- X-energy has been cleared to enter the UK's nuclear reactor design review process.
- The Xe-100 reactor uses TRISO-X particle fuel, which is inherently safe.
- X-energy is working with multiple companies to advance plans for commercial installations.
- The UK review will draw heavily on safety filings already examined by the US Nuclear Regulatory Commission.
US reactor design firm X-energy has cleared a major hurdle in exporting its commercial nuclear technology. The Maryland-based company, in partnership with British energy group Centrica, has been granted entry into the UK's formal regulatory review process for its advanced small modular reactor. The milestone places X-energy's Xe-100 system within the UK's Generic Design Assessment, a national regulatory pathway for evaluating reactor designs that must be completed before a specific site can be licensed and constructed.
Technical features of the Xe-100 reactor
Unlike standard commercial reactors that rely on light-water cooling, X-energy's Xe-100 is a high-temperature gas-cooled system using proprietary TRISO-X particle fuel, an inherently safe fuel form that cannot melt even under extreme heat. According to the company, each reactor module can generate 80 MW of electricity, or a single module can deliver 200 MW of thermal energy to support heavy industrial operations. To meet different energy needs, engineers can arrange modules in multi-unit plant configurations ranging from 320 MW to 960 MW.
The company stressed: "X-energy's inherently safe Xe-100 high-temperature gas-cooled reactor and TRISO-X particle fuel expand the application of nuclear technology to commercial projects covering the grid, industry, and artificial intelligence. Compared with other small modular reactors and conventional nuclear power, X-energy's technology delivers improved safety, lower costs, shorter construction timelines, and scalable deployment." On the commercial front in the US, X-energy has also made significant domestic progress. The company is preparing its first commercial installation on the Texas Gulf Coast with Dow Inc., a unit that will supply clean industrial heat and baseload power.
The company has also established partnerships with regional utility Energy Northwest and tech giant Amazon. The project focuses on generating reliable 24-hour power to support the rapid expansion of artificial intelligence and computing data centers.
The UK review process and its significance
To support the upcoming reactor, X-energy is actively securing its domestic supply chain. Last month, the developer acquired roughly 70 acres of land near 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, providing the physical space needed to scale commercial production of TRISO-X fuel particles. X-energy is now exporting that operating model to the UK. UK regulators are quite familiar with gas-cooled technology, having operated and overseen similar reactor systems for decades.
Furthermore, the basic physics of TRISO particle fuel trace back to early British laboratory research.
The UK review will take roughly three years and will be conducted jointly by the Office for Nuclear Regulation, the Environment Agency, and Natural Resources Wales. Importantly, the assessment will draw heavily on safety filings already examined by the US Nuclear Regulatory Commission. Regulators from both countries are coordinating so that UK assessors can review safety models and design documents that US inspectors have already approved. X-energy plans to build its first UK facility in Hartlepool, with the ultimate goal of deploying a nationwide fleet delivering up to 6 GW of power. Over the past twelve months, X-energy and Centrica have carried out site feasibility studies, sought early feedback from safety authorities, and established a dedicated nuclear and electrical trades academy in Hartlepool to train technicians.
The companies are also awaiting a decision on their application to join the UK government's advanced nuclear pipeline, with an official outcome expected in the coming weeks.
Potential and challenges of X-energy's UK expansion
X-energy's entry into the UK nuclear reactor design review process marks the international expansion of its commercial nuclear technology. The high-temperature gas-cooled system of the Xe-100 reactor and the inherent safety of TRISO-X fuel open new possibilities for nuclear applications. Through partnerships with local companies, X-energy can not only provide clean energy but also support the needs of artificial intelligence and data centers. However, the UK review process takes time and must meet strict regulatory requirements, posing a challenge to its future commercial plans.