TerraPower vs X-energy
October 08, 2025
TerraPower ($1.4B)
TerraPower focuses on developing a sustainable and economic nuclear energy system while reducing proliferation risks.
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Top 34 Nuclear Energy startups
Top 34 Nuclear Energy startups
TerraPower and X-energy are both US startups advancing the development of modern nuclear reactors. They produce small modular reactors that are safer than traditional nuclear power plants. Both companies are still in the development stage and operate thanks to government grants and private investments.
But TerraPower (founded in 2006) is developing the Natrium sodium-cooled fast reactor (345 MW) with a molten salt heat storage system. Its advantage is its flexible power output, allowing it to respond to fluctuating demand when combined with renewable energy sources. It uses liquid sodium as a coolant and highly enriched uranium (HALEU) as fuel (although the company is experiencing supply issues). The demonstration reactor project is expected to be operational by 2030.
X-energy (2009) is developing the Xe-100 gas-cooled reactor with TRISO fuel - uranium microspheres, each coated with several layers of ceramic cladding. This fuel is self-insulating, resistant to high temperatures and retains radioactive products (it "doesn't melt). The basic electrical power of a single module is ~80 MW, but modules can be configured as a "quad" to generate up to ~320 MW.
But TerraPower (founded in 2006) is developing the Natrium sodium-cooled fast reactor (345 MW) with a molten salt heat storage system. Its advantage is its flexible power output, allowing it to respond to fluctuating demand when combined with renewable energy sources. It uses liquid sodium as a coolant and highly enriched uranium (HALEU) as fuel (although the company is experiencing supply issues). The demonstration reactor project is expected to be operational by 2030.
X-energy (2009) is developing the Xe-100 gas-cooled reactor with TRISO fuel - uranium microspheres, each coated with several layers of ceramic cladding. This fuel is self-insulating, resistant to high temperatures and retains radioactive products (it "doesn't melt). The basic electrical power of a single module is ~80 MW, but modules can be configured as a "quad" to generate up to ~320 MW.
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