the accident source term used in design basis radiological analyses with an alternative source term.
Specific to this license amendment was a change to support the use of the SLC System for buffering suppression pool pH, as outlined on page 3 of Reference 1. The design basis source term loss of coolant accident (LOCA) requires the addition of sodium pentaborate solution post-accident to maintain the suppression pool pH equal to, or greater than, 7.0, which will minimize the re-evolution of gaseous iodine.
Based on Energy Northwests submittal, the NRC staff documented their conclusions in Reference 2, which was revised via Reference 3 due to errors. One error, which was not corrected at the time, is located in Item 6 under Section 4.3, which states, Emergency Operating Procedures (EOPs) direct the activation of SLC following a LOCA when reactor water level cannot be maintained above the top of active fuel.
Manual initiation of SLC is also directed in the severe accident management guidelines (SAMGs), which are entered when adequate core cooling cannot be maintained.
This statement could be interpreted to mean that the SLC system will always be activated during the use of the EOPs whenever reactor water level cannot be maintained above the top of active fuel; however, Subsection (b) on page 72 of Reference 1 provides detail that activation of SLC may not occur until the SAMGs are entered.
During a recent NRC inspection, the verbiage in Item 6 of Section 4.3 of Reference 2 was challenged when Energy Northwest could not demonstrate that EOPs would direct activation of SLC in every instance that the reactor water level could not be maintained above the top of active fuel. Activation of SLC while in EOPs is not required for every scenario; therefore, Energy Northwest is requesting clarification of Amendment No. 199 to remove reference to the EOP directing activation of SLC.
Energy Northwest proposes the following clarification of the safety evaluation:
Emergency Operating Procedures (EOPs) allow activation of SLC following a LOCA as an alternate injection source for reactor water inventory control. Manual initiation of SLC is directed in the severe accident management guidelines (SAMGs), which are entered when adequate core cooling cannot be maintained.
GO2-18-005 Enclosure Page 2 of 3 Containment Spray: Continuous vs Intermittent Page 5 of Reference 2 specifies that, EN assumes that a portion of the fission products released from the reactor pressure vessel will be removed by drywell sprays. The sprays are assumed to be initiated at 15 minutes and turned off after 1 day.
Although the term continuous is not explicitly stated in the amendment, a recent NRC inspection demonstrated that the potential exists for misinterpretation of the use of drywell spray for aerosol removal (scrubbing). Reference 2 does not specify continuous spray versus intermittent spray; however, page 23 of Reference 2 affirms the statements of the LOCA analysis submitted for approval with Alternative Source Term.
The EOPs and SAMGs operate the plant in a more conservative manner than the analytical assumption because shorter, intermittent spray duration results in lower LOCA dose consequences due to the bounding assumptions of the LOCA analysis.
Assuming worst case, design basis conditions, the drywell sprays are able to reduce the peak LOCA pressure to less than 5 psig within 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br />. This allows credit for a 50%
reduction in containment leakage after 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br />. The EOPs/SAMGs utilize the sprays to reduce pressure to a conservative 0 - 2 psig. Actual spray performance and peak pressure are expected to be better than design basis; therefore, the EOP/SAMG is written to allow Operators to secure drywell sprays based upon containment pressure, which may be prior to 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br />.
Page 36 of Attachment 1 of Reference 1 shows that the LOCA analysis credits the drywell sprays for aerosol removal (scrubbing). Using a conservative spray removal rate, 98% of the aerosol activity is removed within a time period of 2 hours2.314815e-5 days <br />5.555556e-4 hours <br />3.306878e-6 weeks <br />7.61e-7 months <br />, 11 minutes (15 minutes to 2.44 hours5.092593e-4 days <br />0.0122 hours <br />7.275132e-5 weeks <br />1.6742e-5 months <br /> after the event). The removal rate then drops by a factor of 10 for the remainder of the 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br />. Securing the drywell sprays prior to 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> does not impact the aerosol removal rates assumed in the LOCA analysis.
A separate aerosol removal sensitivity analysis considered the effect of securing drywell sprays during the 24 hour2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> period. The resulting spray removal rates were better than those using the bounding aerosol removal model of the LOCA analysis. The aerosol removal sensitivity analysis was submitted under Enclosure 3 of Reference 4, in response to Items 6.e, 6.h, and 9 of Reference 5.
The EOP/SAMG direction to secure drywell sprays based upon containment pressure is consistent with, and bounded by the design basis LOCA analysis and its assumption regarding drywell sprays. Therefore, Energy Northwest is requesting a revision to the Amendment No. 199 safety evaluation to clearly state that intermittent drywell spray is utilized within the first 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> after an event.
GO2-18-005 Enclosure Page 3 of 3 Energy Northwest proposes the following clarification of the safety evaluation:
EN assumes that a portion of the fission products released from the reactor pressure vessel will be removed by drywell sprays. Fission product removal by drywell sprays is credited from 15 minutes through 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> based upon the approved methodology. The sprays are operated as directed by the EOP/SAMG procedures.
References
- 1. Letter from D. K. Atkinson (Energy Northwest) to NRC, Columbia Generating Station, Docket No. 50-397, License Amendment Request - Alternative Source Term, dated September 30, 2004
- 2. Letter from B. J. Benney (NRC) to J. V. Parrish (Energy Northwest), Columbia Generating Station - Issuance of Amendment RE: Alternative Source Term (TAC No. MC4570), dated November 27, 2006
- 3. Letter from C. F. Lyon (NRC) to J. V. Parrish (Energy Northwest), Columbia Generating Station - Correction to Safety Evaluation for Amendment No. 199, Alternative Source Term (TAC NO. MC4570), dated March 27, 2007
- 4. Letter from W. S. Oxenford (Energy Northwest) to NRC, Columbia Generating Station, Docket No. 50-397, Response to Request for Additional Information Related to Alternative Source Term License Amendment Request, dated March 21, 2006
- 5. Letter from B. J. Benney (NRC) to J. V. Parrish (Energy Northwest), Columbia Generating Station - Request for Additional Information (TAC No. MC4570),
dated February 9, 2006