3 daysu sup 232 u03b1 72 years______________________________________ the uranium 232 decay chain contains eight radioactive daughter nuclides six alpha particles are emitted in the declay from uranium 232 to stable lead 208 the alphas emitted from uranium 232 have energies of about 5 3 mev however the total energy in the complete decay chain from uranium 232 to stable lead 208 is about 42 mev this includes about 35 mev for the six alpha particles and about 7 mev for the beta particles and gamma rays which are also emitted a portion of the above enumerated 7 mev comes from two daughters of uranium 232 namely thallium 208 and bismuth 212 which emit high energy gamma rays the energy range being from about 1 6 to 2 6 mev therefore the presence of uranium 232 in nuclear fuel can serve as a deterrent to misappropriation both because of the high energy gamma rays emitted from the daughter products and because of the heat produced by the decay chain the deterrent effect of high energy gamma rays associated with uranium 232 has long been recognized however the recycling of protactinium 231 in order to increase the production of uranium 232 has not been considered further the deterrent effect of the heat produced by a high concentration of uranium 232 has not been heretofore taken into account this heating effect is similar to the deterrent effect of heating produced by the presence of plutonium 238 in plutonium fuel as noted in the previously mentioned nuclear energy article the thorium fuel cycle may be used in light water reactors heavy water reactors high temperature gas.