Term referring to activities performed following shut-down of a nuclear plant or mine, from site closure to removal of radioactivity from the site, including physical dismantling and decontamination of all non-reusable facilities and equipment.

Decontamination is a physical, chemical or mechanical operation designed to remove or reduce radioactive or chemical materials in a facility, in an open area, on equipment or on personnel.

Before it is used in the fabrication of fuel elements, natural uranium is enriched in uranium 235 (the uranium 235 content going to 3% to 95%). An isotopic separation process is used to "enrich" the natural uranium in uranium 235. The physical and chemical processes used to produce enriched uranium also produce uranium with a uranium 235 content that is lower than the natural content: this is known as depleted uranium.

The DGSNR, stands for "Direction Génerale de la Sûreté Nucléaire et de la Radioprotection (Department of Nuclear Safety and Radiation Protection)" has taken over for the DSIN (Direction de Sûreté des Installations Nucléaires, or Department of nuclear facility safety), the DGS's office of radiation (Direction Générale de la Santé, or Health department), a portion of OPRI (Office de Protection contre les Rayonnements Ionisants, or Office of radiation protection), and CIREA (Commission Interministérielle des Radioéléments Artificiels, the Joint ministerial committee on artificial radioelements). The DGSNR reports to the ministries of Industry, the Environment and Health. It develops, recommends and implements governmental policies on nuclear safety excluding defense-related nuclear facilities and operations and on radiation protection.

Measurement characterizing the exposure of individuals to radiation. Term often misused in place of dose equivalent. - Absorbed dose: amount of energy absorbed by living or inert material exposed to radiation; expressed in gray (Gy). Gray (Gy): Unit of measure for absorbed dose, previously measured in Rad (1 Gray = 100 Rad). Sievert (Sv): Unit of measure for dose equivalent, i.e., the percentage of energy from an ionizing ray that is absorbed by 1 kilogram of living matter. Once the absorbed dose is measured (in Gray), the dose equivalent can be based on the type of radiation absorbed and the type of organ involved. Sievert is abbreviated as Sv. Frequently used sub-multiples are: - the millisievert, abbreviated as mSv, which is 0.001 Sv (a thousandth of a Sv), - the microsievert, abbreviated as µSv, which is 0.000,001 Sv (a millionth of a Sv). The average annual dose equivalent from background radiation in France, for example, is 2.4 mSv/person.