Abstract: A method and a system for catalytic recombination of hydrogen, which is carried in a gas flow, with oxygen, has the gas flow passed through a reaction zone with a number of catalytic converter elements, with steam being added to the gas flow before it enters the reaction zone. The method and system ensure a particularly high operational reliability of the recombination device, even in varying operating conditions or with varying operating methods, in particular with regard to a hydrogen feed, which is provided as required, in the steam/feed water circuit of the installation. For this purpose, the feed rate of the steam to be added is adjusted in dependence on a measured value which is characteristic of a current actual temperature in the reaction zone.

Abstract: A nuclear engineering plant has a containment, whose interior chamber is subdivided by a wall into a systems chamber and an operating chamber which is accessible during normal operation. The containment ensures a particularly high operational reliability, in particular also in incident situations, in which hydrogen is released in the systems chamber. For this purpose, a number of overflow openings are provided in the partition wall, the respective overflow opening is closed by a closure element of a closure apparatus which opens automatically when a trigger condition associated with the respective overflow opening is reached. Closure apparatuses are provided which open both as a function of pressure and independently of pressure. The closure apparatus furthermore has a closure element containing a bursting film or a bursting diaphragm. The closure apparatus is configured such that it frees the overflow opening automatically when a predetermined environment-side trigger temperature is reached.

Abstract: A sampling system for taking a sample from the atmosphere in a reactor containment of a nuclear plant, includes a sampling line which is connected to a vacuum system and to an analysis system. The sampling line opens into the reactor containment and has a restriction device connected upstream thereof on the gas side for connection to the atmosphere in the reactor containment. A method for taking such a sample is also provided.

Abstract: In a method for catalytic oxidation of a gas, the outlay required is kept at a low level for reliably treating even relatively large quantities of gas and/or high concentrations of the gas fraction that needs to be treated. For this purpose, a gas stream including the gas being treated is circulated through a reaction zone and a return-flow zone, which is in communication with the inlet and outlet sides of the reaction zone. The circulation of the gas stream can be maintained effectively in the form of a passive system if the gas stream which includes the gas to be treated is guided in the upward direction in the reaction zone and the upward flow is assisted by convection resulting from the heat released during the oxidation reaction. Furthermore, the gas stream is preferably cooled locally in the return-flow zone by spray cooling.

Abstract: A nuclear installation has a reactor containment which is connected to a pressure relief line. A Venturi scrubber, which is arranged in a vessel containing a washing liquid, and a throttle device are connected in series in the pressure relief line. The novel system restrains, with particularly high reliability, fine air-transported activities or aerosols during decompression such that release thereof into the environment is practically impossible. The Venturi scrubber and the throttle device are dimensioned in such a way that, in the case of a critical drop in pressure of an air-vapor mixture flowing in the decompression line, a flow speed of said air-vapor mixture of more than 150 m/s, preferably more than 200 m/s, can be adjusted with respect to the throttle device in the Venturi scrubber.

Abstract: A recombination device (1, 1?) for catalytically recombining hydrogen and/or carbon monoxide with oxygen in a gaseous mixture comprises at least one catalyst system (2) in which a housing (4) is mounted through which the gaseous mixture can flow in free convection in the operational phase. According to the invention, said catalyst system (2) is provided with a plurality of sub-areas (T1, T2) in the direction of flow. A first sub-area (T1) comprises in the incoming direction a catalyst body (6) with a surrounding throttle layer (8) for inhibiting the diffusion of the incoming and/or discharged reaction gases. A second sub-area (T2) that adjoins the first sub-area (T1) comprises at least one catalyst body (6) that is directly accessible by the reaction gases.

Abstract: In a method for catalytic oxidation of a gas, the outlay required is kept at a low level for reliably treating even relatively large quantities of gas and/or high concentrations of the gas fraction that needs to be treated. For this purpose, a gas stream including the gas being treated is circulated through a reaction zone and a return-flow zone, which is in communication with the inlet and outlet sides of the reaction zone. The circulation of the gas stream can be maintained effectively in the form of a passive system if the gas stream which includes the gas to be treated is guided in the upward direction in the reaction zone and the upward flow is assisted by convection resulting from the heat released during the oxidation reaction. Furthermore, the gas stream is preferably cooled locally in the return-flow zone by spray cooling.

