ML12236A332

Comanche Peak Nuclear Power Plant, Units 1 and 2 - Non-proprietary - Presentation for September 13, 2012, Proposed License Amendment Request for Spend Fuel Pool Criticality Analysis (TAC ME8896 and ME8897)

ML12236A332
Person / Time
Site:	Comanche Peak
Issue date:	08/23/2012
From:	Westinghouse
To:	Plant Licensing Branch IV
Singal B K
References
TAC ME8896, TAC ME8897
Download: ML12236A332 (61)

Text

1 © 2012 Westinghouse Electric Company LLC. All Rights Reserved. Westinghouse Non-Proprietary Class 3 SFP Criticality Methodology for Comanche Peak Westinghouse Electric Company September 13th, 2012 Non-Proprietary attachment to CE-12-656 2 © 2012 Westinghouse Electric Company LLC. All Rights Reserved. Westinghouse Non-Proprietary Class 3 Contents Objectives of the Comanche Peak Nuclear Power Plant (CPNPP) SFP Analysis Methods to be used in the Analysis -Plant Changes from Current AOR -Depletion Calculation Inputs -Biases & Uncertainties -Accidents & Soluble Boron -Interface Conditions 3 © 2012 Westinghouse Electric Company LLC. All Rights Reserved. Westinghouse Non-Proprietary Class 3 Objectives for the Comanche Peak Analysis To provide the NRC with an analysis with appropriate conservatism to meet current NRC expectations while providing as much operational flexibility as possible to CPNPP. -NRC concerns conveyed via the Interim Staff Guidance, and any information notices -ISG suggestions are addressed in each individual section 4 © 2012 Westinghouse Electric Company LLC. All Rights Reserved. Westinghouse Non-Proprietary Class 3 Methodology for CPNPP Analysis The CPNPP analysis will follow the guidance provided in WCAP-17483-P Deviations from WCAP-17483-P guidance will be called out in the site-specific application submitted by CPNPP 5 © 2012 Westinghouse Electric Company LLC. All Rights Reserved. Westinghouse Non-Proprietary Class 3 Plant Changes from Current AOR The following plant changes may be made which are being incorporated into the new criticality AOR -Power: Increase from 3577 MWth to 3612 MWth -Fuel Type: [ ]a,c -Extension of soluble boron credit to all configurations -Peak Assembly Average Power: 1.0 to [ ]a,c -Cycle Ave. Boron Conc.: 1500 ppm to 900 ppm -Configurations: Increase from 5 to a maximum of 8 6 © 2012 Westinghouse Electric Company LLC. All Rights Reserved. Westinghouse Non-Proprietary Class 3 Depletion Calculation Inputs Depletion parameters will impact the isotopic inventory of depleted fuel Major depletion inputs include: -Fuel Type; -Axial burnup and moderator temperature profiles; -Core Power (linked to fuel temperature in PARAGON) -Soluble boron concentration; and -Usage of burnable absorbers/consideration of rodded operation 7 © 2012 Westinghouse Electric Company LLC. All Rights Reserved. Westinghouse Non-Proprietary Class 3 Fuel Type Input CPNPP has gone through several fuel design changes that are significant in terms of criticality safety [ ]a,c 8 © 2012 Westinghouse Electric Company LLC. All Rights Reserved. Westinghouse Non-Proprietary Class 3 Fuel Type Input (cont) [ ]a,c 9 © 2012 Westinghouse Electric Company LLC. All Rights Reserved. Westinghouse Non-Proprietary Class 3 Axial Burnup and Temperature Profiles [ ]a,c 10 © 2012 Westinghouse Electric Company LLC. All Rights Reserved. Westinghouse Non-Proprietary Class 3 Limiting Burnup Profile Selection [ ]a,c 11 © 2012 Westinghouse Electric Company LLC. All Rights Reserved. Westinghouse Non-Proprietary Class 3 Temperature Profile Selection Temperature profiles are based on assembly power distributions [ ]a,c 12 © 2012 Westinghouse Electric Company LLC. All Rights Reserved. Westinghouse Non-Proprietary Class 3 Burnable Absorber Assumptions CPNPP has used: -Pyrex and other Solid discrete B4C based absorbers; -WABA; -IFBA/WABA; and -IFBA [ ]a,c 13 © 2012 Westinghouse Electric Company LLC. All Rights Reserved. Westinghouse Non-Proprietary Class 3 ISG comments on Depletion ISG items 2b, 2c, 2d and 3a relate to depletion parameters. -2b- selection of depletion parameters -2c- selection of burnable absorber modeling -2d- rodded depletion -3a- axial burnup profile 14 © 2012 Westinghouse Electric Company LLC. All Rights Reserved. Westinghouse Non-Proprietary Class 3 ISG Section 2b The ISG states that nominal values may not be appropriate and requests discussion of the values selected -The ISG acknowledges that some parameters cannot physically be maximized in tandem -[ ]a,c 15 © 2012 Westinghouse Electric Company LLC. All Rights Reserved. Westinghouse Non-Proprietary Class 3 ISG Section 2c & 2d Section 2c states that burnable absorber usage should be considered -The analysis conservatively accounts for burnable absorber usage ISG Section 2d indicates that rodded depletion should be considered -There is no sustained rod insertion during full power operation at CPNPP [ ]a,c 16 © 2012 Westinghouse Electric Company LLC. All Rights Reserved. Westinghouse Non-Proprietary Class 3 ISG Section 3a ISG Section 3a discusses selection of a limiting axial burnup profile, including justification of using either NUREG-6801 based or plant specific profiles -[ ]a,c An axially uniform profile will be considered and used at those burnups where it is limiting 17 © 2012 Westinghouse Electric Company LLC. All Rights Reserved. Westinghouse Non-Proprietary Class 3 Biases and Uncertainties Biases and Uncertainties are included in the analysis to ensure that normal variances and real deviations from analysis conditions are accounted for. The analysis will account for: -[ ]a,c 18 © 2012 Westinghouse Electric Company LLC. All Rights Reserved. Westinghouse Non-Proprietary Class 3 ISG Comments on Biases & Uncertainties ISG Sections 2a, 3b and 4 relate to biases and uncertainties -Section 2a- Depletion Uncertainty -Section 3b- Rack Models -Section 4- Code Validation 19 © 2012 Westinghouse Electric Company LLC. All Rights Reserved. Westinghouse Non-Proprietary Class 3 ISG Section 2a ISG Section 2a discusses the use of the 5% decrement method as a depletion uncertainty and what the NRC believes the uncertainty is meant to represent -The analysis will utilize the EPRI depletion uncertainty methodology to either develop an appropriate depletion uncertainty or support the 5% depletion uncertainty -[ ]a,c 20 © 2012 Westinghouse Electric Company LLC. All Rights Reserved. Westinghouse Non-Proprietary Class 3 ISG Section 2a (cont) EPRI Methodology will be used to justify the depletion uncertainty used in CPNPP analysis -[ ]a,c 21 © 2012 Westinghouse Electric Company LLC. All Rights Reserved. Westinghouse Non-Proprietary Class 3 ISG Section 3b ISG Section 3b discusses the modeling of SFP Racks including geometry and neutron absorbers -[ ]a,c -CPNPP credits BORAL in the Region 1 racks, the Region 1 racks were described previously -[ ]a,c -CPNPP credits no fixed neutron absorbers in the Region 2 SFP racks and is not impacted by the neutron absorber efficiency issue

