Molten salt reactors (MSRs) symbolize a captivating intersection of nuclear historical past and fashionable innovation. The idea of utilizing molten salts as each a coolant and gasoline provider dates again to the Nineteen Fifties, with the pioneering work of Alvin Weinberg and his workforce at Oak Ridge Nationwide Laboratory (ORNL). In 1965, ORNL efficiently operated the Molten Salt Reactor Experiment (MSRE), a proof-of-concept reactor that demonstrated the know-how’s feasibility and inherent security options.
The MSRE achieved outstanding outcomes, working for 4 years from January 1965 by way of December 1969, and logging greater than 13,000 hours at full energy throughout that point. The trial showcased the MSR’s capacity to function at excessive temperatures with wonderful thermal effectivity, its inherent security traits as a result of low-pressure liquid gasoline, and its potential for on-line refueling and fission product elimination. Moreover, the MSRE demonstrated the flexibility to breed fissile materials from thorium, a extra considerable and available useful resource than uranium.
Regardless of its success, the molten salt program resulted in 1973, with the Atomic Power Fee deciding to deal with different nuclear reactor designs. Nonetheless, the data gained from the MSRE undertaking laid the groundwork for future MSR improvement.
Right now, MSRs are experiencing a resurgence of curiosity worldwide, with quite a few corporations and analysis establishments actively growing varied designs. MSRs provide a number of potential benefits, together with enhanced security, decreased waste era, and the flexibility to make the most of thorium as a gasoline supply, as beforehand talked about.
“There are a number of molten salt reactor corporations which might be within the strategy of chopping offers and getting MOIs [memorandums of intent] with international international locations,” Mike Conley, creator of the ebook Earth Is a Nuclear Planet: The Environmental Case for Nuclear Energy, stated as a visitor on The POWER Podcast. Conley is a nuclear power advocate and robust believer in MSR know-how. He known as MSRs “a far superior reactor know-how” in comparison with light-water reactors (LWRs).
The thorium gasoline cycle is a key element in at the very least some MSR designs. The thorium gasoline cycle is the trail that thorium transmutes by way of from fertile supply gasoline to uranium gasoline prepared for fission. Thorium-232 (Th-232) absorbs a neutron, transmuting it into Th-233. Th-233 beta decays to protactinium-233 (Pa-233), and at last undergoes a second beta minus decay to grow to be uranium-233 (U-233). That is the a technique of turning pure and considerable Th-232 into one thing fissionable. Since U-233 is just not naturally discovered however makes a super nuclear reactor gasoline, it’s a a lot sought-after gasoline cycle.
“One of the best ways to do that is in a molten salt reactor, which is an unbelievable advance in reactor design. And the large factor is, whether or not you’re fueling a molten salt reactor with uranium or thorium or plutonium or no matter, it’s a far superior reactor know-how. It completely can not soften down underneath any circumstances by any means interval,” stated Conley.
Conley urged that a lot of the concern folks have about nuclear energy revolves across the unfold of radioactive materials. Particularly, regardless of how unlikely it’s, if an accident occurred and contamination went airborne, the truth that it might unfold past the plant boundary is worrisome to many individuals who oppose nuclear energy. “The good factor a couple of molten salt reactor is: if a molten salt reactor simply goes stomach up and breaks or will get destroyed or will get sabotaged, you’ll have a messed-up reactor room with a pancake of rock salt on the ground, however not a cloud of radioactive steam that’s going to go 100 miles downwind,” Conley defined.
And the value for an MSR might be way more engaging than the price of presently obtainable GW-scale LWR models. “The ThorCon firm is predicting that they’ll have the ability to construct for $1 a watt,” stated Conley. “That’s one-fourteenth of what Vogtle was,” he added, referring to Southern Firm’s nuclear growth undertaking in Georgia, which incorporates two Westinghouse AP1000 models. In fact, projections don’t all the time align with actuality, so MSR pilot initiatives shall be keenly watched to validate claims.
There’s progress being made on MSR initiatives. For instance, in February 2022, TerraPower and Southern Firm introduced an settlement to design, assemble, and function the Molten Chloride Reactor Experiment (MCRE)—the world’s first important fast-spectrum salt reactor—at Idaho Nationwide Laboratory (INL). Since then, Southern Firm reported efficiently commencing pumped-salt operations within the Built-in Results Check (IET), signifying a serious achievement for the undertaking. The IET is a non-nuclear, externally heated, 1-MW multiloop system, positioned at TerraPower’s laboratory in Everett, Washington. “The IET will inform the design, licensing, and operation of an roughly 180-MW MCFR [Molten Chloride Fast Reactor] demonstration deliberate for the early 2030s timeframe,” Southern Firm stated.
What might maintain MSRs again within the U.S., nevertheless, is a lack of information inside U.S. Nuclear Regulatory Fee circles. “Sadly, the Nuclear Regulatory Fee is aware of every thing about light-water reactors—high-pressure, water-cooled, solid-fuel reactors—and is aware of nearly nothing about unpressurized liquid-fuel reactors. So, till they stand up to hurry, our nuclear know-how has to remain inside nuclear rules, they usually haven’t studied it sufficient. So, mainly, we’re caught with utilizing pressurized light-water reactors,” Conley stated.
Nonetheless, Conley believes there’s a path for MSRs to get constructed sooner somewhat than later, as he sees regulators in different elements of the world being extra open to the know-how. “Relaxation assured, molten salt reactors shall be constructed within the subsequent 10 years, however they are going to be constructed abroad,” stated Conley.
To listen to the complete interview with Conley, which comprises way more about the advantages of nuclear energy and the function it might play in decarbonizing the world, how nuclear energy can contribute to a diversified grid, methods to cut back prices for nuclear building initiatives, the benefits provided by small modular reactors, how nuclear waste considerations might be addressed, how misinformation is affecting public perceptions round nuclear energy, and extra, take heed to The POWER Podcast. Click on on the SoundCloud participant under to hear in your browser now or use the next hyperlinks to succeed in the present web page in your favourite podcast platform:
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—Aaron Larson is POWER’s government editor (@AaronL_Power, @POWERmagazine).