Criticality safety study of unirradiated Cintichem target storage

Sandia National Laboratories has been chosen by the US Department of Energy as the primary domestic source for the production of molybdenum-99, utilizing the Annular Core Research Reactor. The method to be used to produce {sup 99}Mo through the fission of {sup 235}U in 93% enriched UO{sub 2} is based on the process formerly used by Cintichem, Inc. of Tuxedo, New York. The UO{sub 2} is electroplated in a thin coating to the inside of stainless steel Cintichem targets which will be irradiated in the central region of the reactor core. The proposed on-site storage plan for the unirradiated targets is to store them in a dry, secure compartment similar to a file cabinet. Each cabinet drawer will be initially filled with targets and emptied as targets are removed for irradiation. The main objective of this analysis was to postulate and model a set of incredible accident scenarios beyond the proposed storage plan which would possibly induce criticality with the targets in the safe, and determine the k-effective and its associated standard deviation for these conditions. A parametric analysis was performed using Los Alamos National Laboratory`s MCNP (Monte Carlo Neutral Particle) code, Version 4A