A Model for the Safe Storage of Fissile Solutions

A model has been developed for calculating critically safe storage configurations of cylindrical vessels containing aqueous solutions of UO₂F₂ (93.2% ²³⁵U) and Pu(NO₃)₄ (95% ²³⁹Pu and 5% ²⁴⁰Pu). The method deals with square lattice arrays of cylindrical vessels in air surrounded by concrete walls. This model uses the concepts of surface density and unit surface -to -volume ratio to define safe array parameters. Important factors that influence this storage model are the shape of the individual storage units, storage room height, storage vessel wall thickness, and the effects of body reflection of personnel among the storage vessels. Accidental solution spills in the form of thin slabs of solution on the floor of an array also strongly influence the array parameter, surface density, and, consequently, storage or processing facility capacity.