Fission Cross Section Ratios and Error Analysis for Ten Thorium, Uranium, Neptunium and Plutonium Isotopes at 14.74 MeV Neutron Energy

摘要

The error information from the recent measurements of the fission cross section ratios of nine isotopes, sup 230 Th, sup 232 Th, sup 233 U, sup 234 U, sup 236 U, sup 238 U, sup 237 Np, sup 239 Pu, and sup 242 Pu, relative to sup 235 U at 14.74 MeV neutron energy was used to calculate their correlations. The remaining 36 non-trivial and non-reciprocal cross section ratios and their errors were determined and compared to evaluated (ENDF/B-V) values. There are serious differences but it was concluded that the reduction of three of the evaluated cross sections would remove most of them. The cross sections to be reduced are sup 230 Th - 13%, sup 237 Np - 9.6% and sup 239 Pu - 7.6%. 5 refs., 6 tabs. (ERA citation 12:034180)