Application of zirconium alloys for reprocessing plant components

Zirconium is highly resistant to nitric acid environments and is considered as a candidate material for various applications in spent nuclearfuel reprocessing plants involving concentrated nitric acid medium under highly corrosive oxidizing conditions. Zirconium is insensitive to intergranular corrosion in nitric acid unlike stainless steels of Type AISI304L (304L SS), which is commonly used in reprocessing plants. Also, unlike titanium and its alloys, zirconium is not affected by the vapor and condensate phases of boiling nitric acid. Zirconium and its alloys are thus considered candidate materials for various applications in spent nuclear fuel reprocessing plants involving nitric acid of high concentrations at high temperatures. This paper discusses the international experience on zirconium for reprocessing plant applications and the consideration of Zircaloy-4 (Zr-4)for reprocessing plant applications based on the research and development work carried out at Indira Gandhi Centre for Atomic Research on Zr-4 as well as manufacturing of dissimilar joints between Zr-4 and 304L SS and a mock-up dissolver for fast breeder reactor reprocessing.