Structural Analysis and Evaluation on the Containment Structure of the Pressurized Water Reactor Plants with Consideration of the Aging Effects

摘要

The containment structure of a nuclear power plant (NPP) with pressurized water reactor (PWR) is very critical and the last physical barrier and it is irreplaceable equipment, such that the containment design service life is directly related to the nuclear power plant life. Earlier, the 1000MW PWR nuclear power plants were all designed with the design life period of 40-year considered in China, but now the 60-year requirement of the service age of a plant is put forward in order to improve the operation period of nuclear power plant. Therefore, a comprehensive analysis of the impact on the containment structure durability of several factors is conducted and the main influence factors are extracted as follows: the long term effect of the material properties; loads change caused by design aging change; comprehensive durability evaluation on structure materials. Firstly, the design basis for a 60-year design life should be determined according to the requirement. Then, re-evaluate loads and strengths of the materials etc. to ensure its applicability and adjustment method if needed. At the same time, because of the increase of the design service life, the analysis of the parameters closely related to time factor, such as shrinkage, creep, size of the prestressed force loss effect based on the design life of 60 years should be performed. Finally, the technical requirements for structural durability to meet 60-year old are explored and proposed in this paper. As an example, a PWR containment in China is introduced and evaluated based on the 60-year service age, and the evaluation methodology, steps and results are released in this paper. It could be a very good reference, and could also be applied to other assessments on service life extending of the civil structures of nuclear facilities.