Kärnklyvningskedjereaktionen

Kärnklyvningskedjereaktionen, often translated as nuclear fission chain reaction, is a process where a single atomic nucleus splits into two or more smaller nuclei, releasing a significant amount of energy and neutrons. This phenomenon is central to nuclear power generation and nuclear weapons. The process begins when a fissile material, such as Uranium-235 or Plutonium-239, absorbs a neutron. This absorption makes the nucleus unstable, causing it to split. During this fission event, a substantial amount of energy is released, primarily in the form of kinetic energy of the fission fragments and gamma rays. Crucially, the fission also releases additional neutrons. These newly released neutrons can then go on to strike other fissile nuclei, causing them to fission as well. If, on average, at least one neutron from each fission event causes another fission, the process becomes self-sustaining and is called a chain reaction. The rate at which this chain reaction proceeds depends on factors like the amount and purity of the fissile material and the presence of a moderator, which slows down the fast neutrons released during fission, making them more likely to cause further fissions. In nuclear reactors, this chain reaction is carefully controlled to produce a steady output of energy. In nuclear weapons, the reaction is allowed to proceed explosively, releasing a massive amount of energy in a very short time.