U.K. regulators plan “radical reforms,” begin Xe-100 assessment

Earlier this year, the United Kingdom released plans intended to "fundamentally reshape the regulatory landscape" of the nuclear industry and speed nuclear deployment. A policy paper, "Building Our Nuclear Nation," was released in March 2026, and that same month, then chancellor Rachel Reeves sent a letter to the U.K. Office for Nuclear Regulation that posed five questions on how ONR and other regulators planned to adapt.

On September 10, Michael Finnerty, chief executive and chief nuclear inspector of the ONR, responded. In his response-which ONR published online on September 13-Finnerty touted the "ONR Together" strategy to undertake a "significant program of change" in expediting nuclear power projects in the United Kingdom that can keep pace with the growing demand for nuclear power while meeting safety, security, and safeguards standards.

"I fully support the Review's conclusions that radical reforms are needed. I have instructed my teams to focus on a more outcomes-based regulatory system, without compromising our role to protect people and the environment," Finnerty wrote in the letter, which was addressed to Chancellor John Healey. "The radical reforms we are implementing will maintain robust oversight where hazards are greatest but will also reduce unnecessary bureaucracy, strengthen professional judgment, and provide greater regulatory certainty to enable industry to accelerate its programs."

According to Finnerty, ONR will focus on three areas: creating a more integrated regulatory system; stronger leadership and culture; and shifting toward smarter, digital, risk-informed regulation. ONR's letter provided some examples as to how it plans to adapt, such as through creating a Lead Nuclear Regulator Group, revising safety case guidance, and adopting a more flexible approach to the GDA process.

"ONR is not seeking incremental improvement. We are transforming how regulation is delivered and how change is enabled across the nuclear sector," Finnerty wrote. "We will move beyond measuring success through activity and process, focusing instead on outcomes, impact, and the value we create. Success will be reflected in the confidence our decisions inspire, the improvements our regulation enables, and the lasting change we help deliver."

New reactor news: Significant reforms are not the only the latest development from ONR in the last week. The U.K. government has directed regulators to commence the three-step generic design assessment process for X-energy's Xe-100 high-temperature, gas-cooled reactor.

X-energy and U.K. energy company Centrica announced plans last year to deploy a fleet of Xe-100s, most notably at Hartlepool, where a currently operating nuclear plant is scheduled to be shut down as early as 2028. A total of up to 6 GW of new nuclear power capacity has been proposed.

ONR, along with the U.K.'s Environment Agency and Natural Resources Wales, will conduct the GDA of the Xe-100, which is expected to take approximately three years, according to X-energy. While it is a voluntary process, a GDA allows regulatory authorities to assess reactor designs ahead of formal site licensing, environmental permits, and planning permission.

U.K. regulators are already engaged in a tier 3 preliminary design review on selected topical areas of the Xe-100.

"Across both sides of the Atlantic, X-energy is advancing fleet-scale deployment of our technology, and it begins with a strong regulatory foundation that enables us to drive efficiency from the first project to a full commercial fleet," X-energy CEO Clay Sell said in a statement. "Together with Centrica, we are advancing the development work required to move from a first project at Hartlepool to a fleet of Xe-100 plants across the country."

ONR also announced on September 10 that it had conducted a workshop with Swedish nuclear regulators to strengthen collaboration between the two countries as they work on Swedish utility Videberg Kraft's plans to deploy reactors from Rolls-Royce SMR at the existing Ringhals nuclear facility in southwestern Sweden.

"Discussions covered a range of topics, including U.K. regulators' work on the [GDA] of the Rolls-Royce SMR technology, as well as the knowledge and experience developed through the regulation of new build projects such as Hinkley Point C and Sizewell C," the announcement said.

ONR plans to conduct a similar workshop later this year with regulators from the Czech Republic as Rolls-Royce SMR works with Czech-based ČEZ Group on the deployment of SMRs at two new locations in that European country.