EFFECT OF MEASUREMENT METHODS AND SOLUTION CHEMISTRY ON THEEVALUATION OF THE LOCALIZED CORROSION OF CANDIDATE HIGH-LEVEL WASTECONTAINER MATERIALS

摘要

The formation of concentrated brines and inorganic salts is predicted to occur due to groundwaterrnevaporation within the emplacement drifts of the proposed Yucca Mountain repository. These brines arernimportant because they can increase the boiling point of the aqueous solutions well above 100 ℃ and arnliquid phase can be stable at very low values of relative humidity. In addition, they provide a source ofrnconcentrated anions that could initiate or inhibit localized corrosion of the waste package (WP). Criticalrnpotentials such as the repassivation potential for crevice corrosion are used to determine the localizedrncorrosion susceptibility of the WP materials under a given set of environmental conditions. However, thernmeasurement of the repassivation potential can be influenced by several factors such as choice of thernpotential scanning method, scan rate, and initiation of transpassive dissolution. This study provides anrnassessment of various methods to accurately determine the repassivation potential in conjunction with thernsimulation of concentrated Yucca Mountain groundwaters to determine concentrations of anionic speciesrnthat influence localized corrosion.