Steam Generator Aging Management Research Of Qinshan Phase Ⅲ CANDU Reactor

This paper does research on aging management of steam generator (SG) in Qinshan Phase III, a CANDU nuclear power plant (NPP). Steam generator is one of the most important nuclear Class-1 equipments in nuclear power plant systems. It contains maximum pressure boundary area in primary heat transfer system. The integrity of SG affects directly the safety and economics of nuclear power plant, moreover SG cannot be replaced during the whole NPP life. SG is selected and chosen as one of the equipment for aging management in nuclear power plants.First of all, the investigation and analysis are conducted in SG structure of CANDU reactor, process of designing、manufacturing and operation parameters. The failure models occurred in same kind of international steam generators and their working experience in developing SG aging management are investigated. Secondly, re-circulation type of SG is thoroughly analyzed for the performance worsening mechanism.Next, SG Aging mechanism of Qinshan Phase III is deeply analyzed based on the above results. During the research, 10 SG parts necessary to conduct aging management are selected in accordance with recommended rules of IAEA and a certain of principles. The aging mechanism classification is introduced into aging management for different components. Each SG components is analyzed and researched for their aging mechanisms through detecting test, contrast and induction. Especially, the research on the corrosion mechanism of Incoloy-800 heat transfer tube determines the aging mechanisms of each SG components, and also clarifies classification of SG Aging mechanism, aging locations, aging conditions, aging causes and main counter measures.Finally, this paper puts forward the detecting testing and delaying measures required to be introduced and the needs to develop aging evaluation aftertime. A collecting list of Aging mechanism of Qinshan Phase III SG components is also prepared. In addition, the paper brings forward the intention to structure Steam Generator Aging Mechanism Data Base (SGAMDB) in order to lay a solid foundation of PDCA Management System, which takes SGAMP as the core.Since SG aging management is in the process of continual improving and consummating, aging management shoulders heavy responsibilities and has long way to go. However, it has a significant realistic importance to the safe, reliable and economic operation of nuclear power plant. The research results in this paper are in possession of reference value in equipment aging management of Qinshan Phase III.