Patent Number: 042657075
Section: claims

1. A method of separating nuclear fission and activation products from a gaseous atmosphere in which said products are found, said method comprising the step of introducing and dispersing, into said gaseous atmosphere containing said products, at least 1 kg, per 50 m.sup.3 of atmosphere volume of fine dry particles of a substance inert with respect to said atmosphere having an average particle size in the range of from 0.3 to 5 .mu.m. 2. A method as defined in claim 1 in which said particles are particles of ceramic material which is inert with respect to oxygen. 3. A method as defined in claim 2 in which said particles are fire extinguisher power. 4. Apparatus for separating nuclear fission and activation products from a gas atmosphere containing said products within the reactor building of a gas-cooled nuclear reactor having outer walls (9) of pre-stressed concrete equipped with a liner (10), comprising: a supply hopper container containing fine dry particles of a substance inert with respect to said atmosphere and having an average particle size in the range of from 0.3 to 5 .mu.m (1) a pneumatic feed ine (3) and a source of compressed gas (4,5,6,7) for supplying to said atmosphere said fine dry particles pneumatically, said hopper container having a feed outlet (2) opening into said pneumatic feed line (3),  said feed line being connected at its external end to said source of compressed gas (4,5,6,7), and also passing through said concrete wall structure,  and having at least one dispersion nozzle for said particles connected to said feed line and which is situated in the internal space (11) of said reactor building within said concrete wall structure (9). 5. Apparatus as defined in claim 4 in which said hopper container (1) is located outside said reactor building. 6. Apparatus as defined in claim 4 or claim 5 in which said pneumatic feed line has a plurality of branches (3a,3b,3c), each equipped with at least one said dust-dispersion nozzle, said at least one nozzle being located in the internal space (11) of said reactor building and located on the ceiling (15) of said building. 7. A method of separating nuclear fission and activation products from a gaseous atmosphere in which said products are found, said method comprising the step of introducing and dispersing, into said gaseous atmosphere containing said products, at least 0.5 kg, per 50 m.sup.3 of atmosphere volume, of fine dry particles having an average particle size in the range of from 0.3 to 5 .mu.m which are inert with respect to said gaseous atmosphere.