22 © 2012 Westinghouse Electric Company LLC. All Rights Reserved. Westinghouse Non-Proprietary Class 3 ISG Section 4 ISG Section 4 discusses the validation of codes used in SFP criticality analyses -The analysis incorporates a code validation suite which addresses the concerns brought up in Section 4 of the ISG -[ ]a,c 23 © 2012 Westinghouse Electric Company LLC. All Rights Reserved. Westinghouse Non-Proprietary Class 3 Accident Conditions & Soluble Boron [ ]a,c 24 © 2012 Westinghouse Electric Company LLC. All Rights Reserved. Westinghouse Non-Proprietary Class 3 ISG Comments on Accidents & Soluble Boron Credit The ISG requests that all 'normal' operation be considered to determine the limiting precursor to an accident -This analysis will consider normal operation scenarios 25 © 2012 Westinghouse Electric Company LLC. All Rights Reserved. Westinghouse Non-Proprietary Class 3 Interface Conditions Interface conditions exist at the boundaries of fuel configurations, SFP regions, and rack modules -[ ]a,c 26 © 2012 Westinghouse Electric Company LLC. All Rights Reserved. Westinghouse Non-Proprietary Class 3 ISG Comments on Interfaces The ISG comments that the maximum set of biases and uncertainties from the configurations making up the interface needs to be used -[ ]a,c 27 © 2012 Westinghouse Electric Company LLC. All Rights Reserved. Westinghouse Non-Proprietary Class 3 Questions?

