X-Energy, Inc.

The company was founded in 2009 by Kam Ghaffarian. In January 2016, X-energy was provided a five-year grant of up to $40 million, as part of the DOE's Advanced Reactor Concept Cooperative Agreement to advance elements of their reactor development. Former Deputy Secretary of Energy, Clay Sell, was appointed CEO of X-energy in 2019.

In 2019, X-energy received funding from the United States Department of Defense to develop small military reactors for use at forward bases as part of Project Pele. However, the Department of Defense selected BWX Technologies instead in 2022.

In October 2020, the company was chosen by the DOE as a recipient of a matching grant totaling between $400 million and $4 billion over the next 5 to 7 years for the cost of building a demonstration reactor of their Xe-100, helium-cooled pebble-bed reactor design. The grant is a part of the DOE's Advanced Reactor Demonstration Program, which also awarded the same grant to TerraPower.

In 2022, Curtiss-Wright agreed to act as the preferred supplier of three critical components of the Xe-100 reactor. The initial installation of the reactor was projected to be for Energy Northwest in Washington State. However, in March 2023, X-energy and Dow Chemical Company agreed to develop the project at one of Dow's sites on the U.S. Gulf Coast, to be called the Long Mott Generating Station. Dow and X-energy submitted a construction permit application for the plant to the Nuclear Regulatory Commission (NRC) in 2025.

In December 2022, X-energy planned to go public in a $2 billion deal using the special-purpose acquisition company Ares Acquisition, but this was called off in October 2023 due to the then macroeconomic situation and the effect on the market of the cancellation of the first U.S. SMR deployment project, the Carbon Free Power Project, because of cost increases. The company laid off some staff in November 2023. In December 2023, the company raised $235 million of investment in a new funding round from existing investors.

In July 2023, X-energy and Energy Northwest signed an agreement to consider deploying up to 12 Xe-100 modules at the previously considered Washington site. Amazon joined the project in October 2024, and announced that it would fund four Xe-100 reactors due to increased electricity demand from the AI boom. The project, called the Cascade Advanced Energy Facility, is part of a deal between Amazon and X-energy to build up to 5 GW of Xe-100 reactors to power Amazon's data centers. As of 2025, the facility is expected to start operating in the mid-2030s.

In September 2025 X-Energy announced plans with British multinational energy and services company Centrica to deploy up to 12 Xe-100 reactors at the Hartlepool site in the UK, as part of a broader goal of building 6 gigawatts of Xe-100s in the UK.

On April 24, 2026, X-energy went public via an initial public offering (IPO) on the NASDAQ, raising over $1 billion. It was the largest nuclear IPO on record.