TerraPower’s Natrium Reactor Moves Into UK Generic Design Assessment

Nat rium 345 MWe reactor accepted into UK GDA process – TerraPower’s sodium‑cooled fast reactor with a molten‑salt energy‑storage system entered the UK’s Generic Design Assessment after submitting its application in October, marking the first regulatory filing for Natrium outside the United States [1].

Company will collaborate with UK regulators – President and CEO Chris Levesque said TerraPower will work with the Department for Energy Security and Net Zero, the Office for Nuclear Regulation and the Environment Agency throughout the review, aiming to bring the design to the United Kingdom [1].

ONR to begin assessment once resources are set – The Office for Nuclear Regulation confirmed the GDA will start after arrangements on timescales and resources are finalized, emphasizing that the process evaluates safety, security and environmental impacts at the design stage and can apply to multiple future sites [1].

Other SMR designs already progressing in UK GDA – Rolls‑Royce’s SMR is in Step 3 (final stage), Holtec’s SMR‑300 is in Step 2, and GE Vernova Hitachi’s BWRX‑300 completed Step 2 in December 2025, showing Natrium joins an expanding portfolio of small modular reactors under review [1].

Nat rium’s storage enables load‑following capability – The molten‑salt system lets the plant temporarily boost output to 500 MWe, allowing it to match daily electricity demand and integrate with variable renewable generation; Bill Gates has chaired TerraPower since 2006 [1].

US Nat rium plant construction underway, Meta pledges funding – TerraPower began non‑nuclear construction of its first Natrium plant in Kemmerer, Wyoming in June 2024, targeting completion in 2030 under the DOE Advanced Reactor Demonstration Program, while Meta announced support for up to eight Natrium reactors in the United States with deliveries from 2032 to 2035 [1].