Abstract: A method for replacing a nozzle in a pressure vessel. The existing nozzle is cut approximately at the inside surface of the pressure vessel wall. The portion of the existing nozzle that extends beyond the exterior of the pressure vessel wall is removed. A weld pad is deposited on the exterior of the pressure vessel wall around the nozzle bore. The remainder of the existing nozzle is removed. A corrosion resistant thermal spray coating is applied to the nozzle bore. A replacement nozzle is installed in the nozzle bore and seal welded to the weld pad on the exterior of the pressure vessel wall.

Abstract: A device for restricting the motion of a thimble tube in a nuclear reactor during normal reactor operating conditions. A cylindrical sleeve open at each end has upper, middle, and lower sections. The upper section has an over-expanded area adjacent the top end to aid in proper positioning in the lower core support plate. The middle section is formed from inner and outer sections attached at their ends and formed from material having different coefficients of thermal expansion. The inner portion of the middle section moves from a first normal relaxed state during cold conditions in the reactor to a second flexed state during hot conditions in the reactor to provide a clamping action on the thimble tube received by the sleeve. A baffle in the lower section reduces coolant flow velocity and pressure through the sleeve.