Patent Number: 039909417
Section: abstract

A nuclear reactor pressure vessel is installed in the pit of a biological shield forming a concrete wall surrounding the vessel and which defines an annular space around the vessel. A heat insulating layer of concrete surrounds the vessel within the annular space and partially fills the latter, and between the insulation and the concrete wall, steam I or H beams are vertically positioned with their flanges engaging the heat insulating layer and the concrete wall so as to support the heat insulating layer against radial motion when the pressure vessel thermally expands radially, thereby providing the latter with rupture protection. The steel beams are circumferentially interspaced very closely together and possibly with their flange edges abutting, thus forming a large number of vertically extending coolant flow passages which are open at the tops of the vertical beams around the periphery at the top of the vessel, and which are interconnected by an annular manifold at their bottom ends so that a coolant under pressure can be introduced for upward flow, thus protecting the concrete wall from excessive thermal stressing.