CT: A barrier which surrounds the main parts of a facility containing radioactive materials and which is designed to prevent or mitigate the uncontrolled release of radioactive material to the environment in operational states or design basis accidents.
Confinement is similar in meaning to containment, but is typically used to refer to the barriers immediately surrounding the radioactive material, whereas containment refers to the additional layers of defence intended to prevent the radioactive materials reaching the environment if the confinement is breached. Hence, for example, in a nuclear power plant confinement may be provided by the reactor pressure vessel, whereas containment may be provided by the building housing the reactor. In a repository, confinement may be provided by the waste form and its container, whereas containment may be provided by the surrounding host rock.
S: http://www.iaea.org/ns/tutorials/regcontrol/intro/glossaryc.htm (last access: 20 February 2015)
N: 1. 1590s, from French confinement (16c.; the Old French word was confinacion), from confiner (see confine).
2. A process used to control a spill or release of a hazardous material and to capture the material at a specified location.
3. confinement: not to be confused with “containment” (a process used to stop the further release or spill of a hazardous material).
4. confinement: term and definition standardized by the Canadian Capability-Based Planning Terminology Committee and the Translation Bureau.
5. Two confinement techniques are employed: magnetic confinement, which may be classed as static and inertial confinement, which may be classed as kinetic.
6. containment: Methods or physical structures designed to prevent the dispersion of radioactive substances.
Although approximately synonymous with confinement, containment is normally used to refer to methods or structures that prevent radioactive substances being dispersed in the environment if confinement fails.
S: 1. OED – http://www.etymonline.com/index.php?term=confinement (20 February 2015). 2, 3 & 4. TERMIUMPLUS. 5. GDT. 6. http://www.iaea.org/ns/tutorials/regcontrol/intro/glossaryc.htm (last access: 20 February 2015).