TerraPower 345MWe sodium fast reactor GDA: design implications for UK engineers
Reviewed by Tom Sullivan
First reported on New Civil Engineer
30 Second Briefing
UK regulators have been formally asked to start a Generic Design Assessment of TerraPower’s Natrium reactor, a 345MWe sodium‑cooled fast reactor with integrated molten salt energy storage. The design, backed by Bill Gates and developed with GE Hitachi, couples a liquid sodium primary loop with a molten salt heat storage system to shift output up to around 500MWe during peak demand. For UK civil and nuclear engineers, this signals potential future projects involving non‑water coolants, high‑temperature materials behaviour, and novel seismic and thermal design requirements for reactor and storage structures.
Technical Brief
- TerraPower’s Natrium design must be adapted to UK site conditions, licensing basis and grid integration requirements.
- GDA outcome will heavily influence future detailed design, construction sequencing and supply-chain qualification in the UK.
- For UK infrastructure and construction sectors, GDA progress will shape timing of any first-of-a-kind build.
Our Take
TerraPower’s 345 MWe Natrium design entering UK assessment comes as the company is also tied to Meta’s US nuclear supply plans for data centres, signalling that regulators will be scrutinising a technology already being positioned for high‑reliability digital loads rather than just conventional grid demand.
Among recent Infrastructure coverage, very few pieces involve advanced fast reactors in the United Kingdom, so this UK assessment process will be watched as a bellwether for how other non‑light‑water designs might fare with British regulators.
For UK civil and grid planners, a single 345 MWe unit is sized closer to large industrial or data‑centre clusters than to legacy gigawatt‑scale nuclear, which could influence how future projects are integrated into industrial parks or digital infrastructure hubs rather than only centralised baseload sites.
Prepared by collating external sources, AI-assisted tools, and Geomechanics.io’s proprietary mining database, then reviewed for technical accuracy & edited by our geotechnical team.
