So how is it possible to get clean energy from fusion? The answer is you have to use the right fuel source. When most people speak of fusion they are speaking of proton-proton fusion. This is much better than current fission reactors, but still produces nuclear waste and uses radioactive isotopes. But other fuels can be used, such as proton-boron. This fuel source is not radioactive and doesn’t produce radioactive waste. This is because it produces helium ions and x-rays, instead of fast moving neutrons (which creates radioactive waste).