Neutron-induced fission cross section of 242Pu from 0.3 MeV to 3 MeV

The majority of the next generation of nuclear power plants (GEN-IV) will work in the fast neutron energy region, as opposed to present day thermal reactors. This leads to new and more accurate nuclear data needs for some minor actinides and structural materials. Following those upcoming demands, the OECD-Nuclear Energy Agency performed a sensitivity study. Based on the later, an accuracy improvement from the present 20% to a 5% is required for the 242Pu(n,f) cross section. Within the same project both the 240Pu(n,f) cross section and the 242Pu(n,f) cross section were measured at the Van de Graaff accelerator of the JRC-IRMM, where quasi-monoenergetic neutrons have been produced in an energy range from 0.3 MeV up to 3 MeV. A Twin Frisch-Grid Ionization Chamber (TFGIC) has been used in a back-to-back configuration as fission fragment detector. The 242Pu(n,f) cross section has been normalized to three different isotopes: 237Np(n,f),235U(n,f) and 238U(n,f). A comprehensive study of the corrections applied to the data and the uncertainties associated is given. The results obtained are in agreement with previous experimental data at the threshold region up to 0.8 MeV. The resonance-like structure at 0.8-1.1 MeV, visible in the evaluations and in most of previous experimental values, was not reproduced with the same intensity in this experiment. For neutron energies higher than 1.1 MeV, the results of this experiment are slightly lower than the ENDF/B-VII.1 evaluation, but in agreement with the experiment of Tovesson et al. (2009) as well as Staples and Morley (1998). Finally, for energies above 1.5 MeV, the results show consistency with the present evaluations.JRC.D.4-Standards for Nuclear Safety, Security and Safeguard