Method for repairing boiling water reactor shrouds

Abstract

A method of repairing nuclear reactor core shrouds having horizontal cracks in heat affected zones of welds includes applying vertical compressive forces to the shroud in situ to urge opposed surfaces of the cracks toward one another. A plurality of tie rods, angularly spaced about the shroud periphery, is used to selectively apply the longitudinally compressive forces. Preferably, the method utilizes existing hardware secured to the shroud for attaching the tie rods thereto. The tie rods may be used in connection with horizontal and/or vertical spacers inserted between the shroud and the reactor vessel. Horizontal spacers serve to resist horizontal seismic loads and hold the shroud in place in spite of cracking. Vertical spacers resist vertically upward loads resulting from main steam line breaks.

Dependencies are inferred from the claim text.