Summary and conclusions of a program addressing aging of nuclear power plant concrete structures

Research has been conducted by the Oak Ridge National Laboratory to address aging management of nuclear power plant concrete structures. The purpose was to identify potential structural safety issues and acceptance criteria for use in continued service assessments. The focus of this program was on structural integrity rather than on leaktightness or pressure retention of concrete structures. Primary program accomplishments include formulation of a Structural Materials Information Center that contains data and information on the time variation of material properties under the influence of pertinent environmental stressors and aging factors for 144 materials, an aging assessment methodology to identify critical structures and degradation factors that can potentially impact their performance, guidelines and evaluation criteria for use in condition assessments of reinforced concrete structures, and a reliability-based methodology for current condition assessments and estimations of future performance of reinforced concrete nuclear power plant structures. In addition, in-depth evaluations were conducted of several nondestructive evaluation and repair-related technologies to develop guidance on their applicability.