Thorium bulls are rare. Of all the competing visions for what kind of technology should dominate a global nuclear renaissance, thorium-fueled reactors have remained avant garde even as other once-experimental concepts such as high-temperature gas-cooled reactors and molten salt reactors found their champions.
But unlike its proponents, thorium itself is not rare. In fact, it’s as much as four times more abundant than uranium, the fuel used in every one of the 415 commercial reactors in operation worldwide today.
Back in the 1960s, when the rapid growth of the world’s fleet of atomic power stations spurred fears that uranium would run out, scientists in the U.S., Germany, and India began experimenting with thorium reactors. Then the post-war electricity demand surge spurred by next-generation electric appliances and booming factories eventually plateaued, curbing the need for more reactors — just as the meltdowns at Three Mile Island and Chernobyl reduced public support for the industry. Following a brief resurgence in the early 2000s, thorium fever mostly subsided. That is, until this past fall, when China made a major breakthrough in developing a thorium-fueled molten salt reactor.
India, meanwhile, stayed set on transitioning to a thorium-fueled fleet, which, given its large deposits of the metal and virtually nonexistent reserves of uranium, would give the subcontinent greater energy independence.
Now an American startup — which last year became one of the first U.S. companies granted permission to export nuclear materials to India — is taking a major step toward helping India realize its 72-year-old thorium dream. On Thursday, Chicago-based Clean Core Thorium Energy plans to announce a pilot manufacturing deal with the Canadian National Laboratories, Heatmap has learned.
“This is the biggest advance toward commercializing thorium in recent history,” Milan Shah, Clean Core’s chief operating officer, told me.
Thorium is “fertile” but not “fissile,” meaning it cannot sustain a chain reaction on its own, which creates an obvious challenge. But when exposed to neutron radiation, the material converts into fissile uranium-233. Rather than build a new type of reactor designed to run on thorium, as the Chinese government is now doing, Clean Core blends thorium fuel with a small amount of high-assay, low-enriched uranium, or HALEU, the type of fuel many next-generation reactor companies aim to use, which kicks off the reaction.
The proprietary fuel assemblies Clean Core manufactures are made to be used in the reactors that make up the bulk of the Indian and Canadian nuclear fleets without any upgrades or changes needed to go from enriched uranium to this new material. While the company waits for the units — they’re expected to be ready to go sometime around the second quarter of next year — it has begun talks with utilities in Canada, Romania, South Korea, and India about taking one of the assemblies for a test run.
Combined, Canada and India operate more than three quarters of the world’s pressurized heavy water reactors. Heavy water absorbs far fewer neutrons than the light water used in most reactors, resulting in a better “neutron economy” that allows the chain reaction to continue using lower concentrations of fissile uranium. That’s a big part of the reason why Canada chose the technology for its pioneering CANDU reactor, one of the world’s first widely built PHWRs, as the reactors are known. Using heavy water as a coolant makes it possible to burn up raw, natural uranium instead of the enriched fuel most reactors use, allowing Canada to divorce its CANDU fleet from the mid-century industrial complex pumping out atomic weapons.
The International Atomic Energy Agency’s data shows 46 PHWRs operating in the world today: 19 in India, 17 in Canada, three each in Argentina and South Korea, and two each in China and Romania.
“We’re looking at Canada, Romania, South Korea, and India — in that order,” Mehul Shah, Clean Core’s founder and chief executive (and Milan’s father), told me. That ranking, he said, is according to the perceived priorities of the U.S. government. Canada is a natural place to test Clean Core’s material because it’s right over the border; the Canadian Nuclear Safety Commission works closely with the Nuclear Regulatory Commission; and much of the world’s PHWR fleet is based on Canuck technology.
At a moment when HALEU is rare, the Canadian government is providing the material to Clean Core for its debut fuel bundles. But the U.S. has made Romania a high priority for nuclear exports, facilitating several high-profile deals with American vendors such as Westinghouse and GE Vernova Hitachi Nuclear Energy and offering federal financial support.
While Canada has some of the world’s richest reserves of uranium, India’s push for thorium means that it is likely the biggest near-term market for Clean Core. The elder Shah’s connections have helped win strong support. Anil Kakodkar, the former chairman of India’s Atomic Energy Commission, was his mentor. The country’s regulators have already embraced Clean Core’s technology.
Demonstrating that the fuel bundles work effectively and safely in a full-scale reactor is “the last step to commercialization,” Mehul Shah said.
If successful, Clean Core’s effort could have geopolitical ramifications for an industry that — by dint of its unique global regulations, and the fact that it’s dominated by the adversarial superpowers such as Russia, China, and the U.S. — is always subject to the travails of foreign affairs.
For one thing, the company’s technology represents one of, if not the most serious gamble in the democratic world on the future of thorium after China’s experimental reactor successfully converted thorium into fuel in a reaction. The Swiss startup Transmutex has promised to build a thorium reactor, but hasn’t announced anything significant in the past year. A rival developer, Copenhagen Atomics, has pledged to build its own thorium reactor, but has — aside from a modest European Union award — has announced little progress in the past year and is based in a country that still bans nuclear energy and only started officially reconsidering atomic power this year. Thor Energy, an early-stage Norwegian venture, has said it plans to follow Clean Core’s path in devising a thorium-based fuel for existing reactors. But the company’s website shows it hasn’t issued a press release since 2018, and a government commission in Norway just advised against pursuing atomic energy in the hydropower-rich Nordic nation.
For another, Clean Core could chart a path for other American companies into India. For years, India was effectively closed off to foreign nuclear companies due to a law that was written to avoid a scenario like the 1984 Bhopal disaster, where an accident at the Union Carbide plant killed thousands while the American corporation largely avoided liability. With that much liability on the vendors, however, the only overseas nuclear vendor willing to roll the dice was Russia’s state-owned Rosatom. But in December, as I wrote over in the Heatmap AM newsletter at the time, India passed legislation to reform the liability law and open the market for American, European, and Asian reactor developers.
If Clean Core can make India’s thorium ambitions a reality, American reactor exporters may have a new reason to start taking the fuel seriously again.
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