In the search for alternative fuels, thorium — a common, inexpensive radioactive element used to power nuclear reactors – could be used as an emission-free energy source for everything, from a car to a spacecraft.

Thorium is found in many regions around the world, including North America, Norway, India and Australia, and it already powers nuclear reactors in India. China is racing to perfect thorium nuclear power in molten salt reactors, considered much safer than uranium reactors because there is no emergency cooling system.

But innovators like Charles Stevens, the CEO of Laser Power Systems in Massachusetts, are trying to harness thorium in laser-form to power turbines and generators in smaller machines.

“This is far safer than a reactor, with a small quantity of thorium and no chain reaction or nuclear fission,” he said.

Stevens is developing custom generators that will work with his thorium-powered laser system, and turbines that are small and lightweight enough to fit under the hood of a car. His plan is to use the laser to heat the thorium, which gives off pressurized steam to power the turbine and turn the generator.

The idea, which has yet to pass the patent process, is years away from implementation. And even then, it’s still too soon to tell whether big car companies will move past hybrids and whether the general public will accept radioactive material, no matter how small an amount, in their vehicles.