Patent ID: 7649970

Claim:
A nuclear reactor pressure vessel and a repair apparatus for repairing horizontal cracks in a core shroud in the nuclear reactor pressure vessel, the core shroud defining an annulus with said reactor pressure vessel and surrounding a reactor core that also includes a core shroud support cylinder underlying the core shroud and a horizontal core shroud support plate extending radially outwardly of said core shroud support cylinder, wherein plural stacked and welded shroud cylinders define the core shroud, the repair apparatus comprising; a plurality of upper support assemblies substantially uniformly spaced circumferentially one from the other for securement to an upper end of said core shroud; a plurality of tie rods secured at upper ends thereof to said upper support assemblies, respectively, and extending axially in an annulus between a shell of the pressure vessel and said core shroud; a plurality of lower stabilizer assemblies attached to said tie rods, respectively, with wedges bearing against the vessel shell enabling alignment of the tie rods to pass closely adjacent to said core shroud support cylinder; lower ends of said tie rods extending through respective openings in the core shroud support plate; and an anchor attached to each said lower end of each tie rod and attached directly to a lower edge of said core shroud support cylinder at a location below and spaced from said core shroud support plate, wherein the lower end of each said tie rod is threaded and extends through said anchor, and wherein a nut is threaded to said lower end of each tie rod to secure said anchor and said tie rod to one another thereby enabling the tie rods to apply a compressive load to said plural shroud cylinders via said upper support assemblies and said core shroud support cylinder sufficient to repair horizontal cracks at welded joints between said plural shroud cylinders.