An assessment of loading capabilities of OCRWM burnup credit casks

A new generation of spent fuel shipping casks are being developed for the DOE in support of transportation system development activities for the Civilian Radioactive Waste Management (CRWM) program. As part of subcriticality control for design basis accident condition, credit is taken for the burnup of Pressurized Water Reactor (PWR) spent fuel assemblies for a full loading configuration. Therefore, the PWR casks can be used for transporting those PWR spent fuel assemblies which have a certain minimum burnup and maximum enrichment. No burnup credit was needed in the design of casks for transporting boiling water reactor spent fuel assemblies. This paper presents the results of an analysis performed to determine the GA-4 and the BR-100 cask loading capabilities from a criticality standpoint, given the spent fuel discharge from commercial reactors as projected by the DOE Energy Information Administration (EIA). The results indicate that the BR-100 cask can accommodate 96% of the current PWR spent fuel inventory, and the GA-4 cask 99% of the inventory if a full loading requirement is imposed. The PWR spent fuel accommodation by the GA-4 and BR-100 casks are reduced considerably for the No-New-Orders, Lower-Reference, and Upper-Reference cases. The results also indicate that there will be a considerable number of PWR spent fuel assemblies with initial enrichments higher than that used for designing the GA-4 and BR-100 casks