NRC Completes Safety Review of X-energy's Xe-100 Reactor, Advancing Dow Project

X-energy said the U.S. Nuclear Regulatory Commission completed its safety review of the Xe-100 high-temperature gas-cooled reactor, issuing a Final Safety Evaluation Report that supports a construction permit for the proposed Long Mott Generating Station. The company announced the milestone on October 30, 2026, according to GlobeNewswire.

What the NRC Review Covered

X-energy is an advanced nuclear technology company based in Rockville, Maryland, that develops small modular reactors and TRISO-X fuel for power and industrial heat. The NRC's report followed a review of the Xe-100 plant's principal design criteria, preliminary design, safety analyses, probabilistic risk assessment and research and development programs. The NRC staff concluded the proposed plant and site provide the safety basis to begin construction under 10 CFR Part 50.

The Advisory Committee on Reactor Safeguards, an independent body that advises the Commission, separately reviewed the staff evaluation and supports issuing the construction permit. The proposed Long Mott station would be the first grid-scale advanced nuclear reactor at an industrial facility in U.S. history, advancing in partnership with Dow under the Department of Energy's Advanced Reactor Demonstration Program.

The Xe-100's safety case relies on the passive physics of its TRISO-X coated particle fuel and pebble-bed core design, alongside traditional defense-in-depth systems. The design allows a 400-meter emergency planning zone, compared with 10 miles for conventional light-water reactors, which the company says lets new generation be sited closer to the point of need, including inside a large industrial facility.

"Licensing a new reactor is earned through the quality of the application and the rigor of the regulator's review," said Dragan Popovic, Chief Global Operating Officer at X-energy. "The NRC's completion of its safety review reflects years of disciplined work by our team and the NRC staff, establishing the foundations to support every Xe-100 application that follows on the path to scale."

X-energy's Licensing Record

According to akta.pro company records, the NRC issued an Environmental Assessment with a Finding of No Significant Impact for the Dow and X-energy Long Mott Generating Station in Seadrift, Texas, in May 2026, the first commercial advanced reactor to clear environmental review through an Environmental Assessment rather than a full Environmental Impact Statement. The same records show X-energy completed its IPO on Nasdaq under the ticker XE in April 2026, raising approximately $1.02 billion at $23 per share.

Earlier Steps Toward Long Mott

In September 2026, the Department of Energy awarded $1 billion to X-energy, doubling its federal commitment, with the funding supporting the Xe-100 reactor at a Dow facility in Texas and construction expected in early 2027, Canary Media reported. In October 2026, AEP, Amazon and X-energy announced a joint development plan for a 960-MW advanced nuclear project in Sullivan County, Indiana, using Xe-100 reactors, PR Newswire reported.

What Comes Next for the Construction Permit

With both primary reviews complete, the project moves to the final stages of the NRC's construction permit review. In the United Kingdom, the Xe-100 was recently accepted into Generic Design Assessment, a step in the licensing process for U.K. deployment.