Patent Number: 051924927
Section: abstract

Method and apparatus for maintaining a water level which immerses heat exchanger tubes, containing radioactive emitting material, within an inner shell of a steam generator while permitting space between the inner shell and a coaxial outer shell to be free of water during operations performed by workmen in such space after the apparatus is installed thereby reducing exposure of the workmen to harmful radiation. Seal support segments are installed around the inner shell at the lower end of the space and in engagement with the inner and outer shells. A pair of inflatable tubes are placed end-to-end on the support segments so as to encircle the inner shell. Seal retention segments which, together, form a ring around the inner shell are placed on the inflatable tubes and the latter tubes are inflated to form a water tight seal between the shells. The water level in the shells can be lowered to a level below the inflatable tubes during installation of the components and the water level within the inner shell can be raised so as to immerse the radiation emitting tubes after inflation of the inflatable tubes, but preferably, the radiation emitting tubes are maintained immersed in water until the components are installed and the inflation of the inflatable tubes, and water in the space is then pumped out.