Method of repairing a labyrinth seal of a diffuser in a primary pump of a nuclear power station

摘要

The invention relates to a method of repairing the labyrinth seal of a diffuser in a primary pump, the diffuser being of the type comprising a peripheral skirt and a circular end wall having an orifice provided with the labyrinth seal. The method consists in making a bore in the circular end wall having a diameter greater than that of the orifice, in reducing the thickness of the remaining portion of the end wall, in forming a chamfer on the edge of the bore, in positioning a replacement part in said bore, the replacement part including a central orifice and a chamfer on its own peripheral edge, in making a bead of welding between the chamfers, and in making a new labyrinth seal in the central orifice of the replacement part.