The World's First Thorium Molten Salt Reactor in China

In a groundbreaking advancement for nuclear energy, China has successfully achieved the world’s first thorium-to-uranium fuel conversion in an operational thorium-based molten salt reactor (TMSR).

This milestone, announced on November 1, 2025, by the Shanghai Institute of Applied Physics under the Chinese Academy of Sciences, marks a significant step toward sustainable and abundant nuclear power.

The experimental reactor, known as TMSR-LF1, is located in the Gobi Desert and represents China’s leadership in next-generation nuclear technologies.

As the global energy landscape shifts toward cleaner sources, this development could reshape how nations approach nuclear fuel and energy security.

China’s Current Energy Mix

China, the world’s largest energy consumer, relies on a diverse but coal-dominated energy portfolio. As of 2025, coal accounts for approximately 55% of electricity generation, making it the backbone of the country’s power system.

Hydropower contributes around 14%, while solar power has surged to 11%, reflecting rapid growth in renewables.

Wind and other clean sources are also expanding, with wind generation up 16% and solar up 43% in the first half of 2025 compared to the previous year.

Nuclear power currently makes up about 2.8% of the total energy mix, but it is projected to grow significantly, with output expected to increase by 56% by 2040.

In terms of total primary energy, coal dominates at 60.9%, followed by oil at 18.3% and natural gas at 7.9%.

However, China’s push for carbon neutrality by 2060 is driving a transition, with renewables (including hydro) comprising 91% of new capacity additions in early 2025.

Clean electricity generation hit a record 951 TWh in the first quarter of 2025, up 19% year-over-year, as solar and wind overtook hydro for the first time.

This evolving mix underscores the need for innovative technologies like thorium reactors to reduce reliance on fossil fuels and enhance energy independence.

Energy Source	Share in Electricity Generation (2025)	Key Trends
Coal	55%	Declining share amid clean energy push
Hydropower	14%	Stable but overtaken by solar/wind in Q1
Solar	11%	43% growth in H1 2025
Wind	~10% (estimated from growth)	16% growth in H1 2025
Nuclear	~3-5% (growing)	Expected 56% expansion by 2040
Other (Gas, Oil, etc.)	Remaining	Fossil fuels falling overall

Details of the Experimental Thorium-to-Uranium Fuel Conversion

The TMSR-LF1 reactor utilizes a unique process to convert thorium-232 into fissile uranium-233, enabling sustained nuclear fission.

Unlike traditional uranium reactors, this molten salt design dissolves nuclear fuel in a liquid coolant, allowing for continuous circulation and real-time fuel management.

The conversion begins with thorium-232, a naturally abundant isotope, absorbing a neutron to form thorium-233.

Thorium-233 then undergoes beta decay to become protactinium-233, which further decays into uranium-233—a fissile material capable of sustaining a chain reaction.

This “breeding” process occurs in a precise sequence within the reactor, where thorium-232 continuously captures neutrons and transforms into uranium-233, which then releases energy through fission.

The reactor uses fuel enriched to under 20% uranium-235, with an initial thorium inventory of about 50 kg and a conversion ratio of approximately 0.1.

This setup not only initiates the reaction but also allows for online refueling without shutdown, as demonstrated earlier in 2025.

The entire process paves the way for scaling up to a 100 MW commercial version, highlighting its efficiency in fuel utilization.

Benefits of Using Thorium as a Fuel SourceThorium offers several advantages over conventional uranium-235 as a nuclear fuel, making it a promising option for future energy systems.

Abundance and Availability: Thorium is three to four times more abundant in the Earth’s crust than uranium and is often found in monazite sands, making it easier and cheaper to mine.

Nearly all thorium can be converted into fuel, vastly expanding global reserves.
Reduced Nuclear Waste: Thorium reactors produce significantly less long-lived radioactive waste, with half-lives around 500 years compared to tens of thousands for uranium waste.

They also generate less plutonium, reducing proliferation risks.

Safety and Efficiency: Thorium oxide has a higher melting point (3,300°C) than uranium dioxide, enhancing reactor safety.

Molten salt designs like TMSR require no water for cooling, minimizing meltdown risks, and allow for higher burn-up rates and longer reactor lifecycles.

Breeding Capability: Thorium can “breed” more fissile material (uranium-233) than it consumes, potentially providing an almost endless energy supply.

This improves fuel efficiency and supports energy independence.

These benefits position thorium as a cleaner, safer alternative, particularly in molten salt reactors.

Implications for Global Nuclear Markets

China’s success with the TMSR could disrupt the global nuclear industry, where uranium-based reactors currently dominate.

By pioneering thorium technology, China—responsible for about 90% of its development—may become the leading exporter of advanced nuclear systems, challenging Western dominance.

This could accelerate the adoption of fourth-generation reactors worldwide, emphasizing waste reduction and proliferation resistance.

For markets, thorium’s abundance might stabilize fuel prices and reduce dependence on uranium imports, benefiting resource-poor nations.

However, challenges like reprocessing needs and initial costs could slow global uptake.

If scaled, this technology could position China as a key player in clean energy, influencing international policies and investments toward thorium-based solutions.

The Bottom line:

China’s breakthrough in thorium molten salt reactors heralds a new era in nuclear energy, offering a path to sustainable power amid its shifting energy mix. With benefits like reduced waste and enhanced safety, thorium could transform global markets, fostering innovation and energy security. As the world watches, this development underscores the potential for thorium to power the future. For the U.S., this is a wake-up call on critical mineral processing. We had better get rolling on critical and rare-earth mineral processing for all the needed minerals, including Uranium and Thorium, or we could lose the AI race that Secretary Chris Wright has called our Manhattan Project.

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