A Modular Method for Obtaining the Failure Probability of the Top Items in the Fault Tree of Nuclear Power Plant

Abstract

The invention belongs to the technical field of fault analysis and relates to a modularized method for obtaining a nuclear power station fault tree top item failure probability. The method comprises the steps of: establishing a fault tree; carrying out modularization on the fault tree; converting the modularized fault tree into a BDD structure; and carrying out traversal on the BDD structure containing modules. The modularized method for obtaining the nuclear power station fault tree top item failure probability is a fault tree analysis method low in energy consumption and high in speed, the most simplified BDD structure subjected to absorption simplification is transverse, all minimal cut sets (MCSs) are directly obtained, and non-cross cut sets of the MCSs are simultaneously obtained; and compared with a conventional BDD method, the method provided by the invention is higher in calculation efficiency and more precise in result. The modularized BDD method has the advantages that the scale and number of the complex fault trees are reduced to lower the calculation cost, the memory consumption of the conventional BDD method is effectively reduced, and the calculation efficiency is simultaneously improved.

Description

technical field [0001] The invention belongs to the technical field of fault analysis, and relates to a method for modularly obtaining the failure probability of items at the top of a fault tree in a nuclear power plant. Background technique [0002] The key to Fault Tree Analysis (FTA) is risk analysis. In the nuclear industry, fault tree and event tree models have been widely used in the probabilistic safety analysis of nuclear power plants, and almost all risk analysis studies and calculations rely on these models. In order to design and build systems that meet safety standards, such as nuclear power plant risk monitoring systems, it is necessary to know the safety of these systems at the time of design, and take appropriate measures for systems that do not meet safety requirements in a timely manner. With the development of technology, various control and fault-tolerant technologies are widely used, and the structure of many systems is increasingly complex, showing the ...

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Problems solved by technology

But in practical engineering applications, it is almost impossible to directly use the BDD method without any approximate processing, because there is a combinatorial explosion problem in the process of transforming the fault tree into a BDD structure, and the BDD structure of a complex fault tree is so huge that the computer The memory cannot be stored, and the number of disjoint cut sets of a huge BDD structure is also very large. It is very time-consuming to find all the disjoint cut sets and calculate the results

In addition, the fault tree analysis not only needs as accurate quantitative analysis as possible, but also needs to obtain the MCS qualitatively. Obviously, the disjoint cut set obtained without approximate processing is not the MCS of the fault tree

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