The Tennessee Valley Authority (TVA) announced this week it will perform geophysical testing on the dam at Raccoon Mountain’s upper reservoir, part of its 1,652-MW Raccoon Mountain pumped-storage project.
TVA officials say this testing is part of a nondestructive investigation to determine material properties of the dam and its foundation. The dam is 230-ft high and 8,500-ft long and is the largest rockfill dam ever built by TVA.
Testing is set to begin on National Dam Safety Awareness Day, Tuesday, May 31 and end June 15.
Of TVA’s hydroelectric facilities, the Raccoon Mountain pumped-storage project has the highest installed capacity, generating energy via a four-unit underground power station in Marion County, just west of Chattanooga in Tennessee.
Construction at Raccoon Mountain began in 1970 and was completed in 1978 at a cost of US$310 million. The reservoir constructed at the top of the mountain has 528 acres of water surface.
TVA took the facility offline in March 2012 after being alerted of possible cracks in generator rotors.
Inspections found widespread evidence of rotor cracks in three of the facility’s four units and TVA immediately suspended power production.
TVA replaced most of the 7,000-pound rotor poles and rotor rims for about $90 million, and the facility went back on line in April 2014.