Seismic Strength Evaluation of Corroded Reactor Containment Building

The purpose of this study is to investigate the effects of the corrosion phenomenon on the seismic strength of a reactor containment building (RCB) in nuclear power plants (NPPs). A corrosion degradation model is proposed based on the rationale of NPP structures and applied to the reinforcements near the base mat of RCB. Three corrosion levels associated with the service life of the structure up to 60 years are considered in this study. Seven different cases are considered depending on the location of corrosion. A series of pushover analyses are performed to evaluate the seismic responses of the corroded RCB, considering all cases with different levels of damage due to corrosion. The results are obtained in terms of global responses, in which capacity curves, base shear at different limit states, demand–capacity ratios, and reserve strength ratios (RSR) are quantified. The findings of this study demonstrate that corrosion can cause a reduction in structural capacity in terms of base shear of up to 19.5% during its service life of 60 years and that is dependent on how the corrosion is propagated within RCB. The results also illustrate that corrosion in the elements in the tension zone increases the sensitivity of the responses subjected to seismic loads.