Abstract: A hydrogen/oxygen reaction is initiated in a catalytic recombination or ignition device. The device has one or more catalyst bodies with a predetermined catalytic surface. Only a small portion of the entire available catalytic surface, preferably less than 5% of the surface, is permanently maintained at a temperature level above ambient temperature. The temperature is raised by introducing energy with a heater. The heated surface portion acts as an initial igniter.

Abstract: A catalytic element includes a catalyst body with a catalytic surface and a restrictor layer disposed on the catalyst body for inhibiting diffusion of reaction gases. The catalyst body recombines hydrogen with oxygen and/or carbon monoxide with oxygen. The restrictor layer is porous, is disposed on the catalytic surface, and has a layer thickness varying in the direction of flow of the reaction gasses. The restrictor layer also can have a varying pore diameter that varies in the direction of flow of the reaction gasses. The restrictor layer can be ceramic and include aluminum oxide or silicon oxide, include minerals, be formed from a mineral bed, be metallic, be a metal foil, or include metallic or ceramic fibers forming a mesh.

Abstract: A device and a method for recombining hydrogen and oxygen in a gas mixture, especially for a nuclear plant, includes feeding the gas mixture to a heating chamber through a feed line in which a blower is connected. A control unit associated with the blower is provided to adjust the delivery rate of the blower in accordance with the hydrogen content of the gas mixture. This provides a particularly simple measure for reliably reducing the hydrogen present in the gas mixture, even in different operating states.

Abstract: An ignition system has a plurality of spark igniters for the recombination of hydrogen in a gas mixture. The ignition system provides and ensures reliable early ignition of an ignitable gas mixture, even in the case of comparatively fast gas displacement. Each spark igniter is, according to the invention, configured as a high-speed igniter with an operating frequency in excess of about 10 Hz. In order to ensure reliable ignition of the ignitable gas mixture both in the event of a temporary failure of external units, and when the ignition system has a particularly long operating time, the spark igniters are advantageously connected together in groups for supplying them with energy. Each group of spark igniters is connected to an intermediate energy store common to them, and the intermediate energy stores are connected to a central energy supply unit.

Abstract: An apparatus for the recombination of hydrogen in a gas mixture, in particular for a nuclear power station, during the operation of which unintentional ignition of the gas mixture is avoided in a particularly reliable way. The apparatus contains a catalyst configuration that is disposed in a housing through which the gas mixture can flow by free convection in the operating situation and the catalyst configuration is assigned a flame retention device. In this case, a sediment trap is preferably integrated into the flame retention device, so that hot catalyst particles that become detached from the catalyst configuration are reliably prevented from flowing out counter to the direction of flow of the gas mixture.

Abstract: In order to determine a concentration of a gas mixture, especially a hydrogen concentration of a containment atmosphere of a nuclear power station, a temperature change resulting from a catalytic reaction is measured. The gas mixture is diluted with a motive gas of known composition. The dilution is carried out by a jet pump.

Abstract: A catalyst system and a recombination device for recombining hydrogen and oxygen, and a method for operating a catalyst system, are used in particular for a nuclear power station. The catalyst system includes a metallic carrier plate which is coated with a first and a second catalytic noble or precious metal. The carrier plate has a low mass and is constructed with high heat conductivity. It is coated in a first zone with the first catalytic noble or precious metal and in a second zone with the second noble or precious metal. The first and second zones are preferably located on the same side of the carrier plate. Platinum and palladium are preferably used as the noble or precious metals. The palladium serves for early ignition, and the platinum ensures good activation along with sufficient catalyst poison resistance.

