Patent Number: 051223333
Section: summary

This invention relates to an apparatus for eliminating aerosols from air escaping from a nuclear reactor containment vessel. As is known, various types of apparatus have been used for the elimination of aerosols contained in air which has escaped from the containment vessel of a nuclear reactor plant, for example, in the event of an excess pressure occurring in the containment vessel. In such apparatus, the air is usually ID feed to a water bath by means of a conduit connected to the containment vessel. In one known apparatus of this kind, venturi scrubbers have been disposed in a water bath with each having a venturi tube to which the aerosol-laden air is feed while water is added to the air flowing through each venturi tube at the narrowest point of such tube. The purpose of such scrubbers is to fix a considerable proportion of the aerosols in the water by mixing the water and air. In addition, above the water bath in a tank containing the same, there is disposed a filter of high-grade steel fibers, through which the air emerging from the water bath has to pass before being discharged to atmosphere via a chimney. The purpose of this filter is to retain the residual aerosols in the air. In the known apparatus, separate containers are required to accommodate the water bath and the filter. Further, the extremely fine high-quality steel fibers of the filter have a thickness of 2 .mu.m and require special protective steps to guard against corrosion. After any trial runs of the apparatus, each of the filters normally has to be replaced. In addition, the filter retention power is restricted. Further, the venturi scrubbers disposed vertically in the water bath take up a relatively considerable height. The constructional requirements and overall volume of the known apparatus are therefore quite large. Accordingly, it is an object in the invention to reduce the expense of removing aerosols from air vented from a nuclear reactor containment vessel. It is another object of the invention to reduce the constructional outlay for an apparatus for eliminating aerosols from the air of a nuclear reactor containment vessel. It is another object of the invention to provide a relative simple apparatus for eliminating aerosols from air vented from a nuclear reactor containment vessel. Briefly, the invention provides an apparatus for eliminating aerosols from air escaping from a nuclear reactor containment vessel. In this respect, the apparatus includes a water basin for holding a bath of water and a conduit for delivering a flow of aerosol-laden air into the water bath from a containment vessel of a nuclear reactor plant, for example, in response to an excess pressure in the containment vessel. In addition, a plurality of nozzles are disposed in the basin and are connected in parallel with the air delivery conduit in order to discharge jets of aerosol-laden air into the water bath for entrainment of water therein. Also, a baffle plate extends over the nozzles and has perforations therein for mixing the water-entrained aerosol-laden air passing therethrough. Still further, a plurality of static mixer elements are disposed in stacked array within the water bath above the baffle plate for conducting the mixture of water-entrained aerosol-laden air therethrough. These static mixer elements have intersecting flow passages for splitting up elongating and re-arranging the components of the water and air mixture in order to disperse the air in the water while separating the aerosols into at least one of the water and the static mixer elements. The apparatus also includes a jacket which circumferentially surrounds the mixer elements. This jacket may also extend downwardly into a zone of the nozzles. A further conduit is also connected to the basin above the water bath and the static mixer elements for discharging a flow of aerosol-depleted air therefrom. The use of a plurality of nozzles with a perforated baffle plate reduces the overall height required of the aerosol-eliminating apparatus considerably as compared with known venturi scrubbers. Hence, the space requirements for the apparatus are reduced. The use of static mixer elements enables practically all the aerosols to be fixed. Thus, the air emerging from the water bath can be discharged directly to the surroundings, that is, without having to pass through a filter. Also, there is no need to provide a special closed container for the apparatus. The nozzles, baffle plates and static mixer elements can be accommodated in a water basin which, in any case, is present in a nuclear reactor plant. The apparatus permits trials to be carried out at any time without any need to subsequently replace any parts. Further, the parts of the apparatus can be easily inspected an the static mixer elements can be easily removed, and, if necessary, cleaned by conventional processes.