GB965977A - Improvements in and relating to nuclear reactors - Google Patents

Abstract

965,977. Reactors. NUCLEAR POWER PLANT CO. Ltd., and A.E.I.-JOHN THOMPSON NUCLEAR ENERGY CO. Ltd., [trading as NUCLEAR POWER GROUP]. July 25, 1963 [Aug. 8, 1962 ], No. 30425/62. Heading G6C. A solid moderated nuclear reactor having fuel channels located in the moderator core has charge pans near a surface of the core but supported independently of it, the charge pans having holes or tubular extensions aligned with the channels. The reactor comprises a gas cooled graphite core 1 in a steel or concrete pressure vessel 3; if the vessel is steel, it is surrounded by a concrete biological shield. Standpipes 4 have tubular guide extensions 5 for fuel elements and control rods. The charge pans, only one of which is shown in the drawing, are supported either by the guide tubes as shown or by other suitable means, independently of the core. The extensions 6b, 6c are a clearance fit in the upper ends of the core channels 2; alternatively, they may be a close fit, relative movement between the core and charge pans being catered for by mounting the extensions 6b, 6c pivotally in the plates 6a. It is preferred to mount all but one of the extensions in this way, the exception being the centremost extension associated with a given charge pan which would be rigidly secured to the charge pan to maintain alignment of the charge pan with a given area of the core face. Fuel element leak detection. Frequently coolant sample tapping points are located in the charge pans, and include sample piping supported by the guide tubes; the failure of such piping due to relative movement of the charge pans and guide tubes is avoided in the present invention.