[en] The invention relates to the design of the gas flow system in a gas-cooled high-temperature reactor, which is provided for gases of high temperatures and high pressures. To guide the gases within the pressurized vessel enclosing the reactor core, internally insulated pipelines are provided each of which has with a pressure jacket, they are cooled by means of a cold gas flow. They may be laid separately or be guided as ducts within the wall of the prestressed-concrete pressurized vessel. In detail, the advantageous anchoring elements, compensating elements for balancing heat expansion and the design of the disconnectable connections are described. The system meets all safety requirements and provides for repair and replacement of parts of the system. (orig./PW)