Pyroprocessing is a promising technology for recycling used nuclear fuel and improving the associated waste management options. The process electrochemically treats the fuel, causing fission products from the used fuel to accumulate in molten salt electrolytes. An LDRD project with University of Idaho developed methods for reusing the nonradioactive salts to produce a more concentrated radioactive waste form with less volume. By combining optimized salt freezing with optimized salt sorption by zeolites, the volume of high-level waste could be reduced by a factor of five or more compared to baseline pyroprocessing waste technology, which would vastly improve pyroprocessing’s commercial viability.
Crystals from a molten salt deposited on a "cold finger," left, represent a potential method for reducing nuclear waste volume.