Scientists differentiate between hot fusion and cold fusion.

Hot fusion is trying to bring the sun down to earth. Hot fusion requires temperatures of up to 150.000.000 degree celsius (ITER reactor), extrem vacuum or pressure and very strong magnetic fields. The aim is to bring hydrogen atoms or its isotops so close together that they unite and release a very large amount of heat energy. With hot nuclear fusion still radioactive waste will occur and deadly radiation too, but much less than in nuclear fission reactors.

Cold fusion is the catalytic way to unite two heavy hydrogen atom (from heavy water) to harmless Helium gas and a moderate level of heat energy. This type of fusion takes place already at room temperatur …