In the quiet deserts of China’s Gansu Province, a small experimental reactor has quietly turned a long-discussed nuclear idea into working reality.

China now claims to be operating the world’s first thorium-fuelled molten salt reactor, an achievement explored in detail in the ColdFusion video “How China Won the Thorium Nuclear Energy Race.” (watch below) built on declassified American research from the 1960s, this reactor marks a turning point: thorium power has finally moved from theory and advocacy talks into a functioning system connected to real hardware and real data.

Zhangye Danxia Landform Geological Park, Gansu China

From Fossil Fuels to a New Nuclear Option

Since the Industrial Revolution, most of our energy has come from burning fossil fuels (coal, oil, and gas) to make heat, turn turbines, and light up cities. It works, but at a heavy cost: air pollution, enormous healthcare burdens, millions of premature deaths, and greenhouse gas emissions driving climate change.

Conventional nuclear power arrived after World War II as a radically more energy-dense alternative. A small amount of uranium fuel can replace mountains of coal. But accidents like Three Mile Island, Chernobyl, and Fukushima have shaped public perception for decades, and the association with nuclear weapons never helped.

Thorium has long been discussed as a way to keep the advantages of nuclear energy while reducing many of its risks. It is more abundant than uranium, more proliferation-resistant, and used in molten salt reactors, can be engineered so that a classic “meltdown” is physically impossible. For years, this was mostly the subject of research papers, conference talks, and hopeful YouTube explainers. As highlighted in the ColdFusion documentary, China has now taken the next step and actually built a working prototype.

What Makes a Thorium Reactor Different?

Thorium itself is a naturally occurring element found in rocks, sands, and mining waste. But there’s a key catch: the main isotope, thorium-232, is not fissile. It cannot sustain a chain reaction on its own. Instead, it is fertile—it can be converted into a usable fuel.

Thorium

Here’s the basic thorium fuel cycle:
  1. Thorium-232 absorbs a neutron and becomes thorium-233.
  2. Thorium-233 beta decays into protactinium-233.
  3. Protactinium-233 beta decays into uranium-233.
  4. Uranium-233 is fissile: when struck by neutrons, it splits, releasing energy and more neutrons.

Those released neutrons keep the chain reaction going and also convert more thorium into fresh fuel. In principle, this allows a self-sustaining thorium fuel cycle, but only if the reactor is designed to handle the chemistry involved in isolating and managing those intermediate materials, especially protactinium.

This is where molten salt reactors come in.

Why Molten Salt Reactors Matter

Most existing nuclear plants use solid fuel rods cooled by pressurised water. That design is familiar and well understood, but it makes thorium’s complex fuel cycle awkward. Trying to handle intermediate elements inside solid fuel assemblies is technically difficult and expensive.

Molten salt reactors flip the script:
  • The nuclear fuel (including thorium and uranium-233) is dissolved in a hot, liquid salt.
  • That fuel-salt mixture circulates through pipes and a reactor core at high temperature but low pressure.
  • Because the fuel is a liquid, you can, in principle, siphon off and process parts of it while the reactor is running/isolating protactinium, removing fission products, and topping up fuel continuously.

This design enables features that are especially attractive for safety:
  • No high-pressure water: There is no giant vessel full of super-pressurised water that can flash to steam in an accident.
  • Passive shutdown: In designs like China’s test reactor, a “freeze plug” made of solidified salt sits at the bottom of the core. If the system overheats or loses power, that plug melts, and gravity drains the fuel into separate, passively cooled tanks where the reaction stops. No pumps, no operator intervention, no grid power required.

In short: molten salt reactors are a natural partner for thorium. They make the tricky fuel chemistry possible and enable safety features that directly address the nightmare scenarios people associate with older nuclear designs.

The Four Big Promises of Thorium

Advocates highlight four main advantages of thorium-based molten salt reactors:

1. Abundance

Thorium is at least three times more abundant than uranium in the Earth’s crust. It shows up in common minerals and in the waste from rare earth mining.

For China, this is especially convenient. Thorium is already a waste byproduct of its rare earth industry, meaning:
  • No need for dedicated thorium mines.
  • Existing waste piles could, in principle, become valuable energy reserves.

Some estimates suggest that China’s thorium reserves alone could power the country for many thousands of years if the technology scales.

