GB867825A - Improvements in wall means and in panels for use in such wall means and in or relating to nuclear reactors - Google Patents

Abstract

867,825. Nuclear reactors. BABCOCK & WILCOX Ltd. Nov. 4, 1959 [Nov. 6, 1958], No. 35700/58. Class 39(4). A biological shield for a nuclear reactor is formed of panels provided with sealing means between adjacent edges of panels to limit leakage from one side to the other, the sealing means being of tongue and groove form enabling relative movements of adjacent parts of neighbouring panels to occur through sliding action at tongue and groove joints, tongue members of sealing means at each of a number of junctions where several panels meet extending in overlapping relationship in the region of adjacent corners of neighbouring panels to seal the gap at the corners. In the nuclear reactor of Fig. 1, a spherical pressure vessel 1 is mounted in an enclosure which is polygonal in plan and comprises inner and outer walls 4, 5; the outer wall 4 constitutes the main biological shield and is of concrete and the inner wall 5 constitutes an inner shield which replaces the usual thermal shield. A coolant such as atmospheric air circulates from an inlet duct 12 to the space between walls 4 and 5, then through apertures through which stand pipes 11 pass into the space inside the inner wall, and then out through a duct 13. As shown in Fig. 3 the roof of the inner wall comprises a number of concrete panels 14 faced on their lower sides by mild steel plates 23. The panels are generally rectangular, except for the ones near the edges which are shaped to give the desired polygonal form, and one separated by gaps 15 to allow thermal expansion. The panels are supported from the outer wall by hangers 20, hangers on one side of each panel being constrained for pivotal movement in a plane parallel to that side whereas the other hangers are free to pivot in two planes. Gas is prevented from passing through gaps 15 by stainless steel tongues 48 each of which is fixed to a panel on one side of a gap and free to slide in a slot formed on the adjacent panel. Where three or more panels meet, the tongues overlap and may be pressed against each other by resilient means. The vertical walls are of similar construction and comprise a number of concrete panels 18 spaced apart by expansion gaps 19 covered by stainless steel tongues. Each panel is supported from the outer wall by an angle member 31 secured to the panel which rests on an angle member 30 secured to the outer wall; the arrangement allows relative movement parallel to the wall and movement away from the wall is restrained by studs secured to one of the members 30, 31 and passing through slots in the other, one of the studs engaging an aperture closely to locate the panel at one point in fixed relationship to the wall. Where the wall meets the roof the gap between them is covered by a right-angled section stainless steel tongue 43 which is free to slide horizontally in a slot on the roof panel 14 and vertically in a slot on the wall panel 18.