ML19168A159

June 20 Public Meeting Slides (Exelon)

ML19168A159
Person / Time
Site:	FitzPatrick
Issue date:	06/17/2019
From:	Exelon Generation Co
To:	Office of Nuclear Reactor Regulation
Parker C
References
Download: ML19168A159 (37)

Text

JAF BWR MSIV Leakage OptimizationNRC Pre-Submittal MeetingJune 20, 2019 AgendaIntroductionsMeeting ObjectivesProject Purpose / Background InformationScope of Technical Specification ChangesApproach of the LAR SubmittalDetailed Technical ReviewOverview of Licensing Schedule and Outage NeedsSummary and Wrap-up1 IntroductionsProject ManagerJohn MassariProject Technical LeadShane GardnerLicensing LeadChristian WilliamsSite Technical LeadKatherine Leaveck2 Meeting Objectives3Present information to NRC to enable a clear understanding of the overall project and proposed site-specific License Amendment Request (LAR) submittalTechnical Specification (TS) ChangesAnalysis ApproachFull Scope Alternative Source Term (AST) Scope AST LOCA Analysis DetailsObtain feedback from the NRC on the proposed LAR to ensure high quality submittal and minimize the need for future RAIsMutual understanding of the proposed schedule and corresponding outage need date in order to ensure adequate NRC resource availability Benchmark of U.S. Fleet4 Project Purpose / Background InformationOptimize AST LOCA analysis to increase MSIV local leak rate testing (LLRT) limitsReduce outage dose and increase safetyReduce number of reportable MSIV LLRT eventsReduce MSIV maintenance costsExtend effective MSIV service lifeConversion of partial AST licensing basis to full implementationExisting licensing basis has FHA analysis only approved for ASTRequesting approval to expand to full implementation-Based on LOCA analysis onlySupporting analyses and changes-Drawdown analysis-Standby Liquid Control evaluation and TS changes-Definition of Dose Equivalent Iodine change-SGT and CR filter efficiency TS changes-Appendix J exemption to separate MSIV leakage from La5 Approach of the LAR Submittal 6Evaluate the change impacts due to MSIV leakage rate change in accordance with Exelon configuration change process. Planned AST LOCA dose analysis requires prior NRC review:Existing RG 1.3 methodology replaced with RG 1.183 ASTProvide information directly in support of the proposed Technical Specification ChangesApproach to the full scope AST implementation technical evaluationAST LOCA analysis utilizing a revised core inventory for future implementation of an increased core average exposure (CAVEX)New drawdown analysisPost-LOCA pH analysis to address suppression pool pHEnvironmental Qualification evaluation for Standby Liquid Control (SLC) and deletion of Main Steam Leakage Collection (MSLC)New Control Room X/Q values for ground-level MSIV releasePlant parameter input changes: MSIV Leakage, filter efficiencies.

Detailed Technical Review: Overview of LOCA Dose Analysis7Current analysis based on RG 1.3Dose pathwaysCombined Containment & MSIV leakage (all leakage via stack)ESF leakage (all leakage via stack)Direct ShineProposed analysis based on RG 1.183 & RIS 2006-04Dose pathwaysContainment leakage (ground-level during drawdown, stack thereafter)ESF leakage (ground-level during drawdown, stack thereafter)MSIV leakage (ground-level)Direct ShineNotable plant input changesMSIV leak rate increaseSGT and CR filter efficiency increasedMore conservative core radionuclide inventory for future implementation Detailed Technical Review: MSL Aerosol Deposition8Uses 20-group model previously approved at Clinton (ML052570461), Limerick (ML062210214), and LaSalle (ML101750625)Model is based on AEB 98-03 using JAF-specific inputs, which is acceptable per RIS 2006-04. Assumptions and justifications for applicability to the revised analysis provided in accordance with RIS 2006-04The settling velocity is a randomly sampled range of the three (3) critical aerosol parameters, density/weight (logarithmically distributed), diameter/size (uniformly distributed), and shape (uniformly distributed); and three (3) constants; gravitational acceleration, Cunningham slip factor, and viscosity.A distribution of removal factors are calculated using the typical AEB 98-03 formulations and are combined statistically to determine a net removal fraction. This accounts for a range of aerosol particle parameters and also accounts for change in the aerosol characteristics as the particles transport through the MSL Detailed Technical Review: MSL Aerosol Deposition Cont.90.00%10.00%20.00%30.00%40.00%50.00%60.00%70.00%80.00%90.00%100.00%0.00E+005.00E-041.00E-031.50E-032.00E-032.50E-033.00E-033.50E-034.00E-03Cumulative Probability Settling Velocity (m/s)(NMP2 Example)1st Node2nd NodeExitParticles are shifting from larger/heavier to smaller/lighter Detailed Technical Review: Other Analyses & Changes10Drawdown AnalysisRequired for TSTF-551 & RG 1.183 Appendix AGOTHIC based analysis; 4 external environment cases for conservatismFollows Quad Cities LAR as precedentResult: 20 minute drawdown time in dose modelPost-LOCA pH AnalysisMethodology is based on NUREG/CR-5950Maximum injection duration of SLC buffer (< 1 hour1.157407e-5 days <br />2.777778e-4 hours <br />1.653439e-6 weeks <br />3.805e-7 months <br />) before 71 hour8.217593e-4 days <br />0.0197 hours <br />1.173942e-4 weeks <br />2.70155e-5 months <br />sResult: Minimum pH: 8.1 at 30 daysSLC Evaluation12, 2004, (ADAMS Accession No. ML040640364)All requirements met, including 50.49 Environmental QualificationAn attachment detailing this evaluation will be provided in the LARSGT and CR Filter Efficiency ChangesTS change to lower charcoal penetration to 1.5%Filter efficiencies credited in AST dose analysis increased Detailed Technical Review: Other Analyses & Changes11Leakage Collection System Removal EQ EvaluationChange results in a post-LOCA source term in the TB LOCA dose in the TB not previously evaluatedAnalysis is performed to determine radiological environment using TID MethodologyEQ Evaluation is performed to evaluate SR equipment for inclusionEQ documentation will be updated to reflect the new evaluation and disposition of equipment Overview of Licensing Schedule and Outage NeedsPlantLAR SubmittalNRC ApprovalFirst OpportunityFitzpatrickJune 2019July 2020September 202012Goal is to implement at first outage opportunitySubmit LAR according to schedule outlined belowRequest NRC review and approval in 12 months Summary and Wrap-upSummaryNRC approval of full scope AST and the increased MSIV leakage limits will:Reduce outage dose and increase safetyReduce number of reportable MSIV LLRT eventsReduce MSIV maintenance costsExtend effective MSIV service lifeA revised AST LOCA dose analysis is planned that supports increased MSIV leakage while maintaining margin by:Beneficially optimizing Control Room dose while retaining substantial margin to the limitsAdjusting inputs and elements of the method to provide additional margin in some cases and extract margins in other casesAggregate effect of all revisions maintains reasonable conservatismRecap of Actions13 Fitzpatrick Full Scope ASTDISCUSSION14 Fitzpatrick Full Scope ASTBackup Slides15 Scope of Technical Specification Changes16100200Preliminary MSIV leakage rate Scope of Technical Specification Changes Continued17Exemption to Appendix J to remove MSIV leakage from La requirement.

