Assessment of Benefits for Extended Burnup Credit in Transporting PWR Spent Nuclear Fuel in the USA

This paper presents an assessment of the benefits for extended burnup credit in transporting
pressurized-water-reactor (PWR) spent nuclear fuel (SNF) in the United States. A prototypic 32-
assembly cask and the current regulatory guidance were used as bases for this assessment. By
comparing recently released PWR discharge data with actinide-only-based loading curves, this
evaluation shows that additional negative reactivity (through either increased credit for fuel burnup or
cask design/utilization modifications) is necessary to accommodate the majority of U.S. SNF
assemblies in high-capacity storage and transportation casks. Given sufficient data for validation, the
most significant component that would improve accuracy, and subsequently enhance the utilization of
burnup credit, is the inclusion of fission products (i.e., extended burnup credit). A simple, conservative
assessment of the cost benefits of extended burnup credit is also presented. Based on the estimated
reduction in the number of shipments, achievable with extended burnup credit in the criticality safety
evaluation, the cost savings for the U.S. Department of Energy (DOE) is estimated to be at least
$150M and is most likely in the $200M–$300M range. Evaluation of variations in the relevant input
assumptions used to develop these estimates provides confidence that the actual cost savings may be
much higher but are not likely to be lower.