barre grise

OBS: barre de commande : Barre ou ensemble de tiges solidaires mobiles, contenant une matière absorbant les neutrons et qui, suivant sa position dans le coeur d'un réacteur nucléaire, influe sur sa réactivité.

CONT: ... the reactivity of the advanced pressurized water reactor is controlled by three types of rods, conventional control rods, water displacer rods and gray rods. ... In addition to the control rods and water displacer rods, the advanced PWR [pressurized water reactor] also has gray rods which are between the control rods and water displacer rods in neutron absorption capacity. These gray rods are used in control of the neutron population and, like the water displacer rods, are either fully inserted or fully withdrawn. Like the control rods, the water displacer rods and grays rods are mounted on spiders to form rod clusters which are operated simultaneously with clusters symmetrically located in each quadrant of the core to avoid radial distortion of the power distribution.