An Analysis of the Fission Cross Sections of ²³²Th, ²³³U, ²³⁴U, ²³⁵U, ²³⁶U, ²³⁷Np, ²³⁸U, ²³⁹Pu, ²⁴⁰Pu, ²⁴¹PU, and ²⁴²Pu from 1 keV to 10 MeV

The published cross sections of ²³²Th, ²³³U, ²³⁴U, ²³⁵U, ²³⁶U, ²³⁷Np, ²³⁸U, ²³⁹Pu, ²⁴⁰Pu, ²⁴¹Pu, and ²⁴²Pu from 1 keV to 10 MeV have been carefully studied to select best cross sections for fast reactor analysis. Frequently, the measurement is not of the absolute cross section but of the ratio between the unknown and some reference cross section; thus, in comparing measurements, it is important to determine if the same reference data were used in all cases. In this study, emphasis has been placed on determining the reference data used and, where necessary, the published data have been revised to accord with more accurate, currently accepted cross sections. Thus, it is believed that a consistent set of cross-section data has been derived. Some cross checks have been made by comparing calculations based on the selected cross sections with integral measurements in broad fast-neutron spectra. The study shows the great importance of the ²³⁵U fission cross section in deriving other cross sections and emphasizes the necessity of re-evaluating nearly all fission cross sections, if it proves necessary to revise the ²³⁵U data.