Abstract :
NaturalexposureandacceleratedcorrosiontestsofconventionalstainlesssteelsforcanistersofTypes304,304L,and316(LN)forconcretecaskswereconductedusingseveraltestspecimensand1/5scalecanistermodels.Theweldingresidualstressofafull-scalemodelcanisterwasalsomeasuredandthelifetimeofsealabilityofcanistersagainstcorrosionevaluated.ThemaximumpittingrateandcrevicecorrosionrateofType304wereapproximately20and30μm/year.ManySCCinthe4PointBending(4PB)testspecimenswerefoundtoinitiatefromthebottomofthecorrosionareabypittingorcrevicecorrosion.TheSCCpropagationratesinTypes304and304Lundernaturalconditionswerearound1.2E−12to1.8E−11m/sintheK(StressIntensityFactor)rangeof0.6–9.0MPam1/2,andthatoftheacceleratedtest(60°C,95%RHS,filledwithNaClmist)around1.0E−10to3.5E−9m/sintheKrangeof0.5–30MPam1/2.TheSCCpropagationratesunderbothnaturalandacceleratedconditionswereindependentofK.Thelifetimeofsealabilityestimatedfrom1/5scalemodelswaslongerthanthatfromthesmallbendingtestspecimensandhasasafetymarginasastructure.