Spent Fuel Pool CriticalityLicenseAmendmentRequestLicense Amendment RequestPre-SubmittalMeetingPre-Submittal MeetingStb132012September 13, 2012 SFP Meeting Agenda*Introductions*Purpose*CPNPP Spent Fuel Pool Criticality Background and Status*CPNPP Fuel Assembly Configuration Control POiProgram Overview*Westinghouse Analysis Introduction**Meeting Summary and Conclusion* Will contain proprietary information1 IntroductionsLuminant Power CompanyDave GoodwinDirector, Projects EngineeringFred MaddenDirector, Oversight and Regulatory AffairsTim HopeManager, Nuclear LicensingJiSihtCltiEiRltAffiJimmy SeawrightConsulting Engineer -Regulatory AffairsMatt WeeksManager, Core Performance EngineeringCodyLemonsCorePerformanceEngineerCody LemonsCore Performance Engineer2 IntroductionsWestinghouse Electric CompanyAndrew BlancoCriticality AnalystDarrin SmithProject Manager for CriticalityEd MercierU.S. BWR & Criticality ManagerKiCiFlLiiMKris CummingsFuel Licensing ManagerEPRIAlbertMachielsSeniorTechnicalExecutiveAlbert MachielsSenior Technical Executive3 PurposeTo provide the NRC an overview of the upcoming Spent Fuel Pool criticality analysis License Amendment Request to update the Comanche Peak Technical Specifications regarding Spent Fuel Pool Storage configurations and receive NRC comments on the planned submittal.4 Licensing ActionsLicenseAmendmentRequestforrevisedSpentLicense Amendment Request for revised Spent Fuel Pool Criticality Analysis *SubmittedinAugust2007(withUprate)*Submitted in August 2007 (with Uprate)*Credit additional margins in the spent fuel pool(suchasdecaytime)pool (such as decay time)*Increase spent fuel storage capacity.RequestwaswithdrawnAug2009Request was withdrawn Aug 2009Uprate Amendment Request approved in 2008*U1C14 -October 2008 to April 2010*U2C12 -October 2009 to March 2011Dry Cask Storage5 ComanchePeakComanche PeakSpent Fuel Pool CfitiConfiguration ControlsPresented by Cody LemonsCore Performance Engineering Topics for DiscussionCurrent CPNPP Inventory and LimitsCurrent Configuration Control methodsProposed Configuration Controls to support revised Technical Specificationsp7

Background

Information The Comanche Peak Nuclear Power Plant (CPNPP) *Two Unit Station -Westinghouse 4 Loop PWRs*Initial License*Unit 1 -February 8, 1990*Unit 2 -February 3, 1993*Current Operating Cycles (18 Month)Uit1Cl16*Unit 1 -Cycle 16*Unit 2 -Cycle 138 CPNPP Wet Fuel StorageThe two Spent Fuel Pools are connected by a Transfer Canal, and each pool is divided into 2 Regions*Region I*441 total storage locations*BORAL neutron absorbers and Flux Trap geometry*Analysis of Record demonstrates keff <0.95 for fresh fuel whilefloodedwithunboratedwaterwhile flooded with unborated water9 CPNPP Wet Fuel Storage*Region II*2932 total storage locations*No fixed neutron absorbers *Boraflex was physically removed prior to installation pyypof the racks*Developed cell design (no flux trap)*Technical Specifications require configuration be maintained for criticality controls*"1 of 4", "2 of 4", "3 of 4", "4 of 4" configurations*Dependent upon Initial Enrichment and Burnup*Credit for soluble boron to demonstrate Keff <0.9510 Dry Storage ActivitiesAccelerated Dry Storage of Spent Fuel Five Years.Dry Storage Status:*Nine (9) Casks completed in 2012()p*Nine (9) Casks scheduled in 2013Currently288FuelAssembliesinDryStorageCurrently 288 Fuel Assemblies in Dry Storage*Approximate discharge volume from 3 cycles ofoperationof operation11 Current CPNPP Fuel Storage ControlsCurrent Method for Configuration Control:*A Technical Specification Surveillance Report is generated when needed(typicallyeachrefuelingoutage)needed (typically each refueling outage)*This report may be used as the basis for multiple fuel move plans, since enrichment/burnup values are static*Burnup/Enrichment values for input are obtained from the database used for Special Nuclear Material Reporting (TracWorksŽ Fuel Data Management System database)*Software is used to determine Maximum Allowable Storage Configuration (MASC) by comparing Enrichment / Burnup to theTechnicalSpecificationlimitsthe Technical Specification limitsTracWorks, the TracWorkslogo, and ShuffleWorksare trademarks or registered trademarks of Westinghouse Electric Company LLC, its Affiliates and/or its Subsidiaries in the United States of America and may be registered in other 12countries throughout the world. All rights reserved. Unauthorized use is strictly prohibited. Other names may be trademarks of their respective owners."

