Critical Parameters of Plutonium Systems. Part I: Analysis of Experiments

To predict the critical parameters of plutonium fueled systems one must establish the accuracy of the computational methods to be employed and the accuracy and applicability of the available critical experiment data with which the calculations are to be compared. The accuracy of a multigroup diffusion theory code, HFN, and a multigroup transport theory code, DTF-IV, was examined by analyzing recent plutonium critical experiments. The experiments cover the entire range of possible moderation ratios, and the plutonium fuels contain as much as 23.2 isotopic percent ²⁴⁰Pu. All three basic geometries are represented by the experimental data examined. Where necessary, the criticality data were corrected, by means of additional experiments and/or calculations, to conform to one-dimensional, clean, homogeneous critical assemblies which could be adequately defined and used as a basis for establishing nuclear criticality safety guidelines.