THERMODYNAMIC SIMULATION OF BRINE CHEMISTRY ON REPOSITORY HIGH-LEVEL WASTE

摘要

The long life of waste packages (WPs) and drip shieldsrn(DSs) is a key attribute of the U.S. Department of Energyrn(DOE) safety strategy for the potential disposal of highlevelrnwaste (HLW) at Yucca Mountain (YM), Nevada.rnAqueous corrosion is expected to be a primaryrndegradation process limiting the life of WPs and DSs.rnThe type, rate, and duration of WP and DS corrosion thatrnmay occur at the repository are dependent on waterrnchemistry and temperature. Conditions that could lead tornaqueous corrosion of WP and DS surfaces could resultrnfrom (i) seepage of groundwater into the drift or (ii)rndeliquescence of dusts on the WP and DS surfaces. In arnhot repository setting, evaporation processes couldrnincrease the aqueous concentrations of corrosionrnenhancing anions (e.g., chloride and fluoride) andrncorrosion inhibiting anions (e.g., nitrate, carbonate andrnsulfate). This increased concentration could lead to thernaccumulation of multi-component salt deposits on WPrnand DS surfaces. Inorganic salts are generallyrnhygroscopic and will absorb moisture from humid air,rngenerating small volumes of potentially corrosive brines.rnDepending on the types of salts, various deliquescentrnaqueous environments could form at various temperaturesrnas high as 80 ℃ [6 ℉].