Canadian laboratory validates molten salt separation process with real spent fuel, extracting nearly 90% of plutonium in 24 hours

A chemical experiment in Canada involving real commercial reactor spent fuel has achieved noteworthy progress. Canadian Nuclear Laboratories, in shielded hot cells at Chalk River, used irradiated spent fuel from CANDU reactors to validate the first phase of Moltex Energy's waste-to-stable-salt process. The experiment showed that within 24 hours, 89.4% of the plutonium was transferred into the molten salt; by 60 hours, this proportion rose to 94.3%. Meanwhile, the vast majority of uranium remained outside the salt phase, indicating that the process exhibits strong selectivity in separating target elements. This process, named WATSS, is not a plutonium purification route but rather a group separation technology. In addition to large quantities of uranium, spent fuel contains fission products as well as transuranic elements such as plutonium and americium, the latter being a significant source of long-term radiological risk. WATSS uses high-temperature chloride molten salt and specific reducing metals to convert transuranic oxides into salt-soluble forms, while most uranium oxides remain solid. In this experiment, researchers used niobium as the reducing metal; after 24 hours, only 0.05% of uranium entered the salt, dropping to 0.02% after 60 hours, demonstrating that it does not carry large amounts of uranium into the molten salt system.

2026-08-09