grosse brèche

CONT: Grosse brèche. Ce type d'accident de perte de réfrigérant primaire (APRP) est supposé initié par la rupture franche et complète d'une branche froide du circuit primaire (dite rupture guillotine). Le fluide s'écoule alors par les deux tronçons ouverts. La décompression est rapide : l'écoulement est homogène et les phénomènes gravitaires ne jouent qu'un rôle marginal.

CONT: A second cooling funtion is provided for safety reasons, to deal with the possibility of a loss of primary coolant circuit function during operation of the reactor. A breach in the primary coolant circuit, for example, could allow the core to overheat, resulting in damage to the nuclear fuel. A pressurizer arrangement injects additional coolant into the circuit to maintain operational pressure and to replace coolant that may be lost through a minor breach or leak in the coolant circuit. Various techniques are known for cooling the reactor core in the event of a major breach such as the rupture of a conduit in the primary coolant circuit. Neutron absorbing control rods can be inserted into the fuel array quickly to damp the nuclear reaction, for example when the sensed coolant pressure drops.