Patent ID: 6654437
Filing Date: 2003-11-25
Classification: G21C,Y02E

Abstract:
A method of repairing the labyrinth seal of a nuclear power station primary pump diffuser, said diffuser including a peripheral skirt provided at its base with a circular end wall having an original central orifice, a wall of the central orifice having the labyrinth seal formed therein, the method comprising the steps:enlarging the original orifice of the circular end wall for removing a central portion of the circular end wall and eliminating the labyrinth seal; reducing a thickness of a remaining portion of the circular end wall adjacent to the enlarged orifice; forming a circular chamfer in a wall of the enlarged orifice; positioning a circular replacement part in the enlarged orifice, the replacement part including a reduced central orifice having the same diameter as the original orifice; forming a circular chamfer in a peripheral edge of the replacement part; positioning the chamfer of the enlarged orifice in spaced adjacent relation to the chamfer of the peripheral edge; welding the two chamfers; smoothing a flash on a resulting bead of welding; and forming a new labyrinth seal in the reduced central orifice of the replacement part.