Impact of added Inconel and stainless steel on zirconium-based alloys for nuclear waste applications.

Three alloys were made to represent waste forms for ZIRLO® cladding and metallic fuel wastes by alloying ZIRLO® and a surrogate metallic fuel waste mixture with various amounts of Inconel 718, 304 stainless steel, trim chromium, and trim copper. The objective was to establish if metallic wastes that contain ZIRLO® can be manufactured into durable waste forms for geological repository. Specimens were metallurgically characterized and subjected to electrochemical tests to assess their corrosion resistance. Tests were conducted in acidic and alkaline electrolytes prepared with and without NaCl to simulate ranges of environmental redox and chemical conditions that could occur within a breached waste package in a disposal facility. The microstructures and potentiodynamic scans of these alloys are presented. Surface analyses after the potentiodynamic scans indicate intermetallics enriched in iron, nickel, and copper corroded at relatively low potentials in Cl− solutions and were less durable than the zirconium-chromium phases. [ABSTRACT FROM AUTHOR]