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Molten salt reactors were first built in the 1950s but have not been used in the United States since the 1970s.
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The U.S. Nuclear Regulatory Commission recently issued a permit to build a molten salt nuclear power plant.
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Kairos Power is managing the project, which it hopes to complete by 2027.
The US has given permission to build a different type of nuclear reactor.
Known as a molten salt reactor, it could lead to smaller, easier-to-build nuclear power plants in the future that would power ships and other off-grid locations.
What makes this reactor different is how it cools its core using molten salt instead of water.
water and salt
Almost All Nuclear reactors operating today use water for cooling. Their beans can reach temperatures of 572 degrees Fahrenheit, much higher than the 212-degree boiling point of water.
It takes a lot of pressure to prevent water from evaporating and keeping it in a liquid state at such high temperatures, costing additional technology, space and money.
On the other hand, some salts have much higher boiling points and do not require the same expensive, high-pressure environments.
“You can use it at these high temperatures and it won’t boil,” Nicholas V. Smith, project director of the molten chloride reactor experiment at Idaho National Laboratory, told Business Insider. “You don’t need to have big, thick pressure vessels to contain the refrigerant.”
For example, the first molten salt reactor tested in the 1950s was small enough to fit on an airplane; However, according to Berkeley Engineering, the energy-producing part of the Diablo Canyon Nuclear Power Plant in California covered 12 acres of land.
This benefit and others, U.S. Nuclear Regulatory Commission recently issued the first permit to build a non-water-cooled nuclear power plant.
Mike Laufer, CEO of Kairos Power, told Bloomberg this would be the first since 1968.
Kairos Power is the company that plans to build a test facility it calls Hermes that will be cooled by molten fluoride salt in Oak Ridge, Tennessee, by 2027.
The first version of the plant will not provide electricity, but the company hopes its successor, Hermes 2, will provide electricity by 2028.
Why is molten salt worth rediscovering?
Molten salt reactors have been around since the 1950s, but the U.S. mostly abandoned them in the 1970s in favor of water-cooled reactors, many of which had already been built.
But recently, companies and laboratories, including Kairos, have been re-investigating salt-cooled reactors.
“When the engineering details are considered, salt is superior to water as a coolant,” Smith told BI.
Molten salt reactors have more design flexibility because they don’t need thick pressure vessels to keep water liquid at high temperatures, Smith said.
Reactors can be smaller than water-cooled options and can be built in a wider range of locations, for example.
“Molten salt opens up a lot of design options that you can’t do without,” Smith said. “As we move to the low-pressure paradigm, production becomes much easier.”
“I see molten salt reactors being deployed efficiently in everything from remote locations to shipping vessels to large power plants,” he added.
How will Hermes work?
Hermes will operate At temperatures up to 1,200 degrees Fahrenheit. However, the molten salt cooler known as FLiBe, which is a mixture of lithium fluoride and beryllium fluoride – boils at about 2,606 degrees Fahrenheit, well above the temperature of the reactor core.
FLiBe will therefore remain liquid at these high temperatures without additional pressure. This will make reactors easier and cheaper to build, Smith said.
The fuel proposed by Kairos Power is also different from a typical nuclear reactor. The company plans to use TRISO or TRi-structural ISOtropic particle fuel.
It can withstand extreme temperatures better than existing fuels, reducing the likelihood of radioactive fission products being released. US Office of Nuclear Energy.
Challenges continue
Some challenges include limiting corrosion.
“Oxygen is the driving force of corrosion in molten salt,” Smith said.
The challenge is to limit the salt’s exposure to oxygen. “It’s not exactly the same processes, but it’s the same principles as other refrigerants,” he said. “You should check the chemistry.”
Molten salt reactors have disadvantages. For example, physicist MV Ramana says they will “produce several different waste streams, all of which will require extensive processing and face disposal challenges.” Wrote In 2022.
One study suggested that reactors could produce more nuclear waste than current systems and would use “highly corrosive and pyrophoric fuels and coolants, which would become highly radioactive following radiation exposure.”
Read the original article on Business Insider