1. The problem statement, all variables and given/known data For some isotopes of some very heavy nuclei, including nuclei of thorium,
uranium, and plutonium, the nucleus will fission (split apart) when it absorbs a slow-moving neutron. Thorium-227, with 90 protons and 137 neutrons, can fission when it absorbs a neutron and becomes Thorium-228. The two ...