Performance of Up-to-Date Evaluated Nuclear Data Files on Predicted Integral Parameters of Metal Fueled Fast Critical Assemblies

A performance of up-to-date evaluated nuclear data files, ENDF/B-VII.0, JEFF-3.1, JENDL-3.3, JENDL-AC2008 was assessed for three metallic fuelled BFS critical assemblies, BFS-73-1, BFS-75-1, and BFS-55-1 by using Monte-Carlo analysis code MCNP. The impacts of microscopic cross sections in the up-to-date evaluated nuclear data files on integral parameters were clarified by the analyses. The update of Zr cross section leads to the calculated k-effective lower than that of ENDF/B-VI.6. The revision of U-238 inelastic scattering cross section makes large difference in the predicted k-effectives between the libraries, which depends on the amount of U-238 in the fuel among the critical assemblies. The results of the spectral indices and reaction rate ratios shows the improvement of the up-to-date evaluated nuclear data files for the U-238, Np-237, Pu-240 fission reactions, however, there are still need of further improvement for other minor actinide cross sections. In addition to the analyses with existing evaluated nuclear data files, a few isotope-wise combination from the up-to-date data files for better prediction of integral parameters were made and assessed for the BFS critical assemblies. KCI Citation Count: 2