NUCLEAR ENERGY

摘要

Nuclear fission is the formal name for the splitting of an atom. In self-sustained fission, a neutron causes an atomic nucleus to split, and this gives off more neutrons that cause nearby atoms to break apart, giving off yet more neutrons, in a chain reaction (see diagram, below). Heat from this process can be used to generate electrical energy. Atoms of many elements can be split to release a small amount of energy, but only uranium or Plutonium can generate the neutrons necessary for a self-sustaining fission reaction. Plutonium is not found in nature, but mined uranium has three naturally occurring isotopes with atomic masses 234,235 and 238. The latter is the most abundant of these, but cannot sustain a fission reaction.