Thorium Molten Salt Reactor TMSR-500 Reaches Full Power in Gansu: China's Gen-IV Nuclear Enters Commercial Validation

Thorium Molten Salt Reactor TMSR-500 Reates Full Power in Gansu: China's Gen-IV Nuclear Enters Commercial Validation

On July 25, 2028, the Chinese Academy of Sciences' Shanghai Institute of Applied Physics announced that the thorium molten salt reactor TMSR-500 in Wuwei, Gansu Province achieved 100 consecutive days of full-power operation (500MW thermal) at design specifications. This is the world's first thorium molten salt reactor to reach commercial power levels, marking fourth-generation nuclear energy's transition from experimental to commercial validation.

TMSR-500 uses liquid fluoride thorium fuel with graphite as moderator, with molten salt circulating between the reactor core and heat exchangers. Compared to traditional uranium-fueled reactors, thorium reactors have more prominent inherent safety characteristics: if temperature rises abnormally, the fuel salt's negative temperature coefficient automatically reduces reaction rates; in extreme accidents, a freeze plug at the reactor bottom melts, allowing fuel salt to drain into a safe storage vessel without human intervention or external power.

Xu Hongjie, chief scientist of the CAS TMSR project, said: "TMSR-500's safety is not guaranteed by complex engineered safety systems but is determined by physical principles themselves. This is the most fundamental difference from traditional nuclear power plants."

Thorium resource abundance is another major advantage of this technology route. China's thorium reserves are approximately 300,000 tons, and at TMSR-500's consumption rate, China's explored thorium resources alone could sustain national electricity demand for over 1,000 years. Thorium fuel waste contains far fewer long-lived radioactive nuclides than uranium spent fuel, with high-level waste volumes approximately one-thousandth of traditional pressurized water reactors.

TMSR-500's current levelized cost of electricity is approximately 0.35 yuan per kilowatt-hour, higher than wind and solar (0.15-0.25 yuan) but lower than offshore nuclear and traditional nuclear (0.40-0.50 yuan). CAS says that as technology maturity and scale effects improve, TMSR's electricity cost could drop below 0.20 yuan by 2032, at which point it will have full commercial competitiveness.

The project also faces challenges. While corrosion of piping materials by molten salt has been controlled in TMSR-500 using Hastelloy-N, long-term operation (20+ years) material reliability still needs more data validation. Additionally, thorium fuel cycle reprocessing technology -- particularly extracting fissile material uranium-233 from spent fuel salt -- has not been fully validated at engineering scale.