go hydrogen fusion reactions nuclear reaction a good example of fission is the splitting of a uranium nucleus the conceptual sketch below is grossly oversimplified since the engineering for handling lithium is quite complex pp chain equations examples of the two types of nuclear reactions however a controlled fusion reaction has yet to be fully demonstrated due to many problems that present themselves including the difficulty of forcing the it is important to observe that one of the protons turn into a neutron otherwise the would not be deuterium in figure 3 schematic visualization of the chain reaction in a sample go in proton proton fusion the final helium 4 atom weighs less than the original four hydrogen atoms that fused together this excess mass was converted to energy conservation in nuclear fission difference between nuclear fission and fusion reaction a typical uranium fission reaction u 235 fission chain reaction credit wikimedia commons nuclear fission of uranium 235 credit wikimedia commons nuclear fission vs fusion sun the ultimate nuclear fusion reactor why is fusion energy so challenging to achieve nuclear reaction definition examples lesson transcript study com cno equations 3 nuclear fusion radioactive decays source chemwiki ucdavis edu the proton proton chain that fuels nuclear fusion inside the core of our sun print nuclear reaction definition examples worksheet the proton proton chain fission may happens spontaneously in our planet but fusion occurs naturally only in stars and its main reaction is hydrogen forming helium 1 2 all the gamma ray photons are tered many many times as they leave the stellar core each tering exchanges energy so that the photons convert into the most efficient fusion reaction in the laboratory setting is the reaction between two hydrogen isotopes the sun is effectively a self balancing system between the kinetic energy released from the exothermic fusion nuclear reaction within the core and gravity topic 7 atomic and nuclear physics7 3 nuclear reactions fission and fusion