Patent Number: 050930710
Section: description

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The illustrated containment 1 of a nuclear reactor is surrounded by a steel containment shell 1'. In the containment are arranged the reactor and the steam generators, heat exchangers, etc. which are subjected to radioactivity. If a loss of cooling water accident occurs a large quantity of hydrogen is liberated by radiolytic decomposition of the water, there being the risk at 4 vol. % and above of an oxyhydrogen gas explosion and hence the risk of damage to the containment itself. In order to prevent the formation of oxyhydrogen gas, two internal combustion engines 3 and 4, for example, are arranged in the containment. Via their intake branches 5, these internal combustion engines suck in the air from the containment, which, following combustion in the internal combustion engine, emerges into the containment again via the exhaust gas branch 6. Internal combustion engines eligible for consideration are those which are suitable for mixed operation (H.sub.2 / liquid or gaseous fuel), for example, reciprocating piston engines, rotary piston engines, jet engines, steam generators, or the like, in which the combustion process takes place in confined, rigid housings, namely the engine housings of these internal combustion engines, at elevated pressure. As fuels, it is also possible to use gasoline, diesel oil, alcohol, hydrazide, gaseous fuels or the like. In the arrangement shown schematically in FIG. 2, the internal combustion engines 4a, 4b are situated outside the containment 1, according to the exemplary embodiment, between the outer steel containment shell 1' and the containment 1. The intake branches 5a, 5b and the exhaust gas branches 6a, 6b are passed gastightly through the containment. The internal combustion engines 4a, 4b are provided with protection devices against the escape of radioactive containment air. These can comprise, for example, a crankcase ventilation 9 (internal combustion engine 4a) which opens gastightly into the containment 1. Fuel is fed to the individual internal combustion engines via pipes 16 which are connected to a fuel tank 15. The internal combustion engine 3 according to FIG. 1 is arranged in a subcompartment of the containment 1 in such a way that its intake branch 5 and its exhaust gas branch 6 are likewise situated in this subcompartment. It can be advantageous to have the branches 5 and 6 open into other subcompartments and/or to provide a plurality of intake and exhaust gas branches, each opening into different subcompartments. If a plurality of internal combustion engines from the containment 1 and/or from subcompartments of the containment can be drawn off via separate intake and exhaust gas branches 5a, 5b, 6a, 6b, with the exhaust gases similarly being piped into subcompartments of the containment. By virtue of the fact that the intake branches and/or exhaust gas branches open into different subcompartments of the containment 1, the oxygen partial pressure prevailing in these local areas of the containment is lowered rapidly and uniformly by combustion of the air present in this area. The formation of oxyhydrogen gas is thereby counteracted. To reduce the pollutants introduced into the containment 1 with the exhaust gases, it is advantageous to arrange a catalyst 10 in the exhaust gas branches 6, 6b of the internal combustion engines 4, 4b. In order to continue to ensure complete combustion in the internal combustion engine as the oxygen partial pressure falls, provision is furthermore made for the feed of extraneous air to the intake branches 5, 5a, 5b on the intake side of the internal combustion engines 3, 4a, 4b, this being possible in the exemplary embodiments shown via pipes 8. The pipes 8 are advantageously connected to oxygen cylinders 7, enabling pure oxygen to be admixed. It is also possible, in addition to the provision according to the invention of internal combustion engines, for another recombiner to be introduced for inerting, for example, other subcompartments la of the containment 1. The blowing in of an inert gas, such as helium or nitrogen, is advantageous, said gas being fed in via the pipe 12a from a gas cylinder 12. The feeding of an inert gas into the containment or into subcompartments of the containment into which the intake branches 5, 5a, 5b of the internal combustion engines 3, 4, 4a, 4b open is also advantageous for compensating a vacuum produced. Thus, for example, an inert gas, such as for example nitrogen or helium, is blown in from a gas cylinder 12 via the pipe 12b in order to achieve a pressure compensation. In an advantageous further development of the method and apparatus according to the invention, the internal combustion engine(s), engine 4 shown in FIG. 1, drives a pump 2 or a set of pumps. Since the internal combustion engines are put into operation in the case of an accident, and by virtue of the feeding in of oxygen, can run trouble free in any operating situation, motive energy is available which can be used for controlling the accident. The intake line 2a of the pump 2 thus driven, or its delivery line 2b, is connected to the reactor cooling system, thus ensuring, for example, the borated water supply to the cooling system. The pump 2 can also be used to ensure the removal of afterheat. The pump 2 is advantageously used for supplying water to a spray system 11 (FIG. 1). The spray system 11 is inserted in the containment vessel of the reactor for the purpose of pressure relief in the case of an accident. The use of the spray system 11 for cooling the reactor pressure vessel is also appropriate.