Plans for a Southern Nevada national nuclear waste repository are all but kaput. The U.S. Energy Dept. said Feb. 1 it will withdraw its Nuclear Regulatory Commission application within 30 days. The move comes after DOE spent nearly three decades and $38 billion on waste repository tests and studies at Yucca Mountain, 90 miles northwest of Las Vegas. The agency planned to store up to 77,000 tons of radioactive waste there from 80 sites in 35 states. Spent utility fuel and high-level defense waste would be placed in specially engineered containers housed inside a network of tunnels built deep within
Arch dams, classically curved monoliths situated in narrow valleys, are not as common as other types of dams, such as embankment dams and gravity dams. ENR takes a look at some of the biggest arch dams in the world, both completed and under construction.