Abstract: When hydrogen is generated within the containment of a nuclear power station, its containment atmosphere must be inerted. An undesired pressure buildup within the containment is prevented during such inerting with the apparatus and the method. It is possible to vent and inert the containment atmosphere simultaneously. A reversible activity holdup device is provided, which makes it possible to vent the containment atmosphere, without radioactive material being released into the surroundings. It is thereby also possible for the containment of a nuclear power station to be inerted even as a preventive measure, so that the safety of the nuclear power station plant is markedly increased.

Abstract: A process for generating an inerting gas for rendering an atmosphere inert, such as within a containment shell of a nuclear power plant. Inert gas is kept in liquid or solid phase in a first reservoir. A sufficient amount of heat to vaporize the liquefied or solidified inert gas is made available in a heat transfer medium in a second reservoir. When inerting gas is needed, the heat transfer medium and the liquefied or solidified inert gas are brought into thermal contact with one another. An apparatus for generating the inerting gas is provided as well. The process and the apparatus are particularly suitable for generating a large amount of inerting gas, as a result of which it can be ensured that the containment shell of a nuclear power plant is rendered inert within a short time.

Abstract: A process for obtaining a sample from an atmosphere in a closed gastight vessel, preferably from a reactor safety vessel of a nuclear power station, includes passing a sample through a venturi nozzle immediately upon entry of the sample into a sample-taking container in a vessel. The sample is mixed in the venturi nozzle with a transport fluid serving as a washing liquid. Gaseous constituents of the sample being soluble and/or condensable in the washing liquid are subsequently discharged together with the washing liquid from the sample-taking container and from the vessel by triggering a pressure reduction. A device for obtaining samples from an atmosphere in a closed gastight vessel, preferably from a reactor safety vessel of a nuclear power station, includes a sample-taking container having a bottom and a given volume. A washing liquid is disposed in the sample-taking container and has a volume being at most approximately equal to half of the given volume.

Abstract: A process for obtaining a sample from an atmosphere in a closed gastight vessel, preferably from a reactor safety vessel of a nuclear power station, includes passing a sample through a venturi nozzle immediately upon entry of the sample into a sample-taking container in a vessel. The sample is mixed in the venturi nozzle with a transport fluid serving as a washing liquid. Gaseous constituents of the sample being soluble and/or condensable in the washing liquid are subsequently discharged together with the washing liquid from the sample-taking container and from the vessel by triggering a pressure reduction. A device for obtaining samples from an atmosphere in a closed gastight vessel, preferably from a reactor safety vessel of a nuclear power station, includes a sample-taking container having a bottom and a given volume. A washing liquid is disposed in the sample-taking container and has a volume being at most approximately equal to half of the given volume.

Abstract: A process for oxidation of hydrogen in a containment of a nuclear reactor plant with the aid of finely distributed catalyst particles, includes spraying catalyst particles in the form of a solution or suspension inside or outside the containment. The sprayed solution or suspension is subsequently dried by heating inside or outside the containment to produce aerosols. The aerosols produced outside are introduced into the containment. A device for oxidation of hydrogen in a containment of a nuclear reactor plant with the aid of finely distributed catalyst particles includes a container for receiving catalyst particles in the form of a solution or suspension. A distributor configuration is connected to the container for spraying the solution or suspension inside or outside the containment. A heater dries the sprayed solution or suspension before the solution or suspension is released into the containment.

Abstract: A method for pressure relief of a containment of a nuclear power plant includes heating a washing fluid in a filter disposed inside a containment at a rated heating power through a thermal bridge, with a gas-steam mixture filling the containment, prior to initial operation of the filter. The thermal bridge is rendered substantially ineffective in an operating state of the filter, leaving the washing fluid with a continuous rated heating power being negligible in terms of filtration. In a nuclear power plant having a containment, a system for pressure relief of the containment includes a filter being disposed inside the containment and having a container. At least part of the container has two walls defining a chamber between the walls. A heat-conducting fluid at least partly fills the chamber during a heating period and is at least half evaporated after attainment of an operating temperature.