barre de commande
- Domaine
-
- physiqueréacteur nucléaire
- Dernière mise à jour
Définitions :
Barre composée d'un matériau absorbeur de neutrons.
Élément de commande en forme de barre.
Note :
On insère un faisceau de ces barres dans le cœur d'un réacteur nucléaire et leur déplacement permet d'accélérer ou de ralentir la vitesse de la réaction de fission.
Terme privilégié :
- barre de commande n. f.
Termes utilisés dans certains contextes :
- barre de réglage n. f.
- barre de régulation n. f.
Terme déconseillé :
- barre de contrôle
Traductions
-
anglais
Auteur : Office québécois de la langue française,Notes :
It is commonly a rod of neutron-absorbing material, eg cadmium or boron, usually in an alloy steel. Fine control rods (regulating rods) and coarse control rods (shim rods) are inserted into the core of the nuclear reactor. To start up the chain reaction the rods are slowly withdrawn so the neutron density increases. When criticality is achieved, usually when the rods are near the centre of their travel path, they are repositioned and the rate of reactions stabilized. To shut down the reactor the rods are reinserted into the core. This control of reactivity is possible only because about 1 in 150 of the neutrons feeding the chain reaction is "delayed", ie it emerges later than the instant of fission because it is emitted by one of the fission products. Without delayed neutrons the speed of the chain reaction is such that it would be far more difficult to control.
By absorbing neutrons, a control rod prevents the neutrons from causing further fission.Terme :
- control rod