b'HFIR Irradiation of Coated-Zr ATF CladdingPrincipal Investigator: Kory LintonTeam Members/ Collaborator: Patrick Champlin, Padhraic Mulligan, Chris Petrie and Annabelle Le CoqCoated claddingT he understanding of radiationof ~11015 n/cm2s during each effects on coated zirconium~24-day cycle. Full-length targets can experiments in ORNLsaccident tolerant fuel (ATF)also be inserted into the flux trap, High Flux Isotopecladding concepts is being acceler- allowing for irradiation of longer Reactor (HFIR) areated using large-scale science toolscladding samples (~100 mm).The being leveragedlike the High Flux Isotope Reactorthree irradiation vehicle designs to accelerate ATF(HFIR) at Oak Ridge National Labora- currently being utilized to explore qualification. tory (ORNL). ATF vendor teamsATF coatings are the FlexClad leveraging various HFIR irradiationrabbit, full-length cladding target, vehicles such as rabbits or full- and pressurized creep tube rabbit.length targets can quickly achieveFlexClad light water reactor (LWR)-relevantThe FlexClad rabbit capsule design temperatures and neutron fluencesfor standard pressurized water for a wide range of cladding samplereactor (PWR) geometries accom-lengths and geometries. After irradia- modates three different specimen tion, the sample coating performancegeometries in two configurations can be evaluated in hot cells and low- at a target temperature of 350C. level radiation facilities to collect dataThe rabbits hold either two 23.45 on coating adhesion and mechanicalmm long standard PWR geometry properties, including fatigue, creepcladding specimens (9.50 mm outer and simulated loss-of-coolant-acci- diameter) with molybdenum inserts dent (LOCA) burst behavior. [1],[2] or up to four 12 mm long Project Description: standard cladding, axial tension, or HFIR irradiations of cladding samplesplane strain specimens in a single and creep tubes provide a uniquerabbit with zirconium inserts (Figure opportunity to accelerate separate1). The axial tension geometry effects testing of coated zirconiumfeatures an upper and a lower ring ATF concepts by attaining end-of- connected by two gauge regions, life fluences in about 8 cycles, orwhereas the plane strain geometry approximately one year in-core.is a standard cladding tube with two Rabbit capsules are 64 mm longindentions at the top and the bottom. aluminum cylinders used for irradi- Both experiment configurations ating a variety of samples in HFIR.achieve the target temperatures by For the coated cladding irradiations,controlling the size of the specimen the capsules are loaded in a target rodinsert (i.e., gamma heating) and rabbit holder (TRRH) or peripheralthe specimen-to-housing insulating target position (PTP) in the flux trapgas gap. Thermal analyses have been located at the radial center of theperformed to determine temperatures reactor coreexposing the samplesat both beginning-of-life (BOL) and to a nearly constant fast neutron fluxend-of-life (EOL) neutron fluences 18 2020|AFC ACCOMPLISHMENTS'