Numerical Calculation Of Source Term Of Activated Corrosion Products Cased On Multi-Nuclear And Multi-Node

Under normal operating conditions,activation of corrosion products(ACPs)is an important radioactive sources of the main loop of the water cooled reactor,the reactor shield design,personnel protection and accident analysis has important influence,therefore accurate calculation of activation of corrosion products in the main changes over time and space distribution in the cooling circuit is of important theoretical and practical significance.Reactor activation corrosion products produced in the main circuit and migration is a very complicated process,related to the source term calculation and analysis of nuclide,multistage nuclear reactions,multi-node coupling calculation,the essence of mathematics is to solve the large-scale,strong rigidity,nonlinear ordinary differential equations,which is the core of this article needs to solve problems.This paper conducts research based on the CATE program developed by IRPS laboratory of north China electric power university.The calculation model applied by this program has limitations in nuclide type(more than 100),node number(3 nodes)and calculation method(analytical method).The calculation accuracy and engineering applicability need to be improved.In this paper,the main behaviors of activated corrosion products in the reactor main circuit,including corrosion,dissolution,deposition,activation and decay,were studied,and the calculation process of correlation coefficient was clarified.Then,the calculation of multiple nuclides is realized by reading EAF-2007 database in the pre-processing and constructing activation corrosion matrix.Through the analysis and research of theoretical model,the primary circuit is divided into more detailed regions according to different conditions to realize multi-node calculation.After considering multi-nuclides and multi-nodes,the calculation of activated corrosion becomes a large-scale,strongly rigid,nonlinear ordinary differential equations problem,which cannot be calculated by linear chain analysis method.Therefore,based on the rigid and stable GEAR method,this paper developed a numerical solver and applied it to CATE program,so as to realize the calculation of source terms of activated corrosion products with multiple nuclides and nodes.ITER LIM-OBB loop and qinshan main loop are selected to verify the effect of multi-nuclide and multi-node numerical calculation.The results show that the increase of nuclides and types of nuclear reactions makes the calculation results more accurate and the types of materials that can be simulated by CATE program are more extensive.The realization of multi-node model can not only improve the calculation accuracy,but also meet the requirements of dividing nodes according to different material,flux,temperature and other conditions in engineering design.In addition,from the accuracy and efficiency of the calculation results,GEAR numerical method is also very appropriate.This paper is of certain value for the numerical calculation of the multi-nuclide multi-node model for activated corrosion products,and it also improves the engineering applicability of CATE program.