In the remote northwestern province of Gansu, Chinese scientists have successfully designed and built an experimental thorium-powered molten salt reactor and are about to power it up.
Originally, the expected completion date for the prototype was 2024. But pressure from Beijing, along with a healthy research and design budget, pushed completion of the reactor ahead of schedule.
The technology behind molten salt reactors is nothing new: Alvin Weinberg at Oak Ridge National Laboratory operated a similar prototype in the 1960s. However, a conventional water-cooled reactor was used instead.
If China succeeds in switching from uranium to thorium and proves the new reactor’s commercial viability, China hopes to obtain full intellectual property rights.
In January 2011, the Shanghai Institute of Applied Physics (SINAP) launched a $444 million Thorium Breeder Molten Salt Reactor (TMSR) research and design program. The research and development were successful, and in September 2018 he began construction of TMSR, with an expected completion date of 2024.
But 2024 was too far away. After successfully expediting construction, the Ministry of Ecology and Environment approved his SINAP request to start his 2 megawatt thermal (MWt) reactor on August 2. according to to the World Nuclear Association.
“Our Department has conducted a technical review of the application documents you have submitted and believes that your 2 MWt liquid fuel thorium-based molten salt experimental reactor commissioning plan has been accepted and hereby approved.”
The ministry stipulated that if “significant anomalies occur” during the commissioning process, the anomalies must be reported “in time” to the Northwest Nuclear and Radiation Safety Monitoring Station.
In terms of energy generation, 2 MWt can power about 1,000 homes. That is, the prototype will not produce a large amount of energy compared to conventional nuclear reactors. But if the prototype is successful, China wants to build 373 MWt by 2030.
Initially, thorium will only account for 20% of TMSR’s fuel source. The plan is to increase the fission rate of thorium from 20% to 80%.
China has strictly adhered to the design of the TMSR. However, the World Nuclear Association reports that the new design is based on his 1965 molten salt reactor at Oak Ridge National Laboratory. experiment (MSRE).
Similar to China, Oak Ridge’s MSRE began with a blend of depleted and enriched uranium. Uranium-233 was then added to the mixture in 1968. Thorium does not split and does not release energy. Instead, thorium converts 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, allowing the liquid to act as both coolant and fuel. As an added benefit, molten salt reactors operate at lower pressures, reducing the risk of explosive meltdowns. Expert Claim.
After including U-233, Oak Ridge’s MSRE operated normally until December 1968. However, due to competing nuclear technology advances and lack of political support, MSRE was shut down. As a result, his MSRE at Oak Ridge Lab was never commercially viable.
thorium vs uranium
Current nuclear technology relies on uranium ore as fuel, which is as common as zinc and tin, but is not a renewable resource.
In addition, the world’s total uranium resources are not known, but currently known sources are sufficient to supply conventional nuclear reactors for about 90 years. That may sound worrying, but it is “a sure resource at higher than normal levels for most minerals.” according to to the World Nuclear Association.
Still, uranium reactors have some drawbacks, at least one of which is that the uranium waste has been radioactive for thousands of years.
Conversely, thorium is also abundant, perhaps three times as much as uranium, and does not produce radioactive waste with a dangerous lifespan of about 300 years. It is also chemically stable and relatively inert, which simplifies storage and disposal.
As an added benefit, molten salt reactors do not require water for cooling, so they can operate in desert areas. China plans to capitalize on this factor by building his TMSR in the western desert. report.
Still, thorium reactors have some drawbacks.
For example, the materials used to manufacture the components of molten salt reactors must maintain their integrity in highly corrosive and radioactive environments.
In 1995, the Defense Nuclear Installation Safety Commission reviewed MSRE at Oak Ridge National Laboratory. “The fuel drain tank is believed to be corroded, and stress corrosion cracking may occur in the off-gas system piping and charcoal bed vessels,” the report said. (pdf) found.
A related issue involves radioactive fission products. Specifically, fission products and actinides are radioactive, and their chemical effects can erode containment and migrate to other areas generated at the Oak Ridge MSRE.
“Since molten salt reactor testing was shut down 25 years ago, several kilograms of fissile uranium (mainly 233U) have migrated from fuel drain tanks through offgas system piping and deposited in short sections of the charcoal bed. The Defense Nuclear Commission report states:
Shortcomings aside, China believes that the future of nuclear power requires thorium molten salt reactors. If China succeeds in proving the commercial viability of his TMSR, the Chinese Academy of Sciences plans to pursue full intellectual property rights on the technology. according to to the World Nuclear Association.