Investigations in support of assessment of corrosion and hydriding trends in N Reactor Zircaloy-2 pressure tubes

Two studies were made to support the assessment of corrosion and hydriding trends in N-Reactor Zircaloy-2 pressure tubes. The first study consisted of chemical, microchemical (chemistry of microstructural features) and microstructural analyses of six lots of Zircaloy-2 which had demonstrated differences in corrosion and hydriding behavior during previous in-reactor and ex-reactor corrosion testing. The second study included chemical, microchemical and microstructural examinations on archive specimens of pressure tubes 2755, 2566, and 1054 to investigate the low hydriding of tube 2755. Metallography, x-ray diffraction, and a review of factors affecting hydrogen uptake were also conducted to support the assessment of the low hydriding of tube 2755. Results of these examinations are given in this report