Mortal dose of nuclear or chemical origin.

In France, these are nuclear facilities that have undergone a licensing and administrative review process under Executive Order 63-1228 of December 11, 1963, amended. This regulation pertains to "nuclear reactors, particle accelerators, plants that separate or fabricate radioactive substances (particularly plants for nuclear fuel fabrication, spent fuel processing, or radioactive waste conditioning), and facilities used for the storage, disposal or utilization of radioactive substances, including waste." The listed facilities are subject to regulation only when the quantity or total activity of radioactive substances they contain is above a pre-determined threshold established for each type of facility and each radionuclide. Licensed nuclear facilities are monitored and inspected by inspectors from DSIN, Direction de la Sûreté des Installations Nucléaires (the department of nuclear facility safety) and DRIRE, Directions Régionales de l'Industrie, de la Recherche et de l'Environnement (regional departments of the ministries of industry, research and the environment).

(See also "REACTOR") Ordinary water (H2O), as opposed to heavy water (D2O), which is a combination of oxygen and deuterium (heavy hydrogen atom). Light water is used to slow neutrons in order to trigger fission in certain reactors.

Extraction of certain compounds contained in a pulverulent, permeable or porous medium, by passing an appropriate solvent, which flows naturally through the mass to be treated. It can be applied directly to a very fragmented soil (in situ leaching), or on the contrary leaching an extracted mass, crushed and placed on an appropriate area (heap leaching). It is a method of extracting metallic elements, including uranium. It is also the way in which rainwater runoff extracts certain components from a mass of waste.