Abstract: Disclosed is a high temperature power plant construction, preferably a nuclear power plant, including a plurality of plant components comprising at least one gas-cooled high temperature source, contained in a sealed vessel, and a transport system, connecting the plant components, for gas of high temperature and high pressure, the improvement which comprises the gas transport system comprising at least one internally insulated hot gas transport conduit formed from a plurality of separate sections, a pressure jacket surrounding said hot gas transport conduit, at least one closed channel formed inside of the vessel for transporting a cool gas stream, and means for freely and removably mounting the hot gas transport conduit coaxially inside of the cool gas transport channel.

Abstract: Joints for high temperature and high pressure conduits are disclosed wherein two conduit members are joined in such a manner that permits axial and radial movement due to temperature variations therein while at the same time provides sealing of the joints by means of segmented sealing rings disposed in grooves and extending into a space defined by a sleeve-like extension on one conduit member and a bushing like extension on a second conduit member.