The Nuclear Design Spectra Considering Near-source Pulse

With the continuing development of Chinese economy, the exploitation of clean and environment-friendly energy as well as safe has become an important part of it. Comparing to fire power and hydropower, nuclear power has various advantages, making it a vigorously developing power in our country. The inland nuclear plant has been taken into consideration while the coastal ones are not enough. Other than the coastal nuclear power plants, inland nuclear plant may face a more complex geological environment. Restricted to the technical level of geological survey, the comprehensive and accurate geological environment of the plants may be very hard. So when the nuclear power plant is built, there may be uncovered faults lying around it, making the power plant exposing to the near-fault earthquakes. Chinese nuclear standard does not make a clear statement of what should be done while face potential near-fault threat. To solve this problem, this thesis proposed a way to build near-fault nuclear spectra on the base of probability seismic hazard analysis. The main work are listed as follows.1. This thesis summarized the research status of nuclear design spectra at home and abroad, and introduced the characteristics of near-fault earthquake which should be taken into consideration in nuclear design spectra.2. This thesis introduced the concept and cause of the near-fault effect as well as the Baker pulse amplification coefficient. We chose 115 near-fault earthquake records with pulse and related ones without pulse, then the records were divided into different groups according to their magnitude and minimum fault distance. Via the rates of spectral acceleration with pulse to the ones without pulse, we came up with the amendatory pulse amplification coefficient and compared it with the Baker amplification coefficient.3. This thesis introduced the computational process of the probability seismic hazard analysis(PSHA) and how to choose the parameters in the computation. We got the near source probability seismic hazard analysis(NS-PSHA) by introducing pulse into PSHA. On the basis of it, we built a simple fault model to simulate the near-fault scenario of a nuclear power plant. Through the PSHA, the uniform hazard spectra of different sites around the fault were calculated and the effect of limit earthquake and site condition.4. The results of PSHA are disaggregated at the period of 0.1s and 1s. The results of disaggregation demonstrated the most hazardous magnitude and minimum fault distance for each site in this simple model. When the most dangerous magnitude. We take the most hazardous parameters into a ground movement prediction equation to get a design spectrum. After it is modified by the near-fault pulse amplification coefficient, the design spectrum could be applied in a near-fault scenario.