Abstract: A supporting floor for the core of a nuclear reactor utilizes a plurality of independent support columns forming the floor of the reactor and resting on the bottom layers of the reactor. The support columns are surrounded by a side reflector which is in turn surrounded by a thermal side shield. Between the thermal side shield and the side reflector are disposed retaining means for maintaining the columns close together and preventing the formation of large gaps during operation.

Abstract: The invention concerns a roof reflector suspended from the thermal cover shield of a gas-cooled pebble-bed reactor with a plurality of passages for absorber rods arranged in a triangular lattice, and with channels for the passage of the cooling gas. The roof reflector comprises a plurality of essentially hexagonal graphite blocks arranged in several layers to form vertical, closely-adjacent columns. A process for the disassembly of the roof reflector is further provided.

Abstract: Disclosed is a support structure consisting of several layers of prismatic graphite blocks arranged over each other. The layers are constructed as closed units without expansion gaps and the blocks of one layer are keyed together with the blocks of the adjacent layers. The upper layers are composed of a plurality of preferably hexagonal graphite blocks equipped with passages for the cooling gas, while the bottom layer is formed by a number of support structures, each consisting of several support segments fitted together preferably into a hexagonal cross section, with each support unit resting at its central section on a column head of a round column and carrying a limited number of the hexagonal graphite blocks and that cooling gas channels are provided at the locations of the bottom layer where three support units meet.