Analysis and Design for Irradiation of High Power TRISO Fuel Compact Specimens in HFIR

Irradiation of MiniFuel Targets Bearing TRISO Fuel Compacts (Status Report)

“…The numerical analysis detailed in the report on MiniFuel target assembly [4] and reported in a previous KP MiniFuel report [3] considered targets KP02/KP03 and KP04/KP05 in position R=2 and R=3, respectively, whereas they were loaded in HFIR in position R=3 and R=2, respectively. Radial positions 2 and 3 of the MiniFuel basket are equidistant from the core and are expected to provide similar irradiation conditions.…”

“…The heat generation rate (HGR) was calculated for every component in the experiment using a wrapper code called HFIRCON that passes information between MCNP and ORIGEN. The wrapper scheme was described in a previous KP MiniFuel report [3], and the same methodology is used for this work. The results presented in this section differ from previous work only due to the change in loading position for KP02 -KP05 and the unexpected HFIR shutdowns.…”

“…HGRs used for the nonfuel components range from roughly 3.8 to 5.8 W/g depending on the material and relative location within the subcapsule. Gallagher et al [3] reported the design of all five MiniFuel targets irradiated in HFIR: the design temperatures were 500-900°C, had holder outer diameters of 8.44-9.60 mm, and the fill gas compositions were either Ne, Ar, or a mixture consisting of 22% He and 78% Ar. The design temperature was defined as the time and volume-averaged temperature of the SiC layer of the TRISO particles.…”

“…Previous design studies of the TRISO MiniFuel experiment used a full target capsule model containing six subcapsules with the particles arranged in an ordered pattern [3]. This section compares model predictions between the full target model and the single subcapsule model as well as those between the ordered particle arrangement, a measured particle arrangement from the XCT analysis, and a sampled particle arrangement from the sensitivity study.…”

Assembly of MiniFuel Targets for Irradiation of U-Mo Fuel Specimens in the High Flux Isotope Reactor

“…The fuel burnup was predicted using HFIRCON, and a Python script was used to read the predicted fuel burnup into ANSYS. The Python script was also used to read HGRs for each target component based on the number of days and position in HFIR and to set the internal heat generation in each component in the ANSYS model [4]. Convective boundary conditions on the target housing have been calculated in RELAP5 for previous MiniFuel irradiations in the inner small vertical experiment facility (VXF).…”