2. Safety and Proliferation Resistance

Thorium-232’s very weakness—its inability to fission directly—is also a safety advantage:
  • The reactor’s fissile inventory can be more tightly controlled.
  • The system naturally tends toward a kind of “automatic throttling,” because the fuel salt expands as it heats, reducing reaction rates.

Pro-thorium experts also emphasise that thorium fuel cycles are less attractive for weapons. It is not that weapons are impossible, but that using thorium as a feedstock for bombs is more complex and more expensive than conventional plutonium routes, which is exactly what you want from a civil power system.

Finally, the use of molten salt and low pressure eliminates many of the pathways to catastrophic steam explosions or fuel rod failures seen in legacy designs.

3. Cleaner Waste

Thorium reactors still produce radioactive waste, but the profile of that waste is different:
  • Far less long-lived transuranic elements (like plutonium and americium).
  • Most waste becomes relatively safe on the timescale of a few hundred years, instead of tens of thousands.
  • The compact, high-burnup fuel cycle means less total waste for the same energy output.

Compared to coal, whose ash piles actually contain more dispersed radioactivity than the emissions of a well-run nuclear plant, thorium reactors are an enormous environmental upgrade.

4. High Efficiency

One of thorium’s most eye-catching claims is efficiency. In an ideal molten salt thorium system, the energy extracted per unit of fuel could be up to 200 times higher than in today’s once-through uranium fuel cycles.

ColdFusion illustrates this with a simple analogy:
  • If a “uranium battery” powers you for one day,
  • a “thorium battery” of the same size could, in theory, power you for over six months.

High efficiency means fewer mines, less transport, less waste, and a much smaller environmental footprint per unit of energy delivered.

The American Blueprint China Picked Up

None of this is entirely new. The core ideas were tested in the United States at Oak Ridge National Laboratory in Tennessee.

In the 1960s, under director Alvin Weinberg, Oak Ridge built and operated the Molten Salt Reactor Experiment (MSRE). Running from 1965 to 1969, it demonstrated that:
  • Molten salt fuel can be circulated safely.
  • The reactor can be stable and controllable.
  • Thorium-based cycles are technically viable.

The Molten Salt Reactor Experiment, 1965, Oark Ridge, USA

As the Bulletin of the Atomic Scientists later noted, essentially all modern molten salt reactor designs trace back to Oak Ridge in one way or another.

Weinberg imagined a future where thorium reactors would:
  • Desalinate seawater.
  • Grow crops in deserts.
  • Provide abundant, low-carbon power to regions without fossil fuel reserves.

His vision was ambitious and deeply focused on civil prosperity, not weapons. That, ironically, was part of the problem.

Why Oak Ridge Was Shut Down

Despite its technical success, the molten salt project was cancelled in the early 1970s. Weinberg himself lost his job. In his memoirs, he wrote that there were no technical reasons for abandoning the concept. So what happened?

Several factors converged:
  • Cold War priorities: The U.S. military wanted reactors that produced plutonium and supported the weapons programme. Thorium and uranium-233 were less interesting for that purpose.
  • Institutional inertia: The nuclear establishment was already heavily invested—financially and intellectually—in solid-fuel, water-cooled designs.
  • Regulatory path dependence: As later noted, U.S. regulations ended up effectively discouraging fluid-fuel reactors by making them much harder to license above trivial power levels.

In short, thorium and molten salt reactors were “too different,” too chemical, and not aligned with the strategic and industrial priorities of the day. So the reports were archived, the blueprints filed away, and the concept went dormant.

China Picks Up the Thorium Torch

Fast-forward to the 2000s. NASA engineer Kirk Sorensen, researching how to power a lunar base, rediscovered the Oak Ridge documents and became one of thorium’s most vocal modern advocates. He argued that, had the U.S. continued Weinberg’s work, the country might already be energy independent on thorium today.

While his warnings were mostly ignored in Washington, they resonated elsewhere.

China's Thorium Molten Salt Reactor (TMSR)

Chinese scientists began combing through the declassified Oak Ridge material—thousands of pages of design notes, experimental logs, and chemistry data. They saw a path to:
  • Secure, long-term domestic energy.
  • Reduced dependence on imported fuels.
  • A leadership position in next-generation nuclear technology.

In 2009, China formally launched its thorium molten salt reactor (TMSR) programme. Construction of a small experimental reactor in the Gobi Desert began in 2018. Hundreds of scientists worked long hours to:
  • Reproduce Oak Ridge’s results.
  • Develop new materials to handle hot, corrosive salts.
  • Adapt the designs to modern engineering standards.

