The Alpha and Bravo cooling towers at the Three Mile Island Nuclear Generating Station are hyperbolic reinforced concrete structures that were exhibiting moderate signs of visual distress raising concern of long term durability. CTLGroup was contracted by Exelon Corporation to perform an investigation on the 50 year old structures related to the concrete quality of the cooling towers and assess future durability and any related repair recommendations.
CTLGroup performed an on-site investigation of the cooling towers over the course of a week, which included an overall visual survey of the towers as well as accessing selected elevated platforms at each of the cooling towers for close-up visual inspection, hammer sounding, ground penetrating radar scanning and concrete core sampling. The team documented suspected areas of concrete distress including concrete staining, cracking, and potential fall hazards. CTLGroup’s in-house laboratory determined overall concrete quality through petrographic examination, chloride content, and compressive strength. CTLGroup’s conclusion, based on our investigation, were that both structures, despite their age, are performing well and indiciated no signs of immediate concern regarding durability at this time.