b'Over Power Transient Testing of LWR FuelsPrincipal Investigator: David KamermanTeam Members/ Collaborators: Leigh Ann Astle, Charlie Folsom, Colby Jensen, Austin Fleming, Connor Woolum and Wes SmithThis test programT he HERA project (Highical interaction (PCMI). The HERA Burnup Experiments in Reac- proposal is designed to (1) quantify will help inform thetivity initiated Accidents) is athe impact of pulse width on fuel development of safetypart of the Nuclear Energy Agencysperformance, offering new insight margins for high burnup(NEAs) Framework for Irradiationinto the applicability of existing data, light water reactor fuelExperiments (FIDES) initiative. The(2) generate new data on high burnup in reactivity-initiatedproject aims to conduct integralfuel under pulse conditions prototypic accidents.Reactivity-Initiated Accident (RIA)of LWRs (3) quantify the additional testing of both pre-hydrided andmargin provided by modern cladding actual high burnup test specimens. alloys to PCMI failure limits and (4) Project Description: offer improved data for modelers HERA is a joint experimental programusing specially designed tests that (JEEP) operating within the NEAeliminate key uncertainties in high-framework for irradiation experimentsburnup fuel tests.(FIDES). HERA is dedicated to theAccomplishments:understanding of light water reactorThis year Idaho National Labora-(LWR) fuel performance at hightory (INL) developed a new static burnup under RIA. In-pile RIA experi- water capsule design to be used in ments have been performed on highthe HERA experiments. The design burnup fuels (above 60 GWD/MTU)features several new instruments in the CABRI reactor in France, andincluding a fuel centerline ther-the NSRR reactor in Japan. However,mocouple and 2 water pressure the majority of these experimentssensors to help detect the moment have taken place with heavily corrodedof any cladding failures. The design Zircaloy claddings in test reactors withalso features an improved cladding pulse widths that are more narrowthermocouple holder to improve (5ms30ms full-width-half-maxthe reliability and aid in the ease of (FWHM)) than what would be likelyassembly for the cladding thermo-in a commercial LWR (30ms80mscouples. Weld development for the FWHM). Heavy waterside corrosionintegral junction cladding thermo-and narrow pulse widths are bothcouples also yielded very fruitful known to increase the vulnerability ofoutcomes with a reliable process LWR fuel to pellet cladding mechan- being developed to better attach the cladding thermocouples in a consis-tent and repeatable manner. 38 2021|AFC ACCOMPLISHMENTS'