Scope of Technical Specification Changes Continued18Deletion of Main Steam Leakage Collection System. No longer credited in safety analysis.

Scope of Technical Specification Changes Continued19Ventilation Filter Testing Program penetration requirement reduction Scope of Technical Specification Changes Continued20Standby Liquid Control System mode requirements Scope of Technical Specification Changes Continued21TSTF-551 associated modifications Scope of Technical Specification Changes Continued22Dose Equivalent I-131 definition update for AST Detailed Technical Review: Overview of Revised Core Inventory23Revised core radionuclide inventoryIncreases the range of Core AVerageEXposure(CAVEX) and enrichment previously evaluatedProvides margin for future optimization of core designUtilizes ORIGEN-ARP in accordance with RG 1.183 Section 3.1 Detailed Technical Review: Overview of MSIV Model24 Detailed Technical Review: Comparison of LOCA AST Analysis25(Preliminary)

Detailed Technical Review: Comparison of LOCA AST Analysis26 Detailed Technical Review: Comparison of LOCA AST Analysis27 Detailed Technical Review: Drawdown Analysis28Required to fully implement TSTF-GOTHIC v8.2 analysis to determine time that Secondary Containment is positive with respect to ambient pressureRG 1.183 requirements that lead to the four cases evaluated (summer, no wind; summer, with wind; winter, no wind; winter, with wind)Evaluate high wind impact on ability to maintain negative pressureConservative ambient temperature assumption Conservative assumptions for heat transfer, initial temperatures, heat loads, etc. within the GOTHIC modelAssume ground-level release anytime Secondary Containment does not meet TS defined criteria for negative pressure20 minute drawdown time used in dose analysis Detailed Technical Review: Drawdown Analysis29 Detailed Technical Review: Post-LOCA Suppression Pool pH30Methodology is based on NUREG/CR-5950Acids: Hydriodic, Carbonic, Nitric, Hydrochloric (cable jacket), Boric (from Sodium Pentaborate)Bases: Cesium Hydroxide (fuel), Sodium Pentaborate(SLC buffer)Fuel inputs include increased CAVEXCalculate buffered and unbuffered pH responseMaximum injection duration of SLC buffer ( < 1 hour1.157407e-5 days <br />2.777778e-4 hours <br />1.653439e-6 weeks <br />3.805e-7 months <br />)Maximum time to inject 71 hour8.217593e-4 days <br />0.0197 hours <br />1.173942e-4 weeks <br />2.70155e-5 months <br />sValidate pH remains > 7Minimum pH: 8.1 at 30 daysNotable AssumptionsNitric acid production rate conservatively assumed at 86 deg. F rather than high TMinimum suppression pool water volume; no credit for additions100 gal of buffer solution held up in SLC piping for conservatism Detailed Technical Review: Post-LOCA Suppression Pool pH31 Detailed Technical Review: SLC Design Evaluation32System Capability Evaluated12, 2004, (ADAMS Accession No. ML040640364)All requirements met, without issue50.49 Environmental QualificationBounding SLC radiation environment establishedEquipment evaluated against EQ service environmentsProcedure to ensure SLC injection evaluated and are acceptable or will be updated accordingly as part of the engineering changeAn attachment detailing this evaluation will be provided in the LAR Detailed Technical Review: Filter Efficiency Changes33Proposed change to Technical Specification 5.5.8 to reduce filter penetration testingThis is supported based on review of filter capability and past testingCharcoal penetration changed from 5% to 1.5% (charcoal).AST LOCA dose analysis credits a higher filter efficiencyGeneric Letter (GL) 99-02 safety factor of 2 includedNew charcoal filter efficiency of 97% is determinedNew HEPA filter efficiency of 98% is determinedFilter efficiency changes applied to SGT and CR models LOCA AST RADTRAD Models34 LOCA AST RADTRAD Models35 LOCA AST RADTRAD Models36