Transatomic, an MIT spinoff, is developing a nuclear reactor that it estimates will cut the overall cost of a nuclear power plant in half. It’s an updated molten-salt reactor, a type that’s highly resistant to meltdowns. Molten-salt reactors were demonstrated in the 1960s at Oak Ridge National Lab, where one test reactor ran for six years, but the technology hasn’t been used commercially.

The new reactor design, which so far exists only on paper, produces 20 times as much power for its size as Oak Ridge’s technology. That means relatively small, yet powerful, reactors could be built less expensively in factories and shipped by rail instead of being built on site like conventional ones. Transatomic also modified the original molten-salt design to allow it to run on nuclear waste.