Experimental investigation of copper-Zircaloy interactions under possible tuff repository conditions.

摘要

As part of its evaluation of copper and copper alloys for use as a container material for spent fuel, the Nevada Nuclear Waste Storage Investigations Project sponsored this experimental study to determine if the presence of copper would influence the corrosion rate of Zircaloy spent fuel cladding under possible tuff repository conditions. The experiment consisted of exposing copper/Zircaloy clad spent fuel packages to two different environments for up to 9 months. Detailed evaluation of the cladding via metallography, electron probe microanalysis, scanning electron microscopy with microanalysis, and Auger electron spectroscopy/ion milling to chemically profile the surface film failed to provide an evidence of copper-enhanced corrosion of the Zircaloy cladding. The difference in thickness of the oxide films between the 2-month and 5-month experiments, and the 2-month and 9-month experiments as indicated by the time to ion mill through the films, was on the order of 50 (angstrom), and 100 (angstrom), respectively, indicating a very low rate of film growth during the experiments. 20 refs., 21 figs., 8 tabs.