The project features a 345 megawatt sodium-cooled fast reactor with molten salt-based energy storage that could boost the system’s power output to 500MW during peak power demand. TerraPower said last year that the plants would cost about $1bn.

Late last year the US energy department awarded TerraPower $80m in initial funding to demonstrate Natrium technology, and the department has committed additional funding in coming years subject to congressional appropriations.