Corrosion studies on materials of construction for spent nuclear fuel reprocessing plant equipment

Corrosion studies on specimens of commercial Type 304L stainless steel (SS), nuclear grade type 304L SS, extra low-carbon nitric acid grade (NAG) Uranus-16 SS, NAG Uranus-65 SS, Ti, Ti-5% Ta, Ti-0.25% Pd, Zircaloy-2, weldments of Ti and of Ti-5% Ta, and surface-modified (thermally oxidised and anodised) Ti were carried out to assess their corrosion resistance in nitric acid medium. The results indicated that Zircaloy-2, Ti-5% Ta, Uranus-16 SS and Uranus-65 SS have excellent corrosion resistance in boiling nitric acid solution. Specimens of Zircaloy-2, Ti-5% Ta and thermally-oxidised Ti showed excellent corrosion resistance also in a simulated uranium-containing reprocessing medium in a concentrated nitric acid solution. SEM and XRD analyses were carried out on the tested specimens to examine the scale morphology and phases present on the surface. (orig.)