Abstract: Heat retarding closure system for partitions having pressure relief openings formed therein especially in nuclear reactor buildings where main coolant nozzles of a reactor pressure vessel penetrate a biological shield, including lightweight construction closure elements having a side facing the reactor and anchors for holding the closure elements, the closure elements being pushable out of the anchors by an overpressure in a given pressure difference direction on the reactor side, and an outer sealing blowout skin, the closure elements being in the form of heat-retarding cassette inserts having a front surface with a peripheral shearing edge formed thereon resting against the blowout skin, and the blowout skin having a given thickness in the given pressure difference direction enabling the cassette insert to shear off the blowout skin and be pushed out of the anchors when a given pressure difference is at least reached.

Abstract: Heat insulation for domeshaped bottom and/or cover regions of a pressure vessel, the heat insulation being penetrated by a multiplicity of pressure vessel unions extending parallel to the axis of the pressure vessel, including an integral dome formed of heat insulation having a passage formed therein for each of the pressure vessel unions, guide elements extending parallel to the axis of the pressure vessel for centering the heat-insulation dome with respect to the pressure vessel and for axially movably mounting the heat-insulation dome so that it can be lowered from a largely convection-proof operating position thereof to a storage position thereof onto an assembly platform, whereby the union passages of the pressure vessel are exposed for in-service testing, and can be raised back to the operating position thereof.

Abstract: Heat insulating casing for structural components having curved surfaces, including insulating plates formed of compressed material based on pyrogenic silica, reinforcement fibers and on an opacifier, the insulating plates being divided into insulating elements having trapezoidal cross sections, and the insulating elements being combined to form a polygonal insulating shell.