Reliable Analysis And Safe Assessment For The Structure Of Nuclear Power Crane

The nuclear power crane is the key equipment in the construction and operation of the nuclear power plant.It is responsible for lifting heavy equipment and reactor refueling in nuclear reactors during construction and maintenance of nuclear islands.As the main bearing structure in the whole machine,no matter from the perspective of the performance of the whole machine or from the perspective of safety and reliability,the main beam structure has an extremely important influence on the nuclear power crane.The main basis for the main beam structure design check is the “Crane Design Code”.However,in the crane structure design process,not considered due to the manufacturing process and the level of technical limitations,improper operation and other uncertain factors,such as lifting load,structure size and material properties,which may lead to the traditional design method of the reliability can not meet the requirements of crane.Therefore,it is of great significance to analyze the structural reliability,to study the structural design method based on reliability,and to guarantee the reliability and safety of nuclear power cranes.This project relies on the project of Liaoning major equipment collaborative innovation center.In this paper,the third generation of nuclear power cranes as the research object,the mechanical model and finite element model of the main beam structure were established.The failure modes and vulnerable areas of the main girder structure were determined through the calculation results of the two models.This paper made a comparative study of structural reliability methods to establish a probability-non-probabilistic reliability model and determine the uncertain variables in the nuclear power crane.Then the reliability index of the strength,stiffness and fatigue strength of the main beam structure were calculated respectively.The Monte Carlo method was used to study the effect of uncertainties on the structural reliability of the main girder.The degree of influence of various uncertainties on the structural failure was analyzed,and a reasonable structure size was given to improve the reliability of the nuclear girder crane girder structure.Then the initial values of some parameters of the main beam structure were changed and the reliability calculation was carried out again.The results show that the reliability of the main beam structure has been effectively improved after the modification of parameters,which proves the feasibility of improving the reliability of the structure through this method.According to the calculated reliability index of the main beam structure,by using AHP and fuzzy comprehensive evaluation method to evaluate the safety ofthe main beam structure.The relative weight of each evaluation index and the comprehensive evaluation result of the main beam structure are obtained,which can provide reference for the periodic maintenance and optimization of the type of crane during service.