Method for repairing riser pipe elbow weld in boiling water nuclear reactor

A support clamp assembly for mechanically securing a thermal sleeve to an elbow conduit in a jet pump of a nuclear reactor vessel, the support clamp assembly including: a tension shaft having a first end extendable through an opening in a sidewall of the elbow conduit and an opposite end with a head; a cruciform assembly having a base with an opening to receive the tension shaft and to abut the head of the shaft, wherein the cruciform assembly seats in the thermal sleeve; a boss slidable over the first end of the tension shaft and having a curved surface seating an outside surface of the elbow conduit, and a coupling device engaging the first end of the tension shaft and abutting the boss, wherein the coupling device places the tension shaft under tension to secure the cruciform assembly to the thermal sleeve and the boss to the elbow conduit.