Patent Number: 052176819
Section: abstract

A prestressed pressure vessel safety enclosure is used as a pressure safety enclosure for a nuclear reactor pressure vessel or other primary system vessel containing fluid or gaseous material under high pressure, such as, steam generators, pressurizers and pumps. The special pressure vessel enclosure comprises a first pressure vessel containment assembly surrounding the primary pressure vessel. A pair of first upper and lower pressure vessel jackets are adapted to enclose and be spaced apart, respectively, from the upper and lower portions of the first pressure vessel containment assembly with the rims of the jackets adapted to be slidable and sealed with respect to the first pressure vessel containment assembly. The spaces between the jackets and pressure vessel containment assembly are filled with a high boiling point, low melting point metal. Upper and lower ring girders, connected to each other by tension tendon members, in conjunction with upper and lower jacket bearing plates and skirts are used to apply a force to the respective upper and lower jackets for moving the jackets toward or away from each other This application of force achieves continuously adjustable compression in the pressure vessel safety enclosure walls in order to compensate for creep and relaxation of tendon members and of the enclosure walls.