STATUS OF UNDERGROUND TESTING PROGRAM

Considerable progress has been made in the last year in the area of underground testing. The arrival of El Nifio has allowed the Project to implement tests in two locations of the Exploratory Studies facility (ESF) (Upper Tiva Canyon Alcove (Alcove 1) and Southern Ghost Dance Fault Drift (Alcove 7), which will provide the ability to monitor the climatic effects associated with an increased rainfall event. In Alcoves 3 and 4, vertical boreholes were drilled/cored in the invert in order to bound hydrogeologic characteristics of the bedded tuffs overlying the potential repository horizon unit. In Alcove 4, a small field scale unsaturated percolation/seepage test will be conducted utilizing short boreholes. In Alcove 5, the Drift Scale Test began, and in Alcove 6, a slot was excavated to allow for collection of dyes and tracers for a fracture matrix interaction test. Construction was completed on Busted Butte Test Facility, located approx. 5 km from Yucca Mountain in preparation for a large scale Unsaturated Zone (UZ) transport test. This paper focuses on the various advances made in the Underground-testing program in the last year and discussion of their current status. Particular emphasis will be placed on the ‘El Nit’io Studies, Drift Scale Test, and Busted Butte because of their importance to understanding importance of the natural system to Repository Performance.