Current CPNPP Fuel Storage ControlsSoftware Requirements:*for initial implementation or software revision, testing and dttiifdbiddtidocumentation is performed by an independent reviewer*configuration controls ensure integrity of executable files and data files*cyber security controls prevent tampering / inadvertent changesDatabase Requirements:*All database updates are independently reviewed and approved*Administrative controls provide method for users to ensure integrity of database prior to utilizing the data13 Current CPNPP Fuel Storage ControlsExample TS Surveillance ReportInitial Enrichment and Burnup values are input from the TracWorks databasedatabase.MASC (Maximum Allowable Storage Configuration) determined by software based oninptaleson input values.14 Results are plotted graphically versustheTSlimitstoassistinversus the TS limits to assist in identifying errors. (Based on internal OE regarding a violation of TS limits) (reference LER-04-001, ML041260217)15 Current CPNPP Fuel Storage ControlsPrior to any fuel movement within Region II, a color coded map of the new planned configuration is created*Mapiscolor-codedusingtheMASCfromtheSurveillanceReportMap is color-coded using the MASC from the Surveillance Report*Acceptability of planned configuration is verified visuallyAdministrative procedural controls are in place to ensure TS configuration is maintained during the sequence, and for any alterationstotheplannedsequencealterations to the planned sequence.16 17 Verification MethodsCurrently, verification of TS compliance relies on a manual review.This method is effective due to the simplicity of the current limits:*All fuel falls into one of 4 homogeneous categories*The vast majority of all fuel stored in Region II is limited to a "3 of 4" configurationg*The small number of "2 of 4" and "4 of 4" assemblies are verified, then the remainder of the pool can be reviewed to ensure a "3 of 4"patternismaintained4 pattern is maintained*Region II Interface requirements from the AOR can be simplified down to two requirements:*No "1 of 4" assemblies adjacent to the Region I racks*For any 2x2 array containing an assembly, the number of assembliesinthearrayis<theassembly'sMASC(ie"3of4"assemblies in the array is <the assembly's MASC (i.e. 3 of 4" or "4 of 4")18 Verification of TS Interface RequirementsExample of SAT Configuration -Location D2 ( )All potential 2x2 arrays containing this location satisfy the TS requiredcheckerboardpatternrequired checkerboard pattern.19 Verification of TS Interface RequirementsExampleviolationof 4assembliesin2x2"3 of 4" requirement for assemblies at KK4, LL4, and MM44 assemblies in 2x2 array, limit is "3 of 4"Exampleviolationof2blii22Exampleviolationof "1 of 4" requirement for assembly at S22 assemblies in 2x2 array, limit is "1 of 4"20 Controls to support revised Technical SpecificationsThe proposed new TS Limits will be more complex than the current limits, potentially crediting:*NeutronAbsorbingInserts(iedischargedControlRods)Neutron Absorbing Inserts (i.e. discharged Control Rods)*Decay Time*Differences in reactivity based on fuel type / fuel historyyyp/y*Non-homogeneous configurations (or "high/low" configurations)*A pattern may contain separate reactivity limitations for "A" and "B" locations21 Controls to support revised Technical SpecificationsSafety and efficiency with the increased complexity requires:*Updated / new software:*Technical Specification Surveillance Reports which document acceptability for each configuration*Graphical output to assist in the review process for these Gpppreports*Verification of planned Fuel Move Sequences ANDConfigurationsConfigurations*Visual aid maps (color coded), for review and fuel move planning purposes*Detailed procedures for implementation22 Controls to support revised Technical SpecificationsExample Surveillance Report:Example based on 6 storage configurations.A01couldbestoredin"4of4"ONLYinaconfigurationwhichcreditsA01 could be stored in 4 of 4 ONLY in a configuration which credits RCCAs (in either "A" or "B" location).T89 in "3 of 4":*Could only be in "B" location with NO RCCA*Couldbeineitherlocationina*Could be in either location in a configuration with RCCA credit.23 Controls to support revised Technical SpecificationsExample of Graphical Output which may aid in discovering outliers within the data.The assembly with over 10,000 MWD/MTU excess biiburnup is in error. 