The company's technology could usher in a new era of reactors that are cheaper and safer to operate.

Kairos is trying to reinvent nuclear power. Its molten-salt-cooled reactor could generate safe, reliable, carbon-free electricity that's potentially as cheap as power generated from natural gas.

The nuclear industry in much of the world can seem stuck 30 years in the past, thanks to an outdated fleet of huge fission reactors that remain expensive to build and operate and are haunted by safety concerns. Kairos wants to change that with small, safe, modular reactors that could be cost-competitive with the cheapest fossil fuel -- natural gas. Ironically, it hopes to use molten-salt-cooled reactors, a technology pioneered and then abandoned in the 1950s and '60s in favor of designs that were further along at that time.

Kairos will use a molten salt called Flibe, which contains fluorine, lithium, and beryllium, to cool its fission reaction and then transport the heat it absorbs to a steam turbine to generate power. Today's reactors use water for the same task, which requires an expensive, ultra-high-pressure containment system and is less efficient overall. Kairos also uses a modern nuclear fuel called TRISO, which is made of tiny kernels of uranium, carbon, and oxygen encapsulated within protective layers of carbon and ceramic. These particles are then embedded into golf-ball-size graphite "pebbles." This form of fuel could enable safer, cheaper nuclear reactors, since each particle acts as its own containment system and is highly resistant to corrosion, oxidation, and melting.