Evaluation of flooded 3 x3x3 arrays of plutonium metal

In the early 1980's, thirteen experiments using plutonium metal cylinders were performed at the Rocky Flats Critical Mass Laboratory. The experimental method consisted of flooding a 3 x3 x3 array with water until criticality was achieved. Ten of the thirteen experiments went critical while the other three remained subcritical upon full reflection. This paper evaluates these experiments to develop benchmark descriptions for validation of computational tools used by criticality safety specialists. Six of the ten critical experiments were found acceptable as benchmark experiments. Sensitivity studies were performed to find the effect of experimental limits and uncertainties on the keff value. Analysis of the experiments was performed by MCNP with continuous energy ENDF/B-V cross section data. Keff values for all benchmark experiments were computed using MCNP with ENDF/B-V data, KENO-Va with Hansen Roach cross section, and KENO-Va with 27-group ENDF/B-IV cross sections. Although these experiments were flooded, KENO-Va calculations show that these were, in fact, fast systems. 3 refs., 1 fig., 7 tabs