ABSTRACT
This chapter explores the heat generation process and discusses the aspects of nuclear reactor design concerned with removing and utilizing the heat. The fuel elements are embodied in a structure that allows them to be surrounded by the moderator. The whole is contained in a pre-stressed concrete pressure vessel retaining the high-pressure carbon dioxide gas. The coolant extracts the heat from the fuel elements. In the boiling-water reactor the steam is generated directly in the reactor core. The coolant is circulated through a core that consists of the moderator structure, which is built from graphite bricks containing holes through which the coolant flows and in which the fuel elements are placed. Fuel elements consist of natural uranium bars clad in cans of a magnesium alloy known by the trade name. The uranium fuel is in the form of coated partides. A kernel of low-enriched uranium carbide is coated with successive layers of pyrolytically deposited carbon and impervious silicon carbide.
