Continue stress corrosion cracking/ electrochemical testing and model support

The work reported here is focused on measuring values for various model parameters for the General Corrosion Model (GCM). The objective of the UNR work is to obtain the parameter values under Quality Assurance protocols, so that the data can be incorporated into models that might be used to address licensing issues, for example. The derived kinetic parameters may be used in models for predicting the accumulation of general and localized corrosion damage to Alloy-22 canisters over the 10,000-year lifetime of the YM repository. The work focuses on obtaining data of the highest possible accuracy to derive kinetic parameters for the dominant processes in the growth and breakdown of passive films on Alloy-22. This work also forms the basis of Mr. Glen McMillion\u27s dissertation for the Ph.D. degree from the University of Nevada, which he is scheduled to complete at the end of 2004. This project has made significant progress and has produced important data since its inception in mid-FY2002: 1. All work has been performed under the control of the UCCSN Quality Assurance Program, which is approved by the DOE YMP. Data generated to date are being submitted to the Technical Data Archive (TDA). 2. Experimental apparatus specifically designed for this task has been built, thoroughly tested, and proven to generate high-accuracy data. 3. Data have been collected for approximately two-thirds of the first of three conditions identified in the experimental matrix developed in the Scientific Investigation Plan. 4. Data generated include cyclic polarization, electrochemical impedance spectroscopy (EIS), potentiostatic passive current density (Ip), and Ip transients in response to step changes in potential. Conditions for which these data have been generated are listed below. 5. Crevice corrosion of Alloy-22 has been observed and documented. 6. Significant variability of corrosion behavior and microstructure among mill-annealed specimens has been observed and documented