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Rolls-Royce SMR

Rolls-Royce SMR

🇬🇧 Derby, GB · Founded 2020-11-24 · Active

Rolls-Royce SMR is a UK company based in Derby, majority owned by Rolls-Royce, developing a factory-built pressurised water reactor of 470 MWe, larger than most designs called small modular reactors. Rolls-Royce began design work around 2015, and the UK government has provided development funding since 2017. The design entered Great Britain's Generic Design Assessment, run by the Office for Nuclear Regulation and the environment agencies, in April 2022; the assessment reviews a design and is not a licence to build at a site. In October 2024 the Czech utility ČEZ took a 20% stake, and in November 2025 the UK government chose Wylfa on Anglesey for Great British Energy–Nuclear's first SMR project using the design. No Rolls-Royce SMR has been built.

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Sector
Fission
Technology
Pressurised water reactor
Fuel
Low-enriched uranium
Role
Reactor developer

2 regulatory milestones are tracked here, none yet anchored to a docket reference in the regulator's own record.

Terms

Pressurised water reactor
Ordinary (light) water kept under high pressure so it heats without boiling, transferring heat to a separate steam loop; the water is both coolant and moderator. Fuel is low-enriched uranium oxide pellets in zirconium-alloy rods. The most common reactor type in service worldwide.
Low-enriched uranium
Uranium enriched to 5% uranium-235 or less, typically 3 to 5%: the range almost all power reactors use. Formally, anything below 20% is low-enriched; this site holds the band from 5% to just under 20% separately as HALEU, with its 5 to 10% part also tagged as LEU+. A fuel above 5% uranium-235 belongs in one of those, never here, whatever a developer's own materials call it.

Designs

Design Developer Approach Electrical output per unit Size class Licensing stage
Rolls-Royce SMR Rolls-Royce SMR Pressurised water reactor 470 MWe planned Large reactor Accepted for review for the design · Office for Nuclear Regulation · 2022-04

Licensing

  1. 2022-04achieved
    Accepted for review
    UK Generic Design Assessment begun (Step 1) · Office for Nuclear Regulation
    No public anchor for this stage
  2. 2026-08target
    Design approval or certification
    UK Generic Design Assessment completion (Design Acceptance Confirmation) — not yet issued · Office for Nuclear Regulation
    Downgraded from a claimed design approval: ONR has NOT issued a Design Acceptance Confirmation. As checked 2026-09-22, ONR lists the assessment as ongoing in Step 3. ONR's Step 1 statement (3 April 2023) expected completion in August 2026; that date has passed with no DAC published on the ONR page.
    No public anchor for this stage

Related companies

Sources