PROVING RELIABILITY | SMRS & ADVANCED REACTORS
successive generations of testing. Crucially, the ability to manufacture pumps internally at relatively low cost has enabled the company’s high-volume testing model.
Curing the corrosion issue Among the most persistent technical concerns in MSR development is corrosion. High-temperature fluoride and chloride salts are inherently reactive and are associated with significant material degradation. However, new research conducted jointly with the University of Liverpool and Copenhagen Atomics suggests that this issue may be far more manageable than previously assumed provided that salt chemistry is properly controlled. The study, published in the Journal of Nuclear Materials,
examined corrosion behaviour in standard 316L stainless steel exposed to molten salts at temperatures up to 700°C. The results found that salts containing moisture and oxides caused severe corrosion within 1000 hours. Conversely, purified salts resulted in negligible corrosion even after 3000 hours, with only a thin protective layer forming on the exposed surface of the steel. The salt purification process is a patented and
commercially sensitive approach which has also been developed in-house by the Copenhagen Atomics team. Crucially, in addressing the corrosion issue this process enables the use standard 316L stainless steel rather than exotic high-nickel alloys such as Inconel or Hastelloy. This has far-reaching implications for MSR economics as stainless steel is not only significantly cheaper, but also more widely available and easier to fabricate. “Stainless steel is roughly 10 times less expensive than some of the exotic materials,” Pedersen explains. “That directly reduces the cost of the reactor and ultimately the cost of energy.” There are also downstream benefits in terms of lifecycle
management as stainless steel is more straightforward to recycle. In the Copenhagen Atomics’ design, structural components such as pumps, heat exchangers and the reactor core are replaced approximately every five years due to neutron-induced material degradation. While these components become highly radioactive and cannot be refurbished, they can eventually be recycled after sufficient cooling. “The great thing about metals is that we’re very good at recycling them. After about 30 years, you can melt everything down, separate the radioactive slag, and reuse most of the steel,” says Pedersen. This approach reduces long-term waste volumes, with less than 10% of material ultimately requiring disposal as high-level waste.
A reactor based on reliability Underlying both the pump and corrosion developments is a consistent theme: reliability as the foundation of commercial viability. Pedersen points to historical experience with advanced reactor concepts such as sodium- cooled fast reactors and argues that technical feasibility alone is insufficient to achieve commercial success. He observes that many advanced reactor designs have failed to achieve widespread deployment due to operational complexity and reliability challenges. High capacity factors are essential not only for nuclear competitiveness, but for industrial applications requiring continuous, low-cost energy, Pedersen states, explaining: “If the very first commercial reactor only runs 20 or 30% of the time, it will be seen as a failure. We need to be successful from the beginning and the only way to do that is through extensive testing.”
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Beyond the testing programme, Copenhagen Atomics
ultimately aims to deliver energy at a cost significantly below that of conventional nuclear and even fossil-fuelled generation. Indeed, Pedersen suggests that their technology could achieve prices “roughly half” those of coal-fired power. While such claims have yet to be validated, they do reflect
the company’s strategic focus on core industrial energy markets such as steel, aluminium and ammonia where energy cost is a primary driver of competitiveness. Pedersen believes that molten salt reactors, with their high
operating temperatures and potential for high load factors, are both well suited to such applications and cost effective. Nonetheless, despite reaching important milestones in terms of technical progress, significant hurdles remain. Chief among these is regulatory approval, which Pedersen acknowledges will likely take longer than initially anticipated. Commercial deployment is now projected around 2030–2031, contingent on licensing timelines in multiple jurisdictions. “We expect it will take a number of years before customers
receive licenses and we can start building,” Pedersen says. Even so, by systematically generating long-term data
on component performance and materials behaviour, the company is building the evidence base required for regulatory approval and investor confidence. As Pedersen puts it: “What matters is whether the underlying components have been tested long enough to satisfy regulators and customers. This is how we turn molten salt reactors from a promising concept into an engineered, licensable technology.” In a sector where ambition has often outpaced execution, that distinction may prove critical. ■
A study looking at corrosion behaviour in standard 316L stainless steel exposed to molten salts at temperatures up to 700°C found purified salts resulted in negligible corrosion. Source: Copenhagen Atomics
A conceptual graphic of a Copenhagen Atomics MSR power plant. Source: Copenhagen Atomics
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