Thorium: Sustainable Energy Within Reach

30 November 2025

On 1 November 2025, the Shanghai Institute of Applied Physics (SINAP) within the Chinese Academy of Sciences announced that its experimental reactor TMSR-LF1 has succeeded in performing the first conversion of thorium into uranium-233 in a molten salt reactor (MSR).

Molten Salt Reactor

To understand properly what has happened and why it matters for the Netherlands, we must take a step back.

In the early 1960s, the first experimental molten salt reactor (MSRE) was built in the United States at Oak Ridge National Laboratory. As the name suggests, the reactor uses liquid salt instead of solid fuel rods in high-pressure water systems. The “salt” is a special mixture that melts at high temperatures and can dissolve thorium or uranium. This molten salt acts as both coolant and fuel.

The fission of uranium generates heat, which produces steam. As in any power plant, the steam drives a turbine which produces electricity.

Where a conventional reactor using fuel rods can suffer a “meltdown” (Fukushima) and, in case of system failures, a steam explosion (Chernobyl), these problems do not occur in a molten salt reactor.

The fuel is already molten, mixed with the salt, and the salt remains liquid and stable well above 1000°C. There is no pressure, and none can build up, because the salt stays liquid. In fact, this reactor has a self-regulating capability: when the salt becomes too hot, the fission process slows down and the reactor cools itself. An MSR also produces no significant nuclear waste. Moreover, the newest designs can even use nuclear waste as fuel. The MSR is therefore nuclear energy without the drawbacks!

As early as the 1960s, the American MSRE proved to be a technical success. It demonstrated that the salt was indeed self-regulating and stable at high temperatures. In addition, the reactor could use multiple fuels: enriched uranium and plutonium.

MSR revival

It is no coincidence that molten salt reactors have once again attracted scientific attention. Although the United States ultimately abandoned the MSR program in the 1970s, they made the knowledge gained publicly available.

This brings us to the current Chinese test reactor. In fact, the Chinese MSR is built directly according to the American design from the 1960s.

The Chinese MSR was therefore able to build on American knowledge. This somewhat tempers the scientific significance of the breeding of uranium-233 from thorium, since it was already known that this was possible.

On the other hand, the Chinese reactor includes an improved Hastelloy nickel alloy system, which makes the vessel containing the molten salt more resistant to corrosion from the aggressive salts and intense radiation. Another improvement is newly manufactured graphite. Graphite is the moderator that makes the thorium cycle possible. Its quality is crucial for the reactor’s lifespan, as it can warp or become brittle due to high temperatures.

For now, the Chinese TMSR-LF1 research reactor is still unsuitable for commercial use, but it is not unthinkable that China will soon take steps toward thorium-based energy production.

A thorium plant in the Netherlands

The Netherlands has a unique opportunity to capitalize on these developments. The promising startup Thorizon is already working on developing a commercial molten salt reactor. The offshore company Allseas also intends to equip its fleet with a self-developed SMR (small modular reactor) propulsion system by 2035. Dutch industry is therefore ready to embrace this technology; it is up to the Dutch government to support these efforts to the fullest.

Moreover, large thorium reserves are available; globally, thorium is three times more abundant than uranium. And thorium does not need enrichment, it can simply be converted into a thorium salt for the reactor. Worldwide mining already produces more than enough thorium as waste to power the world, and it costs practically nothing. A single thorium plant uses only a few hundred kilograms of thorium per year, making it a very sustainable form of energy production.

While the Netherlands is effectively already in an energy crisis due to current climate policy, the government continues to ignore a real solution. Instead of investing in sustainable thorium plants, it continues with wind turbines and solar parks, both very unpredictable in energy production. Dutch landscapes and natural areas must give way to unreliable wind and solar energy, even though technology exists which can generate sustainable energy and preserve our natural environment.

It is high time for the government to turn its good intentions to build nuclear plants into real action, and to give full support to initiatives for new forms of nuclear energy in our country.