Benchmark experiment on molybdenum with DT neutrons at JAEA/FNS

Ota, Masayuki; Kwon, Saerom; Ochiai, Kentaro; Sato, Satoshi; Konno, Chikara  

We perform a benchmark experiment with a Mo assembly and the DT neutron source at JAEA/FNS to validate recent nuclear data of Mo. A rectangular Mo assembly, the size of which is 253 mm 253 mm 354 mm, is covered with 51, 202 and 253 mm thick Li2O blocks around the front, side and back surfaces in order to eliminate background neutrons in the measuring points, respectively. The assembly is placed at a distance of 150 mm from the DT neutron source. Several dosimetry reaction rates and fission rates measured in the assembly are compared to those calculated with the Monte Carlo neutron transport code MCNP5-1.40 and the recent nuclear data libraries of ENDF/B-VII.1, JEFF-3.2 and JENDL-4.0 (FENDL-3.0). The ratios of the calculated reaction rates to the experimental ones generally decrease with the increasing distance from the front surface of the assembly. Reasons of the discrepancies are discussed in the presentation.