Photo Courtesy of Washington Closure Hanford N Reactor is the last of nine aging reactors to be partly demolished and sealed for long-term decay of radioactivity. Related Links: Engineering News-Record Architectural Record The last and largest of nine defunct nuclear reactors once used for weapons production at the U.S. Energy Dept.'s huge Hanford site in Washington state has been placed in safe storage, or "cocooned," so its remaining high radioactivity can safely decay, the agency said on June 14.The new status for the site's N Reactor follows a $65-million cleanup and demolition project, which included demolishing the 85,450-sq-ft building to
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.