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: Lifting device for a horizontally seated cover of a nuclear-reactor pressure vessel includes a traverse having means for holding a cover to be lifted and having a substantially central point of application for a lifting tool, and means for compensating for deviations from the horizontal of the cover held by the traverse, the compensating means including a pair of mutually connected eccentrics cooperable for adjusting the point of application on the traverse in a horizontal plane.