R&D On An Analytical Code For Flow Induced Vibration And Fretting Wear Of Heat Exchange Tube In Steam Generator Of Fast Reactor

The steam generator is a key facility for fast reactors and has the function of transferring heat from the sodium coolant of the second circuit to the water and steam of tertiary circuit.The damage of steam generator heat exchanger tube will make sodium and water contact,which may affect the safety operation of nuclear power plants.To ensure the integrity of the heat transfer tube is very important.For heat exchange tubes,the washing effect of the liquid sodium on the shell side is one of the main causes of tube wall abrasion,rupture and fatigue failure,especially the lateral flow of sodium at the inlet and outlet of the steam generator.The calculation of fretting wear is an important part of the life assessment.In 1991,the exchange tube of Japan's Mihama 2 nuclear power station was damaged due to fretting wear of the vibration-proof strip.Flow induced vibration and fretting wear of heat exchange tubes are closely related to the section-diameter ratio,the arrangement of tube bundles,and the flow field on the shell side.Flow-induced vibration assessment and fretting wear calculation are required at design time.There is no flow-induced vibration and fretting wear calculation software for the actual structure and operating conditions of the fast reactor currently.In addition,there are many design specifications for flow induced vibration.How these specifications are applied and the evaluation results under specific design parameters need to be further analyzed.In this paper,a three-dimensional flow field velocity processing method is proposed for the actual working conditions of heat transfer tubes of fast reactor steam generator.The three mechanisms of vortex shedding,turbulent excitation and fluid elastic instability are studied.A modified Achard fretting wear model is applied.With reference to ASME,TEMA,GB151 and a large number of related research literature,we analyzed the real structure and working conditions of the fast reactors and establish a reasonable and complete flow-induced vibration and fretting wear calculation mathematical model.The software of flow induced vibration assessment and fretting wear for heat exchanger tubes of fast reactor steam generator was developed,providing reference for designers.This article also summarizes the mainstream standards,and finally carries out the comparative calculation through examples.By comparing with the calculation results of commercial software ANSYS,GB151 and nonlinear finite element software VIBIC,the mathematical model established in this paper,the analysis and calculation methods and the developed software are proved to be reliable.The software can be used to carry out calculation of flow induced vibration and fretting wear of the heat exchanger tubes of fast reactor steam generator.