By 2023, the reactor achieved a sustained chain reaction. By mid-2024, it was declared operational—albeit at a small experimental scale of about 2 megawatts thermal.

For context, that is tiny compared to a commercial gigawatt-scale power reactor. But technically, it is a world first: a working, thorium-capable molten salt reactor, informed by Oak Ridge but implemented in a new national context.

Chinese researchers have also demonstrated the ability to add fresh fuel while the reactor is running—one of the key steps toward continuous, long-term operation.

Plans now call for a larger, roughly 60-megawatt version by around 2030, stepping gradually toward practical power generation.

The Hard Problems: Cost, Chemistry, and Materials

For all the promise, the ColdFusion video also emphasises the realities and caveats that thorium advocates must confront.

Economics

Thorium itself is cheap and abundant, but fuel cycle infrastructure is not. Turning thorium from ore into reactor-ready material, then managing the complex in-reactor chemistry and reprocessing, is expensive and technically demanding.

Historically, several thorium-using test reactors in Germany, India, the Netherlands, and the U.S. were shut down not because they did not work at all, but because:
  • They were more expensive than uranium systems under prevailing conditions.
  • Fuel handling and reprocessing costs outweighed the theoretical efficiency gains.

If thorium is to compete today, it must do so in a world where solar, wind, and advanced uranium reactors have also become cheaper and more mature.

Reprocessing and Waste Management

To reach the full “200× energy” potential, thorium fuel needs to be reprocessed:
  • Fission products that poison the reaction must be removed.
  • Protactinium and uranium-233 must be managed carefully.

That means building and operating complex chemical plants alongside each reactor. These facilities must be safe, reliable, and economical over decades.

Materials and Corrosion

Molten salts at 600–700°C (and higher) are harsh on metals. Long-term operation demands structural materials that can survive:
  • High temperatures.
  • Strong radiation fields.
  • Chemically aggressive salts.

China’s team has developed and tested a custom alloy (often referred to as Hastelloy-type materials) to handle these conditions, but real-world performance over decades remains to be proven.

A Global Race Slowly Wakes Up

China may be in the lead, but it is not alone in exploring molten salt and thorium combinations.
  • India has massive thorium reserves and has investigated thorium fuels for decades, though its path has been complicated by international non-proliferation politics and other priorities.
  • European startups, such as Copenhagen Atomics, are working on modular molten salt reactors and plan test systems in Switzerland and beyond.
  • U.S. and other Western companies are reviving molten salt concepts, though most projects remain on paper or in small-scale R&D.

What distinguishes China is the combination of:
  • Long-term state funding.
  • Clear strategic motivation (energy security and technology leadership).
  • Willingness to invest 20–30 years into a single technological bet, as quoted in the ColdFusion feature.

If their programme succeeds, thorium molten salt reactors could:
  • Deliver compact, high-temperature reactors that do not require river or coastal water for cooling—ideal for deserts.
  • Support industrial heat applications (steel, cement, hydrogen) that renewables alone struggle to serve.
  • Eventually extend to off-world use, where thorium’s presence on the Moon makes it a candidate for extraterrestrial power systems.

Hype, Hope, and the Path Ahead

So is thorium the “holy grail” of clean energy, or a beautiful idea that will struggle to escape niche demonstration projects?

The honest answer, reflected in the tone of “How China Won the Thorium Nuclear Energy Race,” is: it’s both promising and unproven.
  • The physics is sound.
  • The safety concept is elegant and addresses real historical failures.
  • The fuel abundance and waste profile are genuinely attractive.

But:
  • The engineering is still being shaken out at small scales.
  • The economics are uncertain in a world where renewables and storage are rapidly improving.
  • The regulatory environment in many countries is still geared toward older reactor types, making licensing something radically new a long, bureaucratic slog.

What China has done is show that:
  1. The molten salt thorium concept can be turned into actual hardware in the 21st century.
  2. Declassified public research from one era can seed breakthrough projects in another, if someone is willing to commit for decades.

For supporters of thorium and molten salt reactors, that is an encouraging sign. For skeptics, it is still just an early experiment.

Either way, the race has restarted—and this time, China is out in front with the design that America once pioneered and then put on the shelf.

The real question now is not whether thorium is theoretically attractive, but whether governments and industries around the world are willing to invest the time, money, and political capital to find out how far this technology can really go.