'Green light' given for first thorium molten salt nuclear reactor in China

China’s Ministry of Ecology and Environment has approved the commissioning of an experimental molten salt thorium nuclear reactor in Wuwei City.
Christopher McFadden
A thermal nuclear powerplant.
A thermal nuclear powerplant.


Chinese authorities have officially given the green light to commission a working thorium-based molten salt nuclear reactor. Currently under construction since 2018, the reactor in question, "Thorium Molten Salt Reactor - Liquid Fuel 1" (TMSR-LF1), is being built at the Hongshagang Industrial Cluster, Wuwei City, Gansu Province.

If successful, the TMSR-LF1 has the potential to open doors for developing and constructing a more extensive demonstration facility by 2030. Additionally, it could lead to constructing a TMSR fuel salt batch pyro-process demonstration facility, which would enable the utilization of the thorium-uranium cycle by the early 2040s.

This makes it China's first authorized thorium molten salt reactor

"The thorium-fueled molten salt experimental reactor operation application and related technical documents were reviewed, and it was considered that the application met the relevant safety requirements, and it was decided to issue the two MWt liquid fuel thorium-based molten salt experimental reactor an operating license," the National Nuclear Security Administration(NNSA) said in a statement on June 7.

According to the World Nuclear Association(WNA), Thorium(Th) is more plentiful compared to uranium(U). However, it is "fertile" instead of "fissile," meaning it can only be used as fuel in combination with a fissile material such as recycled plutonium. While using thorium as a primary energy source has been enticing for a long time, cost-effectively extracting its potential energy value has been difficult.

The TMSR-LF1 reactor is an experimental liquid fluoride thorium reactor that utilizes a fuel salt mixture of LiF-BeF2 -ZrF4 -UF4 [+ThF4 ] and a coolant salt of LiF-BeF2. It runs on a combination of thorium and uranium-235, enriched at 19.75 percent by weight, and can operate at a maximum temperature of 650C for up to 10 years. The liquid fuel design is based on the Molten-Salt Reactor Experiment conducted by Oak Ridge National Laboratory in the 1960s.

According to SINAP documents, the reactor aims to test pyro-processing, refueling, and continuous gas removal techniques, study the stability and safety of its operation, and experiment with a thorium-uranium fuel cycle.

According to the NNSA, SINAP must prioritize safety while operating TMSR-LF1. They must comply with operating license regulations and permit conditions to ensure the safe operation of the reactor. Although construction of the reactor was initially expected to be finished in 2024, it was completed earlier in August 2021 due to accelerated work.

If successful, China plans on building a larger one by 2030

Last August, SINAP received the Ministry of Ecology and Environment's approval to commission the TMSR-LF1 reactor. Its fuel will be enriched to under 20 percent U-235, with a thorium inventory of approximately 50 kg and a conversion ratio of about 0.1. The reactor will fuel a fertile blanket of lithium-beryllium fluoride(FLiBe) with 99.95 percen Li-7 and UF4.

China intends to construct a reactor with a capacity of 373 MWt by 2030 if the TMSR-LF1 succeeds.

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