Process for the production of a tubular zircaloy 2 blank internally clad with zirconium and suitable for ultrasound monitoring of the zirconium thickness

摘要

The invention concerns a process for the production of a tubular zircaloy 2 blank which is internally clad with zirconium for use in producing composite cladding tubes for nuclear fuel. The internal zirconium cladding is rendered suitable for ultrasound monitoring of its thickness by an appropriate thermomechanical treatment which takes place during one or more of the production steps for said blank. The aim is to adjust the grain size to an ASTM index of between 9 and 12 for the zircaloy 2 and between 6 and 10 for the unalloyed zirconium, retaining a grain size difference between the zircaloy 2 and the unalloyed zirconium of at least 2 ASTM index numbers.