TerraPower’s Natrium Fast Reactor Enters UK Generic Design Assessment Process
Updated (3 articles)
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Natrium Reactor Accepted Into UK GDA After October Filing TerraPower’s 345 MWe sodium‑cooled fast reactor with a molten‑salt energy‑storage system entered the United Kingdom’s Generic Design Assessment (GDA) after submitting its application in October, marking the first regulatory filing for the Natrium design outside the United States [1]. The acceptance places the Natrium alongside other small modular reactor (SMR) projects under review in the UK [1]. The GDA process evaluates the design before any site selection or construction begins [1].
Collaboration Planned With British Regulators and Agencies President and CEO Chris Levesque said TerraPower will cooperate with the Department for Energy Security and Net Zero, the Office for Nuclear Regulation (ONR), and the Environment Agency throughout the assessment [1]. The company aims to adapt the Natrium design for deployment on UK soil, leveraging the regulatory dialogue to address safety and environmental concerns [1]. Ongoing collaboration is intended to streamline the path toward potential licensing and construction [1].
Assessment Timeline Dependent on Resources, Safety Review Emphasized The ONR confirmed that the GDA will commence once appropriate timescales and resources are arranged, underscoring that the review will focus on safety, security, and environmental impacts at the design stage [1]. The assessment can be applied to multiple future sites, offering flexibility for later deployment decisions [1]. Resource allocation and scheduling remain the primary variables affecting the start of the formal review [1].
Natrium’s Load‑Following Capability Distinguishes It From Other SMRs The reactor’s molten‑salt storage allows temporary output increases to 500 MWe, enabling load‑following to match daily electricity demand and support variable renewable generation [1]. Bill Gates has chaired TerraPower since 2006, and the company is already constructing its first Natrium plant in Kemmerer, Wyoming, slated for completion in 2030 [1]. Other SMR designs progressing in the UK GDA include Rolls‑Royce’s SMR (Step 3), Holtec’s SMR‑300 (Step 2), and GE Vernova Hitachi’s BWRX‑300 (completed Step 2 in December 2025) [1].
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Timeline
2006 – Bill Gates chairs TerraPower, giving the Natrium reactor program high‑profile backing that helps attract investment and policy support. [3]
Jun 2024 – TerraPower begins non‑nuclear construction of its first Natrium plant in Kemmerer, Wyoming, targeting full completion in 2030 under the DOE Advanced Reactor Demonstration Program. [3]
Jun 2025 – Meta signs a 20‑year power‑purchase agreement with Constellation Energy, its first major nuclear‑supply contract for the upcoming Prometheus AI data center in Ohio. [2]
Oct 2025 – TerraPower submits its Natrium 345 MWe design to the UK Generic Design Assessment, becoming the first Natrium filing outside the United States. [3]
Jan 9, 2026 – Meta inks three nuclear power deals with TerraPower, Oklo and Vistra to fuel the 1‑GW Prometheus AI data center in New Albany, Ohio; the agreements secure up to 6.6 GW of clean energy by 2035 and aim to create jobs and stabilize the Mid‑Atlantic grid. [1][2]
Jan 9, 2026 – TerraPower’s deal with Meta includes two Natrium units capable of up to 690 MW of firm power, with delivery possible as early as 2032 and rights to six additional Natrium units that could supply about 2.1 GW by 2035. [1][2]
Jan 9, 2026 – Oklo commits to build a 1.2‑GW nuclear campus in Pike County, Ohio, backed by investors such as OpenAI co‑founder Sam Altman, to support Meta’s regional data‑center cluster. [1][2]
Jan 9, 2026 – Vistra agrees to sell more than 2.1 GW of electricity from its operating Ohio reactors (Davis‑Besse and Perry) and a planned Pennsylvania plant, while seeking 20‑year license renewals that the Meta contracts help justify. [1][2]
Jan 9, 2026 – Industry analysts note that the Mid‑Atlantic grid faces strain from data‑center demand, pushing ratepayers toward higher electricity bills as large‑scale digital infrastructure expands. [1][2]
Feb 20, 2026 – The UK Office for Nuclear Regulation moves TerraPower’s Natrium 345 MWe reactor into the Generic Design Assessment, beginning a safety, security and environmental review that could enable multiple future UK sites. [3]
Feb 20, 2026 – TerraPower CEO Chris Levesque says the company will collaborate closely with the Department for Energy Security and Net Zero, the Office for Nuclear Regulation and the Environment Agency throughout the GDA process. [3]
Feb 20, 2026 – The GDA step follows other SMR designs—Rolls‑Royce’s SMR (Step 3), Holtec’s SMR‑300 (Step 2) and GE Vernova Hitachi’s BWRX‑300 (completed Step 2 in Dec 2025)—highlighting a growing UK SMR pipeline. [3]
2026 (expected) – The Prometheus AI data center aims to become operational later in 2026, delivering a 1‑GW compute cluster powered largely by the newly contracted nuclear sources. [1][2]
2030 (planned) – TerraPower targets completion of its first Natrium plant in Kemmerer, Wyoming, providing a prototype for the eight reactors Meta pledges to fund with deliveries from 2032 to 2035. [3]
2032‑2035 (planned) – Meta expects deliveries of up to eight Natrium reactors across the United States, beginning in 2032, to expand firm nuclear capacity for its AI workloads. [3]
2035 (target) – The combined nuclear agreements aim to support up to 6.6 GW of new and existing clean energy capacity, cementing Meta’s long‑term nuclear supply strategy. [1]