The Helium-Cooled Nuclear Reactors of X-Energy

Meta description: X-energy Xe-100 helium-cooled small modular reactors aim to deliver high-temperature heat and 80 MW power for industry, data centers, and low-carbon processes.

Tags: X-energy, Xe-100, small modular reactors, industrial heat, nuclear power

Featured image: Abstract visualization of a helium-cooled reactor core with pebble fuel channels and steam lines, no real people, company logos, or text.

X-energy is developing its Xe-100 small modular reactor, moving the design from concept into licensing and project planning to give some of the planet’s most power-hungry industrial manufacturers what solar panels and wind turbines do not easily provide: large amounts of reliable raw heat. The company, founded in 2009 and headquartered in Rockville, Maryland, US, operates in the nuclear fission industry and targets factories that need high temperatures to produce billions of tons of concrete, plastics, fibers, and chemicals.

Background: The Heat Gap Left by Water-Cooled Reactors

Concrete, glass, steel, chemicals, plastics, and fertilizers still depend heavily on fossil fuels because their manufacturing processes require intense heat. Traditional nuclear reactors fall short of the temperatures many industrial uses need. Their cooling systems depend on liquid water; even when pressure is used to raise water’s boiling point, maximum operating temperatures remain hundreds of degrees cooler than what heavy industry needs.

Helium-cooled fission is not new. The first helium-cooled reactor was proposed for the World War II Manhattan Project, but it was passed over in favor of a simpler and cheaper water-cooled design. That choice shaped the nuclear industry, but it left a gap for applications needing high-temperature heat as well as power.

Development: How the Xe-100 Turns Helium Into Heat and Electricity

X-energy’s proposed Xe-100 reactor uses helium gas as a coolant instead of water. That allows it to operate at much lower pressures and much higher temperatures. The helium heats water to create super-heated steam, which industry can use directly, pass through a turbine to generate 80 megawatts (MW) of electricity, or split between both uses. The 80 MW output is about one-tenth of the capacity of most reactors operating today.

Like other small modular reactors, or SMRs, the Xe-100 uses TRISO fuel, short for tristructural-isotropic, a modern uranium-based fuel extremely resistant to corrosion and melting. Compact TRISO pebbles are added continuously to the top of the reactor and flow slowly to the bottom, where they are recycled or removed as waste. X-energy says the design is intrinsically safe during a loss of power: if temperatures inside rise, the nuclear reaction naturally slows and stops.

Latest Progress: Dow, Amazon, Licensing, and Fuel Factories

The Xe-100 has begun to appear in real project plans. The US Nuclear Regulatory Commission has issued X-energy’s subsidiary a fuel fabrication license for TRISO-X pebbles, and the first factory is due for completion in 2028. A Xe-100 intended to supply heat and power for a large chemical facility in Texas operated by Dow has cleared its first regulatory hurdle and could be operational by the early 2030s.

X-energy is also working with Amazon toward a 320 MW cluster of four Xe-100 reactors in Richland, Washington, and on a larger 6 GW fleet in the UK’s northeast. Both projects target electricity generation in the 2030s. The company says up to 12 of its reactors could be clustered together to provide 24/7 power on site at a lower cost than a traditional nuclear power station and without the hassle of adding transmission infrastructure.

What It Could Change for Industry and AI

Industrial heating accounts for 18 percent of annual global greenhouse-gas emissions, and about half of that comes from high-temperature processes that are difficult to electrify. Co-locating small nuclear reactors at large manufacturing facilities could shrink some of the biggest carbon footprints in the world. The Xe-100 could also serve the fossil fuel industry, which uses vast quantities of natural gas to recover oil from tar sands and refine oil.

The flexibility of the Xe-100 also means it can be used for traditional electricity generation. By scaling down in size and power from today’s gigawatt-scale fission plants, small reactors like the Xe-100 can serve more markets, even down to individual data centers. AI and data centers now represent the single largest component of new demand for electricity in the US, and their consumption is expected to double again by 2030.

Risks That Remain Before Commercial Rollout

The technology behind helium-cooled fission may be well understood, but the only commercial-scale power generation of this type today is in China, where two reactors have struggled to operate on a continuous basis. X-energy says its vertically integrated fuel supply should ensure reliable operation, with reactors having a lifetime of 60 years.

The economic case for SMRs is largely unproven. Nuclear costs and timelines have a habit of ballooning, and the US Energy Information Administration calculates that electricity from SMRs will cost more than six times that from solar farms. The current US environment for regulation and funding favors nuclear, but that could change over X-energy’s long development time frame.

TRISO fuel appears excellent for safety and nonproliferation because the tough spheres would be difficult to turn into weapons, but it is less impressive for waste. The Xe-100 might produce 10 times the volume of spent nuclear fuel per unit of energy as existing reactors, although its lower-level waste will need less sophisticated storage.

The current stage is one of building the supply chain, clearing regulatory hurdles, and testing demand for high-temperature heat and around-the-clock electricity. Xe-100 deployments are not yet proven at commercial scale, but the 2028 fuel factory, Texas project, Washington cluster, and UK fleet plans place X-energy’s technology in the early bridge from design to possible deployment in the 2030s.