Criticality Experiments with Mixed Plutonium and Uranium Nitrate Solution at a Plutonium Fraction of 0.2 and 1.0 in Annular Cylindrical Geometry

Abstract

A series of critical experiments was completed with mixed plutoniumuranium solutions having Pu/(Pu + U) ratios of approximately 0.2 and 1.0. These experiments were a part of the Criticality Data Development Program between the United States Department of Energy (USDOE), and the Power Reactor and Nuclear Fuel Development Corporation (PNC) of Japan. A complete description of, and data from, the experiments are included in this report. The experiments were performed with mixed plutonium-uranium solutions in annular cylindrical geometry. The measurements were made with a water reflector. The central region included a concrete, polyethylene or void annular cylindrical insert. Interior to the insert was a stainless steel bottle containing plutonium-uranium solution or a void region. In one experiment the central region was filled with a solid cadmium-covered polyethylene insert. The concentration of the solution in the annular region was varied from 61 to 489 g (Pu + U)/liter. The ratio of plutonium to total heavy metal (plutonium plus uranium) was 0.22 or 0.97 for all experiments.