Gas-Cooled Reactors in the Usa: A Survey and Recommendation

Abstract

Among the reports investigated are several by General Electric Company/64-66) General Atomics,(39-47) and Oak Ridge National Laboratory,(111-120) These reports are thorough and well done, and cover the selection of gas coolants, gas cycles, and materials for use in a hightemperature gas environment. For the most part, these reports describe reactors for use up to a maximum gas outlet temperature of 1300°F. From all the reports studied, a number of charts and tables have been duplicated and are incorporated in Section VI; these are briefly described as follows: Several others are in the authorized research and development phase, such as the General Nuclear Engineering Company pressure tube reactor (Column K), the Sanderson and Porter Company pebble bed reactor (Column L), and the General Atomics Company marine direct-cycle reactor (Column F). The Kaiser-AC reactor(68) for ORNL is similar to the later British reactors except for the use of enriched fuel, stainless steel cladding, and helium gas as a coolant. This effects a net reduction in size. The reactor is well designed and should operate satisfactorily. The General Atonnics helium-cooled reactor for Philadelphia Electric Companyl'*^) is very similar to the British Advanced Reactor Concepts, except that the former employs an indirect steam cycle. The fact that the No. 2 core employs UC and ThC canned in graphite tubes for fuel is an interesting development, as is the design feature of a fission product trapping system. The No. 1 core, however, uses stainless steel cladding. Since the exit gas temperature is 1382°F, this reactor could also be used in a direct closed cycle once helium turbines and compressors in this range are developed. The Aero-Jet General Reactor (GCRE-l)^ •' for the Army is a pressure tube design wherein the entire pressure tube assemblies, plenums, and associated mechanisms are totally immersed in a tank of H2O. This is a small, unique military reactor designed to use H2O, which is available in most areas, for moderator and reflector, and N2 as a coolant, so that conventional air compressors and turbines may be used. The General Nuclear Engineering Company D20-moderated and C02-cooled pressure tube prototype reactor(150) ^g aimed at the ultimate use of natural uranium as fuel. The Sanderson and Porter Corporation pebble bed reactorl^^S, 109) using graphite balls containing fissile or fertile material for fuel offers a flexible arrangement for the use of a combination of thorium and uranium. This design has an excellent potential since the problem of loading and unloading fuel is simplified. The Brown-Boveri-Krupp Combine in Germamy are building a reactor similar to this, except that they are using a gas mix ture of about 25% helium and 75% neon. The General Atomics Marine Gas-cooled Reactor(45) is the only direct closed cycle concept being seriously considered. The successful development of this reactor would be a major advancement in reactor technology. The facts that gas outlet temperatures of 1300°F are contemplated and that beryllium oxi...