共查询到17条相似文献,搜索用时 234 毫秒
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《核标准计量与质量》2016,(1)
文章以N36锆合金管材试制工艺流程为对象,利用FMECA进行工艺设计优化,对工艺故障模式进行系统地识别、分析了故障模式成因及对后续工序和产品使用的影响,分析了风险优先数(RPN),建立了FMECA分析表,识别出了高RPN数值的故障模式及薄弱工艺环节。以降低RPN为目标,采取了改进措施。结果表明:(1)N36锆合金管材研制过程应用FMECA能够系统识别薄弱工艺环节,对工艺设计优化起到有效的作用;(2)FMECA分析表明,铸锭熔炼和锻造、管坯轧制等过程集中了高RPN值的故障模式,将其作为关键工艺实施工艺确认和工艺优化可降低RPN;(3)工艺设计FMECA是一个迭代过程,随试制进展应不断采取有效的改进措施。 相似文献
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实验包层(TBM)输出吹洗气前处理系统将安装在国际热核聚变实验堆(ITER)装卸TBM的通道内(Port Cell),它的功能是将TBM输出的含氚吹洗气进行过滤、除HTO、冷却、调流量等处理,处理后输出到氚提取系统。介绍了该系统的工艺过程和系统组件,以氚释放危险为判据,对该系统进行FMECA(故障模式、影响及危害性分析),并作出分析表。找出了几种故障模式或薄弱环节,进行了尝试性的风险优先数和故障模式危害度计算,提出了设计改进措施和使用补偿措施;最后确定了需要重点关注的4种需导致释非正常过量释放的潜在故障模式。这些故障分析为降低系统氚过量释放危险设计提供了依据,也为TBM其他附属氚系统的安全分析奠定了基础。 相似文献
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介绍中国实验快堆通风控制系统的功能和组成结构,并本文以故障模式影响分析(FMEA)和FTA为基础进行了可靠性分析,采用故障树进行定量分析和计算,得到该故障树的失效概率和最小割集,从而为中国实验快堆通风系统风险管理提供数据支持。 相似文献
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非能动余热排出(PRHR)系统是AP1000核电站重要安全系统之一。采用故障树方法对该系统可靠性进行评价,得到系统可能失效机理,并运用Risk Spectrum软件进行定量分析,得出系统失效概率约为9.215×10-5。结果表明,余热排出热交换器入口管线上电动阀失效关闭是导致系统失效的最主要因素。基于计算结果提出两种方法对系统进行优化:1) 在另一回路增加同样1套PRHR系统;2) 在原有系统基础上增加一PRHR热交换器。通过故障树分析计算,并分别从系统可靠性、复杂性、经济性等方面对两种方法进行比较发现,方法2更具可行性,建议工程上采用此方法对系统进行优化。 相似文献
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《Annals of Nuclear Energy》2005,32(5):479-492
We have developed a method for detecting and diagnosing a disk wear failure and a foreign object failure among the various failure modes of check valves. The method is based on the acoustic emission sensors which can detect the sound wave of the leakage flow and the estimation of the power spectral densities with an auto-regressive model. For validating the method, we implemented a hydraulic test loop with an artificially failed check valve. We have found that the frequency spectrums from the acoustic signals are strongly dependent on the failure modes of the check valve and that they are nearly independent of the failure size and operating pressure through an estimation of the power spectral density with an auto-regressive signal processing model. In addition, the root mean square values of the acoustic signal and the amplitudes of the power spectral density as well as the loop pressure have a strong dependency on the failure size in each failure mode of the check valve. We developed a diagnosis algorithm by using neural network models in order to identify the type and size of the failure in the check valve. The diagnosis algorithm consists of a hierarchical model composed of three back-propagation neural networks. The results of our research and the experiments show that the diagnosis algorithm is proven to be a good solution for identifying the failures of the check valves without any disassembling work. 相似文献
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《Fusion Engineering and Design》2014,89(2):88-93
