Lianhe Zaobao
Yu Zeyuan
Beijing Report
2025-11-03
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The Chinese Academy of Sciences (CAS) announced last Saturday (November 1) that the 2-megawatt liquid-fuel thorium-based molten salt experimental reactor, located in the desert of Minqin County, Gansu Province, has recently achieved thorium-uranium nuclear fuel conversion for the first time. It has become the world's only currently operating molten salt reactor that has realized thorium fuel loading, preliminarily proving the technical feasibility of using thorium resources in the molten salt reactor nuclear energy system.
This progress is regarded as a "trump card" played by China in the field of fourth-generation nuclear energy, marking that China has mastered the key technology for "overtaking on a new track" in nuclear energy R&D. This will help China break free from its dependence on imported uranium and provide a brand-new solution for China's energy security.
China's nuclear energy development has long been constrained by the scarcity of uranium resources. Theoretically, each 1-megawatt nuclear power plant consumes approximately 200 tons of natural uranium annually. Over 80% of the uranium resources consumed by China each year rely on imports, making it vulnerable to geopolitical impacts. After the 2011 Fukushima nuclear accident in Japan, global uranium prices fluctuated sharply, and China's nuclear power projects were forced to slow down due to uncertainties in fuel supply.
China's proven reserves of thorium resources have exceeded 1.4 million tons, accounting for nearly three-quarters of the world's total reserves. Moreover, most of these thorium resources are associated with rare earths—for every ton of rare earths mined, 200 kilograms of thorium can be recovered as a by-product. This is equivalent to obtaining thorium resources for free while mining rare earths, which not only significantly reduces the cost of acquiring nuclear fuel but also solves the problem of value-added utilization in rare earth mining.
Thorium itself cannot undergo fission directly; it requires neutron bombardment of thorium atomic nuclei to convert it into uranium-233, which is highly fissionable. Compared with traditional uranium-based nuclear power plants, thorium-based molten salt reactors have significant advantages in terms of safety and site selection flexibility. Traditional uranium-based reactors are veritable water guzzlers—a 1-megawatt conventional nuclear power unit consumes thousands of tons of cooling water per hour to remove the massive heat generated by the reactor core; otherwise, the core may melt down due to overheating.
However, the high-temperature molten salt used in thorium-based molten salt reactors can remain in a stable liquid state at temperatures ranging from 600°C to 700°C. During operation, no external water supply is needed, and the heat generated by the core can be continuously removed solely through the natural circulation of the molten salt in a closed loop, fundamentally eliminating safety hazards caused by cooling system failure.
China is not the first country to utilize thorium resources. During the Cold War, the United States took the lead in conducting research on thorium-based molten salt reactors but abandoned the effort because thorium cannot be used to manufacture nuclear weapons, shifting its focus entirely to the development of uranium-based reactors. Countries such as the Soviet Union and India also conducted research and development on thorium-based molten salt reactors, but they were stuck at technical bottlenecks such as molten salt corrosion and on-line fuel processing.
China incorporated thorium-based molten salt reactors into its national strategic pilot program in 2011, bringing together more than 20 scientific research institutions, including the Shanghai Institute of Applied Physics under CAS, to conduct joint research. Finally, a major breakthrough has been achieved recently.
Among the challenges, the most intractable one is molten salt corrosion. High-temperature fluoride salts can dissolve most metals, which once caused the pipelines of a U.S. experimental reactor to be scrapped within three months. Chinese research teams have developed nickel-based alloy materials and, after conducting tens of thousands of corrosion tests, finally developed an "anti-corrosion formula," extending the service life of the pipelines to more than 10 years.
Thorium-based molten salt reactors do not require large amounts of water, so they do not need to be built near the sea or large rivers like traditional nuclear power plants. Instead, they can be constructed in remote deserts. Once the technology matures, a large number of thorium-based molten salt reactors can be built in arid inland areas of China to provide stable and clean energy.
In addition, thorium-based molten salt reactors are small in size and high in power density, and can be modularly designed into "nuclear power packs." China has already conducted research on marine nuclear power. If applied to ocean-going cargo ships, a single thorium fuel refueling can enable a 10-year navigation period with near-zero carbon emissions. In the future, this technology may also be used to supply power to extreme environments such as polar research stations and lunar bases, and even applied to military projects such as aircraft carriers.
According to the plan, China's thorium-based molten salt reactor construction will be carried out in three phases:
1. By 2025, build a 2-megawatt experimental reactor to realize thorium-uranium conversion and stable operation, and obtain key data;
2. By 2029, construct a 10-megawatt small modular demonstration reactor to verify commercial feasibility and form a core equipment industrial chain;
3. By 2035, promote the construction of 100-megawatt-level power plants, realize large-scale application in thorium ore-rich areas such as Gansu and Xinjiang, and drive the development of industrial clusters in equipment manufacturing, molten salt materials, and other fields.
In addition, China has recently made an important breakthrough in nuclear fusion technology. On October 1, the key component of the compact fusion energy experimental device project located in Hefei, Anhui Province—the dewar base—was successfully hoisted and accurately installed in the main hall of the device. It is expected to be completed and demonstrate fusion power generation for the first time in 2027, and by 2030, it is expected to light up the first light through nuclear fusion.
Once China succeeds in achieving "overtaking on a new track" in the nuclear energy sector, it will further consolidate its leading position in clean energy and is expected to change the energy pattern of China and even the world.
Yu Zeyuan
Beijing Report
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