China Successfully Tests World's First Meltdown-Free Nuclear Reactor

China has successfully tested a nuclear reactor that is the first in the world to pose no risk of a meltdown. This breakthrough addresses a major concern associated with nuclear reactors, alongside the issue of nuclear waste.

While nuclear reactors are generally very safe, the rare instances when things go wrong can lead to catastrophic consequences. The fear of a meltdown, though rare, lingers due to past nuclear disasters such as Chernobyl and Fukushima. In nuclear fission, immense heat is generated to produce electricity, requiring constant cooling to prevent overheating and a potential meltdown.

The challenge until now has been that cooling had to be actively managed, which involves risks of mechanical failure, incorrect settings, or power outages. Thus, active cooling has been a constant concern once the reactor is operational. Passive cooling, on the other hand, would eliminate this worry, allowing the reactor to cool itself. Since 2016, Tsinghua University in China has been working on such a design, and they have now successfully demonstrated a meltdown-free nuclear reactor.

Reversed Method

To achieve passive cooling, the approach had to be reversed. Traditionally, reactors use fuel rods with high concentrations of uranium in a small amount of graphite. The Chinese reactor flips this, using multiple small fuel rods, akin to 'pebbles', with less uranium and a larger amount of graphite surrounding the fuel.

This results in a slower nuclear reaction than in conventional reactors, with the increased graphite volume capable of withstanding high temperatures for longer periods. Additionally, the heat generated is spread over a larger surface area, allowing for passive cooling through cold water or air.

This method has been previously demonstrated on a smaller scale in Germany and China, according to Interesting Engineering. However, this marks the first large-scale reactor of its kind to be built and operational. In December 2023, the reactor was first activated, and once it reached full power, the fission in both modules was halted to observe the temperature changes—a critical moment where past nuclear disasters have occurred. The reactor's design performed as expected, cooling both modules autonomously to a stable temperature within 35 hours.

Potential for Rapid Deployment

A reactor capable of self-cooling in case of cooling failure is extremely safe, notes Professor Mamdouh El-Shanawany, formerly with the International Atomic Energy Agency. The main drawback of this new technology is that it cannot be retrofitted to existing nuclear reactors, necessitating new installations. However, the technology allows for reactors to be constructed off-site, presenting significant opportunities for rapid deployment.

The Chinese plant, with its two reactors, has a capacity of 105 megawatts. While this is small compared to the Borssele nuclear plant in the Netherlands (485 MW) or Europe’s largest nuclear plant in Finland (1600 MW), it aligns with China’s strategy to build small, modular reactors that can be quickly deployed. China aims to become the leading player in nuclear energy.

The Dutch government also plans to expand its nuclear energy capabilities, proposing the construction of four new nuclear plants. These new plants are expected to lower electricity prices and reduce CO2 emissions. Currently, electricity costs in the Netherlands are among the highest in the world at 35 cents per kWh, compared to France’s 20 cents per kWh, thanks to its extensive network of nuclear power plants.