Effect of Aging on Ultimate Pressure Capacity of Nuclear Reactor Containment Building

Abstract

Sara Abdullah AlHanaee, 'Effect of Aging on Ultimate Pressure Capacity of Nuclear Reactor Containment Building', M.Sc. Thesis, M.Sc. in Nuclear Engineering, Khalifa University of Science, Technology and Research, United Arab Emirates, June 2016. Reactor containment buildings (RCBs) in nuclear power plants (NPPs) provide structural support and protection of the systems and components as well as shielding against radiation release to the public and environment. Therefore, it is vital to ensure their structural integrity over the service lives against design basis accidents (DBAs) and severe accidents. During severe accidents internal pressure may increase by hydrogen combustion, direct containment heating, vapor explosion, etc. The performance of RCBs during such severe accidents may be evaluated by the ultimate pressure capacity (UPC). The UPC is an estimate of the maximum internal pressure at which the RCB is still capable to sustain its structural and functional integrity. The determination of UPC of containment buildings is a complex structural analysis problem, which can be solved by computational methods. In this study, a non-linear finite element analysis (FEA) was performed in ABAQUS to examine the sensitivity of UPC of the APR1400 PWR's RCB to various aging/degradation mechanisms. Nevertheless, RCBs undergo various degradation mechanisms that affect the UPC of RCBs. The main degradation mechanisms identified in the literature are: sulfate attack, alkali-silica reaction, corrosion and prestress loss. There were two main sets of FE calculations that were performed: unaged (new) and aged (degraded) RCB. The effects of the main aging mechanisms on the UPC of RCBs were quantitatively evaluated and were relatively compared to the unaged RCB. The aging simulations in ABAQUS were based on four established parameters, which are: concrete aging, corrosion of rebar and liner, and prestress loss. Both local and global rebar and liner corrosion were considered, Results of the numerical analysis show that liner failure is governed by the tension stiffening parameter associated with tensile cracking of the reinforced concrete. Among the four degradation parameters used in this study, local rebar corrosion was found to be the most influential degradation mechanism. In addition, the prestress loss has significant effect on the UPC but less than rebar corrosion. Indexing Terms: Reactor containment building, ultimate pressure capacity, aging, finite element analysis

Date of Award	Jun 2016
Original language	American English
Supervisor	Yongsun Yi (Supervisor)