Nuclear fusion - Advanced fuels under debate

At present, attempts to harness the energy released by nuclear fusion centre on the so-called first-generation fuel, a deuterium-tritium plasma. This combination has the considerable drawback of intense neutron emission, which damages the plasma-confining structures. Hence the interest in investigating second- and third-generation fuels which emit few or no neutrons. But many hurdles remain to be surmounted if such fuels are to prove viable.