China has achieved a potentially transformative breakthrough in advanced nuclear energy, successfully converting thorium into fissionable uranium for the first time in an experimental molten salt reactor.

Hailed as a "game-changer", industry experts said the development could fundamentally reshape the nation's energy security, significantly reducing reliance on imported uranium and positioning China at the forefront of a new generation of nuclear power technology.

The Chinese Academy of Sciences announced earlier this month that its thorium-based molten salt reactor (TMSR) in Gansu province had achieved thorium-uranium conversion, proving the technical feasibility of utilizing China's vast thorium reserves.

This experimental reactor, a fourth-generation advanced fission nuclear energy system, is also currently the world's sole operational molten salt reactor to integrate thorium fuel, it said.

Widely seen as China's "trump card" in the fourth-generation nuclear energy race, this progress signifies that Beijing has mastered a crucial technology for "overtaking on a different track", said Lin Boqiang, head of the China Institute for Studies in Energy Policy at Xiamen University.

Lin said he believes it could free China from its long-standing dependence on imported uranium, offering a novel solution to bolster energy independence.

Lin said: "It offers a domestically controlled pathway to meeting future power demands, significantly de-risking China's energy supply chain from geopolitical volatilities and commodity market fluctuations.

"It places China at the forefront of what many consider to be the safest and most sustainable path for future nuclear energy."

As countries are stepping up green energy transition and striving for carbon neutrality, demand for uranium — which is used to run nuclear power plants — is intensifying.

China's nuclear energy ambitions have historically been constrained by limited domestic uranium resources. While a single million-kilowatt nuclear power plant consumes around 200 metric tons of natural uranium annually, over 80 percent of China's yearly uranium consumption is imported.

China is actively working to lessen its dependence on foreign uranium suppliers by boosting domestic production. This drive is a response to geopolitical risks that could disrupt essential resource imports, said Zhao Xiangbin, chief strategist at Beijing Gold and Forex Fortune Investment Management.

In contrast, China holds over 1.4 million tons in proven thorium reserves, nearly three quarters of the global total. Thorium itself is not directly fissile but can be transmuted into highly fissionable uranium-233.

Since its 2011 inception, research teams have overcome critical hurdles in materials science, instrumentation, equipment development and system integration. The TMSR now boasts over 90 percent domestic content, with all key core equipment 100 percent domestically produced, ensuring an autonomous supply chain, according to the Chinese Academy of Sciences.

Compared to conventional uranium-based nuclear power plants, thorium-based molten salt reactors offer significant advantages in terms of safety and siting flexibility, it said.

The TMSR employs high-temperature molten salt, stable and liquid at 600-700 C. Crucially, it requires no external water for cooling during operation. Natural circulation of the molten salt within a closed loop continuously removes heat from the reactor core, fundamentally eliminating safety risks from cooling failures.

This inherent design means TMSRs do not need proximity to large water bodies, unlike traditional nuclear plants, enabling their construction in remote desert regions.

Once mature, TMSRs could be deployed across China's arid inland areas, providing stable, clean energy while unlocking vast new markets for clean power, said Lin.

zhengxin@chinadaily.com.cn