b'3.3 IRRADIATION TESTINGAND POSTIRRADIATION EXAMINATIONSFission Accelerated Steady-state Testing (FAST)Principal Investigator: Geoffrey Beausoleil, INLTeam Members/ Collaborators: Nate Oldham, Bryon Curnutt, Kyle Gagnon, Chris Murdock, and Randy Fielding (INL)The AFC-FAST experiment is providing the campaign with high burnup fast reactor fuel in a fraction of the time previously available with 50 fueled specimens being irradiated up to 5 %FIMA in a single ATR cycle.I n an effort to accelerate theProject Description: irradiation time for advancedPrevious advanced reactor fuels, reactor fuels, a revised capsulenamely fast reactor fuels, have been design was analyzed and developedsuccessfully irradiated within the at Idaho National Laboratory (INL)ATR. However, these tests have been for the Advanced Fuels Campaignproblematic in that they require (AFC). This design incorporates aadjustments to the experiment highly enriched, reduced scale fueldesign to make the power profile pin that is doubly encapsulated bymore prototypic (introduction of a two steel capsules. This design alloyscadmium shroud), a tight-tolerance accelerated irradiations and reducedhelium bond between the cladding sensitivity to fabrication variancesand the capsule wall (a high-heat and eccentricities. The capsuleflux zone for increasing the cladding designs utilize existing experimenttemperature to prototypic tempera-designs from the AFC capsules in thetures), high sensitivity to fabrication Advanced Test Reactor (ATR) outervariances and eccentricities (lower A position (FAST-OA) and the ATF-1limit of fabrication tolerances still have capsules in the small I positionsa significant effect on the outcome (FAST-SI). of the experiments), and ultimately very long irradiation times in order to achieve high burnup targets. These challenges have been addressed by the FAST experiment design.196 2019|AFC ACCOMPLISHMENTS'