GB1354280A - Vessels - Google Patents

Abstract

1354280 Reactor pressure vessels TAYLOR WOODROW CONSTRUCTION Ltd 20 Dec 1971 [31 Dec 1970] 62071/70 Heading G6C A pressure vessel comprises an inner cylindrical steel chamber 1 housed in an outer prestressed concrete container 2, the chamber 1 having a wrapping of steel wire 5 around its outer periphery that serves to resist the radial forces set up when the interior of the chamber 1 is pressurized, the container 2 serving to resist the axial forces that are applied to the chamber ends under this condition. The tension to which the wire 5 is subjected during winding can be such that no substantial stress is applied to the chamber 1, the stress in the chamber 1 then tending to pass from compression to tension when the chamber is pressurized; or such that the chamber 1 is always in compression. The chamber 1 is closed by flat end plates 3, 4, a protruding peripheral portion 4A of the plate 4 and a flange 6 at the other end of the chamber 1 acting as end retaining members for the wire 5. The steel chamber 1 is disposed in a cavity 7 in the outer concrete container 2 with an annular air space between the wire wrapping and the cavity wall, the lower end plate 4 of the chamber 1 being supported by the base 2B of the container 2. A prestressed concrete plug 8 which supports the upper end plate 3 when the chamber 1 is pressurized is retained in position by spacer struts 9 held in position by a prestressed concrete retaining ring 2A forming an upper part of the container 2. Skims 10 can be removed to permit release of the struts 9. In alternative embodiments, the adjustable spacers are provided by screw mechanisms or hydraulic jacks. Anti-friction elements 13 are provided between the plate 3 or 4 and a further steel plate 14 forming an end face of the plug 8 or base 2B to which it is keyed. Access to the interior of the chamber 1 is permitted via a central aperture in the end plate 3 communicating with a passage 15 through the plug 8 and closed by a submarinetype hatch 16. The plug 8 also houses fuelling tubes and control rod mechanisms. The outer container 2 serves as a secondary radial pressure containment member should the need arise, e.g. if a whole core accident should occur to the reactor housed in the chamber 1. In an alternative construction (not shown), the closure components 8, 9, 10 and 2A are replaced by a single closure component, e.g. a concrete plug or disc which is connected to the container 2 by a series of prestressing tendons passing through this central concrete plug.