Patent Number: 048658030
Section: summary

BACKGROUND OF THE INVENTION The present invention relates to a pressurized gas discharge system for the safety containment of a nuclear reactor which includes a conduit having a filter arrangement with serially arranged filter elements consisting of stainless steel fiber packs. It is assumed that, after a reactor melt-down accident, the gas pressure within the safety containment of a nuclear reactor will increase within a couple of days to a degree that gas should be discharged therefrom. There are provided therefore discharge apparatus for limiting or reducing the pressure by way of a duct which provides communication of the containment interior and the atmosphere, that is, a discharge stack via a filtering system. The present invention relates to such a filtering system. The filtering systems utilized so far are not capable of safely handling the discharge of the gases under the given conditions involving a combination of water, steam, high temperatures and radiation. It is therefore the object of the present invention to provide a gas discharge system for the safety containment of a nuclear reactor which, with the use of stainless steel filter element packs, will permit to limit the containment pressure over a longer period of time and which remains functional over the whole period. Such a system needs to be resistant to high temperatures and corrosion, require little servicing and be highly reliable. SUMMARY OF THE INVENTION In a pressurized gas discharge system for the safety containment of a nuclear reactor which includes a conduit structure connected to the safety containment for receiving the gases to be discharged from the interior thereof and which consists of a plurality of modular conduit units flanged together end-to-end and provided with side openings with circumferential flanges, a plurality of frame members are flanged to the sides of the modular conduit units in end-to-end relationship and in alignment with the side openings of the modular conduit units and filter packs of stainless steel fibers are clamped with their circumferential edges between the flanges of adjacent frame members such that the filter packs extend fully across the frame members, one of the flanges of adjacent frame members having a U-shaped member disposed on its face such that the legs thereof project toward the flange of the adjacent frame member and firmly engage the circumferential edges of the filter packs which are compressed thereby to a fraction of their original thickness and form with the legs of the U-shaped member a double seal strip between the frame member flanges. The system according to the present invention provides for a substantial improvement in nuclear plant safety and reduces the remaining risks without the need for additional emergency measures. The system according to the invention additionally provides for long-term effectiveness and reliable operation even under the described extreme conditions as they would occur during a melt-down accident.