Transportation of Commercial Spent Nuclear Fuel Regulatory Issues Resolution

The U.S. industry’s limited efforts at licensing transportation packages characterized as “highcapacity,”
or containing “high-burnup” (>45 GWd/MTU) commercial spent nuclear fuel
(CSNF), or both, have not been successful considering existing spent-fuel inventories that will
have to be eventually transported. A holistic framework is proposed for resolving several CSNF
transportation issues. The framework considers transportation risks, spent-fuel and cask-design
features, and defense-in-depth in context of present regulations as well as in context of future
potential revisions of regulations that would reflect a risk-informed, technically state-of-the-art
approach. Within the boundary limits of cases analyzed, the EPRI-sponsored work shows that
there are no credible combinations of accident events, accident locations, and fuel misloading or
reconfiguration that would result in a critical configuration during the transportation of spent
nuclear fuel. The non-mechanistic criticality evaluation performed in the as-loaded or as-designed
configuration can be considered the bounding case for all conditions of transportation
because this hypothetical reactivity case bounds all those normal and hypothetical accident cases
that can credibly exist for spent-fuel transportation packages. Criticality during hypothetical
transportation accidents should be a regulatory non-issue, given that misallocation of regulatory
requirements can lead to greater overall risks, specifically by increasing the number of shipments
when overly restricting spent-fuel transportation payloads.