Use of natural tracers in identification and characterisation. Of water-conducting features at Yucca Mountain, Nevada

Understanding rates and pathways of water movement at the potential repository site is crucial in assessing the probable performance in isolating waste from the accessible environment. Of major concern is the amount of water migrating through the mountain and entering the repository. Studies of water migration are being performed in the Exploratory Studies Facility at Yucca Mountain (ESF). The ESF is an eight-km long tunnel, which was constructed between 1995 and 1997. Samples collected in this facility were analyzed for natural tracers that may indicate water presence and movement. Some natural tracers have proven to be very useful in conjunction with other data, but others, such as tritium and stable isotopes, that can be found in gas, liquid and solid phases, have been difficult to understand and correlate to water movement. (author)