Experimentalanalysisoftheaqueouschemicalenvironmentfollowingaloss-of-coolantaccidentOriginalResearchArticle

Fivedifferent30-daytestswereconductedtosimulatethechemicalenvironmentinapressurizedwaterreactorcontainmentwaterpoolafteraloss-of-coolantaccident(LOCA).Allchemicalenvironmentswithinthetestapparatusincludedboricacid,lithiumhydroxide,andhydrochloricacid.Inaddition,trisodiumphosphate,sodiumhydroxide,andsodiumtetraboratewereusedtocontrolpHinseparatetests.Materialstestedwithinthisenvironmentincludedrepresentativeamountsofsubmergedandunsubmergedmetalcoupons,concrete,insulationdebrissamples,concreteparticulate,andlatentdebris.Visiblechangeswereseenonthebothsubmergedandunsubmergedmetalcouponsineachtestbecauseofcorrosion.Thetestswithcalciumsilicate(cal-sil)insulationhadconsiderablymoresedimentthantheothertestswithfiberglassinsulation.Particulatedepositswerefoundonlyontheexteriorsurfacesofthefiberglassbundles.Themostparticulatedepositswerefoundonthefiberglassexteriorfromthetestthatinvolvedcal-silinsulationandtrisodiumphosphate(TSP).Inaddition,snow-likewhiteprecipitateswerefoundontopofthesedimentinthattest,thatwererichincalciumandphosphorus.Precipitateswerealsopresentinthesolutionsoftwotestswhenthesolutionwascooledtoroomtemperature.Theseprecipitateshavehighcontentsofaluminumandboronwithsmallamountsofsodiumandcalcium.Thepresenceofinsulationdebris,precipitates,andsedimentsissignificantbecauseoftheimpacttheymayhaveontheECCSrecirculationprocess.