Technology · Nuclear energy and propulsion
Small Modular Reactors
Factory-built fission reactor modules of roughly 20 to 300 MWe each, deployable singly or in multi-unit plants.
Limited fieldingPart of Advanced fission reactors
Inputs
0
0 high or critical
Maturity
Limited fielding
Field-wide rating
Sources
0
Behind these records
Who Builds It20
Fielded0
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Limited fielding0
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Prototype0
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Development20
- Applied AtomicsDeveloper
- Blue Capsule TechnologyDeveloper
- BlykallaDeveloper
- Copenhagen AtomicsDeveloper
- Deep FissionDeveloper
- GE Vernova Hitachi Nuclear EnergyDeveloper
- Kairos PowerDeveloper
- Last EnergyDeveloper
- MoltexFLEXDeveloper
- Natura ResourcesDeveloper
- NewcleoDeveloper
- NuScale PowerDeveloper
- OtreraDeveloper
- Rolls-Royce SMRDeveloper
- Steady Energy OyDeveloper
- TerraPowerDeveloper
- ThorizonDeveloper
- Westinghouse Electric CompanyDeveloper
- X-energyDeveloper
- ZettaJouleDeveloper
Research0
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Concept0
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- Applied AtomicsDeveloperDevelopment
- Blue Capsule TechnologyDeveloper · FRDevelopment
- BlykallaDeveloper · SEDevelopment
- Copenhagen AtomicsDeveloper · DKPrototypes to date are non-fission; first chain reaction planned at PSI in 2028.Development
- Deep FissionDeveloper · USDevelopment
- GE Vernova Hitachi Nuclear EnergyDeveloper · USBWRX-300; first unit under full-scale construction at Darlington, Ontario.Development
- Kairos PowerDeveloper · USKP-FHR; Hermes 2 (up to 50 MW to the TVA grid) broke ground April 2026 with NRC construction permits.Development
- Last EnergyDeveloper · USCompany markets the 20 MWe PWR-20 as an SMR; the PWR-5 pilot is described as a microreactor.Development
- MoltexFLEXDeveloper · GBDevelopment
- Natura ResourcesDeveloper · USDevelopment
- NewcleoDeveloperDevelopment
- NuScale PowerDeveloper · USUS460 77 MWe module received NRC standard design approval in 2025; no plant built yet.Development
- OtreraDeveloper · FRDevelopment
- Rolls-Royce SMRDeveloperDevelopment
- Steady Energy OyDeveloper · FILDR-50 is a heat-only reactor; a non-nuclear full-scale pilot plant is being built in Helsinki.Development
- TerraPowerDeveloper · USDOE, World Nuclear News and ANS call Natrium a small modular reactor even though its 345 MWe (500 MWe with storage) output is above the BRIEF's ~300 MWe SMR band; the capability-level link from batch B stays.Development
- ThorizonDeveloper · NLDevelopment
- Westinghouse Electric CompanyDeveloper · USAP300 SMR (330 MWe), a one-loop derivative of the AP1000; Westinghouse markets it as an SMR although it is slightly above the 300 MWe band.Development
- X-energyDeveloper · USXe-100 (about 80 MWe per reactor; four-pack plant ~320 MWe).Development
- ZettaJouleDeveloper · USDevelopment
Placed by each organization's own maturity for this technology; TRL is self-reported or estimated, see confidence.
Systems16
| BWRX-300 | GE Vernova Hitachi Nuclear Energy | Other | Development | — |
| Hermes 2 | Kairos Power | Other | Development | — |
| Natrium | TerraPower | Other | Development | — |
| NuScale Power Module | NuScale Power | Other | Development | — |
| Xe-100 | X-energy | Other | Development | — |
| Blue Capsule | Blue Capsule Technology | Other | — | — |
| FLEX reactor | MoltexFLEX | Other | — | — |
| Gravity Nuclear Reactor | Deep Fission | Other | — | — |
| LDR-50 | Steady Energy Oy | Other | — | — |
Showing 1–9 of 16 systems
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