According to a new study, the world’s push for Small Modular Nuclear Reactors to address climate change will generate more radioactive waste than the larger, existing reactors, and its chemical complexity will make it more difficult to manage.

Published in the peer-reviewed journal of the National Academy of Sciences, the study compared designs for three small modular reactors (SMRs) with a standard pressurized-water reactor… It concluded that most SMR designs will “entail a significant net disadvantage for nuclear waste disposal” and will produce wastes that aren’t compatible with existing disposal practices and facilities…

Traditional reactors have been capable of generating up to 1,000 or more megawatts of electricity, and are water-cooled; their spent fuel is highly radioactive and must be isolated from the environment for hundreds of thousands of years. SMRs by definition produce less than 300 megawatts, and would be cooled by novel substances such as molten salt or helium, producing different wastes…The smaller a reactor is, the more neutrons tend to escape the core and affect other components. That will create more radioactivity in the materials used in the reactor vessel which will have to be accounted for as a waste product. The researchers also determined that fuels from some SMRs would likely need processing to make them suitable for underground disposal.

The researchers found the SMRs would produce between double and 30-fold the volumes of waste arising from a typical reactor. They estimated spent fuel would contain higher concentrations of fissile materials than that from traditional reactors. That means the fuel could be at risk of renewed fission chain reactions if stored in high concentrations, meaning it would need to occupy more space underground. Such assertions contradict marketing claims from many SMR vendors…

In 2021, the Union of Concerned Scientists published a report that concluded many proposed SMRs would require new facilities to manage their wastes. It called claims that SMRs could burn existing waste “a misleading oversimplification.” The report found that reactors can consume only a fraction of spent fuel as new fuel – and that requires reprocessing to extract plutonium and other materials that could be used in weapons, thus raising what the organization described as an “unacceptable” risk.

Excerpt from MATTHEW MCCLEARN,The world’s push for small nuclear reactors will exacerbate radioactive waste issues, researchers say, Globe and Mail, June 3, 2022