b'Demonstration and Property Measurements onCeramic Test Articles for Accelerated Fuel QualificationPrincipal Investigator: Joshua T. WhiteTeam Members/ Collaborators: David Frazer, Najeb Abdul Jabbar, Chris Grote and Tarik SalehSmall scale testI nterest exists with the Advancedthe ability to densify accident tolerant Fuels Campaign (AFC) andfuel samples, and 2) conduct studies specimens asindustry partners to accelerateon the methods to measure the well as propertiesthe qualification of nuclear fuels.thermophysical properties on small measurements haveOne issue with qualification isscale test specimens. The former been demonstratedconducting irradiations, which canfocused on sintering reference providing a path take considerable time to reach theaccident tolerant fuel candidates, toward accelerated desired burn ups to qualify a givenincluding large grain sized UO 2as fuel qualification offuel. To circumvent the time required,well as UN. In the case of large grain nuclear fuels. two different styles of irradiationssized UO 2 , sintering profiles have have been proposed within the AFC.been determined to sinter undoped The first, FAST in the Advanced TestUO 2microstructures to grain sizes Reactor at Idaho National Laboratoryrepresentative to industry Accident (INL), is a scaled down geometryTolerant Fuel (ATF) doped UO 2 , which of a reference reactor pellet design,is on the order of 30 m as compared where the enrichment is increasedto the reference undoped case of to maintain linear heat generation~10-15 m. Small scale geometries rates across the radius of the pellet.were also expanded in FY20 to MiniFuel irradiations have also beeninclude geometries down to 3 mm as proposed at the High Flux Isotopewell as smaller annular geometries to Reactor (HFIR) at Oak Ridge Nationaldemonstrate FAST advanced reactor Laboratory (ORNL), which limits theceramic geometries.pellet geometry to ~3mm diameterThe focus for the determination of by 0.3mm thick to facilitate separatethermophysical properties on small effects style irradiation tests [1]. Thescale test specimens was directed design for both irradiations is antici- towards building an experimental pated to greatly accelerate irradiationsframework to measure the thermal and also limit sample volumes todiffusivity and high temperature accelerate post irradiation examina- mechanical behavior. This required tion by decreasing the dose from thethe installation of a new light flash irradiated fuel. analysis instrument in the fuels Project Description: research laboratory (FRL), which is The above accelerated irradiation testequipped with a Xe lamp to shorten configurations require the ability tothe light pulse width within the fabricate new pellet geometries. Thetheoretical sample thickness range current work at Los Alamos Nationalof interest for MiniFuel samples. Laboratory (LANL) focused onAlongside, this new flash analysis addressing two issues: 1) extendingcapability, mechanical deformation the range of geometries for the FASTexperiments (via nanoindentation) irradiations as well as demonstrating 46 2020|AFC ACCOMPLISHMENTS'