Review of DOE criteria for safe storage of Pu metals and oxides.

A technical review of the DOE criteria for storage of plutonium metals and oxides determined the maximum pressure that could be obtained from 50-year storage of 5.0-kg of PuO{sub 2} powder under the assumed worst-case conditions derived from the DOE standard [1,2]. Those conditions included a final temperature of 400 F and the reaction to yield H{sub 2} gas in accordance with the equation PuO{sub 2}(c) + x H{sub 2}O {r_arrow} PuO{sub 2+x}(c) + x H{sub 2}(g) where the x moles of sorbed water represents 0.5 wt.% of the PuO{sub 2}. The worst-case conditions also included the generation of He gas from the 50-year {alpha}-decay of the plutonium, that was considered to be power grade plutonium with the maximum limit of 3% for the short-lived isotope, Pu-238. The free volume for containment of the gases generated in the primary containment vessel, assuming failure of its inner boundary container, was assumed to be 2.5-L value given in the original standard