GB888307A - A self compensating side loading restraint unit for use in nuclear reactors - Google Patents

Abstract

888,307. Nuclear reactors. HEAD WRIGHTSON & CO. Ltd. July 19, 1960 [July 21, 1959], No. 25039/59. Class 39(4) A self-compensating side loading assembly for use in a nuclear reactor or other structure subject to expansion and contraction in a radial direction, comprises a series of lever mechanisms adapted, when in use, for connection at their inner ends to joints on the reactor core and for engagement at their outer ends with a fixed base or datum structure, and means for applying a vertically acting load to each lever mechanism, which loading is transmitted through the mechanisms to the core to provide a centripetal stabilising force which varies automatically to allow for expansion and contraction of the core. The reactor core may be in the form of a polygon made up of graphite blocks having horizontal joints, and at each corner of the polygon a U-shaped bracket 7, Fig. 2, is mounted in a recess at each horizontal joint. A lever mechanism 4 is pivoted to lugs 6 and 10, attached respectively to the bracket 7 and to a fixed structure, and is stressed by a weight 18. The fixed structure may be the pressure vessel; a thin walled vessel or shell provided with annular reinforcing bands to which the lugs are secured ; a series of vertical beams secured together by upper and lower horizontal brazing members to form a rigid framework; or a series of horizontal rings of rolled steel beams or of tie bars adjustably supported on vertical struts. The lever mechanism 4 may comprise a short link pivoted to a long link at an intermediate position, the weight 18 being suspended from the free end of the long link, Figs. 8 and 9 (not shown). The weight 18 may be replaced by spring loaded tensioning means carried by a plate secured to the bracket 7 or to the fixed structure may be the pressure vessel; mechanism may be provided with stops to limit its downward movement.