Impact of molybdenum cross sections on FHR analysis

A recent benchmarking effort, under the auspices of Organization for Economic Cooperation and Development (OECD) Nuclear Energy Agency (NEA), has been made to evaluate current state modeling simulation tools available model fluoride salt-cooled high temperature reactors (FHRs). The FHR effort considered in this work consists several cases evaluating neutronic parameters a 2D prismatic fuel assembly using participants’ choice tools. Benchmark participants blindly submitted results comparison with overall good agreement, except some which significantly differed on utilizing molybdenum-bearing control rod. Participants more recently updated explicit isotopic cross sections had consistent results, whereas those elemental molybdenum observed reactivity differences order thousands pcm relative their peers. Through series supporting tests, authors attribute as being nuclear data driven from older legacy sections. Quantitative analysis is conducted rod identify spectral, reaction rate, section phenomena responsible differences. Results confirm are attributable use overestimate rates strong resonance channels.