Patent Number: 047956070
Section: abstract

Gas-cooled high-temperature nuclear reactor having a reactor core comprising individual fuel elements provided with means for forming a barrier against the release of fission products producible therein during reactor operation, the fuel elements being received in a cylindrical barrel formed of an inner graphite layer functioning as a reflector, an outer layer of insulating material surrounding the inner layer, and a metallic receptacle, the inner and outer layers and the receptacle being formed of respective side, bottom and cover portions, the side and cover portions of the inner layer being formed with first channels into which means for controlling the reactors are insertable, the bottom, side and cover portions of the inner layer being further formed with second channels wherein, during reactor operation, cooling gas is circulated under pressure from the bottom to the top of the receptacle, the bottom portion of the inner layer having first openings for introducing cooling gas into the second channels during reactor operation and second openings for withdrawing during reactor operation cooling gas heated by passage through the reactor core; the inner and outer layers and the cylindrical core barrel having a heat conductivity and a thermal capacity and the reactor core having such a size, shape, power density and moderation ratio that a first temperature at which the core becomes subcritical for all possible accident conditions is below a second temperature at which the barrier means are destroyed, and, when loss of pressure of the cooling gas is experienced, after-heat generated in the core being removable by heat conduction and radiation through the inner and outer layers and the core barrel to a heat sink located outside the receptacle, in such a way that the fuel elements remain at a temperature below the second temperature.