Method and installation for repairing and preventing cracking of the inner surface of a vessel bottom penetration pipe of a pressurized water nuclear reactor

摘要

In a stoppage period of the nuclear reactor, the head of the vessel having been removed and the vessel (3) and the pool of the reactor having been filled with water, an internal zone of the penetration tube (6), for the bottom head of the vessel (3), is isolated between two seals (39, 42), this operation being carried out from the upper level of the pool and under water. An electrolyte is made to flow into the isolated zone inside the penetration tube (6) and a current is made to pass through the electrolyte in order to deposit a metal layer of electroplating on the internal surface of the penetration tube (6) in the isolated zone. The metal layer is preferably a nickel layer having a thickness of approximately 0.1 mm. The device comprises a hollow electroplating rod (cane) (25) carried by a pole (14) and connected via a set of pipes and cables (24) to an electroplating module arranged at the upper level of the reactor pool. IMAGE