Thorium-based SMRs: A Potential Nuclear Threat?

While Small Modular Reactors (SMRs) using thorium as fuel promise reduced nuclear waste and improved safety features, they also harbor significant dangers. The production of uranium-232 in these reactors poses a serious threat, as it emits highly penetrating gamma rays, making material handling extremely hazardous. Additionally, the molten salt mixture used in some thorium reactors is highly corrosive, necessitating specialized materials to withstand its harsh effects.

There are also proliferation risks, since thorium reactors can produce uranium-233, which, although less suited for weapons than plutonium, still poses a potential threat if not properly managed.

Although uranium is a finite resource, scientists are searching for long-term solutions for nuclear power. According to a report from the International Atomic Energy Agency (IAEA), thorium-based fuels offer enhanced capabilities for high conversion ratio fuel cycles and improved inherent safety characteristics. However, these benefits come with the caveat of reduced minor actinide production, presenting additional challenges.

What is Thorium?

Thorium, a radioactive metal mined from solidified magma or lava, is significantly more abundant than uranium. However, it is not a nuclear fuel in itself and requires extra steps to be used in nuclear power generation. The natural isotope of thorium, Thorium-232, must undergo nuclear fission with the help of high-energy neutrons to release energy. This process eventually transforms it into uranium-233, which can fuel nuclear reactors. Despite producing less nuclear waste than typical uranium reactors, thorium reactors still pose environmental and health risks.

Environmental Impact: The Piketon Case

In Piketon, Ohio, the EPA found that hazardous radioactive materials, including Technetium-99 (Tc-99) and Thorium-230, were detected this year at levels exceeding administrative thresholds in Little Beaver Creek. The contamination was traced to outflows from the plant’s on-site radioactive waste dump.

Thorium-230:
- Detected at 5.65 pCi/L at X780-SW08 in the first quarter and 2.32 pCi/L at X780-SW06 in the second quarter.
- Thorium-230 emits alpha radiation, which can cause severe internal damage if inhaled or ingested.

While thorium-based SMRs might hold promise, their potential dangers and environmental impact cannot be overlooked. Careful management and stringent safety measures are crucial to mitigating these risks.