X-energy
X-energy is developing the Xe-100 reactor for its first planned deployment at Dow’s chemical manufacturing complex in Texas, while pursuing a larger US nuclear programme backed by Amazon.
What they do
The Xe-100 is a helium-cooled reactor designed to produce 200 MWth of thermal power and some 80 MWe of electricity. Its approximately 750°C reactor outlet temperature is intended to support high-temperature steam for industrial processes.
The reactor is designed to use TRISO fuel particles embedded in graphite pebbles that circulate through the core, enabling continuous refuelling. X-energy’s proposed standard plant configuration consists of four Xe-100 units, providing a combined 320 MWe of electrical capacity.
Pebble-bed reactors are not new: Germany operated experimental designs, and China’s HTR-PM entered commercial operation in 2023.
Where they are
X-energy’s lead project is the proposed Long Mott Generating Station at Dow’s Seadrift chemical complex in Texas, where the company plans to deploy four Xe-100 reactors to support the site’s industrial operations. Dow subsidiary Long Mott Energy submitted a construction permit application to the US Nuclear Regulatory Commission (NRC) in March 2025.
In October 2024, Amazon announced an approximately $500 million investment in X-energy, alongside plans to support more than 5 GW of new nuclear capacity by 2039. The initial development programme involves Energy Northwest in Washington state, with four Xe-100 reactors proposed for its first phase.
Through its TRISO-X subsidiary, X-energy is developing the TX-1 fuel fabrication facility in Oak Ridge, Tennessee, to manufacture the HALEU-based TRISO fuel required by its reactors. The facility has received an NRC fuel fabrication licence, with commercial production targeted for the first half of 2028.
What’s next
The immediate priorities are securing regulatory approval for the Dow project and advancing TX-1 towards commercial fuel production. X-energy must also establish a reliable supply of HALEU, qualify its fuel and complete the engineering required for construction.
The Amazon-backed programme presents a further challenge: turning a proposed multigigawatt deployment pipeline into individual licensed, financed and buildable projects.
As of October 2026, no Xe-100 reactor has entered operation.
Why it matters
X-energy is attempting to commercialise a reactor concept with relevant historical and recent operating experience, but the Xe-100 itself has not yet operated, and the company has no existing commercial fleet or dedicated commercial fuel supply chain.
The Dow project will test whether its design can deliver reliable industrial steam and electricity at a viable cost. Its fuel manufacturing programme and Amazon-backed expansion will test whether the company can move beyond a first project towards repeatable deployment.
Technical note
The Xe-100 uses helium coolant and TRISO fuel embedded in circulating graphite pebbles. Helium remains gaseous during operation, while TRISO’s ceramic coatings are designed to retain fission products at high temperatures.
China’s HTR-PM has demonstrated commercial operation of a pebble-bed HTGR, but the Xe-100’s specific design, fuel and integrated systems have not yet operated. Qualification of these components and their performance together remains necessary before commercial deployment.
Company data
| Founded | 2009 |
|---|---|
| Headquarters | Rockville, Maryland, United States |
| Leadership | J. Clay Sell, CEO |
| Sector | Nuclear energy / Advanced nuclear energy |
| Technology / Product | Xe-100 high-temperature gas-cooled reactor; TRISO-X fuel |
| Key Projects | Dow Long Mott Generating Station, Texas; Energy Northwest project, Washington; TX-1 fuel fabrication facility, Tennessee |
| Development / Commercial Stage | Reactor projects in development and licensing; no operating Xe-100 reactors |
| Ownership / Investors | Publicly traded since 2026; investors include Amazon |
| Funding | Approximately $500 million Amazon-led financing announced in October 2024; DOE cost-shared support under the Advanced Reactor Demonstration Program |
| Markets / Customers | United States; Dow, Amazon and Energy Northwest |
| Website | x-energy.com |
What to watch
- NRC construction permit decision for the Dow Seadrift project.
- TX-1 fuel manufacturing progress and HALEU supply arrangements.
- Conversion of Amazon-backed development plans into licensed and financed reactor projects.
