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

This report investigates trends in the radiological decay properties and changes in relative nuclide importance associated with increasing enrichments and burnup for spent LWR fuel as they affect the areas of criticality safety, thermal analysis (decay heat), and shielding analysis of spent fuel transport and storage casks. To facilitate identifying the changes in the spent fuel compositions that most directly impact these application areas, the dominant nuclides in each area have been identified and ranked by importance.