Rolls-Royce SMR
Under review
Output
470MWe
Rolls-Royce SMR is a light water-cooled reactor design rated at 470 MWe. An application is docketed and under active regulatory review.
At 470 MWe this stretches the definition of "small" — it is closer to a compact conventional PWR than a microreactor, which is deliberate: it uses proven light water technology and factory-built modules to attack cost rather than physics. Selected as the UK's preferred SMR technology in 2025 with three units planned at Wylfa.
Regulatory position
| Tier | Under review |
|---|---|
| Regulator | UK ONR and Environment Agency |
| Application type | Generic Design Assessment |
| Docket / reference | UK GDA, Rolls-Royce SMR Limited — Step 3 |
| Application date | — |
| Review phase | GDA Step 3, the final step, expected to conclude late 2026 |
| Decision expected | 2026 |
Design
| Coolant | Light water |
|---|---|
| Reactor family | Pressurised water reactor (PWR) |
| Electrical output | 470MWe |
| Thermal output | not disclosed |
| Fuel | Uranium dioxide |
| Enrichment | LEUUnder 5% U-235 |
| First site | Wylfa, Anglesey |
| Offtakers | Great British Energy - Nuclear |
Sources
- UK Office for Nuclear Regulation and Rolls-Royce SMR · retrieved 2026-09-06