Performance Assessment Of Nuclear Power Plants Containment And Internal Structure For Earthquake

According to China energy situation that the tension in the power, and shortage inenergy, wind and solar energies are hard to make a large-scale promotion in a shortperiod, nuclear power has become the best way to solve the power shortage of China.However, nuclear power may also bring disaster at the same time. If the nuclear powerplants suffer a strong earthquake, a tsunami or terrorist attack, and there occurs an eventof nuclear leak, it will make human life and property losses heavily. In order to makethe development of the nuclear power industry of China steadily and healthily, we canadopt the method of performance-based assessment to evaluate the seismic capacity ofcontainment and internal structure suffered a safe shutdown earthquake(SSE).At present,the seismic capacity evaluation of nuclear power plants based on performance-basedassessment methodology has just been in their beginning stage, so it is indispensable tostrengthen the study of the seismic capacity evaluation of nuclear power plants usingperformance-based assessment methodology.In this thesis, the containment and internal structure of nuclear power plants aretaken as an object in the following researches. The non-linear dynamic time-historyanalysis is used for the simplified model of containment and internal structure ofnuclear power plants. The shell element model of containment is used for a Push-overanalysis, and we also analyze the fragility of the component level and system level ofthe containment and internal structure of nuclear power plants. The main researches ofthis paper are as follows:(1) In view of the site of China nuclear power plants, this paper considers anidealized site in which the ground-motion hazard is dominated by a single characteristicevent. Referring to the ASCE43-05standard, a seismic hazard analysis is performed toget the safe shut down design spectrum (SSE spectrum).(2) The fragility of the internal equipment of nuclear power plants is analyzed.Monte Carlo method and trial and error method are used to calculate the failureprobability of internal equipment;(3) The fragility of the containment of nuclear power plants is analyzed. Thedamage state of containment cracking is more accurately determined by the Push-overanalysis of the shell element model of containment, at the same time, the method forcalculating the failure probability of internal equipment is used to the containment.(4) Seismic Probability Safety Assessment (SPSA) and Monte Carlo method have been used to system fragility analysis for containment and internal structure of nuclearpower plants. Comparison of mean probability of the unacceptable performanceobtained by convolution of the seismic hazard and seismic system fragility curve andobtained by combination probability of failure of different components directly by theevent tree is performed.