Shaking Table Experiments On CAP1400 Spent Fuel Storage Rack Considering The Effect Of Fluid-structure Interaction

Spent fuel pools and spent fuel storage racks are important components of nuclear power plants.Their function is to ensure the safe and efficient storage of spent fuel assemblies discharged from the reactor core.The structural integrity of spent fuel pools and spent fuel storage racks is of great significance to the overall safety of nuclear power plants.However,spent fuel storage racks exhibit strong nonlinear behavior due to fluid-structure coupling effects under seismic loading,which may lead to collisional impacts,sliding and overturning.Therefore,It is necessary to conduct seismic studies of spent fuel storage racks.But the correlational experimental studies is fairly limited.However,these nonlinear effects introduce large uncertainties in the seismic analysis of the racks and make the numerical simulation more difficult.At present,in the engineering design process,the seismic analysis of spent fuel storage racks is usually conducted with a conservative method.But the conservative margin of the results is so difficult to be determined that it is still necessary to verify the numerical calculation by seismic experiments.However,the seismic experimental studies are very limited.Due to the constraints,the previous studies have not made a more detailed comparative analysis of the seismic response of the racks under different experimental conditions,so it is very necessary to carry out corresponding experimental studies deeply in order to comprehensively evaluate the nonlinear behavior of the racks under seismic loading.In order to reduce the excessive margin in the seismic safety design of CAP 1400 spent fuel storage racks developed by China and to obtain a more comprehensive seismic response of the racks,a 3/10 reduced-scale seismic experiments considering the effect of fluid-structure interaction were carried out to investigete the effects of the number of racks and vertical seismic loading on the seismic response of the racks.Through a series of shaking table experiments,the lubrication friction coefficients between the spent fuel storage rack model and the spent fuel pool model were obtained.Several important experimental data such as the maximum sliding displacement,acceleration response and fluid fluctuating pressure distribution under seismic loading were obtained.Furthermore,the seismic dynamic response of the racks under different experimental parameters such as single-rack or double-rack conditions and vertical seismic loading were also obtained.The experimental results show that there are large uncertainties of the sliding displacements of the racks under all experimental conditions and the significant difference between the sliding displacements of the racks in the single-rack system and the double-rack system indicates that the fluid-stucture interaction has a large influence on the sliding motion of the racks.And the vertical seismic loading significantly changes the fluid pressure distribution in the spent fuel pool.In this paper,the dynamic response behavior of the CAP 1400 spent fuel storage rack under seismic loading is studied in detail and comprehensively.The seismic data of the racks under different experimental parameters are obtained.These results can eventually be the basis for the seismic analysis and the benchmark for the design and processing of China’s self-developed CAP 1400 spent fuel pool and spent fuel storage racks.