Strides in nuclear nonproliferation efforts at an Oak Ridge National Laboratory (ORNL) have reached beyond U.S. borders to make a tangible impact in Kazakhstan, where a novel approach to processing spent highly enriched uranium (HEU) is being piloted. Spearheaded by Kris Gaines, a nonproliferation specialist at ORNL, the project aims to transform spent nuclear fuel into a state that poses significantly reduced risks of misuse, as opposed to its original form which contains greater than 90% of the fissile U-235 isotope, ORNL reported.
The international collaborative effort includes partners such as the National Nuclear Security Administration (NNSA), International Atomic Energy Agency (IAEA), Idaho National Laboratory, along the National Nuclear Center (NNC) of Kazakhstan, and focuses on the Impulse Graphite Reactor (IGR) in the country, according to the details outlined by ORNL. The process involves grinding down the spent fuel, mixing it with natural or depleted uranium to down-blend the enrichment level, and sealing it in concrete-filled drums, making it a significantly safer low-level waste.
"Due to the type of fuel, other down-blending technologies like 'melt dilute' aren’t feasible options because graphite fuel won’t melt," Gaines told ORNL. Instead, the spent fuel is processed using the new technological methodology which involves a crusher/grinder to initiate a batch operation for pulverizing the fuel into fine particles for subsequent stages of the procedure.
Not only does the technology make the spent HEU irretrievable through cementation, it also exempts it from IAEA safeguards due to the lowered enrichment levels this new process is not permanently in place yet but the essential equipment has been installed at a temporary site in Kazakhstan, with further plans involving the development of a permanent facility, continued training programs for operators, and production of mixing drums needed for processing, which offer insight on its future uses and continued integration into nuclear waste management according to ORNL. These significant steps demonstrate a commitment to reducing nuclear threats and advancing safe, long-term storage solutions for radioactive materials.
As for broader implications, the technology is already being considered for other nuclear applications in Kazakhstan, with ongoing experimental work on various fuel types, “This technology is already being considered for the fuel from Kazakhstan’s other reactor, IVG.1M. We are currently working with NNC to conduct experiments on both melt-dilute and oxidation of this fuel. Preliminary results show that oxidation may be the best option, as the oxidized powder would then be run through the same system we are using for the IGR fuel,” Gaines explained to ORNL. A 3D-printed model of the reactor system was created by ORNL to demonstrate the project’s innovation, with the model on display at the International Conference on Nuclear Security (ICONS) in Vienna, which garnered positive feedback from attendees.
