Validation of Np-237 cross sections by analysis of BFS critical experiments with massively neptunium-loaded cores

Abstract
Three series of BFS critical experiments loaded approximately with 10 kg of ²³⁷Np-dioxide were analyzed to verify the performance of major libraries with the ²³⁷Np nuclear data. The latest JENDL-3.3, ENDF/B-VII.0 and JEFF-3.1 showed satisfactory results from the ²³⁷Np data viewpoint; however some other major data such as ²³⁹Pu ν and fission, ²³⁸U µ and/or the sodium inelastic scattering cross sections of some libraries may need re-evaluation. Further, the effect of integral experimental information to obtain better predictions of reactor core parameters was demonstrated by the cross section adjustment method.