b'Postirradiation Examination of FeCrAl Irradiatedat Light Water Reactor ConditionsPrincipal Investigator: Fabiola Cappia (INL)Team Members/ Collaborators: Brian Frickey, Shane Haney, Robert Cox, Francine Rice, Glen Papaioannou,David Sell, Katelyn Wheeler, John Stanek (INL), Jason Harp and Kevin Field (ORNL)O ne of the main strategiesProject Description:in current Research andThe FeCrAl alloys have been studied Development (R&D) offor nuclear applications since Accident Tolerant Fuels (ATFs)the 1960s, due to their attractive The PIE results of thisaims at developing and qualifyingresistance to oxidation at high irradiation campaignnew cladding materials that couldtemperature. Comprehensive studies provide fundamentaloverperform Zr-alloy claddingsof FeCrAl alloys optimized for data to assess the currently used in Light Water Reactorsdeployment as nuclear cladding has fuel-cladding interaction(LWRs). Particularly, Zircaloy suffersbeen performed, but data assessing between UO 2and from rapid exothermic oxidationreactivity between the FeCrAl alloys ATF candidate iron- accompanied by hydrogen gasand LWR fuels during in-reactor based cladding. generation under certain accidentoperation remains limited. As part conditions. If these phenomenaof the ATF-1 irradiation tests, three could be mitigated, a large gain inOak Ridge National Laboratory safety margin could be achieved,(ORNL) Fuel-Cladding Chemical which would imply economicInteraction (FCCI) rodlets were benefit through increased operationaldesigned and fabricated to specifically flexibility. Among others, advancedstudy the potential FCCI between iron-based alloys proved to haveadvanced FeCrAl alloys and UO 2desirable attributes in terms ofunder irradiation. The rodlets improved oxidation resistance inconsist of a series of FeCrAl disks water-vapor containing environment,and UO 2fuel disks whose design which is a fundamental property toresembles diffusion couples. The increase coping time in accidentaldesign incorporates several layers scenarios. Several efforts have beenof clad-fuel specimens enabling the undertaken to develop and qualifytest of different cladding materials nuclear grade FeCrAl alloys, studyingand surface treatments within a radiation tolerance, mechanicalsingle irradiation. The selected alloys properties at elevated temperatures,comprised one alloy from Phase I of aqueous corrosion resistance,the ORNL FeCrAl alloy development oxidation resistance and compatibilitystrategy, namely B135Y3, two alloys with the fuel. from Phase II, C35M and C37M, as well as the commercial alloy, Kanthal 104 2019|AFC ACCOMPLISHMENTS'