Benchmark analysis for accelerator-driven subcritical reactor with pulsed neutron generator in Kyoto University Critical Assembly (KUCA)

This study aims to compare the theoretical and experimental results of an accelerator driven system with a sub-critical core. A benchmark analysis of number of experimentations at Kyoto University Critical Assembly (KUCA) has been made. There were two series of experimentations and each series has four cases. The main objective of these experiments was to study the sub-critical neutronics characteristics (neutron spectrum, reaction rates distributions) and validate measurements techniques appropriate to sub-critical systems. The KUCA core is a thermal neutron spectrum assembly, fuelled with highly enriched uranium fuel, and moderated and reflected by polyethylene. The neutron generator consisted of a Cockcroft-Walton type machine accelerating deuterons onto a tritium target yielding 10⁹ n/s. Theoretical calculations are done with MCNP-5 1.4v with cross-section library ENDF-B-VI-5. Subcriticality, excess reactivity for different core configurations were measured and compared with theoretical calculations. Reaction rates of indium wire from source to inside of the core were compared experimentally and theoretically. In general a good comparison has been seen in this work.