Improvement Of Maintenance Strategy For Electrical Equipment Of HTR-PM Based On RCM

Nuclear power generation is an important part of electric energy with high efficiency,economy,environmental protection and safety.At present,the nuclear power plants in service all over the world have obtained huge economic benefits,and the nuclear power technology is becoming more and more mature,the safety of nuclear power has been greatly improved.However,once a nuclear leakage accident occurs,it will lead to serious environmental pollution and ecological damage.Therefore,how to ensure nuclear safety is the primary task of nuclear power plants.High Temperature Reactor-Pebblebed Modules(HTR-PM)is recognized with high inherent safety characteristics in the world.However,there are few operational reactors in the world at present,and there is relatively lack of experience in equipment safety management,which requires comprehensive and meticulous research.At present,RCM,which stands for Reliability Centred Maintenance,is widely used in the safety management and maintenance strategy analysis of other reactor type nuclear power equipment.This paper mainly aims at the first demonstration project of HTR-PM,combined with the RCM method and experience feedback method of introducing key sensitive equipment,studies the maintenance strategy of the key sensitive electrical equipment of the HTR-PM nuclear power plant,in order to improve the operation reliability of the equipment.Based on the reliability management method of electrical equipment in conventional nuclear power plants,this paper analyses the differences between reliability-centered maintenance(RCM)and traditional maintenance,and the core issues of RCM.The analysis process of RCM is described in detail,the selection principle of key sensitive equipment is given,and the important role of empirical feedback system in equipment reliability analysis and its application method are studied.The reliability index of RCM analysis is given.Secondly,the maintenance strategy of equipment reliability management is analyzed,and the maintenance strategy used to manage failure mode and manage the consequences of failure in maintenance decision logic is introduced.Based on the current operation of plant equipment,the electrical equipment of HTR-PM is classified,the switchgear of main helium fan converter in AC medium voltage auxiliary power system with HTR-PM accident-prone is selected as the key sensitive equipment,and the corresponding maintenance strategy and improvement measures are put forward.Through the analysis of its main functions and auxiliary functions,functional failures,failure modes,failure effects and consequences,a general preventive maintenance strategy is made.On this basis,the preventive maintenance strategy is improved by analyzing the statistical data of equipment failure during initial stage of equipment operation and referring to the experience feedback results of similar products in the nuclear energy industry.By improving the maintenance strategy,the average annual maintenance cost of the equipment decreased from 183000 yuan in the early stage of operation to 54000 yuan,reducing by 70.5%,which saved the cost of equipment maintenance.And at the same time,the equipment failure rate has also decreased from 10.40×10-5in the early stage of operation to 9.54×10-6,reducing by 90.8%,which improved the operation reliability of the equipment.This paper puts forward a new method and idea for reliability management of electrical equipment in HTR-PM,and lays a theoretical and engineering foundation for the next step of using RCM method to analyze preventive maintenance strategies of other electrical equipment and systems.