24 Controls to support revised Technical SpecificationsVerification of planned Fuel Move Sequences and Configurations*CPNPP uses ShuffleWorkssoftware program for fuel move planning. TSifitiftilltiliShfflWkdt*TS verification software will utilize ShuffleWorksdata files to determine the acceptability of fuel move sequencesq*This software will tie together the fuel move plans (from ShuffleWorks) with the TS Allowed Configurations (from the Surveillance Report)*A report will be generated demonstrating acceptability idtififilor identifying failures25 Controls to support revised Technical SpecificationsVisualaidmaps(colorcoded)forreviewandfuelmoveVisual aid maps (color coded), for review and fuel move planning purposes:ElPliMf"3f4NRCCACdit"fitiExample Planning Map for "3 of 4 No RCCA Credit" configurationDuringfuelmovementplanningitDuring fuel movement planning, it is desired to move an assembly to location FF16 (an "A" location). A "blue"assemblywouldbeblue assembly would be selected based on the planning map.AfterthesequenceisplannedtheAfter the sequence is planned, the software would verify the acceptability of the move. 26 Controls to support revised Technical SpecificationsFuel Assembly Inserts*If credited in the analysis, the Technical Specifications apply to fuel inserts, as well as fuel assemblies*Fuel insert moves are controlled via the same ddftdttdiththprocedures and software, and treated with the same level of control as fuel moves*CPNPPhasadamagedRCCAwhichhasa*CPNPP has a damaged RCCA which has a disconnected rodlet. This RCCA will NOT be flagged as a TS creditable insert within the database27 Controls to support revised Technical SpecificationsUnplanned alterations which occur during fuel / insert movement will be administratively controlled:*ItwillbepreferredtomovetheassemblytoRegionIThiswillIt will be preferred to move the assembly to Region I. This will likely be the fastest method to continue fuel movement.*Alternatively, a detailed checklist will be utilized to ensure the liittitlimitations are met.*This checklist will involve obtaining the Surveillance Report, and manually ensuring TS limits are satisfied for the assembly and all surrounding assemblies (or insert).*All fuel movement alterations require Reactor Engineering and FuelHandlingSROapprovalpriortoplacingthefuelorfuelFuel Handling SRO approval prior to placing the fuel or fuel insert.28 BORAL Monitoring ProgramPer 2012 EPRI Report "Strategy for Managing Long Term Use of BORAL in Spent Fuel Storage Racks"The CPNPP Monitoring Program will track industry BORAL experience as well as utilize conservative assumptions for degradation within the analysis.gy29 SummaryCPNPP Current Limits are relatively simple, which allows relatively simple methods to maintain configuration control.ProposedchangestotheTechnicalSpecificationlimitswillresultinaProposed changes to the Technical Specification limits will result in a higher level of complexity. CPNPP recognizes that the increase in complexity requires more btthdtitifititlrobust methods to maintain configuration control.New tools will be necessary to ensure TS limits are maintained during all fuel movement with the Spent Fuel Pool. *Procedural controls*Software30 Questions / Comments?31 SFP Criticality Methodology for Comanche Peak32 Summary and ConclusionsCurrent Schedule Overview*September 2012 -complete scoping studies and determine configurationsconfigurations*December 2012 -complete technical analysis*February 2013 -complete CPNPP specific WCAPy03pCpC*March 2013 (tentative) -submit LAR to NRCBased on Westinghouse Topical Report and EPRI Depletion Uncertainty*WCAP-17483-P -Westinghouse Methodology (ML-11364A066)EPRIDltiUtitRt*EPRI Depletion Uncertainty ReportQuestions / Open Discussion33