Current Status and Potential Benefits of Burnup Credit for Spent Fuel Transportation

Taking credit for the reduction in reactivity associated with fuel depletion can enable more cost-effective, higher-density storage, transportation, and disposal of spent nuclear fuel (SNF) while maintaining a subcritical margin sufficient to establish an adequate safety basis. This paper will review the current status of burnup credit applied to the design and transport of SNF casks in the United States. The effectiveness of burnup credit for accommodating pressurized-water-reactor SNF in high-capacity casks will be demonstrated by comparing loading curves with actual SNF discharge data. The potential benefits that can be realized using the current regulatory guidance for actinide-only burnup credit will be illustrated in terms of the inventory allowed in high-capacity casks and the concurrent reduction in SNF shipments. The additional benefits that might be realized by extending burnup credit to take credit for select fission products are also illustrated together with a discussion of the type of technical information needed to support a safety basis for full burnup credit (i.e., actinide and fission product credit).