Neutron reactions on 239U

Calculations were made of the major reactions induced by neutrons in the energy range of 10 eV to 2.5 MeV incident on 239U. Both the 23.5 m 5/2+ ground state and the 0.78 μs 1/2+ isomeric state of 239U were considered as targets. The bulk of the calculations were performed with the COMNUC and UHL statistical model codes using Moldauer's optical-model parameters, although a rough correction for direct reactions was also made. The total, shape elastic, compound elastic, inelastic, capture, and fission cross sections are presented in tabular and graphic form over the specified neutron energy range. In addition, the fission cross sections were tentatively extrapolated down to thermal energy where they are compared with an unpublished measurement. For neutron energies above 500 keV the fission calculations are compared with predictions derived from published experimental measurements of the (t,pf) reaction on 238U. (11 figures, 9 tables) (U.S.)