Amazon-backed X-energy files to raise up to $800 million in IPO.

Nuclear power startup X-energy began an investor roadshow for its IPO on Wednesday, setting a price target between $16 and $19 per share, according to a document filed with the U.S. Securities and Exchange Commission. Listing at the highest level could net the startup about $814 million.

X-energy and its peers are riding a new wave of interest in nuclear fission power as electricity demand surges, fueled by AI data centers and the electrification of society at large.

Amazon is one of X-energy’s biggest supporters. The tech giant led a $500 million Series C-1 round and pledged to purchase up to 5 gigawatts of nuclear power from the company by 2039.

The IPO is sure to bring relief to X-energy investors, who have invested about $1.8 billion in the company, according to PitchBook. The startup previously attempted to go public through a reverse merger with a special purpose acquisition company, but as the SPAC craze died down, both parties canceled the deal in 2023.

X-energy’s reactors are known as high-temperature gas-cooled reactors. Inside, uranium surrounded by ceramic and carbon spheres is cooled by helium gas. The gases then transfer the heat to a steam turbine loop to generate electricity. The fuel design, known as TRISO, is not currently in widespread use but is expected to be safer than previous fuel arrangements.

The startup said in an SEC filing that it was already embroiled in a patent dispute with another company that recently went bankrupt. Ultra Safe Nuclear Corporation (USNC) went bankrupt in 2024, and its assets were purchased out of bankruptcy to form Standard Nuclear. X-energy claims that USNC infringed on its fuel manufacturing patents and that the issues were not satisfactorily resolved during the bankruptcy proceedings.

Outside China, development of new reactors has come to a near halt due to delays and cost overruns. A new breed of startups hopes that by shrinking nuclear reactors, they can overcome some of the challenges surrounding existing designs.

None of the small modular reactor startups have yet built a power plant, but several are racing to meet the July 4 deadline set by the Trump administration.

Many may miss the arbitrary deadline, but there is still a good chance that the critical point, the moment when the fission reaction becomes self-sustaining, will be reached.

But the road from criticality to profitable power plants appears to be a long one. Mass production helps keep costs down, but it typically takes about 10 years for the process to start paying dividends. Moreover, the number of reactors these companies plan to build may be higher than what other companies have attempted, but may not be high enough to enjoy the true benefits of mass manufacturing.

X-energy expects to reduce costs by 30% compared to the original by the time the technology for producing what experts call the “Nth” reactor has matured. Investors should pay close attention to how much the first reactor will cost. This can make or break a company’s prospects.