OPG’s Origin Nuclear to Help Operate SGE’s 14-Unit UK BWRX-300 Fleet

Origin Nuclear, the operating subsidiary of Canada’s Ontario Power Generation (OPG), has signed a letter of intent with SGE SMR UK, the British project company of Polish developer SGE, to form a joint venture that would operate a planned fleet of 14 BWRX-300 small modular reactors in the United Kingdom. The announcement, made on October 22, builds on SGE’s application earlier this year under the UK’s Advanced Nuclear Framework for a privately financed, 4.2 GW fleet spread across three sites.

What the letter of intent covers

Under the preliminary agreement, Origin Nuclear and SGE SMR UK intend to create a UK-based nuclear operating company. Origin would support licensing, commissioning and operational readiness for the fleet, then run day-to-day plant operations and provide centralized support services once units come online. The letter of intent is not a binding contract, and the companies have not disclosed an ownership split for the proposed joint venture or a timetable for finalizing it.

SGE chief executive Rafał Kasprów said locking in an operating partner was “a significant step forward” for the UK programme, pointing to Origin’s and OPG’s operating record as a source of added confidence for the project. Origin president and chief executive Jos Diening framed the deal in terms of Ontario’s nuclear supply chain, saying Origin is “helping position Ontario’s world-class supply chain to compete for opportunities around the world.”

A 4.2 GW fleet across three UK sites

SGE’s plan calls for 14 GE Vernova Hitachi BWRX-300 units at three multi-unit sites in the UK, with the first site hosting six reactors; the split between the remaining two sites has not been made public. At a combined 4.2 GW, SGE says the fleet could cover roughly 11% of UK electricity demand, or supply close to eight million homes, for at least 60 years. The company is targeting first commercial operation in 2034, with no final investment decision date yet confirmed. SGE has previously said the programme could draw up to £35 billion ($46 billion) in private capital over its build-out, though that figure has not been restated in connection with this week’s announcement.

The BWRX-300 is a 300 MWe water-cooled, natural-circulation SMR with passive safety systems, built on the licensing basis of GE Vernova Hitachi’s NRC-certified ESBWR design and using the already-licensed GNF2 fuel. SGE’s delivery team for the UK fleet also includes GE Vernova Hitachi Nuclear Energy, Samsung C&T, Laing O’Rourke, Aecon Group, Fermi Development and Etara.

OPG’s Darlington project as the reference plant

Origin’s role leans on OPG’s position as the owner of the first BWRX-300 under construction in North America, at the Darlington New Nuclear site near Toronto, Ontario, where OPG and GE Vernova Hitachi have begun construction and ultimately plan four units. That project has served as a reference design for other BWRX-300 customers, including the Tennessee Valley Authority, which received a US Nuclear Regulatory Commission construction permit for a unit at Clinch River, Tennessee, in September. SGE is also a co-investor in the standardized BWRX-300 design alongside GE Vernova Hitachi, OPG and TVA, giving the UK programme a direct line to the design and construction experience accumulated at Darlington.

Part of a wider BWRX-300 push

The UK fleet is one of several BWRX-300 programmes now moving through development in parallel. In Poland, a separate OPG subsidiary, Laurentis Energy Partners, has been supporting early planning for a fleet proposed by OSGE — the joint venture between PKN Orlen and SGE — under a services agreement, while ZE PAK and SGE have separately formed a joint venture for six SMRs at Poland’s Pątnów site. In the US, AEP, Amazon and X-energy are studying a 960 MW SMR plant using X-energy’s Xe-100 design at a retired Indiana coal site, and Indiana utilities are separately weighing up to 6 GW of Canadian-designed Candu reactors under a new AtkinsRéalis memorandum of understanding. The UK deal gives Origin and OPG a foothold in a fourth market, alongside Canada, Poland and the US, as the BWRX-300 design moves from first-of-a-kind construction toward fleet-scale deployment.

Sources

• World Nuclear News, “OPG firm joins UK BWRX-300 project,” October 22, 2026 — JV announcement, quotes, fleet and timeline details.
• ANS Nuclear Newswire, “Polish company SGE hopes to deploy 14 BWRX300 reactors in UK,” July 2026 — background on SGE’s Advanced Nuclear Framework application, partner list and £35 billion investment estimate.
• World Nuclear News, “SGE-led team targets 14 BWRX300 SMRs in UK,” 2026 — site and timeline details for the three-site, 4.2 GW programme.

Illustrative image. Photo: Nuclear Regulatory Commission, Public domain, via Wikimedia Commons — source