b'FAST/Accelerated Testing for Advanced Fuel DesignsPrincipal Investigator: Geoffrey BeausoleilTeam Members/ Collaborators: Christopher Murdock, Nate Oldham, Luca Capriotti, Randall Fielding,and Bryon CurnuttThe FAST testsT he Fission Accelerated Steady- generation reactors. Novel fuel designs state Test (FAST) approach tocan then be paired against controls in performed in FY21 byirradiating fuel completedpost-irradiation furnace tests or tran-the Advanced Fuelsits first irradiation cycle within thesient testing in the Transient Reactor Campaign (AFC)Advanced Test Reactor (ATR) at IdahoTest Facility (TREAT). This allows rapid demonstrated theNational Laboratory (INL). The FASTqualitative comparisons of perfor-viability of reducedmethod to irradiating was shown tomance between novel designs against scale fuel testing foraccelerate irradiation rates by up toestablished performance metrics. The accelerated fuel R&Da factor of six and is based upon thesolution of simply accelerating irradia-with burnup rates thatability to increase the power density oftion, however, requires consideration were up to six timesa test pin by scaling the fuel pin downof many other phenomena that FAST faster than conventionalwhile maintaining an equivalent linearcan provide answers for. Phenomena testing methods. heating rate. The tests were initiallysuch as fission product diffusion and designed to investigate alloy fuels foralloy re-distribution are heavily influ-sodium fast reactors (SFRs). The testsenced by temperature gradients, time performed in the first cycle includeat temperature, and concentration controls fuel pins, sodium free annulargradients. By scaling the geometry to fuel pins, fuel with liners, and fuela reduced size and reducing the total with alloy additives. time under irradiation, the balance Project Description:of time and distance for diffusion The objectives of the FAST experimentcentric phenomena is tested. This has are, at a basic level, to improve theimportant implications to developing timeline of advanced fuel researchhigh burnup alloy fuel as the roles and development (R&D) efforts andof alloy redistribution and fission to support accelerated qualificationproduct concentrations at the cladding methodologies. The project lends itselfare both important fuel performance to support high throughput, rapidmetrics. This adds additional value to prototyping of fuel designs to be ablethe use of FAST as it provides critical to provide qualitative comparisonsdata to the development and imple-to the performance of standard fuelmentation of physics-based models designs. The ability to produce highby virtue of the departure from fully burnup fuel pins of both a controlprototypic irradiation and thus an and novel fuel design within the sameimproved, broader basis for validating capsule and irradiation conditions isperformance codes against.critical to the development of next 118 2021|AFC ACCOMPLISHMENTS'