Front End of the Fuel Cycle

Abstract

This chapter describes the various industrial steps which constitute the front end of the nuclear fuel cycle, i.e., the complete set of operations needed to produce a functional fuel element ready to be loaded in a nuclear reactor. This chapter also provides data concerning the element uranium, its abundance and its most relevant properties. The exploration, mining, concentration and site rehabilitation processes are then described.

Light water reactors (LWR), which make the vast majority of the nuclear reactors operating today, and those under construction, cannot use “natural” uranium for their fuel: it must be “enriched” in isotope 235 and the enrichment process itself requires the uranium to be “converted” into a gaseous compound.

Once enriched to the required assay, uranium is then fabricated into solid ceramic “pellets,” piled into leaktight metallic “pins.” These pins are then “assembled” to constitute the fresh fuel element.

The chapter also provides additional information on MOX fuel assemblies used to recycle plutonium in LWR, as well as some data on plutonium and thorium.

One shall also find an explanation of the fascinating “Oklo Phenomenon,” which occurred almost 2 billion years ago in some uranium deposits of Gabon, in this chapter.

This chapter is expanded and updated from part of a previous Springer publication (Barré, 2005a).