Publication
The determination of resonance parameters for neutron interactions with material is a complex process. In most cases it is very difficult to de termine an ac curate es timate of th e fu ll se t of parameters from an analysis of energy dependent cross section data. In this work, a procedure is presented to adjust the resonance parameters for neutron interaction with Pu-239, Pu-240 and Pu-241 by combining the results of depletion calculations, criticality benchmarks together with energy dependent cross section data from the EXFOR database. The addition of microscopic data in the adjustment is different f rom t he g enerally a ccepted a pproach a nd t he k ey n ovelty o f t his w ork as it ensures that the results of the procedure are in agreement with the microscopic data within the margins specified in the constraints. The overestimation of the reactivity loss with exposure of a recent test version of the JEFF nuclear data library (JEFF-4T2.2) is improved drastically together with the underestimation of the Pu-239 concentration. Both kin f and Pu-239 obtained with JEFF-3.1.1 and JEFF-4T2.2 for the VERA-1C pincell depletion problem are now in agreement, e.g. with 100 pcm and 1% respectively, through the exposure considered.