Centrica, X-energy Advance Nuclear Plans as UK Regulators to Begin Design Review for Xe-100, (but with a warning)

risks relating to the Company’s partnership with Centrica, including the parties’ ability to perform under and realize the anticipated benefits of the Joint Development Agreement, to secure site development, and to meet expected timelines; changes in UK or U.S. government policy, funding, or support for advanced nuclear; supply chain and supplier constraints; and first-of-a-kind risks and the Company’s limited operating experience at intended scale, including latent design or operational issues. More information about potential risks is detailed under “Risk Factors” in X-energy’s Form 10-Q filed with the Securities and Exchange Commission (the “SEC”), and in subsequent SEC filings, available on X-energy’s Investor Relations website at https://investors.x-energy.com/ and on the SEC website at www.sec.gov. Any forward-looking statements herein are based on assumptions believed reasonable as of, and speak only as of, the date of this press release. Except as required by law, X-energy undertakes no obligation to update these statements as a result of new information or future events.

On the one-year anniversary of the Centrica X-energy partnership being signed, the UK Government has directed regulators to accept the X-energy Xe-100 Advanced Modular reactor into the Generic Design Assessment, marking a significant step toward UK commercial licensing.
Under their partnership, the companies intend to deploy up to 6 GW of new nuclear capacity in the UK (10-20 Xe-100 power stations depending on size of each installation)

LONDON, England – September 15, 2026 – Centrica plc (“Centrica”) and X-Energy, Inc. (Nasdaq: XE) (“X-energy”), a leading developer of advanced nuclear reactors and fuel technology, today announced that X-energy’s Xe-100 Generation IV advanced Small Modular Reactor (“SMR”) has been accepted into the United Kingdom’s Generic Design Assessment (“GDA”) process.

GDA acceptance formally triggers the process of assessing the design’s acceptability for deployment and operation ahead of the technical and environmental evaluations required for site-specific licensing and permitting. The assessment is expected to take approximately three years and will be administered by the UK Office for Nuclear Regulation (“ONR”), the Environment Agency (EA), and Natural Resources Wales.

The submission builds on the Xe-100’s U.S. licensing progress and is expected to benefit from expanded collaboration between the UK regulators and the U.S. Nuclear Regulatory Commission (“NRC”), enabling transfer of NRC-reviewed design documentation and safety analyses into UK design reviews.

This press release contains forward-looking statements within the meaning of the Private Securities Litigation Reform Act of 1995, which X-energy and its subsidiary TRISO-X intend to be covered by the safe harbor provisions of Section 27A of the Securities Act of 1933, as amended, and Section 21E of the Securities Exchange Act of 1934, as amended. Words such as “assume,” “believe,” “continue,” “could,” “estimate,” “expect,” “intend,” “may,” “plan,” “potential,” “predict,” “project,” “will,” “seek,” the negative of these words, or similar terms may identify forward-looking statements, but their absence does not mean a statement is not forward-looking. These include, but are not limited to, statements regarding the intended deployment of up to 6 GW of new nuclear capacity; the expected timing, conduct and completion of the GDA; the anticipated benefits of the expanded collaboration between the UK Regulators and the U.S. Nuclear Regulatory Commission; and the anticipated development and completion of X-energy’s other ongoing reactor projects.

You should not rely on these forward-looking statements as predictions of future events. Actual results may differ materially due to a number of factors, including, but not limited to: delays or setbacks in the GDA process; site-specific issues related to licensing, permitting, consenting, or scaling of Xe-100 plants in the UK; changes, delays, or the inability to obtain and maintain licenses or governmental approvals from the UK Office for Nuclear Regulation or other regulatory authorities, and the risk that anticipated cooperation between jurisdictions does not occur as expected; risks relating to the Company’s partnership with Centrica, including the parties’ ability to perform under and realize the anticipated benefits of the Joint Development Agreement, to secure site development, and to meet expected timelines; changes in UK or U.S. government policy, funding, or support for advanced nuclear; supply chain and supplier constraints; and first-of-a-kind risks and the Company’s limited operating experience at intended scale, including latent design or operational issues. More information about potential risks is detailed under “Risk Factors” in X-energy’s Form 10-Q filed with the Securities and Exchange Commission (the “SEC”), and in subsequent SEC filings, available on X-energy’s Investor Relations website at https://investors.x-energy.com/ and on the SEC website at www.sec.gov. Any forward-looking statements herein are based on assumptions believed reasonable as of, and speak only as of, the date of this press release. Except as required by law, X-energy undertakes no obligation to update these statements as a result of new information or future events.