X-energy cleared to build its first small modular nuclear reactors

Nuclear start‑up X‑energy said on Monday that federal officials have authorised it to construct its first four commercial reactors.

The Nuclear Regulatory Commission (NRC) has signed off on a construction permit for four Xe‑100 units to be sited at a Dow chemical facility in Texas. Each unit is designed to produce 80 megawatts of electricity and 200 megawatts of heat. X‑energy notes this marks the inaugural approval for an advanced nuclear reactor on an industrial location in the United States.

The American nuclear sector has placed its expectations on small modular reactors (SMRs) such as those being pursued by X‑energy. Advocates argue that a reduced size could accelerate building times and lower expenses, though these benefits have yet to be demonstrated. No SMR is currently operating in the U.S., and X‑energy projects that the Dow plants will not come online until the early 2030s.

X‑energy asserts that its design, which circulates helium gas over uranium‑laden fuel pellets, offers greater safety than many existing reactors, a claim that the Union of Concerned Scientists has challenged, alongside concerns about the rapidity of the permit.

“The NRC only accomplished this feat by pushing consideration of critical safety questions to a later date—issues the NRC should’ve fully resolved before green lighting construction,” Edwin Lyman, director of nuclear power safety for the organization, said in a statement.

The sector has attracted keen interest from hyperscalers and data‑centre developers seeking reliable power. Amazon’s Climate Pledge Fund led a $500 million Series C‑1 round for X‑energy, and the tech giant has also pledged to purchase 5 gigawatts of capacity from the start‑up.

Earlier this year, X‑energy rode the enthusiasm generated by its April initial public offering, which raised $1 billion. Since that time, investor confidence has cooled.

Such caution is understandable, given that nuclear plants are costly to build and can take many years to complete. X‑energy ultimately aims to shorten construction periods and cut costs, though the first reactors are expected to be expensive.

The recent permit decision gave X‑energy a modest boost yesterday, sufficient only to recoup losses from the previous week. Its shares are now trading at less than half the price at the IPO.