GB984692A - Improvements in nuclear reactor installations - Google Patents

Abstract

984,692. Reactors. BABCOCK & WILCOX Ltd. July 7, 1961 [July 8, 1960], No. 24763/61. Heading G4G. In a gas cooled nuclear reactor circulation of the gas is effected, without a pump, by thermally induced gas flow through vertical ducting connecting the reactor pressure vessel with a heat exchange chamber above it. As shown, the reactor core 1 is cooled by the vertical flow of gas through channels 101, up duct 7 to pressure vessel 5 containing steam generator 4. The gas when cooled at 5 moves down through the annular space 108 to the lower pressure vessel space 110. The gas may be nitrogen, helium, or carbon dioxide at high pressure, and the reactor core is graphite with graphite-cased uranium oxide or carbide fuel elements. The plant is mounted in the ground within the vertical shaft 3. The heat release rate of the core is adjusted by control of the throttling valve 8 in the gas circuit. An automatic safety device directs the steam generated at 4 to a receiver when radio-active contaminations is detected. The gas in container 5 may be caused to recirculate round or by-pass the generator 4. To assist in the rapid removal of heat from the tube 7 at shut-down, cooling ducts may be arranged concentrically about 7. In an alternative reactor construction, not shown, the fuel is in the form of a mass of graphite spheres encasing fissile and fertile material held in a container of moderating material. As fresh fuel is added the resistance to coolant gas flow increases. This is allowed for by admitting gas to the fuel mass at progressively higher levels.