Patent Number: 043604960
Section: summary

The invention relates to a cooling system for auxiliary systems of a nuclear installation for the removal of heat from heat exchangers which, firstly are connected on the primary side to lines which may contain radioactive liquids or gases; secondly are disposed in a secured area of the nuclear installation; and thirdly have connections on the secondary side thereof for cooling-liquid lines. For many of these systems it must be ensured that a given temperature (for instance 30.degree. C.) of the cooling liquid provided for the removal of heat from these auxiliary systems is maintained in operation. In addition, the temperature of the cooling liquid must not drop too far so that material stresses in the heat exchangers for the removal of heat from the auxiliary systems are kept low. The cooling system must furthermore be constructed so that even in the event of a failure of the power supply from the normal network, heat removal from the auxiliary systems is still assured. These three requirements have not generally been met in such cooling systems in the past. It is accordingly an object of the invention to provide a cooling system for auxiliary systems of a nuclear installation which overcomes the hereinafore-mentioned shortcomings of the heretofore-known devices of this general type, and which meets all three of these requirements without the need of having to provide a supplemental water line or supply basin. With the foregoing and other objects in view there is provided, in accordance with the invention, a cooling system for auxiliary systems of a nuclear installation for heat removal from heat exchangers, the heat exchangers being connected on the primary side thereof to lines which may contain radioactive liquids or gases, being disposed in a secured area of the nuclear installation, and having connections on the secondary side thereof for cooling liquid lines, comprising an outgoing line for the cooling liquid connected to the connection on the secondary side of the heat exchangers, a dry cooling tower having cooling elements connected to the outgoing line, a return line for the cooling liquid connected to the cooling elements, a refrigeration loop (compressor, condenser and throttle point) having a supplemental heat exchanger with the primary side thereof connected in the return line, a bypass line connected from the outgoing to the return line parallel to the cooling elements and supplemental heat exchanger, and a control valve connected in the bypass line. In accordance with another feature of the invention, the secured area has a boundary, and there is provided a fast-acting shut off valve connected in each of the outgoing and return lines at the boundary. In accordance with a further feature of the invention, there is provided a rising line connected to the return line in the secured area, and an expansion tank being connected to the rising line and disposed in the secured area. In accordance with an added feature of the invention, the cooling liquid is an antifreeze medium which ensures unrestrained operation of the dry cooling tower for safe heat removal from the nuclear installation. In accordance with a concomitant feature of the invention, a plurality of redundant cooling systems are provided for one nuclear installation, the dry cooling towers of the individual cooling systems being disposed at different locations. Other features which are considered as characteristic for the invention are set forth in the appended claims. Although the invention is illustrated and described herein as embodied in a cooling system for auxiliary systems of a nuclear installation, it is nevertheless not intended to be limited to the details shown, since various modifications and structural changes may be made therein without departing from the spirit of the invention and within the scope and range of equivalents of the claims.