Speaker
Masayuki Ohta
(Japan Atomic Energy Agency)
Description
In our previous benchmark experiment on molybdenum at JAEA/FNS, we found problems of the (n,2n) and (n,γ) cross sections in Mo of JENDL-4.0. However, the Mo data only above a few hundred eV were investigated, because there were few neutrons with lower energy in the Mo assembly in the previous experiment. We perform a new benchmark experiment on Mo in order to validate the Mo data in the lower energy region. A rectangular Mo assembly, the size of which is 253 mm × 253 mm × 354 mm, is covered overall with 152 mm thick graphite blocks. Furthermore, the assembly is covered with 51, 101 and 101 mm thick Li2O blocks around the front, side and back surfaces, respectively. The graphite blocks produce neutrons with the lower energy and the Li2O blocks eliminate background neutrons at the measurement points inside the assembly. The assembly is placed at a distance of 103 mm from a DT neutron source. Several dosimetry reaction rates and fission rates are measured in the assembly and compared with the calculated values with the Monte-Carlo transport code MCNP5-1.40 and the recent nuclear data libraries, ENDF/B-VII.1, JEFF-3.2 and JENDL-4.0. It is suggested that the (n,γ) cross section of 9595Mo is underestimated in the tail region below the large resonance at 45 eV in these nuclear data libraries from the comparison of the reaction rate for the 186186W(n,γ)187187W reaction which have a large resonance at 19 eV. Reasons of the underestimation are discussed in detail.
Co-authors
Chikara Konno
(Japan Atomic Energy Agency, Tokai-mura, Naka-gun, Ibaraki, Japan)
Kentaro Ochiai
(Japan Atomic Energy Agency, Rokkasho-mura, Kamikita-gun, Aomori, Japan)
Masayuki Ohta
(Japan Atomic Energy Agency, Tokai-mura, Naka-gun, Ibaraki, Japan)
Saerom Kwon
(Japan Atomic Energy Agency, Tokai-mura, Naka-gun, Ibaraki, Japan)
Satoshi Sato
(Japan Atomic Energy Agency, Tokai-mura, Naka-gun, Ibaraki, Japan)
