US nuclear reactor designer advances 6-gigawatt SMR fleet across the Atlantic

American reactor designer X-energy has cleared a major hurdle in its push to export commercial nuclear technology. The Maryland-based company, working alongside British energy group Centrica, has secured entry into the United Kingdom’s formal regulatory review process for its advanced small modular reactor. The milestone places X-energy’s Xe-100 system into the UK Generic Design Assessment. This review acts as the established national regulatory pathway for assessing reactor designs before site-specific licensing and construction can take place. Unlike standard commercial reactors that rely on light water for cooling, X-energy’s Xe-100 is a high-temperature gas-cooled system. It uses specialized TRISO-X particle fuel, an intrinsically safe fuel form that can withstand extreme heat without melting. According to the company, each reactor unit can generate 80 megawatts of electricity. Alternatively, a single unit can provide 200 megawatts of thermal heat to serve heavy industrial operations. To meet varying energy demands, engineers can arrange the modular units into multi-unit plant configurations ranging from 320 megawatts to 960 megawatts. “X-energy’s intrinsically safe Xe-100 high-temperature gas-cooled reactor and TRISO-X particle fuel expand applications for nuclear technology, with commercial projects across grid, industrial, and AI. Together, X-energy’s technology drives enhanced safety, lower cost, faster construction timelines, and scalable deployment when compared with other SMRs and conventional nuclear,” highlighted the company. Commercial progress in US The overseas push follows significant progress at home. In the United States, X-energy is preparing its first commercial installation alongside Dow Inc. on the Texas Gulf Coast, where the units will provide clean industrial heat and baseload power. At the same time, the company has partnered with regional utility Energy Northwest and tech giant Amazon. That project focuses on generating reliable, round-the-clock electricity to feed the rapid expansion of artificial intelligence and computing data centers. To support these upcoming reactors, X-energy has moved aggressively to secure its domestic supply chain. Last month, the developer acquired roughly 70 acres of land next to its existing facility at the Horizon Center Industrial Park in Oak Ridge, Tennessee. The purchase expands the company’s fuel-manufacturing campus from 125 acres to more than 180 acres, giving it the physical room required to scale up commercial production of its TRISO-X fuel pebbles. Now, X-energy is exporting that operating model to Britain. British regulators are already familiar with gas-cooled technology, having operated and regulated similar reactor systems for decades. In addition, the underlying physics of TRISO particle fuel traces back to early British laboratory research. Transatlantic licensing and UK deployment strategy The UK review will take approximately three years. It will be carried out jointly by the Office for Nuclear Regulation, the Environment Agency, and Natural Resources Wales. Crucially, the assessment will borrow heavily from safety files already examined by the US Nuclear Regulatory Commission. Regulators from both countries are coordinating their work, allowing British assessors to review safety models and design sheets that American inspectors have already approved. X-energy plans to build its first British facility at Hartlepool, with an ultimate goal of deploying a nationwide fleet delivering up to 6 gigawatts of power. Over the past twelve months, X-energy and Centrica have conducted site feasibility studies, sought early feedback from safety authorities, and helped set up a dedicated Nuclear and Electrical Trades Academy in Hartlepool to train technicians. The companies are also awaiting a decision on their bid to join the UK Government’s Advanced Nuclear Pipeline, with an official outcome expected in the coming weeks. Get the latest in engineering, tech, space & science - delivered daily to your inbox.An active and versatile journalist and news editor. He has covered regular and breaking news for several leading publications and news media, including The Hindu, Economic Times, Tomorrow Makers, and many more. Aman holds expertise in politics, travel, and tech news, especially in AI, advanced algorithms, and blockchain, with a strong curiosity about all things that fall under science and tech.