b'3.3 AR IRRADIATION TESTING AND PIE TECHNIQUES Examination of FAST-1 Accelerated Fission Rate Metallic Fuel TestPrincipal Investigator: Boone Beausoleil, Luca CapriottiTeam Members/Collaborators: S. Patnaik, Todd Jacobsen, Katelyn Baird, Julia CarterT he Fission Accelerated Steady- This PIE data is the state Test (FAST) irradiation test was initiated in 2018 with the first irradiation experimentsfirst destructive data inserted into the Advanced Testshowing the results of Reactor (ATR) in 2020. The first pinsthe FAST irradiation were removed after a single cyclework and captures and were awaiting destructive post- fuel behavior that irradiation examination (PIE) forcontradicts many of several years for equipment modi- the expectations of fications within the hot-cell. Theconventional behavior PIE performed this year includesof metallic fuels.fission gas release analysis through the updated Gas Assay Sample & Recharge (GASR) system, sectioningment by showing the feasibility of of the fuel pins, and metallographyaccelerated irradiation testing. The analysis with an optical microscope. FAST tests differentiate themselves Project Description:from other accelerated methods in The FAST experiments are designedthat they use actual in-pile neutron to interrogate critical fuel perfor- irradiation (vs ion irradiation) and mance behaviors of advancedcapture integral irradiation effects reactor fuels in an acceleratedacross prototypic temperature manner through geometric scalingranges (vs MiniFuel tests, https://doi.of the fuel rods. The first iteration oforg/10.1016/j.jnucmat.2019.151783). this test was completed within ATRThese behaviors include fuel in 2021 and the pins have begunconstituent redistribution, fuel destructive PIE activities this fiscalporosity interconnectivity, bulk year. Modifications were completedfission gas release/retention, fuel-to the GASR equipment to supportcladding chemical interaction, and the collection of fission gas from thefuel-cladding mechanical interac-FAST rodlets. This helps provide ation (FCMI). The first FAST pins to basis for using FAST experimentsundergo PIE includes an annular, to design and test advanced nuclear75% smear density (SD), helium fuels for use in advanced reactors. bonded pin (FAST-007) and an otherwise equivalent solid, sodium Accomplishments:bonded fuel pin (FAST-008) control The Advanced Fuel Campaign (AFC)pin. Both were irradiated to 4.8 % FAST experiments demonstratefissions of initial metal atoms, or an exceptional opportunity forat% and 3.9% with maximum irradi-advanced fuel research and develop- ated cladding temperatures of 470C 160 2023|AFC ACCOMPLISHMENTS'