X-energy, the Amazon-backed reactor startup based in Maryland, is one of three companies to take part in a program with Singapore to the country’s regulators in its licensing department so they can see how an atomic power project goes from planning to approval. The goal is to help train the “nuclear manpower” needed to design a reactor buildout that matches Singapore’s unique needs, according to the name of the program. By observing the process to license reactors, the regulators from Singapore’s Ministry of Energy, Trade, and Industry and its Energy Market Authority hope to lay the groundwork for the city-state to import reactor technology and build its first nuclear plant.
Singapore spans less land area than the city of Memphis, Tennessee, yet the Southeast Asian city-state has plans to expand its electricity generating capacity by more than a quarter in the coming years to around 15 gigawatts — more than four times the U.S. city’s all-time high power demand. The country’s Ministry of Energy, Trade, and Industry and its Energy Market Authority will pay the salaries of its embedded workers for the full length of the program, anywhere from six months to two years. Aside from the free labor, the host companies receive an inside track to sell reactors to Singapore if the country moves forward with a nuclear project.
“They need to pick a technology that suits their very, very specific needs and constraints,” Miriam D'Onofrio, X-energy’s senior director of international markets, told me. (While the company announced the partnership at the Singapore International Energy Week summit late last month, X-energy spoke exclusively with Heatmap about the agreement.)
“We’re proud to be the only American entity — and one that wasn’t facilitated by the U.S. government at all,” she added. “That was something that Singapore evaluated for itself and made a central decision to pursue. That’s a testament to the strength of our technology and the trust that they have in us as a company.”
Another company vying for Singapore’s business is AtkinsRéalis, the Montreal-based nuclear company behind Canada’s homegrown CANDU reactor technology. But a source with direct knowledge of the Singaporean government’s thinking told me the country is already sold on the benefits of building a high-temperature gas-cooled reactor, an expensive option that promises a relatively small footprint on land and minimal risk of a meltdown. The CANDU, by contrast, is a pressurized heavy water reactor, which uses a special kind of water as a coolant to use raw uranium as a fuel and avoid enrichment altogether.
That means the real competition is between X-energy and the China National Nuclear Corporation. CNNC, the second of China’s two state nuclear companies, which currently operates the world’s only commercial high-temperature gas-cooled reactor. Located at Shidao Bay Nuclear Power Plant on the tip of the Shandong Peninsula that juts from northern China into the Yellow Sea, the demonstration reactor came online in December 2023. The completion of the 210-megawatt reactor, which runs on a specialized and fuel known as TRISO that’s specifically engineered for safety, vaulted China to the front of the global race for what are called fourth-generation technologies that use coolants other than water.
While the U.S., Britain, Germany, and Japan all built experimental high-temperature gas-cooled reactors (America also briefly operated a commercial plant in Colorado before shutting it down in the early 1990s due to high costs), China is the first in decades to actually pump its electricity onto the grid. Construction began earlier this month on a second such unit.
That could afford CNNC some advantages. “China has an HTGR that’s been operating,” D'Onofrio told me. “But it is demonstrably more difficult to get information out of China and on that program.”
The trouble is, countries that “are embarking on new nuclear programs want to learn and absorb themselves,” she said. “They don’t just want to buy something off the shelf,” she said. “That’s unfortunately not how nuclear works.” With the Xe-100, an 80-megawatt small modular reactor cooled with helium, D'Onofrio said, “we tried our best to optimize constructability, to optimize manufacturability, to optimize efficiencies in the core.”
X-energy is making progress. On Monday, the U.S. Nuclear Regulatory Commission granted the company a permit to begin construction on its first plant, a small facility on Texas’ Gulf coast to funnel electricity and heat to Dow’s second-largest chemical plant. X-energy has also inked at least two deals with American utilities for full-scale plants in Washington State, with Energy Northwest, and in Indiana with American Electric Power.
Though the company has yet to fully build one of its reactors, she said, “I am confident that once we do, there will be a wave that we’re excited to see of interest from industry, from data centers, and from customers all over the world.”
If China’s edge is having an actual operating reactor, the strongest argument for X-energy may be its plans to manufacture its own fuel.
Both the Chinese and the American reactors run on TRISO. Rather than slotting pellets of enriched uranium into PEZ dispenser-like fuel assemblies that go into conventional reactors, TRISO producers ball the enriched uranium into poppyseed-sized spheres coated in ceramic material. That coating absorbs the dangerous materials produced during fission and makes a meltdown physically impossible, eliminating the need for the massive steel and concrete domes that serve as containment in traditional nuclear plants.
While China fills its TRISO kernels with conventional low-enriched uranium, X-energy is manufacturing its own fuel out of a more potent type of fuel. That fuel, known as high-assay low-enriched uranium or HALEU, burns through more of the energy in the uranium, but it’s also more expensive, and the only major commercial vendor in the world today is Russia’s Rosatom.
“We have the [intellectual property] on some of the most reliable TRISO fabrication that’s ever been invented,” D'Onofrio said.
Some experts doubt that Singapore will actually commission a nuclear plant anytime soon. “The Singaporeans are treating nuclear energy as a long-term risk-monitoring exercise rather than an active engineering [project],” François Morin, the World Nuclear Association’s director in Beijing, told me in a text message. “For now, the state’s priority is maintaining a superficial, multi-directional radar so they aren’t blindsided if regional neighbors like Indonesia or Malaysia move forward with their own nuclear plans.”
While the appeal of a TRISO-fueled high-temperature gas-reactor is the absence of a multi-mile emergency planning zone like those that surround water-cooled plants, Morin said the Singaporean government is “ignoring the reality that no international regulator has universally codified a ‘zero-EPZ’ standard for a hyper-dense metropolitan area.”
X-energy said it doesn’t need to ultimately build a reactor in Singapore for the effort to be worthwhile.
“Even if Singapore doesn’t pursue an HTGR program — we’d love them to — they’re going to play a role in regional development,” D'Onofrio said. “We want to play a role in regional development, and the strength of Singaporean institutions — the ease of doing business here — makes it a really, really interesting option for us for a future footprint.”
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