What is nuclear fission?

Nuclear fission is the process where a large atomic nucleus splits into smaller nuclei, releasing energy.

In more detail, nuclear fission occurs when the nucleus of an atom, typically uranium-235 or plutonium-239, absorbs a neutron. This absorption makes the nucleus unstable, causing it to split into two smaller nuclei, known as fission fragments. Along with these smaller nuclei, a few more neutrons and a significant amount of energy are released. The energy released during fission is primarily in the form of kinetic energy of the fission fragments and as electromagnetic radiation, including gamma rays.

The released neutrons can go on to initiate further fission reactions in nearby nuclei, creating a chain reaction. This chain reaction is the principle behind nuclear reactors and atomic bombs. In a nuclear reactor, the chain reaction is carefully controlled to produce a steady output of energy, which is used to generate electricity. Control rods, made of materials like boron or cadmium, are used to absorb excess neutrons and regulate the rate of the reaction.

The energy produced from nuclear fission is immense. For example, the fission of one kilogram of uranium-235 can release as much energy as burning several thousand tonnes of coal. This makes nuclear fission a very powerful source of energy, but it also comes with significant challenges. The fission process produces radioactive waste, which needs to be managed and stored safely for many years. Additionally, the potential for accidents, such as the Chernobyl disaster, and the risk of nuclear proliferation are serious concerns.

Understanding nuclear fission is crucial for harnessing its power safely and effectively, and it plays a significant role in discussions about sustainable and clean energy sources for the future.