ML17255A636

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Proposed Tech Spec Changes Re Spacing of Recently Discharged Fuel in Spent Fuel Storage Racks
ML17255A636
Person / Time
Site: Ginna Constellation icon.png
Issue date: 01/18/1984
From:
ROCHESTER GAS & ELECTRIC CORP.
To:
Shared Package
ML17255A634 List:
References
NUDOCS 8401250301
Download: ML17255A636 (7)


Text

Attachment A1.Makethefollowing changesintheTechnical Specifications.

RemoveInsertpages3.11-2through3.11-33.11-5pages3.11-2through3.11-3r8401250301 840ii8PDRADOCK05000244PDRj

~C'!~iJl'14 e.Charcoaladsorbers shallbeinstalled intheventilation systemexhaustfromthespentfuel3.11.2storagepitareaandshallbeoperable.

Radiation levelsinthespentfuelstorageareashall3.11.3bemonitored continuously.

Thetrolleyoftheauxiliary buildingcraneshall3.11.43.11.5neverbestationed orpermitted topassoverstoragerackscontaining spentfuel.Thespentfuelpooltemperature shallbelimitedto150F.Thespentfuelshippingcaskshallnotbecarriedbytheauxiliary buildingcrane,pendingtheevaluation ofthespentfuelcaskdropaccidentandthecranedesignbyRGGEandNRCreviewandapproval.

Basis:Charcoaladsorbers willreducesignificantly theconsequences ofarefueling accidentwhichconsiders thecladfailureofasingleirradiated fuelassembly.

Therefore, charcoaladsorbers shouldbeemployedwheneverirradiated fuelisbeinghandled.Thisrequiresthattheventilation systemshouldbeoperating anddrawingairthroughtheadsorbers.

Thedesiredairflowpath,whenhandlingirradiated fuel,isfromI'theoutsideofthebuildingintotheoperating floorarea,towardthespentfuelstoragepit,intotheareaexhaustducts,throughtheadsorbers, andoutthroughtheventilation systemexhausttothefacilityvent.Operation ofamainauxiliary building3.11-2Amendment No.,4,6proposed exhaustfanassuresthatairdischarged intothemainventilation systemexhaustductwillgothroughaHEPAandbedischarged to*thefacilityvent.Operation ofamainauxiliary buildingexhaustfanassuresthatairdischarged intothemainventilation systemexhaustductwillgothroughaHEPAandbedischarged tothefacilityvent.Operation oftheexhaustfanforthespentfuelstoragepitareacausesairmovementontheoperating floortobetowardsthepit.Pioperoperation ofthefansandsettingofdamperswouldresultinanegativepre'ssure ontheoperating floorwhichwillcauseairleakagetobeintothebuilding.

Thus,theoverallairflowisfromthelocationoflowactivity(outsidethebuilding) totheareaofhighestactivity(spentfuelstoragepit).Theexhaustairflowwouldbethrougharoughingfilterandcharcoalbeforebeingdischarged fromthefacility.

Theroughingfilterprotectstheadsorberfrombecomingfouledwithdirt;theadsorberremovesiodine,theisotopeofhighestradiological significance, resulting fromafuelhandlingaccident.

Theeffectiveness ofcharcoalfoiremovingiodineisassuredbyhavingahighthroughput andahighremovalefficiency.

Thethroughput isattainedbyoperation oftheexhaustfans.Thehighremovalefficiency isattainedbyminimizing theamountofiodinethatbypassesthecharcoalandhavingcharcoalwithahighpotenti;al for'removing theiodinethat'doespassthroughthecharcoal.

3~113Amendment No.P1,P6Proposed Attachment BIn1976,Rochester Gas&ElectricreplacedtheoriginalR.E.Ginnaspentfuelstorageracks,increasing thestoragecapacityofthepoolbydecreasing thecenter-to-center spacingofthestoragelocations.

Inevaluating theradiological consequences ofmissiles, RG&Eproposedaspentfuelstoragepatternwherebytheprobability ofamissileimpactonspentfuelthathaddecayedlessthan60dayswasnotincreased.

Therefore, thedensityoffissionproductinventory maintained inanylocalareawaslessthanthatwhichhadbeenstoredintheoriginalstorageracks.ThiswasacceptedbytheNRCandtherequiredstoragepatternwasincorporated intotheTechnical Specifications (Reference 1).Becauseofanticipated requirements uponthestoragecapacityoftheracks,RG&Erequested U.S.Tool&Die(USTD)toperformananalysisoftheeffectofaverticalandhorizontal impactofthemissilewiththegreatestpotential fordamagetotherackandcontained fuelassemblies (attached).

