An experimental reactor developed in the Gobi Desert by the Chinese Academy of Sciences’ Shanghai Institute of Applied Physics has achieved thorium-to-uranium fuel conversion, paving the way for an almost endless supply of nuclear energy.
The achievement makes the 2 megawatt liquid-fuelled thorium-based molten salt reactor (TMSR) the only operating example of the technology in the world to have successfully loaded and used thorium fuel.
According to the academy, the experiment has provided initial proof of the technical feasibility of using thorium resources in molten salt reactor systems and represents a major leap forward for the technology.
It is the first time in the world that scientists have been able to acquire experimental data on thorium operations from inside a molten salt reactor, according to a report by Science and Technology Daily.
The article, published on Saturday, was China’s first official confirmation of its success in the development of TMSR technology, an innovation that is poised to reshape the future of clean sustainable nuclear energy.
Li Qingnuan, Communist Party secretary and deputy director at the Shanghai Institute of Applied Physics, told the newspaper that “since achieving first criticality on October 11, 2023, the thorium molten salt reactor has been steadily generating heat through nuclear fission”.
Thorium is much more abundant and accessible than uranium and has enormous energy potential. One mine tailings site in Inner Mongolia is estimated to hold enough of the element to power China entirely for more than 1,000 years.
At the heart of the breakthrough is a process known as in-core thorium-to-uranium conversion that transforms naturally occurring thorium-232 into uranium-233 – a fissile isotope capable of sustaining nuclear chain reactions.
This transformation occurs through a precise sequence of nuclear reactions. The thorium-232 absorbs a neutron to become thorium-233, which decays into protactinium-233 and then further decays into the final product – a powerful nuclear fuel.
Critically, the entire process takes place inside the reactor core, eliminating the need for external fuel fabrication.
Thorium is dissolved in a fluoride salt into a high-temperature molten mixture which serves as both fuel and coolant. Neutrons from a small initial charge of fissile material, such as enriched uranium-235 or plutonium-239, initiate the chain reaction.
Throughout the operation, thorium-232 continuously captures neutrons and transforms into uranium-233, which then releases energy through nuclear fission to create a self-sustaining “burn while breeding” cycle – one of the technology’s defining advantages.
Unlike conventional pressurised water reactors, which must be shut down periodically to open the pressure vessel and replace solid fuel rods, the TMSR’s liquid fuel – a homogeneous mixture of fissile material dissolved in molten salt circulates continuously, allowing for on-the-fly refuelling without interrupting operations.
“This design not only dramatically improves fuel utilisation but also significantly reduces the volume of long-lived radioactive waste,” Li said. “It’s one of the key advantages that sets thorium molten salt reactors apart.”
Another advantage of the TMSR is that it requires no water at all, in sharp contrast to conventional nuclear power plants that are usually built near coastlines because of their massive cooling needs
An experimental reactor developed in the Gobi Desert by the Chinese Academy of Sciences’ Shanghai Institute of Applied Physics has achieved thorium-to-uranium fuel conversion, paving the way for an almost endless supply of nuclear energy.
The achievement makes the 2 megawatt liquid-fuelled thorium-based molten salt reactor (TMSR) the only operating example of the technology in the world to have successfully loaded and used thorium fuel.
According to the academy, the experiment has provided initial proof of the technical feasibility of using thorium resources in molten salt reactor systems and represents a major leap forward for the technology.
It is the first time in the world that scientists have been able to acquire experimental data on thorium operations from inside a molten salt reactor, according to a report by Science and Technology Daily.
The article, published on Saturday, was China’s first official confirmation of its success in the development of TMSR technology, an innovation that is poised to reshape the future of clean sustainable nuclear energy.
Trump orders US military to resume nuclear weapons tests for first time in 33 years
Trump orders US military to resume nuclear weapons tests for first time in 33 years
Li Qingnuan, Communist Party secretary and deputy director at the Shanghai Institute of Applied Physics, told the newspaper that “since achieving first criticality on October 11, 2023, the thorium molten salt reactor has been steadily generating heat through nuclear fission”.
