The Modeling And Intelligent Diagnosis System Design Of Regeneration System Of Secondary Circuit In Nuclear Power Station

With the rapid economic development in our country,citizens are gradually paying more attention to environmental pollution problems.Domestic energy resources are gradually shifting from traditional energy sources such as thermal power to new energy sources such as nuclear power and solar energy.Nuclear energy is stable due to its energy supply and pollution-free Characteristics,and it's the focus of national energy construction.At the same time,since nuclear power is generated by the huge energy generated of nuclear fission,its requirements for the safety of the unit are particularly strict.Therefore,it is of great significance to monitor the condition of the system equipment during the operation of nuclear power.The traditional method of equipment monitoring is through the alarm of equipment parameters to find fault,but it can't accurately analyze the type of fault.With the development of technology,computer algorithms are used to realize the recognition of equipment abnormal status.In this context,taking a regeneration system of secondary circuit of a certain nuclear power plant of AP1000 as the research object,the intelligent diagnosis system of the conventional island heat recovery system is designed mainly for the regenerative heater equipment therein so as to improve the safety of the operation of the heat recovery system.The main contents and conclusions of this paper are as follows:(1)Based on the IMAGE simulation platform,the establishment of the simulation model of the conventional island heat recovery system of AP1000 was carried out.The main structure of the conventional island heat recovery system of AP1000 and the main modeling mechanism of the simulation platform are studied.The construction and commissioning of the conventional island heat recovery system model are carried out.The model includes thesteam turbine system,the regenerative heating system,the condensate system,etc.Main subsystem and basic PID control device.The model parameters are similar to corresponding design values under 50%,70% and 100% load,which basically meet the needs of simulation experiment.(2)Through the analysis of the failure mechanism of the secondary loop regenerative system,first of all,the leakage of the piping system,the short circuit of the water chamber,the sticking of the exhaust valve,the sticking of the exhaust valve,the fouling of the heat transfer tube,and the trap opening were studied.The basic principle of the common faults of these types of regenerative heaters,and the trapping of traps,was followed by the establishment of a regenerative system fault model on the simulation platform based on the failure mechanism.Finally,the failure model was analyzed based on the loads of 50% and 70% and 100%,the parameters of each typical failure of each stage of Regenerative Heater were changed,and the characteristics of the corresponding parameters of different failure levels were studied.(3)According to the fuzzy theory,the fault symptom is summarized,the S function is used as the calculation formula of fault symptom confidence,and then the fault diagnosis rule is formulated based on the expert system production logic expression method.Compared with the traditional diagnosis scheme,The factors such as the layout of measurement points in actual site and the weight influence of different faults on the symptom parameters should be worked out.In the aspect of diagnosis strategy,the order of diagnosis logic is designed by AHP,and finally the least square method is used to correct the actual field reference value to improve the adaptability of diagnosis system.(4)The research and development of fault diagnosis software are carried out.Firstly,based on SQL SEVER database,the basic scheme of database is designed to ensure the storage and recall of data.Then,based on human factors engineering principle,software interface is designed,Finally,C #object-oriented programming language is used to design the diagnostic software through the program design of the three-tier architecture.The reliability of the fault diagnosis software is verified through the fault data of the simulator.