Minimal cut set based system for monitoring faults of nuclear reactors

Abstract

A minimal cut set based system for monitoring faults of nuclear reactors provides decision support for fault diagnosis of nuclear reactor systems and can also be applied to related fields of aviation, navigation, chemical engineering and the like. The system is mainly composed of a model analyzer, a task dispatcher, a parallel machine, a result collector, a cut set analyzer and a fault diagnostor. The system has the advantages of being high in storage efficiency, fast in calculation, easy to deploy and maintain and the like. Compared with the prior art, the system performs parallel calculation on each layer of nodes of fault trees through the parallel machine, so that the calculating speed and accuracy are improved to a large extent, and faults of nuclear reactors can be diagnosed and monitored effectively.

Description

technical field [0001] The invention relates to a nuclear reactor fault monitoring system based on minimum cut sets, which belongs to the field of reliability and fault diagnosis of complex nuclear reactor systems. Background technique [0002] The fault tree analysis (FaultTreeAnalysis, FTA) method was first developed by Bell Telephone Laboratories in 1964, and was applied in the aerospace industry in the early 1960s. Since then, it has developed rapidly and has become one of the indispensable analysis tools in the fields of reactors and chemicals. . Fault tree analysis is to analyze various factors that may cause system failure during the system design process, draw a logical block diagram, and then determine various combinations and occurrence probabilities of system failure causes, and take corresponding improvement measures, which is to improve A design analysis method for system reliability. The various combinations of system failure causes are the minimum cut set of...

AI Technical Summary

Problems solved by technology

At present, the minimum cut set method of fault tree is mainly divided into the following four categories: (1) The first category is the traditional uplink method and downlink method. Because this kind of method searches all the paths of the fault tree, the fault tree path of the ultra-large complex system The number is as high as hundreds of thousands, and the calculation speed is basically unbearable; (2) The second type is the method based on Petri net and the matrix method. The solution method based on Petri net is actually a variant of the downlink method, and the number of paths has not decreased. Only in the form of an association matrix, the calculation efficiency is still very low; the matrix dimension of the matrix method is too large, which makes it impossible to store in general computer memory, and the amount of calculation is also very large; (3) The third category is based on binary decision diagrams 1. The method of zero-compression binary decision diagram, although the storage efficiency of this method is higher than the above method, but because the calculation process produces more intermediate results, the calculation amount is very large, and the calculation speed still needs to be improved; (4) the fourth category It is a branch deduction method proposed in recent years. The branch deduction method selects event combinations based on certain rules and judges whether the fault tree structure function is satisfied. Although the solution idea of ​​this method is different from the above method, the solution speed depends on the rationality of event combination selection. The number of judgments required under unreasonable circumstances is astonishingly large, and its efficiency has a certain degree of uncertainty

[0004] For large complex systems, such as fault tree models of nuclear reactor systems, the calculation speed and accuracy of these methods still need to be improved, especially for super large complex systems such as nuclear power plants and nuclear reaction experimental devices

After testing the current international mainstream representative commercial systems RiskSpectrum, CAFTA, and XFTA based on the above methods, a super-large nuclear power plant fault tree with 12,000 logic gates and 8,000 bottom events needs to be calculated in 10-20 minutes. The calculation speed is too slow to achieve timely response, which affects the timely identification and diagnosis of these system failures. At the same time, due to the large amount of calculation, the truncation strategy has to be adopted, which leads to certain errors in the final results and is not accurate enough, which affects the system failure. judgment

Images