Criticality parameters of 55-gallon waste drum arrays

This study shows the effects of various parameters on the k-effective of two- and three-dimensionally infinite arrays of 55-gallon drums loaded with plutonium-contaminated wastes. Parameters investigated include fissile material composition, neutron moderation, fissile shape, density and mass, array size, reflectors, iron weight of the drums and array collapse. Changes in fissile density caused very large changes in array k-effective (and k-infinity) of up to 0.30, because of changes in neutron absorption in the drum walls. Differences in k-effective of up to 0.07 were shown between arrays of 17C and 17H drums.