Antiseismic Adaptability Analysis Of Nuclear Power Plant And Uncertainty Analysis Of Floor Response Spectrum

In view of the particularity of the nuclear power plant,it is very important to study on seismic performance of nuclear power plant in order to conform to the rapid development of Chinese nuclear power industry.Against the reactor building of a 1000MW reactor nuclear station,this paper has a study on the effect of different site models and time-history method in the floor response spectrum computation,and then makes an analysis of the nuclear power plant seismic response based on the time-history method considering SSI.At last.the probabilistic-statistical analysis of the reactor plant(RX) only considering model parameter uncertainty is performed by the method of Monte-Carlo on the basis of ASCE Standard.This paper reads as follows:(1) A numerical solution to the soil dynamic impedance for the nuclear power plant based on harmonic response is proposed,and a continued-fraction solution of SBFEM analysis is studied in this paper.Then,the dynamic impedance of different site models is calculated and analysed concretely.The results for the different field models indicate that the proposed algorithm can both solve the dynamic impedance for the semi-infinite homogeneous field and layered field.Besides,it is able to reflect the dynamic impedance changes with excitation frequencies and its accuracy can meet the engineering requirements.(2) Based on the lumped-mass simplified model of the reactor building and the viscouss-elastic boundary model of semi-infinite free field and excavated field,the time-history analysis on the basis of direct method and sub-structrue method has been made in order to determine seismic response of nuclear power plant structure.In addition,different lumped-parameter models of the semi-infinite homogeneous free field and the lumped-mass model of the reactor building are coupled,and then the analysis of SSI has been made. Compared to the results of viscous boundary model,the conservation of the lumped-parameter model is verified.(3) In order to reflect the impact of model-parameters uncertainty,ASCE Standard indicates that peak of the floor response spectrum deduced by the deterministic method may be broaden and reduced,and also shows that the reduction 15%amplitude of floor response spectrum is somewhat conservative for the model-parameters uncertainty analysis in the case of 2%small damping,furthermore,the reduction rate of amplitude is not limited to 15%,as long as it meets 90%guarantee rate.In order to provide technical basis for the reasonable peak broaden and reduction,the probabilitic-statistical analysis of the floor response spectrum is made under the determination of the level of input ground motion and the uncertainty of model parameters.The results indicate that the peak of floor response spectrum is not only more smoothing but also smaller after the probabilitic-statistical analysis.