ABSTRACT
This chapter introduces some of the desired general features of a reactor coolant and discusses the actual processes of heat transfer from the fuel elements to the primary coolants and from the primary coolants to the steam generation system. It reviews the various types of coolant, and provides some examples of the engineering features of cooling circuits used in various types of reactor. The values for carbon dioxide are very much lower than those for water and sodium. This means that the temperature difference would be unacceptably high or the power output unacceptably low, for gas-cooled systems. Air cooling was used in the very first generation of nuclear reactors, namely, graphite-moderated natural uranium “piles,” which were built in both the United Kingdom (UK) and the United States in the 1940s. The largest air-cooled reactors were at the UK Atomic Energy Authority’s Windscale establishment and were designed for plutonium production.
