Subcritical Limits for Special Fissile Actinides

Publisher Website
Google Scholar
Abstract
Critical masses and subcritical mass limits in oxide-water mixtures were calculated for actinide nuclides other than 233U, 235U, and 239Pu that have an odd number of neutrons in the nucleus; Sn transport theory was used together with cross sections, drawn from the GLASS multigroup library, developed to provide accurate forecasts of actinide production at Savannah River. The subcritical limits are: 201 g for 241Pu, 13 g for 242mAm, 90 g for 243Cm, 30 g for 245Cm, 900 g for 247Cm, 10 g for 249Cf and 5 g for 251 Cf Association of 241Pu with an equal mass of 240Pu increases the 241Pu limit to a value greater than that for pure 239Pu. Association of 242mAm with 241 Am increases the limit for the mixture to that for dry, theoretical density AmO2 at isotopic concentrations of 242mAm less than ∼6%. Association of 245Cm with 244Cm increases the limit according to the formula 30 + 0.3 244Cm/245Cm up to the limit for dry CmO2. A limiting mass of 8.15 kg for plutonium containing at least 67% 238Pu as oxide was calculated that applies (provided 240Pu exceeds 241Pu) with no limit on moderation.

This publication has 10 references indexed in Scilit: