SMR-300
US
Basics
Reactor Type
Boiling Water Reactor
Boiling water reactor
Heat transport usually with light (normal) water or vapour
Heat transport usually with light (normal) water or vapour
Reactor Description
Loop operated BWR
Boiling water reactor
Heat transport usually with light (normal) water or vapour
Heat transport usually with light (normal) water or vapour
Electric Output (MWe)
300
Thermal Output (MWt)
1000
Size
Large
'Large' size
Electric output of between 200 MWe and 300 MWe (or more)
Electric output of between 200 MWe and 300 MWe (or more)
Spectrum
Thermal
Kinetic neutron energy of 0.000…0.025 eV
Slow or cold neutron / moderated neutron spectrum
Slow or cold neutron / moderated neutron spectrum
Developer
Holtec International
Pilot Site Details
N/A
Details
Use (goal of commercial operation)
electric power generation
Deployment medium
Land-based
Design Lifetime (Years)
80
Fuel
Fuel class
LEU
Low enriched uranium
Uranium enriched to less than 5 percent U-235
Uranium enriched to less than 5 percent U-235
Fuel Type
UO2 Pellets
Uranium dioxide
Most often used uranium compound for fuel elements
Most often used uranium compound for fuel elements
Fuel Cycle
Open
Refuelling Cycle
N/A
Cooling & Temperature
Reactor cooling of primary loop
Light Water
Deuterium-depleted water
Containing the natural proportion (or less) of deuterium oxide, i.e. about 0.02 percent
Containing the natural proportion (or less) of deuterium oxide, i.e. about 0.02 percent
Reactor moderator
Light Water
Deuterium-depleted water
Containing the natural proportion (or less) of deuterium oxide, i.e. about 0.02 percent
Containing the natural proportion (or less) of deuterium oxide, i.e. about 0.02 percent
Reactor Outlet Temperature (°C)
321
Status
Design status
Conceptual design
Licensing status
- Jan 2026 - NRC
- Jan 2026 - NRC released first part of construction application (limited work authorisation) for two SMR-300 unit project at existing Palisades site in Michigan.
- Aug 2024 - Phase 1 of GDA process completed in UK. Application submitted for phase 2
- Jan 2023 - submitted pre-licensing generic design assessment (GDA) application to UK regulator
Deployment timeline
First deployments in early to mid-2030s
Agreements and Engagement
- Jun 2025 - Holtec lost the final tender...
- Jun 2025 - Holtec lost the final tender in Great British Nuclear (GBN) SMR competition to Rolls-Royce SMR
- Feb 2025 - Holtec invited to submit final bid in UK SMR programme tender (won in Jun 2025 by Rolls-Royce)
- Sep 2024 - Holtec has chosen South Yorkshire as the planned location for a £1.5bn SMR factory
- Sep 2024 - SMR-300 makes it into a further stage of the UK government process among four shortlisted candidates
- Dec 2023 - Holtec announced it will build two SMR-300 plants at the existing Palisades NPP site in Michigan
- Oct 2023 - UK government includes Holtec's design in shortlist for first SMR competition among six vendors
- In late 2023 Holtec renamed its SMR-160 design to SMR-300
- Jul 2022- Holtec sought a loan for plans to deploy pilot SMR-160 at Oyster Creek NPP, New Jersey
