Nonlinear structural analysis for structural integrity re-evaluation of existing spent fuel pool in nuclear power plant under beyond design basis earthquake

Abstract

This paper presents reevaluation of structural integrity for an existing spent fuel pool (SFP) of the pressurized water reactor power plant in Taiwan, as well as to investigate the locations of potential weaknesses in the whole structure under beyond design basis earthquake (BDBE). In addition, the partial cracking effect from BDBE was also considered in this study associated with higher damping ratio and reduced flexural rigidity. At first, the analysis procedure for single wall based on the structural analysis standards and equivalent seismic load assessment introduced in EPRI-3002009564 and ACI 350.3–06 was considered. All structural crucial aspects considered relevant were included in the analyses: the concrete structure, the steel liner, its connections and the containing fluid. Then, evaluations considering more detailed SFP structure and comprehensive loading combinations were conducted and compared. The analyses results reveal that the structural responses raise significantly when considering increasing the damping ratio and reducing the rigidity of the structure. Furthermore, it is found that the most severely damaged location in the SFP structure is on the south wall, because lateral force on the south wall is larger than others. However, even in this case, the steel liner can still maintain the structural integrity under BDBE.