SGE UK and Origin Nuclear sign letter of intent for planned UK SMR fleet

Two companies have agreed in principle to work together on running a fleet of small modular reactors (SMRs) in the UK. SGE SMR UK and Origin Nuclear have signed a letter of intent to form a joint venture that would operate SGE’s planned UK SMR fleet of 14 BWRX-300 reactors across three UK sites, according to The Energyst. The arrangement is not yet finalised: the letter of intent is an early-stage agreement, not a completed deal.

Under the proposed arrangement, the two companies would set up a UK-based nuclear operating company. Origin Nuclear would support the licensing process, commissioning and readiness of the reactors, and would also take on plant operations and shared support services across the fleet.

What is being planned, and how big is it?

SGE’s programme envisages 14 BWRX-300 reactors spread across three sites, with the first unit aimed to start commercial operation in 2034. Together, the reactors would produce 4.2GW of power, enough low-carbon electricity to cover approximately 11% of UK electricity demand, or the equivalent needs of almost eight million homes, for at least 60 years. The first site is planned to host six reactors, with two further multi-unit sites to follow.

SGE announced its plans to deploy these reactors in July 2026. The programme is built around a standardised design, meaning the same technology, supply chain and working practices would be used across all three sites. SGE’s proposal is currently going through the Project Deep Dive under the UK’s Advanced Nuclear Framework.

Rafał Kasprów, CEO of SGE, said: ‘This is a significant step forward for our UK programme. Securing an operating partner is one of the most important decisions in developing a nuclear project, and with Origin Nuclear and its parent company OPG, we have a partner backed by more than a half century of nuclear experience and direct involvement in the first BWRX-300 project in Canada.’

Jos Diening, Origin President and CEO, said: ‘The Darlington New Nuclear Project, where OPG has begun construction of the first BWRX-300, will deliver the reliable, low-carbon electricity Ontario needs to meet rapidly growing demand, while creating opportunities for Origin Nuclear and other Ontario companies to showcase our expertise on the global stage.’

The reactor design and its progress in Canada

The BWRX-300 is a 300MW reactor developed by GE Vernova Hitachi Nuclear Energy, and it is currently the only commercially available SMR technology under construction anywhere in the world. The Canadian Nuclear Safety Commission confirmed that in April 2025 it issued Ontario Power Generation a licence to construct one BWRX-300 reactor at the Darlington site, with three regulatory hold points built into that licence. In April 2026, World Nuclear News reported that OPG had applied for a licence to operate the reactor, with the Province of Ontario having approved a CAD20.9 billion (USD15 billion) budget for the first of four planned units at the site.

In the United States, the Nuclear Regulatory Commission has issued a construction permit to the Tennessee Valley Authority for a BWRX-300 reactor at its Clinch River site in Tennessee. SGE is a co-investor in the standardised BWRX-300 design alongside GE Vernova Hitachi Nuclear Energy, Ontario Power Generation and the Tennessee Valley Authority, and says lessons from the North American projects will feed into its UK and European plans.

SGE’s UK programme is currently at the Project Deep Dive stage under the government’s Advanced Nuclear Framework, with no approval granted yet.