Nuclear Safety Evaluation of Units Containing 238Pu and 239Pu as Oxides

This study evaluates the nuclear safety of 238Pu and PuO2 under a variety of conditions for shipping and storage and is applicable to mixtures of 238Pu-239Pu oxides. Evaluations were made for a three-container shipping package (Plutonium Finishing Shipping Cask) for compliance with AECM Chapter 0529 Shipping Regulations. Some calculations were also made for the two inner containers as a storage unit to extend the usefulness to cover B-Line storage. This safety analysis was developed with 239Pu and 238Pu cross sections using KENO, a multigroup Monte Carlo criticality program. Conservative allowances were made so that the results are valid for all mixtures of 238Pu-239Pu. For storage conditions a planar array one unit tall of two or three container packages is shown to be safe regardless of water moderation provided the spacing is 2.375'' center-to-center or greater