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重大危险源概率风险评价应用研究
Applied Study on Probability Risk Assessment of Major Hazards
【作者】 束钰；
【导师】 陈全；
【作者基本信息】 天津理工大学 ， 安全技术及工程， 2011， 硕士
【摘要】 概率风险评价方法作为一种真正意义上定量评价方法在众多安全评价方法中有明显的优势。目前,在国内外的重大项目中被大量的应用,并得到了专家和工程技术人员的认可。但由于一些缺陷,使得该方法并没有在日常的危险品评价项目中应用。论文在学习现有概率风险评价方法的研究成果和实践积累的基础上,针对方法存在的问题进行了初步的改进。在一定程度上拓宽了该方法的应用范围。对于促进我国安全评价事业的发展具有一定的理论和实践意义。概率风险评价方法分主要分为,危险源辨识、概率估计、事故后果评估、确定可接受风险、对评价结构反馈5个方面的内容。本文主要从概率估计、事故后果评估、评价后管理这几个方面进行讨论。在论文最后用一个民爆仓库的重大危险源作为实例,说明对传统概率风险评价方法的改进是科学的。主要的内容包括:1、针对概率风险评价时基本的失效数据匮乏,且获得效率低下的问题。应用到了模糊数学的方法对单一的概率数据处理成为一个模糊化的置信区间。这样只要应用相关的数据确定事故发生的大概数值。再结合评价人员的经验确定事故概率值与所评价项目多的隶属度,就可以将用这个置信区间来分析说明事故的发生的频率。这样就一方面满足了概率风险评价方法要求的准确性,另一方面又可以幅度提高评价的效率。2、概率风险评价的核心是事故树,但事故树自身存在着一些缺陷。这在一定程度上制约了概率风险评价方法的应用。针对事故树方法不能分析事故的多元状态、相关子事件影响和事故发展的过程这三个主要矛盾。应用到了贝叶斯网络方法和事件序列图方法来修正和补充。3、本文讨论了文实例所用的方法,即燃烧和冲击波的后果影响。对以燃烧,本文主要采用了元胞自动机的方法结合模糊数来仿真分析火灾蔓延的趋势。解决了传统方法不能仿真分析火灾蔓延趋势的劣势。对以爆炸,应用有限元计算对爆炸后冲击波的影响进行分析。由于仓库应用了防护措施,应用传统方法不能分析这些防护措施对爆炸后的冲击波是否有效性控制。4、可接受风险的确定是一件很困难的事情。在各个国家都是很困难的事情。在本文中,综合考虑各方面因素,应用我国重大危险源分级标准和国外同行业标准进行计算确定了一个社会可接受风险度。从计算结果上看是符合实际评价需要的。
【Abstract】 Probability Risk Assessment (PRA) is a quantitative evaluation and its advantages have been emerged when compared with other safety assessment methods. At present, this method has been applied in significant projects all over the world. However, PRA is not applied in the field of hazardous chemicals because of its deficiency.Based on the practices accumulation of PRA, some improvements have been proposed which point to the problems existed. Meanwhile, application range of PRA is wider than before to some extents. This has a positive effect to develop safety assessment in our country.Probability Risk Assessment can be classified into 5 parts, including Hazard identification, probability estimates, the accident consequence assessment, determine acceptable risk and the feedback on the evaluation of the structure. In this paper, it discussed and focused on probability estimates, the accident consequence assessment, the feedback on the evaluation of the structure. An example about fireworks warehouse as major hazards is quoted to demonstrate that it is scientific and effective to improve the traditional PRA. The main contents include:1. Fuzzy Mathematics solved deficiency of basic data and problems of obtaining data ineffectively because of its functions to convert single probability data into confidential interval. Thus, applied Fuzzy Mathematics into PRA can satisfy the precision of PRA and improve the assessment efficiency as well.2. The core of PRA is FTA, however, FTA has some defaults and limits the application of PRA to some extents. In this paper, Bayesian networks method (BN) and Event Sequence Diagram (ESD) can solve and correct 3 main contradictions, including multiple state of analyzing accident, relative effects of sub-event and process of accident development. All of these 3 parts cannot be analyzed by FTA.3. In this paper, effects of fire spread and shock are analyzed through an example. Cellular Automata (CA) and Fuzzy Mathematics simulation combined method is used to analyze the trend of fire spread when discussing fire spread. Effects of shock after exploration are analyzed by FEM. These methods solve the disadvantages of traditional one which it is disable to simulate.4. It is difficult to confirm acceptable Risk all over the world. In this paper, acceptable risk degree is calculated and determined by considering each factor. Based on the results, all of these acceptable risk degrees can satisfy the needs of practical assessment.