FUEL ROD CLADDING TUBE FOR A BOILING WATER REACTOR FUEL ROD AND THE PRODUCTION THEREOF

摘要

Cladding tube for a fuel rod for a boiling water reactor fuel element, and its production. The cladding tube is composed practically homogeneously of the constituents of zircaloy and, with the ductility parameter gamma=3{square root over ((kd)/(fr)2=3.5 (gamma=ductility parameter, KD=mean grain diameter; fr=Kearns factor), has an elongation at break of at least 20%, set by low-temperature treatment of an extruded tube blank. The starting body used for the extrusion has a defined distribution of precipitated secondary particles which is produced by beta-quenching and differs in the areas which form the inner surface and outer surface of the extruded tube. At the inner surface, the particles have a greater diameter and are at a greater average distance apart, this distribution being described by the "spacing".