核设施地震危险性分析方法研究

发布时间：2018-05-02 04:41

本文选题：核安全 + 地震危险性分析　；参考：《国际地震动态》2018年01期

【摘要】：福岛核事故揭示了外部自然灾害引发严重核事故的可能性,为核工程界敲响了警钟。因此,对我国运行和在建核电厂址逐步开展了抗震裕度评价(SMA)或地震概率安全评价(SPSA)工作。本文针对地震危险性分析在核工程应用中存在的问题,从设计基准地震动的确定、核电厂地震概率安全评价、超设计基准地震动安全分析3个方面进行了研究。设计基准地震动确定方面,目前存在的主要问题是某些核设施厂址确定论方法和概率论方法评价结果的显著差异。本文以我国的一些核电厂址为例,分析了确定论和概率论方法评价结果的控制性因素,分析结果表明,反应谱的周期较小时,主要受距厂址较近的发震构造(地震构造区)、潜在震源区控制;随着反应谱周期的增大,距厂址较远的区域性发震构造、高震级潜在震源区的影响逐步增大。通过分解变量MRs对地震动年平均超越概率(HT4)的相对贡献,给出了变量的边际分布和联合分布,说明了变量的分布特征,指出了评价结果差异的主要影响因素为单位面积上高震级档地震年平均发生率和衰减关系的截断水平。根据核设施结构基于性能抗震设计方法的应用要求,以地震引起堆融的年平均概率为目标,推导了反应谱调整系数公式,根据推导结果和中美两国厂址地震危险性曲线变化趋势的对比分析,建立了适用于我国的核设施结构抗震设计反应谱调整系数的近似公式。核电厂地震概率安全评价中的主要问题是概率地震危险性分析中的不确定性处理和表达。论文分析了地震动预测模型截断水平对概率地震危险性分析结果的影响,讨论了厂址地震危险性分析结果的分布形式;验证了随机振动理论方法的适用性,采用随机振动理论方法研究了土层地震反应分析中土层剖面模型参数的不确定性对评价结果的影响;介绍了美国中东部地区概率地震危险性分析认知不确定性处理采用的逻辑树方法,实现了逻辑树模型中多方案的权重确定方法,讨论了该方法的适用范围。关于认知不确定性处理,针对逻辑树模型在实际工程应用中存在的逻辑问题。基于稳定大陆地区最大震级和高震级档地震年平均发生率的研究进展,随机生成完整的地震目录,从中进行小样本抽样,分析了6值和高震级档地震年平均发生率的分布范围,研究了逻辑树模型中相互关联节点分支间的组合问题。根据稳定大陆地区最大震级先验分布的研究成果,利用破坏性地震目录计算似然函数,采用Bayesian方法,初步估计了对我国内陆核电厂址有重要影响的长江中游地震带最大震级的分布。关于抗震裕度评价中的抗震裕度地震确定问题,分析了我国核电厂址的地震危险性背景和不同堆型的抗震设计特点,以某核电厂址为例,采用多种方法确定了抗震裕度地震。根据分析计算结果,按照抗震裕度评价的目的、厂址地震危险性特征、堆型的抗震设计特点,给出了适用的方法和抗震裕度地震谱型。
[Abstract]:The Fukushima nuclear accident reveals the possibility of serious nuclear accidents caused by external natural disasters and a alarm for the nuclear engineering community. Therefore, the seismic margin evaluation (SMA) or earthquake probability safety assessment (SPSA) is gradually carried out in the operation of China and the site of the nuclear power plant. From the determination of the design base ground motion, the seismic probability safety evaluation of the nuclear power plant and the safety analysis of the super design datum ground motion, 3 aspects are studied. The main problems existing in the design of base ground motion are the significant differences in the evaluation results of certain nuclear facility site determinism and probability theory. Some nuclear power plant sites are used as an example to analyze the control factors of the evaluation results of deterministic and probabilistic methods. The results show that the period of the response spectrum is smaller, mainly controlled by the seismotectonic zone near the site of the plant (seismic tectonic area) and the potential source area, and with the increase of the response spectrum period, the regional seismogenic structure far from the site and the high earthquake level potential. The influence on the source area is gradually increased. By the relative contribution of the decomposed variable MRs to the average transcendental probability (HT4) of the earthquake dynamic year, the marginal distribution and joint distribution of the variables are given, and the distribution characteristics of the variables are explained, and the main influencing factors of the difference of the evaluation results are the average annual occurrence rate and attenuation of the high seismic grade in the unit area. According to the application requirements of the nuclear facility structure based on the performance-based seismic design method and the annual average probability of the earthquake induced heap, the formula of the response spectrum adjustment coefficient is derived. According to the contrastive analysis of the derivation results and the change trend of the seismic risk curve of the China and the United States, a nuclear facility suitable for China is established. The approximate formula of the adjustment coefficient of the seismic response spectrum of the structural seismic design. The main problem in the seismic probability safety evaluation of the nuclear power plant is the uncertainty processing and expression in the probabilistic seismic hazard analysis. The paper analyzes the influence of the truncation level of the ground motion prediction model to the probability seismic risk analysis results, and discusses the seismic risk of the site. The distribution of the results is analyzed and the applicability of the stochastic vibration theory is verified. The influence of the uncertainty of the parameters of the soil layer profile model on the evaluation results is studied by the random vibration theory method, and the logic of the probabilistic seismic hazard analysis in the middle east part of the United States is introduced. The method of determining the weight of multiple schemes in logical tree model is realized by tree method. The scope of application of this method is discussed. On the logic problem in the practical engineering application of the cognitive uncertainty processing, the research progress on the average occurrence rate of the maximum earthquake level and the high earthquake grade in the stable continental area is random. A complete seismological catalogue is generated, and a small sample sampling is made from it. The distribution range of the average annual occurrence rate of the 6 value and the high earthquake grade is analyzed. The combination of the interrelated nodes in the logical tree model is studied. According to the research results of the prior distribution of the maximum magnitude in the stable continental area, the likelihood of calculating likelihood is calculated by the destructive seismic catalogue. The distribution of the maximum magnitude of the middle reaches of the Yangtze River, which has an important impact on the site of the inland nuclear power plant in China, is preliminarily estimated by using the Bayesian method. For example, seismic margin earthquakes are determined by various methods. According to the analysis and calculation results, according to the purpose of the seismic margin evaluation, the seismic hazard characteristics of the site and the seismic design characteristics of the heap type, the applicable methods and seismic margin seismic profiles are given.

【作者单位】：中国地震局地球物理研究所;
【分类号】：P315.9;TM623

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