Evaluation of the accuracies on the FBR shielding design with JENDL-4.0 based on the analyses of the mock-up shielding experiments for the FFTF

Masuyama, Daisuke*; Fukuchi, Ikuo*; Morohashi, Yuko 

Analyses with the Japanese latest nuclear data library JENDL-4.0 were carried out on the neutron bulk shielding experiments in Fast Flux Test Facility (FFTF). FFTF is one of the experiments useful to evaluate the FBR shielding design accuracies. Neutron attenuation rates in several materials, such as sodium and stainless steel were measured using activation-foils method and recoil type neutron detectors. An effective macroscopic cross section set composed of 199-group for neutron was calculated with JENDL-4.0, and simulation analyses were performed using the two-dimensional discrete ordinate calculation code, DORT. C/E values for the fast neutron (67 keV-2.2 MeV) and the total neutron (5.5 keV-2.2 MeV) fluxes, and neutron capture reactions for the foils were evaluated. The C/E values become smaller than 1.0 in general, whereas the existing results referred in the current Monju shielding design based on nuclear data library ENDF/B-IV are larger than 1.0.