ITER is the first worldwide international project aiming to design a device that proves the physics and technological basis for fusion power plants to produce nuclear fusion energy. In the project, the RAMI approach (reliability, availability, maintainability and inspectability) has been adopted for technical risk control to guide the design of components in preparation for operation and maintenance. RAMI analysis of the ITER central interlock system (CIS), which shall provide investment protection for the ITER systems was performed on the conceptual design. A functional breakdown was prepared in a bottom-up approach, resulting in the system being divided into 5 main functions and 7 sub-functions which are described using the IDEFØ method. Reliability block diagrams (RBDs) were prepared to estimate the reliability and availability of each function under stipulated operating conditions. Initial and expected scenarios were analyzed to define risk-mitigation actions. The inherent availability of the ITER CIS expected after implementation of mitigating actions was calculated to be 99.86% over 2 years, which is the typical interval of the scheduled maintenance cycles. A failure modes, effects and criticality analysis (FMECA) was performed to initiate risk mitigation action. Criticality matrices highlight the risks of the different failure modes with regard to the probability of their occurrence and impact on operations. It was assessed that the availability of the ITER CIS, with appropriate mitigating actions applied, meets the project availability requirement for the system. 相似文献
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保护系统是保证中国先进研究堆(CARR)安全的重要系统之一,它的高可靠性是保证其完成预期功能的重要条件。本工作以保护系统为研究对象,利用故障模式及影响分析和故障树等可靠性分析方法,建立相应模型,对保护系统进行了定性和定量的分析,得到了保护系统发生故障的概率和最小割集,其可靠性水平达到了CARR工程的设计要求,验证了设计,为CARR其他系统分析和验证奠定了基础。 相似文献
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主蒸汽隔离阀是核电厂核岛与常规岛间主蒸汽管线上最重要的隔离设备,主要介绍了秦山第二核电厂1/2号机组主蒸汽隔离阀控制系统功能及控制原理、故障模式分析。结合历史故障统计得出系统的薄弱点—限位开关,并对限位开关故障失效机理和根本原因分析进行了重点阐述,最后针对系统的可靠性提升从人、机、料、法、环5方面提出了改进措施,对国内其他在役核电厂主蒸汽隔离控制系统维护和改进有一定的借鉴和参考意义。 相似文献
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应急供电系统是保证中国先进研究堆(CARR)安全的重要系统之一,它的高可靠性是保证其完成预期功能的重要条件。本文以应急供电系统为研究对象,利用故障模式及影响分析和故障树等可靠性分析方法,建立相应模型,对应急供电系统进行定性和定量的分析,得到了该系统发生故障的概率和最小割集,找出了薄弱环节,提出了有效提高该系统可靠性的建议和措施,为保证CARR安全可靠地运行提供支撑。 相似文献
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Fault tree analysis (FTA) is a graphical model which has been widely used as a deductive tool for nuclear power plant (NPP) probabilistic safety assessment (PSA). The conventional one assumes that basic events of fault trees always have precise failure probabilities or failure rates. However, in real-world applications, this assumption is still arguable. For example, there is a case where an extremely hazardous accident has never happened or occurs infrequently. Therefore, reasonable historical failure data are unavailable or insufficient to be used for statistically estimating the reliability characteristics of their components. To deal with this problem, fuzzy probability approaches have been proposed and implemented. However, those existing approaches still have limitations, such as lack of fuzzy gate representations and incapability to generate probabilities greater than 1.0E-3. Therefore, a review on the current implementations of fuzzy probabilities in the NPP PSA is necessary. This study has categorized two types of fuzzy probability approaches, i.e. fuzzy based FTA and fuzzy hybrid FTA. This study also confirms that the fuzzy based FTA should be used when the uncertainties are the main focus of the FTA. Meanwhile, the fuzzy hybrid FTA should be used when the reliability of basic events of fault trees can only be expressed by qualitative linguistic terms rather than numerical values. 相似文献