ASTM_C_1454_-_07.pdf

Designation:C145407Standard Guide forPyrophoricity/Combustibility Testing in Support ofPyrophoricity Analyses of Metallic Uranium Spent NuclearFuel1This standard is issued under the fixed designation C1454;the number immediately following the designation indicates the year oforiginal adoption or,in the case of revision,the year of last revision.A number in parentheses indicates the year of last reapproval.Asuperscript epsilon()indicates an editorial change since the last revision or reapproval.1.Scope1.1 This guide covers testing protocols for testing thepyrophoricity/combustibility characteristics of metallicuranium-based spent nuclear fuel(SNF).The testing willprovide basic data for input into more detailed computer codesor analyses of thermal,chemical,and mechanical SNF re-sponses.These analyses would support the engineered barriersystem(EBS)design bases and safety assessment of extendedinterim storage facilities and final disposal in a geologicrepository.The testing also could provide data related tolicensing requirements for the design and operation of amonitored retrievable storage facility(MRS)or independentspent fuel storage installation(ISFSI).1.2 This guide describes testing of metallic uranium andmetallic uranium-based SNF in support of transportation(inaccordance with the requirements of 10CFR71),interim stor-age(in accordance with the requirements of 10CFR72),andgeologic repository disposal(in accordance with the require-ments of 10CFR60/63).The testing described herein is de-signed to provide basic data related to the evaluation of thepyrophoricity/combustibility characteristics of containers orwaste packages containing metallic uranium SNF in support ofsafety analyses(SAR),or performance assessments(PA)oftransport,storage,or disposal systems,or a combinationthereof.1.3 Spent nuclear fuel that is not reprocessed must beemplaced in secure temporary interim storage as a step towardsits final disposal in a geologic repository.In the United States,SNF,from both civilian commercial power reactors anddefense nuclear materials production reactors,will be sent tointerim storage,and subsequently,to deep geologic disposal.U.S.commercial SNF comes predominantly from light waterreactors(LWRs)and is uranium dioxide-based,whereas U.S.Department of Energy(DOE)owned defense reactor SNF is inseveral different chemical forms,but predominantly(approxi-mately 80%by weight of uranium)consists of metallicuranium.1.4 Knowledge of the pyrophoricity/combustibility charac-teristics of the SNF is required to support licensing activitiesfor extended interim storage and ultimate disposition in ageologic repository.These activities could include interimstorage configuration safety analyses,conditioning treatmentdevelopment,preclosure design basis event(DBE)analyses ofthe repository controlled area,and postclosure performanceassessment of the EBS.1.5 Metallic uranium fuels are clad,generally withzirconium,aluminum,stainless steel,or magnesium alloy,toprevent corrosion of the fuel and to contain fission products.Ifthe cladding is damaged and the metallic SNF is stored in waterthe consequent corrosion and swelling of the exposed uraniumenhances the chemical reactivity of the SNF by furtherrupturing the cladding and creating uranium hydride particu-lates and/or inclusions in the uranium metal matrix.Thecondition of the metallic SNF will affect its behavior intransport,interim storage or repository emplacement,or both,and therefore,influence the engineering decisions in designingthe pathway to disposal.1.6 Zircaloy2spent fuel cladding has occasionally demon-strated pyrophoric behavior.This behavior often occurred oncladding pieces or particulate residues left after the chemicaldissolution of metallic uranium or uranium dioxide during fuelreprocessing of commercial spent fuel and/or extraction ofplutonium from defense reactor spent fuel.Although it isgenerally believed that zirconium is not as intrinsically proneto pyrophoric behavior as uranium or plutonium,it has in thepast ignited after being sensitized during the chemical extrac-tion process.Although this guide primarily addresses thepyrophoricity of the metallic uranium component of the spent1This guide is under the jurisdiction of ASTM Committee C26 on Nuclear FuelCycle and is the direct responsibility of Subcommittee C26.13 on Spent Fuel andHigh Level Waste.Current edition approved Feb.1,2007.Published March 2007.Originallyapproved in 2000.Last previous edition approved in 2000 as C1454 00.DOI:10.1520/C1454-07.2Zircaloy,the term,and any of its instances are a trademark of WestinghouseElectric Company.If you are aware of alternative suppliers,please provide thisinformation to ASTM International Headquarters.Your comments will receivecareful consideration at a meeting of the responsible technical committee,1whichyou may attend.Copyright ASTM International,100 Barr Harbor Drive,PO Box C700,West Conshohocken,PA 19428-2959.United States1 fuel,some of the general principles inv