Structural aging program status report

Reinforced concrete structures play a vital role in the safe operation of all light-water reactor plants. In general, the performance of these structures has been satisfactory. However, there have been several instances where the capability of these structures to meet future functional and performance requirements has been challenged due to problems arising from either improper material selection, construction and design deficiencies, or environmental effects. Examples of some of the potentially more serious incidents include post-tensioning anchor head failures, leaching of concrete in tendon galleries, voids under vertical tendon bearing plates, containment dome delaminations, corrosion of steel tendons and rebars, water intrusion through basement cracks, and leakage of corrosion inhibitor from tendon sheaths. Such incidents indicate that there is a need for improved surveillance, inspection and testing, and maintenance to enhance the technical bases for assurance of continued safe operation of nuclear power plants both during the initial licensing period as well as throughout any continued service period