WorldWide Drilling Resource

America’s Planned Nuclear Waste Repository Compiled by the Editorial Staff of WorldWide Drilling Resource ® Yucca Mountain is located on federally owned desert land about 100 miles northwest of Las Vegas, Nevada. Since the early 1980s, the mountain has been under considera- tion to be a site for the geologic disposal of used nuclear fuel and high-level radioactive waste. Experts throughout the world agree the most feasible and safe method for dis- posing of highly radioactive materials is to store them deep underground. Workers drilled and blasted a starter tunnel where a tunnel boring machine (TBM) began its work in 1994. The TBM was 25 feet in diameter, and gripped the sides of the tunnel to push its massive cutter head into the rock. The machine, mapping gantry, and trailing gear stretched more than a football field and were custom-built for the Yucca Mountain Project. While the cutter head bored the tunnel, conveyor belts moved crushed rock to a designated area outside. The TBM pulled 13 special railcars behind it, allowing scientists to study rock samples and take detailed pictures of the tunnels. In 1997, it completed the five-mile-long, horseshoe-shaped exploratory tunnel. At key points along the main tunnel, smaller alcoves were excavated using drill-and-blast technolo- gies, and a machine called the Alpine Miner, used two sets of massive teeth to grind and tear away solid rock. These alcoves were used as underground laboratories where scientists performed tests and collected data about Yucca Mountain's geological features. Scientists also drilled a tunnel with the same size and shape of one which might be used to store radioactive waste. They installed nine canisters filled with heaters, to replicate the high temperatures generated by the waste. In 1997, the heaters were turned on, and the air was heated to nearly 400ºF (205ºC). More than 3000 sensors attached to 10,000 feet of cable measured how water, the air, and the rock reacted to the heat. The heaters were turned off four years later, and the air and rock slowly cooled. Monitoring continued during this cool-down phase with the help of a special webcam, which showed a live picture of the alcove and its readouts. In 1998, it was time to bring in another TBM. It was smaller, measuring 16½ feet in diameter. Miners used this TBM to bore a nearly two-mile-long diagonal tunnel called the "cross drift". It began before the first curve of the main tunnel and cut across the level of the planned repository from northeast to southwest. This TBM remains inside the mountain at the end of the cross drift. The new tunnel allowed scientists to continue testing in the same rock, which would house the waste packages. In 2011, funding for the Yucca Mountain repository was terminated. This action left the United States with- out any long-term storage site for the disposal of civilian spent reactor fuel and defense-generated high-level waste. Currently, the status of the proposed repository at Yucca Mountain remains uncertain. It is abandoned and nothing exists but a boarded up exploratory tunnel. There are no waste disposal tunnels, or receiving and handling facilities. The waste containers and transportation casks have yet to be developed, and no waste has ever been stored on-site. Moreover, there is no railroad to the site for the transportation of waste, and the cost to build a railroad through Nevada could exceed $3 billion. The project was given new life as the Trump Administration made a proposal to add $120 million to continue the licens- ing process. This would only be a fraction of the money needed to pursue storing waste at the site, but it does represent a symbolic move toward this end. Even if l i cens i ng moves f o rwa r d and t he Department of Energy succeeds, it is estimated nuclear waste wouldn’t be going into the ground in Nevada for another 20 years due to approval, expenses, new tun- nels, and infrastructure. 25 WorldWide Drilling Resource ® JANUARY 2018