中國日?qǐng)?bào)：China becomes first to transmute thorium into uranium for nuclear fission

By Wu Wanzhen in Wuwei and Li Menghan in Beijing

A??researcher works at the charging-sampling hot cell of the experimental??Thorium Molten Salt Reactor at the Wuwei campus of the Chinese Academy??of Sciences' Shanghai Institute of Applied Physics in Minqin county of??Wuwei city, Northwest China's Gansu province, Oct 24, 2025.??[Photo/Xinhua]

China's thorium molten salt reactor has become the first in the world??to transmute thorium fuel into uranium fuel for nuclear fission.

Key physical parameter data of protactinium-233 confirms the??successful establishment of a nuclide conversion chain from thorium-232??to uranium-233 within the reactor. The milestone preliminarily verifies??the technical feasibility of the thorium fuel cycle and further??consolidates China's leading position in molten salt reactor research.

The 2-megawatt thermal liquid-fueled thorium molten salt reactor, led??by the Shanghai Institute of Applied Physics of the Chinese Academy of??Sciences, is situated in the Hongshagang industrial cluster in Minqin??county, administered by Wuwei city, Gansu province.

"Nuclear energy, characterized by high energy density, near-zero??carbon emissions and independence from seasonal variations, is a safe,??clean, efficient and low-carbon energy source. It plays a crucial role??in safeguarding energy security and advancing large-scale??commercialization goals," said Cai Xiangzhou, deputy director of the??Shanghai Institute of Applied Physics.

Cai highlighted that China has witnessed consistent growth in newly??installed nuclear power capacity each year. However, the country faces??sustainability challenges due to its heavy reliance on imported uranium —??the most widely used nuclear fuel. The issue underscores the critical??importance of a stable nuclear fuel supply for sustainable development.

Dai Zhimin, director of the Shanghai Institute of Applied Physics,??said that thorium fuel is widely regarded as a promising alternative to??uranium, citing two key advantages: China's abundant thorium reserves??and its negative temperature coefficient of reactivity, which??effectively mitigates the risks of radioactive release. In addition,??thorium-fueled reactors generate spent fuel with reduced volume and??shorter radioactive half-lives, significantly simplifying waste??disposal.

"As a fourth-generation nuclear power reactor type, molten salt??reactors use high-temperature molten salt as a coolant. Endowed with??inherent safety features, water-free cooling, low-pressure operation and??high-temperature output, they are internationally recognized as the??most suitable reactor type for thorium resource utilization," Dai said.

He added that the technology facilitated deep integration with??industries such as solar energy, wind power, high-temperature molten??salt energy storage, high-temperature hydrogen production, and coal, oil??and gas chemical engineering.

In response to the national strategic demands for energy security and??sustainable development, the CAS launched a program in 2011 to enhance??core technological capabilities and develop a thorium-based molten salt??reactor system.

Construction of the reactor commenced in 2020, with equipment??installation completed in 2022. By June 2024, it reached full-power??operation at 650 C. In September, it obtained the world's first??experimental license for thorium loading in a molten salt reactor. Last??October, the first thorium loading was successfully completed,??establishing the world's only research platform dedicated to molten salt??reactors and thorium-uranium fuel cycle studies.

"The program brought together nearly 100 domestic research??institutions, universities and industrial companies. The collaborative??team overcame key challenges in reactor design, the development of??critical materials and equipment, reactor safety, and installation and??commissioning," Cai said.

Cai emphasized that the team had pioneered technologies for??controlling oxygen content in thorium fluoride and established a??preparation process for nuclear-grade thorium-based fuel salt.

"Over 90 percent of the reactor's components are domestically??produced, with 100 percent localization of key parts and a fully??independent supply chain. This achievement marks the initial??establishment of an industrial ecosystem for thorium molten salt reactor??technologies in China," he added.

Dai said: "The Shanghai Institute of Applied Physics will collaborate??with leading energy enterprises, including the State Power Investment??Corporation, to build a comprehensive industrial and supply chain??ecosystem for the thorium molten salt reactors.

"Our goal is to complete the construction and demonstration operation??of a 100-megawatt thermal prototype by 2035 and realize??commercial-scale application. This will accelerate technological??innovation and engineering transformation, ultimately providing China??with a safe, reliable and domestically controlled thorium-based energy??generation solution."

Contact the writers at limenghan@chinadaily.com.cn