Patent Number: 042657075
Section: abstract

As a safety measure to reduce the content of fission and activation produ in the gas atmosphere contained within a nuclear reactor building after a so-called hypothetical malfunction, in a high-temperature gas-cooled reactor, the gas atmosphere within the reactor building is dusted with at least 0.5 kilogram, preferably more than 1 kg per 50 m.sup.3 of gas atmosphere volume, with particles having an average effective particle diameter in the range between 0.3 to 5 .mu.m, preferably of a material inert to oxygen, such as bentonite or clay, although graphite particles may be used if they are carried into the space with an inert gas carrier. The dusting is performed by a pneumatic system comprising a source of compressed gas, such as air or nitrogen, located outside the reactor building, and feed pipes feeding a pattern of dusting nozzles distributed over the ceiling of the interior space of the reactor building. The various feed pipes have dust hopper containers from the bottom of which the flow of gas draws off the dust to the dusting nozzles.