A Safeguards and Security Assessment Comparing the Nuclear Material Attractiveness of Unirradiated and Irradiated Fuels Associated with Existing Power Reactors and Potential Future Small Modular Reactors

The nuclear material attractiveness of fuels from proposed small modular reactors is evaluated relative to fuels from existing commercial power reactors. The methodology for evaluating the materials attractiveness is based on previously used metrics and binning approaches and is consistent with the “attractiveness levels\" that are normally reserved for nuclear materials in DOE nuclear facilities. Commercial power reactor fuels are unattractive at charge but may become attractive years after discharge, depending upon the degree of burn-up, the fuel composition, and the reactor type. Some used Boiling Water Reactor (BWR) and Pressurized Water Reactor (PWR) fuels in the US are over 40 years in age and their radiation dose rates continue to decline, calling into question the “self protecting” nature of these older used fuels. This study examines the attractiveness of used fuel assemblies from typical BWR 7x7, BWR 8x8, PWR 17x17, PWR-MOX 17x17, and VVER-440 reactors. This study indicates that the oldest, very low burn-up US BWR fuels are already attractive, are no longer incapacitating, and in some cases are not even “self-protecting”. A new generation of small modular reactor (SMR) designs promises a number of benefits relative to the existing fleet of commercial power reactors, including portability, viable initial investment level, scalability due to modularity, and improved security. The somewhat shorter length (and hence lighter weight) of SMR fuel assemblies along with the potential for greater decentralization are additional factors that need to be considered. Three PWR SMRs are evaluated. The differences in fuel assembly attractiveness between existing light water reactors (LWRs) and the evaluated SMRs largely come down to differences in fuel assembly size and facility characteristics. This study is consistent with previous studies that demonstrate the importance of ensuring that adequate safeguards and security measures are in place at all nuclear facilities. This study has been performed at the request of the United States Department of Energy/National Nuclear Security Administration (DOE/NNSA).