Abstract
The core of the High Flux Isotope Reactor (HFIR) is composed of two concentric annular elements, inner and outer, each containing highly enriched uranium fuel as a mixture of triuranium octoxide (U3O8) and aluminum encapsulated within aluminum alloy plates. The fuel plates are of involute shape and the fuel within the plates has a distribution across the plate width. Previous KENO code validation efforts have used a relatively simple single region homogeneous fuel model for each of the two annular regions by assuming that the materials in each were homogenized within the total volume of the fueled region. The computed results have tended to be about 2 to 3% greater than experimentally measured results. To improve computed results, a multi-zone fuel model was developed and used to validate the KENO code.