Seismic Design Spectra For Nuclear Power Plant Considering The Hanging Wall/Footwall Effect

As of the end of 2015,there has been 24 nuclear power units in China which ranks first in the world.They are mainly distributed in the eastern coastal areas.With the 13 th five-year-plan approaching,China's economy will enters into a new era.The construction of inland nuclear power plant will be the trend of the times under the pressure of economic growth and the increase of energy demand.In recent years,strong earthquake record database around the world has become increasingly rich,and the site of nuclear power plant in inland region may be close to the fault.The seismic design code nuclear power plant was drafted in the mid-1990 s.There were some defects such as disunity of probability level,conservation in long period phase,without consideration of the influence of magnitude and fault distance.Therefore,it is imperative to revise the design code of nuclear power plant in china.This paper mainly considers influences of hanging wall/footwall effects for nuclear power plants design spectrum.Firstly,we select some strong earthquake records near faults from seven earthquake.Then by using Newmark method and Guo-Wang method,getting seismic design spectra of nuclear power plant considering the hanging wall/footwall effects.The main work and the conclusions are as follow:(1)In this paper,a total of 1024 near fault records at home and abroad are selected,and the format of the record is unified processing,which increases the fault distance and the ground motion peak which is convenient for statistics use.Group these strong earthquake records according to the site of the fault.By contrast,in the same fault distance scope,PGA?PGV?PGD in hanging wall are significantly greater than that of the footwall area and other areas.(2)In this paper,using the Newmark method and the Guo-Wang method analyze the 1024 strong motion records.V/A,AD/V2 which are used in Newmark method not only considering site condition,should also consider fault distance and magnitude and near fault effects influence,this paper gives recommended values considering the hanging wall/footwall effects.Then according to the characteristics of the strong motion record response spectrum Newmark method and Guo-Wang method was respectively improved.In the Newmark method,the third and four control points are changed.However the control period of Guo-Wang method is not changed,and the spectral value of the control point is modified,so that the probability level of each point is consistent.Finally,according to the improved Newmark method and Guo-Wang method get nuclear power plant design spectrum considering the hanging wall/footwall effects.(3)By comparing the results with GB50267-97 spectrum and AP1000 spectra get conclusion that the hanging wall/footwall effects has significant effect in short period of design spectrum than long period.In the Newmark method,the peak value is influenced by many factors,and the discrete model is relatively large.It is recommended to use the Guo-Wang method to get the design spectrum.