China to Activate Experimental Nuclear Molten Salt Reactor, Hopes to Obtain Full Intellectual Rights

British Chancellor of the Exchequer George Osborne (L) speaks with Taishan Nuclear Power Joint Venture general manager Guo Liming (R) in front of a nuclear reactor under construction at a nuclear power plant in Taishan, Guangdong Province, on Oct. 17, 2013. Bobby Yip/AFP/Getty Images

In China’s remote northwest Gansu province, Chinese scientists successfully designed, and built, an experimental thorium-powered molten salt reactor—and they’re about to power it up.

Initially, 2024 was the projected completion date for the prototype; but a healthy research and design budget, plus a push from Beijing, thrust completion of the reactor ahead of schedule.

The technology behind the molten salt reactor isn’t new—Alvin Weinberg at the Oak Ridge National Laboratory operated a similar prototype in the 1960s; but conventional water-cooled reactors were put in use instead.

Pointedly, if the Chinese successfully switch from uranium to thorium and prove commercial viability of their new nuclear reactor, they hope to gain full intellectual property rights.

‘First of Its Kind’

In January 2011, the Shanghai Institute of Applied Physics (SINAP) launched a $444 million research and design program for a thorium-breeding molten salt reactor (TMSR). The R&D was successful, and in September 2018, construction on the TMSR began, with an estimated completion time of 2024.

However, 2024 was too far out for some. After successfully expediting construction, the Ministry of Ecology and Environment approved SINAP’s request to start its 2 megawatts thermal (MWt) reactor on Aug. 2, according to the World Nuclear Association.

“Our bureau has conducted a technical review of the application documents you submitted, and believes that your 2 MWt liquid fuel thorium-based molten salt experimental reactor commissioning plan is acceptable and is hereby approved.”

The Ministry stipulated that if any “major abnormality occurs” during the commissioning process, the abnormality needs to be reported to the Northwest Nuclear and Radiation Safety Supervision Station “in time.”

Local woman paving straw before planting trees in the desert at Mingqin county in Wuwei, Gansu Province, China, on March 28, 2019. Wang He/Getty Images

Concerning energy generation, 2 MWt can power approximately 1,000 homes, meaning the prototype won’t generate a significant amount of energy compared to traditional nuclear reactors. But if the prototype is successful, China hopes to build a 373 MWt by 2030.

Initially, thorium will only account for 20 percent of TMSR’s fuel source. The plan is to work up from 20 percent thorium fission to 80 percent.

China is closely guarding its TMSR design. However, the World Nuclear Association reports that the new design builds on Oak Ridge National Laboratory’s 1965 molten salt reactor experiment (MSRE).

Like China, Oak Ridge’s MSRE started with a fuel mixture of depleted and enriched uranium. Then in 1968, uranium-233 was added to the mix—thorium doesn’t split and release energy; instead, thorium transmutes to the isotope uranium-233 when it absorbs a neutron.

Importantly, the core of a molten salt reactor consists of liquefied salt and converted thorium, making it possible for the liquid to act as both coolant and fuel. As an added benefit, molten salt reactors operate at lower pressure reducing the risk of explosive meltdowns, experts claim.

After including U-233, Oak Ridge’s MSRE operated successfully until Dec. 1968. However, advances in competing nuclear technology and a lack of political support led to its closure. Consequently, Oak Ridge Lab’s MSRE never reached commercial viability.

Thorium Versus Uranium

Current nuclear technology relies on uranium ore for fuel, which is about as common as zinc or tin but is not a renewable resource.

Moreover, while total world resources of uranium aren’t known, current known sources are enough to supply conventional reactors for approximately 90 years. While that may sound concerning, it’s a “higher level of assured resources than is normal for most minerals,” according to the World Nuclear Association.

Still, there are several drawbacks to uranium nuclear reactors, not the least of which is that uranium waste is radioactive for thousands of years.

Conversely, thorium is also abundant, possibly three times more than uranium, and produces less radioactive waste with a hazardous life of about 300 years. It’s also more chemically stable and is relatively inert, making storage and disposal simpler.

Uranium rod elements of a nuclear reactor. Parilov/Adobe Stock

As an added benefit, molten salt reactors don’t require water for cooling, meaning they can operate in desert regions.  China plans to take full advantage of this factor by building TMSRs across its western desert regions, Nuclear Engineering International reports.

Still, thorium reactors do have some drawbacks.

For example, the materials used to manufacture components for molten salt reactors have to maintain their integrity in highly corrosive and radioactive environments.

In 1995, the Defense Nuclear Facilities Safety Board reviewed the MSRE at the Oak Ridge National Laboratory. “The Fuel Drain Tanks are believed to be corroding and the potential exists for stress corrosion cracking in the off-gas system piping and charcoal bed vessel,” the report (pdf) found.

A related problem involves radioactive fission products. Specifically, fission products and actinides are radioactive, and their chemical effects can eat away at the containment and migrate to other areas, which happened to the Oak Ridge MSRE.

“Since the Molten Salt Reactor Experiment shut down 25 years ago, several kilograms of fissile uranium (mostly 233U) have migrated from the Fuel Drain Tanks through the piping of the off-gas system and deposited in a short section of a charcoal bed,” the Defense Nuclear Board report states.

Regardless of the drawbacks, China believes the future of nuclear power involves thorium molten salt reactors. And if China successfully proves commercial viability of its TMSR, the Chinese Academy of Sciences plans to pursue full intellectual property rights on the technology, according to the World Nuclear Association.