A Promising Process For Nuclear Fuel Re-use and Disposal?

A Canadian lab has run a chemical process on real spent nuclear fuel “and pulled out 90% of the long-lived danger in 24 hours, the part that forces a burial site to last 100,000 years,” notes the blog Autonocio, “with the leftovers meant to fuel a reactor.”

The standard plan for spent nuclear fuel is to wait it out. You pull the used bundles from a reactor, sit them in a pool of water for seven to ten years while the heat and radiation come down, seal them in concrete casks, and look for somewhere deep and geologically dull to leave them for the next hundred thousand years. Canada has been hunting for that burial site since the 1980s and still doesn’t have one in the ground.

A company in Saint John, New Brunswick thinks most of what makes that waste dangerous never needed to go in the ground at all. Moltex Energy Canada says a chemical process it calls WATSS can strip 90% of the long-lived material out of used Canada Deuterium Uranium [CANDU] fuel in 24 hours, and that the concentrated leftovers become fuel for a reactor it wants to build on the same site. The recovery step isn’t a slide in a pitch deck anymore. In 2025, World Nuclear News reported that Canadian Nuclear Laboratories ran the process on real used fuel from a commercial Canadian reactor and confirmed the 90% figure.

None of it is generating power yet. What exists is a validated chemical step and a reactor design waiting in line at a regulator. The rest is a 2030s problem.
“The chemistry has a lab result behind it. The reactor does not exist…” the article points out. “Moltex is aiming to have its first WATSS and SSR-W units running at Point Lepreau by the early-to-mid 2030s… Not everyone buys the pitch. Critics have argued the reprocessing creates its own stream of byproducts, that the economics are unproven, and that a single site’s stockpile is finite.”

But Moltex “isn’t alone in trying to burn nuclear waste instead of bury it,” the article notes, with Switzerland and Denmark “chasing the same goal a different way.”

Switzerland’s Transmutex drives a subcritical reactor with a particle accelerator, feeding it spent fuel alongside thorium… Denmark’s Copenhagen Atomics is building a thorium molten-salt reactor that fits inside a shipping container and runs on the leftovers from conventional plants.

Thanks to long-time Slashdot reader kwelch007 for sharing the article.