在核电厂的设计中，抗震设计是一个十分关键的环节。在地震风险评价方法中，地震易损性分析是后续工作的一个重要基础，为地震概率安全评价(PSA)与抗震裕量评价(SMA)都提供了数据。地震易损性分析中所得到的设备的高置信度低失效概率(HCLPF)能力，是判断设备实际抗震能力的关键参数。目前国外对于易损性分析的研究，在美国核管会(NRC)与美国电力科学院(EPRI)提出相关规范与相关导则之后，大多停留在针对类似设备的应用上。国内对于易损性分析的研究则更少，在2012年才开始要求对地震事件进行地震安全裕量评价。而在此之后易损性分析也作为PSA与SMA中的一个重要过程受到重视，但也仅限于对于规范的应用。因此，研究易损性方法在各类设备中应当如何实施是相当必要的。本论文首先对国际上较为通用的EPRI提出的易损性分析评价方法进行了详细的解析，分析了其中的数学模型原理，以及其参数化计算方法的应用过程。对其中各个相关的易损性因子的成因以及计算方法，进行了分类探讨。以辅助给水系统(ASG)水箱作为储液容器设备中的范例，本论文进行了从抗震计算到易损性参数化计算的完整的易损性分析过程。针对易损性分析中反应谱形状因子以及设备能力因子等几项因子，本文提出了针对特定设备的计算方法。利用设备抗震计算中所获得的各项数据开展针对性的易损性分析，使得所得结果更接近于设备的真实情况，而不仅仅局限于应用规范中所推荐的数值。在现有的针对单一失效模式的易损性分析基础上，本文提出了考虑多种失效模式因素的易损性分析方法。在多种失效模式各自独立的假设前提下，利用抽样的手段，进行了综合考虑多种失效模式后的HCLPF值计算，并对计算中抽样过程的方法应用进行了总结。结果表明该计算方法在一定次数抽样后可达到收敛，并且可得到一个更为保守的HCLPF值。本论文针对高温气冷堆所特有的具有较强的材料非线性、整体呈散体结构形式的石墨构件，利用已有的抗震计算模型以及失效概率模型进行了石墨构件的地震易损性分析。对于石墨构件的抗震计算方法，针对其中参数获得过程的不确定性，提出了抗震计算过程中的易损性因子不确定性计算方法。对于石墨构件的能力评价，本文提出了用函数来描述其失效率评价模型的不确定性的方法，并将其与传统的易损性因子相结合，绘制出石墨构件的易损性曲线，最终得到了其HCLPF值，证明了石墨构件是较为安全的。
Seismic design plays a very important role in the design of nuclear power plants. In the seismic risk assessment method, seismic Fragility analysis is an important basis for the subsequent work. It provides data for seismic Probability Safety Assessment (PSA) and Seismic Margin Assessment (SMA). The High Confidence Low Probability of Failure (HCLPF) capability of the equipment, which is obtained from the seismic Fragility analysis, is a key parameter for judging the actual seismic capacity of the equipment. At present, international studies on Fragility analysis have been focusing on the applications of relevant specifications and related guidelines provided by the United States Nuclear Regulatory Commission (NRC) and the American Electric Power Research Institute (EPRI) for similar equipments. There are few studies on Fragility analysis in China. It is not until 2012 that the earthquake safety margins assessment is required for earthquake events, after which Fragility analysis is also considered as an important process in PSA and SMA. But its application is also limited to the application of the specifications. Therefore, it is necessary to study how the Fragility method should be implemented on various type of equipment.This thesis explicates the internationally commonly used Fragility analysis method proposed by EPRI at first. Its mathematical model principle and the application process of the parametric calculation method are analyzed. The causes and the calculation methods of the various factors are classified and discussed. Taking the auxiliary water supply system (ASG) water tank as an example of the liquid storage container, this thesis carried out a complete Fragility analysis process ranging from the seismic calculation to the Fragility parameterization calculation. Focusing on several factors in Fragility analysis, such as the response spectrum shape factor and the equipment capability factor, this thesis has proposed a specific device-based calculation method which can make use of various data obtained from equipment seismic calculation rather than just take the recommended values in the specification. The results are closer to the real situation of the equipment. Based on the existing Fragility analysis for a single failure mode, this thesis has proposed a Fragility analysis method that considers multiple failure mode factors. Under the assumption that each failure mode is independent, the sampling method is used and the HCLPF value are calculated after considering multiple failure modes. The application of the sampling process in the calculation is summarized. The results show that the calculation method can reach convergence after a certain number of sampling, and a more conservative HCLPF value can be obtained.This thesis also analyzes the graphite components in High-Temperature Gas-Cooled Reactor, which have strong nonlinear material properties and construct a multi-body structure. Based on the existing seismic calculation model and the failure probability models, the seismic Fragility analysis of graphite components is carried out. For the seismic calculation method of graphite components, the uncertainty calculation method of the Fragility factor in the seismic calculation process is proposed based on the uncertainty of the parameter obtaining process. For the evaluation of the ability of graphite components, a particular method has been proposed which describes the uncertainty of the failure rate model as the function of earthquake acceleration. This method has been combined with the traditional Fragility factors and then the Fragility curve of the graphite components can be obtained. Finally the HCLPF value of the graphite components is calculated, which proves that the graphite components are safe enough.
