ABSTRACT

In the 1960s, the US Government, as well as other countries, promoted the development and application of nuclear energy for the production of electric power. The employment of nuclear navies throughout the world provided a knowledge base for the type of reactor using high-pressure “light” water as coolant and moderator. The fuel selected for domestic power stations was uranium dioxide in pellet form, slightly enriched in the isotope U-235, and protected from the coolant by stainless steel or a modified zirconium–tin alloy that came to be known as “Zircaloy.” Zircaloy-4 has been the tubular cladding material of choice today because of its corrosion resistance when pre-oxidized and its low absorptive “cross section” for neutrons. In the present century, pressurized water reactors (PWRs) are the most popular design, providing nearly two-thirds of the installed nuclear capacity throughout the world.