Bentonite exposed to corroding copper: nature of secondary phases and species formed by Cu diffusion within bentonite

Copper coupons embedded within compacted bentonite have corroded for up to 7 years in an underground research laboratory, mimicking the canister/bentonite
interface of waste packages in a geologic repository for nuclear waste. Bentonite adjacent to corroded coupons prepared as crosscuts will be analyzed at ID21. µXRF data will allow determining how far Cu diffused within bentonite, its integration will allow estimating which fraction of corroded Cu diffused within bentonite and µXANES will allow determining the nature and distribution of species at the micrometric scale, and also identifying solid products formed at the coupon/bentonite interface . Analysing 3 contact times will shed light on the temporal evolution of processes that is needed for extrapolation to relevant time scales not achievable in laboratory. Analyzing 2 bentonite compaction will indicate whether it affects Cu diffusion. Such information is important input for repository performance assessment.