Abstract: A replacement nozzle and method for replacing a nozzle in a pressure vessel. The original nozzle is removed and a weld preparation is machined into the original weld. The vacated nozzle hole is partially drilled out from the interior of the vessel. A weld land sleeve is received in the drilled out portion of the nozzle hole and a replacement nozzle is received in the weld land sleeve. The sleeve and replacement nozzle are welded in place on the inside of the vessel wall.

Abstract: A nuclear reactor vessel cavity seal plate. An annular support plate is positioned over the cavity between the reactor vessel and the shield structure. The inner diameter of the support plate rests freely upon the reactor vessel flange to allow movement of the vessel thereunder during thermal expansion and contraction. A flexible annular seal positioned over the support plate has its inner diameter seal welded to the reactor vessel flange and its outer diameter seal welded to the shield structure. Matching ports in the support plate and seal provide access to nuclear instruments below the support plate. A mounting block around each port accepts a cover plate that seals the port. This provides a permanent seal plate that allows flooding of the cavity for refueling with it only being necessary to remove the cove plates for normal reactor operations.