Thorium is much more abundant and accessible than uranium and has enormous energy potential. One mine tailings site in Inner Mongolia is estimated to hold enough of the element to power China entirely for more than 1,000 years.
At the heart of the breakthrough is a process known as in-core thorium-to-uranium conversion that transforms naturally occurring thorium-232 into uranium-233 – a fissile isotope capable of sustaining nuclear chain reactions.
This transformation occurs through a precise sequence of nuclear reactions. The thorium-232 absorbs a neutron to become thorium-233, which decays into protactinium-233 and then further decays into the final product – a powerful nuclear fuel.
Critically, the entire process takes place inside the reactor core, eliminating the need for external fuel fabrication.
Thorium is dissolved in a fluoride salt into a high-temperature molten mixture which serves as both fuel and coolant. Neutrons from a small initial charge of fissile material, such as enriched uranium-235 or plutonium-239, initiate the chain reaction.
Throughout the operation, thorium-232 continuously captures neutrons and transforms into uranium-233, which then releases energy through nuclear fission to create a self-sustaining “burn while breeding” cycle – one of the technology’s defining advantages.
Unlike conventional pressurised water reactors, which must be shut down periodically to open the pressure vessel and replace solid fuel rods, the TMSR’s liquid fuel – a homogeneous mixture of fissile material dissolved in molten salt circulates continuously, allowing for on-the-fly refuelling without interrupting operations.
“This design not only dramatically improves fuel utilisation but also significantly reduces the volume of long-lived radioactive waste,” Li said. “It’s one of the key advantages that sets thorium molten salt reactors apart.”
Another advantage of the TMSR is that it requires no water at all, in sharp contrast to conventional nuclear power plants that are usually built near coastlines because of their massive cooling needs.
The constraint has limited deployment of nuclear reactors in arid or inland regions but is no impediment to a TMSR system which uses high-temperature molten fluoride salts instead of water as both the fuel carrier and coolant.
Because the salts efficiently transfer heat at atmospheric pressure and extreme temperatures, the technology is opening the door to safe, efficient nuclear power plants deep inland – and even on mobile platforms such as large ships, according to the report.
The Chinese Academy of Sciences launched the TMSR nuclear energy system in 2011 as a strategic priority research programme aimed at addressing national goals in sustainable energy and carbon reduction.
The move was in recognition of the potential for China’s rich thorium reserves to achieve true energy independence using this next-generation technology, along with vast commercial and strategic possibilities.
After nearly 15 years of research and development, a team led by Xu Hongjie, former director of the Shanghai institute, overcame formidable challenges to establish a solid scientific and industrial foundation for China’s advanced nuclear energy industry chain.
Their hard work – ranging from assembling expert teams and building specialised research platforms to developing new materials and core technologies – culminated at 11.08am on October 11, 2023, when the 2MW liquid-fuelled TMSR achieved first criticality.
On June 17, 2024, another milestone was reached when the TMSR achieved full power operation. A few months later in October, the team conducted the world’s first experiment that involved adding thorium to a molten salt reactor.
The achievement by Xu and his colleagues meant that China was home to the only operational thorium-fuelled molten salt reactor in the world – a comprehensive experimental platform for next-generation nuclear research.
Safety remains the top concern with any nuclear technology. As a fourth-generation advanced reactor, the thorium molten salt reactor boasts inherent safety features, according to its developers.
The system operates at atmospheric pressure, eliminating the risk of high-pressure explosions. It is built underground with full radiation shielding and the chemically stable molten salts can also effectively trap radioactive materials.
In the unlikely event of a leak, the molten salt would flow into a passive safety drain tank, solidifying as it cooled and effectively containing any release.
A complete industrial ecosystem for TMSR technology is taking shape in China, according to the academy, with nearly 100 research institutions collaborating on reactor design, materials science and other key challenges.
Crucially, all core components of the experimental reactor are 100 per cent domestically produced, ensuring full supply chain autonomy and technological self-reliance, the academy said.
China is building a 100MW demonstration reactor in the Gobi Desert with the goal of proving the technology’s viability for large-scale commercial deployment by around 2035, according to the latest official timeline.
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