Nuclear breakthrough: China's experimental reactor refuels WITHOUT shutting down - taking the world closer towards limitless clean energy

Daily Mail​

30-04-2025

In the quest to safely generate limitless clean energy, China has just taken a giant step closer.
Scientists in Gansu province in the country's west have achieved the milestone of reloading fuel to an operational nuclear fission reactor while it was running.
The achievement shows fission reactors can run and be refueled continuously – potentially offering a constant source of power generation.
Drawing upon declassified US research, Chinese engineers began constructing the experimental machine – a thorium molten salt reactor (MSR) – back in 2018.
Thorium MSRs are a type of advanced nuclear technology that use liquid fuels, typically molten salts, as both a fuel and a coolant – and are generally safer than existing fission reactors which use uranium.
It marks the first long-term, stable operation of the technology, reports South China Morning Post (SCMP), citing Chinese communist party newspaper Guangming Daily.
Xu Hongjie, the project's chief scientist, said China 'now leads the global frontier' in the energy revolution, following decades of intensive research.
Xu said: 'The US left its research publicly available, waiting for the right successor. We were that successor.'
The world-first was announced by Mr Xu during a meeting at the Chinese Academy of Sciences in Beijing on April 8.
In a cheeky dig, Xu referred to America's research into molten salt reactors in the 1960s and 1970s, eventually abandoned in favour of uranium-based systems.
'In the nuclear game, there are no quick wins,' he was quoted as saying. 'You need to have strategic stamina, focusing on doing just one thing for 20, 30 years.'
In reference to Aesop's famous fable, he said: 'Rabbits sometimes make mistakes or grow lazy. That's when the tortoise seizes its chance.'
His team at the CAS Shanghai Institute of Applied Physics spent years dissecting declassified American documents and bettering their experiments, SCMP reports.
'We mastered every technique in the literature – then pushed further,' Xu added.
This experimental reactor is hidden away in the Gobi Desert city of Wuwei in Gansu province and can generate two megawatts (2MW) of energy – enough to power 2,000 households.
Only reaching full-power operation in June last year, it is the only operational thorium reactor in the world.
What is thorium?
Thorium is a naturally-occurring, slightly radioactive metal discovered in 1828 by Swedish chemist Jons Jakob Berzelius.
More abundant in nature than uranium, thorium can be used as a fuel source for nuclear energy, but not directly.
Thorium itself is not a nuclear fuel, although it can be used to create such a fuel (in conjunction with a fissile material such as recycled plutonium).
But a much bigger thorium molten salt reactor now being built is set to achieve its first sustained nuclear chain reaction by 2030.
Estimated to be 500 times more abundant than the uranium-232 used in conventional nuclear reactors, thorium has been hailed as a potential solution to the demand for nuclear power.
Nuclear reactors already in operation around the world create energy by forcing radioactive elements to undergo a process called fission.
During this process, the element breaks down into smaller, more stable elements and releases heat which can be used to drive steam turbines, in turn producing electricity.
Thorium on its own is not fissile, meaning it cannot be used for fission, but it can provide the basis for a fission reaction.
This is because thorium is 'fertile', meaning it can transmute into uranium-233 (U-233) when bombarded with neutrons.
In a molten-salt reactor, thorium is mixed with a chemical called lithium fluoride and heated to about 1400°C (2550°F).
This mixture is then bombarded with neutrons until some of the thorium starts to transform into uranium-232, which then decays in a fission reaction.
Nuclear fusion vs. nuclear fission
Nuclear fusion and fission are nuclear processes; they involve nuclear forces to change the nucleus of atoms.
Fusion joins two light elements (low atomic mass number), forming a heavier element. For fusion to occur, hydrogen atoms are put under high heat & pressure so they fuse together.
Meanwhile, fission splits a heavy element (with a high atomic mass number) into fragments.
In both cases, energy is freed because mass of the remaining nucleus is smaller than mass of reacting nuclei.
Both reactions release energy which, in a power plant, can boil water to drive a steam generator, making electricity.
Source: International Atomic Energy Agency
As it decays, this uranium then produces more neutrons which convert additional thorium into fuel. In theory, this reactor design could turn the extremely abundant element into a nearly limitless source of power.
Molten-salt reactors also produce significantly less nuclear waste and remove the risk of dangerous nuclear meltdown by keeping the levels of fissile material relatively low.
What's more, China has a thorium source that could supply enough fuel to power the country for 60,000 years, geologists in Beijing have claimed.
The Bayan Obo mining complex in Inner Mongolia, an autonomous region of northern China, could contain enough thorium to supply China's household energy demands 'almost forever', a national survey reportedly found.
It identified 233 thorium-rich zones across the country and, if accurate, suggests that thorium reserves in China significantly exceed previous estimates.
The Wuwei experimental reactor is different from the 'Experimental Advanced Superconducting Tokamak' (EAST), a fusion reactor located in Hefei in Anhui province.
Known as China's artificial sun, it set the record for running for as hot and as long as possible – for 1,066 seconds at 180million°F (100million°C) – seven times hotter than the sun's core.
EAST could be a precursor to the first ever fusion power plants that supply power directly to the grid and electricity to people's homes.
These power plants could reduce greenhouse gas emissions from the power-generation sector by diverting away from the use of fossil fuels like coal and gas.
Meanwhile, the SPARC nuclear fusion reactor, a US project involving MIT, is currently in development in Devens, Massachusetts and scheduled to start operations in 2026.
South Korea also has its own 'artificial sun', the Korea Superconducting Tokamak Advanced Research (KSTAR), which has run at 180million°F (100million°C) for 48 seconds.
And Japan's reactor, called JT-60SA and switched on in Naka north of Tokyo late 2023, is a six-storey-high machine measuring 50 feet high and 44 feet wide.
Built and operated jointly by Europe and Japan, JT-60SA will be the world's largest fusion reactor until the completion of the the International Thermonuclear Experimental Reactor (ITER) in France, set to begin delivering power in 2035.
How could thorium be used to produce limitless energy?
Thorium is a relatively abundant, slightly radioactive element which is commonly produced as a byproduct of mining rare-earth metals.
On its own, thorium isn't fissile, which means it doesn't decay into any other isotopes. That means it can't be used in a standard nuclear reactor like uranium-232.
However, thorium could be used to make a new type of reactor called a molten-salt reactor.
Thorium is 'fertile', which means that an atom of thorium can be transformed into an atom of uranium-232 when it is bombarded with neutrons.
In a molten-salt reactor, thorium is dissolved in hot liquid salt and used to 'breed' uranium which then undergoes fission to produce heat.
This liquid is then circulated through a heat exchange to remove excess energy and fission materials, leaving behind the thorium to start the reaction again.
Molten-salt reactors have a number of benefits but the main advantage is they can be small, produce little radioactive waste, and avoid the risk of a meltdown.