matériau fertile

Traductions

• anglais

  Date : 1987

  Note :

  Nuclear fission fuels are classified as fertile or fissile by the behaviour or their nuclei in fission reactions. The fertile fuels are those whose nuclei, if they react with a neutron, will be likely to capture it and undergo transmutation into the nuclei of fissile fuels. Uranium-238 is them most commonly used fertile fuel. It decays on absorption of a neutron and loss of a beta-particle into plutonium-239. This happens in all reactors, even 'thermal' or 'burner' reactors. They all use a mixture of fertile and fissile material in the composition of their fuel and, although the conversion ratio in less than 1, plutonium-239 is produced and may undergo fission, making a significant contribution to the energy output, particularly in the CANDU reactor. When the fuel is reprocessed outside the reactor, the plutonium-239 is recovered and used for weapons material. Thorium-232 is also fertile, being transmuted by neutron absorption into uranium-233. Thorium-232 is being used in the fuel of some designs of high-temperature gas-cooled reactors, HTGR. The conversion of fertile to fissile fuel is the principle on which the fast breeder reactor operates. This is a reactor designed with a conversion ratio greater than 1 which over a period of years may produce more fissile fuel than it consumes.

  Terme :

  1. fertile fuel

  Terme associé :

  1. fertile material