Following the Fukushima Daiichi nuclear reactor crisis in Japan, the U.S. nuclear industry is more closely scrutinizing existing facilities, and long-standing problems are placing some plants under the microscope . Courtesy of Progress Energy Crystal River plant has cracks in walls. Courtesy of NextEra Energy Engineers note alkali silica reaction at Seabrook. “U.S. nuclear facilities are under constant inspection regimens, but since the earthquake we are going at it even stronger,” says Mitch Singer, spokesman for the Nuclear Energy Institute, a Washington, D.C.-based industry organization.In one example, Progress Energy's Crystal River plant in Florida—offline since September 2009 for a refueling
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.