thermal seitenschild of a high temperature gas cooled reactor with spherical fuel elements

摘要

A gas-cooled, high-temp. reactor, esp. pebble bed reactor, has its core surrounded by top, bottom and cylindrical side reflectors of graphite blocks; the radial outward forces from the side reflector are transmitted by support elements to the surrounding thermal side shield. This cylindrical side shield is built up from a number of annular segments fitted together with keyed butt joints (26,25) and each having an outward projecting flange (28) at the joint; the abutting flanges are bolted together by bolt connections each composed of a necked-down bolt (30) two nuts (32) and two washers (31); the form of the nuts and washers is such that the bearing surface (33) beneath each washer is kept small and as near as possible to the throat (34) of the flange (28). The side thermal shield is constructed to fulfil its structural function of withstanding the radial outward forces transmitted from the side reflector but is nevertheless built up from comparatively small and easily handled segmental components. The arrangement of the bearing surfaces (33) as close as possible to the throat of the associated flange reduces the bending moment occurring in the segments due to the bolted joints.