b'First Experiments and Evaluation of uranium silicidefuel and SiC Composite during an In-Pile Overpower TransientPrincipal Investigator: David KamermanTeam Members/ Collaborators: Nicolas Woolstenhulme, Devin Imhote, Austin Flemming, Colby Jensen, Charles Folsom, Connor Woolum, Korbin Tritthart, Jason Schulthess and Daniel WachsIntegral testing ofA ccident Tolerant Fuel (ATF)to confirm the expected core-to-concepts include a widespecimen energy coupling factor ATF concepts in RIAvariety of fuel and cladding(ECF) of 0.44 J/g-MJ (J/g of conditions is used tomaterials, both as variants of thespecimen energy per MJ of TREAT develop the regulatorycurrent Zircaloy-UO 2system andreactor energy). The purpose of safety criteria whichalso as novel fuel and claddingthe second test was to explore govern their operation inconcepts such as Uranium Silicidethe behavior of U 3 Si 2fuel at an commercial power plants.(U 3 Si 2 ) fuel and Silicon Carbideenergy deposition slightly above composite (SiC-SiC) cladding [1] the melting enthalpies. The SETH-G [2]. These new materials willtransient was tested at an even more likely behave very differently inaggressive transient to determine if accident conditions requiringchanges in coolable geometry could the development of new fuelbe induced when pellet enthalpies safety criteria to regulate theirsignificantly above the melting point performance. One of the mostoccurred. The transients with the challenging design basis accidentsSiC-SiC clad rodlets (SETH-H and (DBAs) for LWRs are rapid high- SETH-I) took place later in the fall power excursions that are knownof 2019 in October and November as Reactivity Initiated Accidentsrespectively. The purpose of SETH-H (RIA). The first ATF concepts to bewas to explore interactions of integrally testing in RIA conditionsmolten U 3 Si 2with SiC, and the are U 3 Si 2in Zircaloy cladding andpurpose of SETH-I was to explore U 3 Si 2in SiC-SiC cladding. Thesepellet cladding interactions between tests were performed in the TREATa still solid U 3 Si 2fuel pellet and reactor. (50150 words). SiC cladding. Cladding temperature Project Description:during the transient was recorded These first transient tests withusing 4 thermocouples and two ATF occurred in July of 2019 andinfrared pyrometers. It was also involved the two rodlets withcalculated using the BISON fuel U 3 Si 2fuel and Zircaloy-4 claddingperformance code. Temperatures (SETH-F and SETH-G). The firstfor the SETH-G transient are shown rodlet (SETH-F) underwent twobelow in Measured and Calculated transients, the first of which wasTemperatures During the SETH-G Transient. The SETH capsules 100 2020|AFC ACCOMPLISHMENTS'