This draft report was prepared as required by Task No. 2 of the US Department of Energy, Grant No. DE-FG07-89ID12850 Reverse Trade Mission to Acquaint International Representatives with US Power Plant and Drilling Technology'' (mission). As described in the grant proposal, this report covers the reactions of attendees toward US technology, its possible use in their countries, and an evaluation of the mission by the staff leaders. Note this is the draft report of one of two missions carried out under the same contract number. Because of the diversity of the mission subjects and the different attendees at each, a separate report for each mission has been prepared. This draft report has been sent to all mission attendees, specific persons in the US Department of Energy and Los Alamos National Lab., the California Energy Commission (CEC), and various other governmental agencies.

A mathematical and numerical model for evaluation of crevice and pitting corrosion in radioactive waste containers is presented. The model considers mass transport, mass transfer at the metal/solution interface, and chemical speciation in the corrosion cavity. The model is compared against experimental data obtained in artificial crevices. Excellent agreement is found between modeled and experimental values. The importance of full consideration of complex ion formation in the aqueous solution is emphasized and illustrated. 10 refs., 5 figs.

The geochemistry surrounding a waste package is likely to be affected by corrosion of portions of the waste package such as the container. The phenomena involved represent a strong interaction or coupling of corrosion and geochemical processes. A generalized model is developed which can describe the electrochemistry developed in corrosion cells and its interaction with the surrounding geochemical environment. The model is first applied to laboratory data on crevice corrosion and then used to perform a parametric study. The results suggest that all components of the waste package, and their potential interactions must be carefully considered in evaluation of the likely geochemical environment for containment and controlled release of radionuclides. Development of geochemical microenvironments with conditions significantly different from the bulk solution appears likely. Electrical contact between metallic solids can locally raise of lower the potential leading to large accelerations or reductions in corrosion rates. 9 refs., 9 figs.