Moltex’s WATSS process for converting used uranium oxide fuel into molten salt reactor fuel has been validated on spent nuclear fuel from a commercial nuclear reactor.
     WATSS is short for Waste to Stable Salt. The innovative process extracts valuable materials and radioactive byproducts from spent nuclear fuels in oxide form, including CANDU, light water reactor and certain fast reactor fuels, such as mixed oxide (MOX) fuels. It does this in a single, streamlined twenty four-hour chemical process, with a pretreatment step that the company says can accommodate exotic, experimental, or advanced reactor fuels.
     The extracted transuranic elements are concentrated to produce molten salt fuel. Fission byproducts are removed. This process reduces waste volumes dramatically but also transforms nuclear waste into clean, dispatchable energy. This permanently eliminates long-lived transuranic elements like plutonium, the company says. Coupled with Moltex’s Stable Salt Reactor-Wasteburner (SSR-W) reactor technology, the process enables the creation of a closed fuel cycle.
     The WATSS process has now been validated on spent nuclear fuel bundles from a “commercial reactor in Canada” through hot cell experiments carried out by Canadian Nuclear Laboratories (CNL). CNL has the only facilities in Canada equipped to handle spent nuclear fuel. The experiments revealed that the process can extract ninety percent of the transuranic material from spent nuclear fuel in twenty-four hours, with greater efficiency over longer periods of time, the company said.
     Rory O’Sullivan is the CEO of Moltex. He said, “It’s crucial that increased demand for nuclear energy is matched by increased back-end fuel cycle capabilities. WATSS is a transformative solution that not only reduces liabilities but also adds value, turning waste into a valuable energy asset.”
     The company plans to deploy the first WATSS unit at NB Power’s Point Lepreau site in New Brunswick. It also plans to deploy the first SSR-W by the early to mid-2030s. In a recently released report on its work, Moltex said the commercial-scale demonstration facility will recycle an anticipated two hundred and sixty thousand spent nuclear fuel bundles from existing Candu pressurized heavy water reactors and create recycled fuel for the entire sixty-year operating life of one three-hundred megawatt demonstration SSR-W.
      The development of WATSS has received funding from the Government of Canada, the Province of New Brunswick, and NB Power. Indigenous communities in New Brunswick are also supporting the technology and have invested in its development.
     The North Shore Mi’kmaq Tribal Council and its seven First Nation member communities announced in 2023 that it would be taking a stake in both Moltex Energy Canada Inc and ARC Clean Technology Canada Inc. It has recently signed a memorandum of understanding (MoU) to promote the selection and deployment of Westinghouse technology for nuclear new build projects in New Brunswick.
     Jim Ward is the General Manager of the North Shore Mi’kmaq Tribal Council. He said that the Council’s investment in Moltex was driven by the potential to make nuclear power more sustainable and reduce nuclear waste liability. He added that “Moltex also engaged with us at the earliest stages of the project. We are pleased to see this important milestone being met and look forward to more to come.”

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