Application Of Thermal Stratification Analysis In Nuclear Power Plant Of Priessurized Water Reactor

With the development of nuclear power technology and the accumulation of operating experience in nuclear power plant,the thermal stratification and the thermal cycle,striping attracts more and more attention.In order to ensure the long-term safe operation of nuclear power plants,it is necessary to identify and analyze the pipeline in the design stage,which is easy to be affected by the phenomenon of thermal stratification.Through the analysis on the mechanism of thermal stratification,this paper has summarized the screening method for identifying the pipeline or pipe line which is potentially affected by the phenomenon of thermal stratification.Through this screening method,the pipeline or piping system where the thermal stratification happens is initially determined in a pressurized water reactor nuclear power plant.The numerical simulation can be carried out by means of three-dimensional CFD software for these pipelines or piping system,and the weaknesses in design can be identified through the calculation and analysis.Finally,the corresponding mitigation measures are suggested.The level 4 ADS pipeline in AP1000 nuclear power plant have been evaluated,and then the improvement suggestions finally is given by using CFX software.