Designvaluesfortornado.windspeedandmissilecharacteristics werethoseestablished in'-.theNRCreviewofSystematic Evaluation Program(SEP)TopicsIII-2,WindandTornadoLoadings, andIII-4.A,TornadoMissiles(Ref.4and5).Thismissileischaracterized asa1490lb.woodpole,35ft.inlengthwithadiameterof13.5inches.USTDassumedatornadowindvelocityof132mphandaccounted forthedrageffectsofthepoolwaterabovetheracksusingReference 3.Theresultsofthisanalysisindicated thatverticaldefor-mationwouldbenogreaterthan1.40inchesandtherewouldbenodeformation fromahorizontal impact.Thislimiteddeformation doesnotchangeappreciably forhighertornadowindspeeds.Additional marginsareavailable toaccommodate highertornadowindspeeds.Forexample,calculations performed assumingatornadowindspeedof200mphyieldaverticaldeformation of1.8inchesandatworstasmallamountoflocalized plasticdeformation forahorizontal impact.Theseresultsareconservative forthefollowing reasons:1.Theenergyabsorbedbythepoleisneglected.

Itislikelythat.uponimpactthepole,would,split,.along thegrainreducingthefractionoftotalenergyabsorbedbytherack.2.Itisassumedthatthemissileentersthewateratanorientation exposingtheminimumcrosssectional areaperpendicular tothedirection oftravel.Foraverticalimpactinthe132mphcase,achangeinthemissileorientation ofonly5'oulddecreasethekineticenergyonimpactfrom79,000ft./lb.toapproximately 12,000ft./lb.Similarreductions wouldoccurathigherwindspeedsalso.

3.Forahorizontal impact,theincreaseinthedistancethatthemissilemusttravelthroughwaterrelativetoaverticalimpactwasneglected.

InOctober1981,theNRCcompleted anevaluation oftheconsequences ofapostulated fuelhandlingaccidentinsidecontain-ment(Reference 2).In'thisevaluation thestaffcalculated theoffsitedoseconsequences assumingdamagetoalltherodsofonefuelassemblyoccurring 100hoursaftershutdown, and100%oftheactivityreleasedfromthepoolwasreleasedtotheatmosphere.

Theresulting calculated doseattheEABwas96rem.4.3ThisanalysisusedaX/Qvalueof4.8x10sec/mcorres-pondingtoaprobability levelof.5%.TheRG&Esubmittal ofJune30,1981forSEPTopicII-2.Cdetermined that5thedirection dependent X/Qat.a5%probability levelis6x10sec/m.Thisvalueisstillveryconservative andmoreappropriate giventhehighwindsandexcellent dispersion associated withtornadoconditions.

Ifthe5%X/Qvaluewasused,thedoseatthe(Exclusion5 Areaboundary)

EABwouldbereducedbyafactorof8(6x10/4.4x10)resulting inavalueof12remfordamagetoallrodsof=.onefuelassembly100hoursaftershutdown.

Theworstpositionforimpactofamissilewouldbecenteredonafuelstoragelocationwhere,becauseofthe13.5inchmissileradiuscomparedtoadiagonaldimension oftheboxof11.9inches,thecornersoffourotherfuelstoragelocations wouldbedamaged.Becauseofthelimiteddeformation ofthestoragebox,itisdifficult topostulate damagebeyondtheequivalent ofoneassembly.

However,evenassumingthatall5fuelassemblies wereseverelydamaged,andthatallfuelassemblies couldbemovedtothespentfuelpoolwithin100hours,andthatall5fuelassemblies werepeakpowerassemblies, theupperboundonthedoseattheEABwouldbe5x12or60rem.Thisresultiswellwithintheguide-linesof10CFR100(300rem)andislessthanwhattheNRCpreviously considered acceptable andapprovedforGinnaforthepostulated fuelhandlingaccidentinsidecontainment.

Therefore itisacceptable todeletetherestriction onstorageofrecentlydischarged fuelinthespentfuelpool.

References 1.Letter,A.Schwencer, USNRCtoL.D.White,RGSE,November15,1976.2.Letter,D.M.Crutchfield, USNRC,toJ.E.Maier,RG&E,October7,1981.3.D.R.Miller,W.A.Williams, "TornadoProtection fortheSpentFuelStoragePool,"GeneralElectricAPED-5696, November1968.4.5.Letter,D.M.Crutchfield, USNRCtoJ.E.Maier,RG&E,August22,1983.NUREG-0821, Supplement No.1,Integrated PlantSafetyAssessment, Systematic Evaluation Program,August1983.3