Flow accelerated corrosion（FAC） is the main failure cause of the secondary circuit carbon steel piping in nuclear power plants.The piping failures caused by FAC have resulted in numerous unplanned outages and tragic...Flow accelerated corrosion（FAC） is the main failure cause of the secondary circuit carbon steel piping in nuclear power plants.The piping failures caused by FAC have resulted in numerous unplanned outages and tragic fatalities.The existing researches focus on the main factors contributing to FAC,which include metallurgical factors,environmental factors and hydrodynamic factors. Some effective FAC management methods and programs with long term monitoring and inspection data analysis are recommended.But a comprehensive FAC management system should be developed in order to mitigate and manage FAC systematically.In this paper,the FAC influencing factors are analyzed in combination with the operating conditions of the secondary circuit piping in the Third Qinshan Nuclear Power Plant（TQNPP）,China（Third Qinshan Nuclear Power Company Limited,China）.A comprehensive FAC mitigation and management system is developed for TQNPP secondary circuit piping.The system is composed of five processes,viz.materials substitution,water chemical optimization,long-term monitor strategy for the susceptible piping,integrity evaluation of the local thinning defects,and repair or replacement.With the implementation of the five processes,the material of FAC sensitive pipe fittings are modified from carbon steel to stainless steel,N_2H_4 and NH_3 are finally selected as the water chemical regulator of secondary circuit,the secondary circuit pips are classified according to FAC susceptibility in order to conduct long term monitoring strategy,and an integrity evaluation flow for local thinning caused by FAC in carbon steel piping is developed.If the component with local thinning defects is not fit-for-service,corresponding repair or replacement should be conducted.The comprehensive FAC mitigation and management system with five interrelated processes would be a cost-effective method of increasing personnel safety,plant safety and availability.展开更多
本文采用一步制粒法制备降脂宁颗粒,考察浸膏相对密度、喷液速度、进风温度、进风量、雾化压力对颗粒成品率、水分、流动性、溶化性的影响。确定了最佳的一步制粒工艺参数条件,即浸膏相对密度为1.10~1.15(50℃)时,喷液速度10~20 m L...本文采用一步制粒法制备降脂宁颗粒,考察浸膏相对密度、喷液速度、进风温度、进风量、雾化压力对颗粒成品率、水分、流动性、溶化性的影响。确定了最佳的一步制粒工艺参数条件,即浸膏相对密度为1.10~1.15(50℃)时,喷液速度10~20 m L·min^(-1),进风温度70~80℃,物料温度为50~60℃,进风量110~130 m^3·h^(-1),喷液压力0.2 MPa。该工艺稳定可行,产品稳定性好,可为批量生产提供依据。展开更多
文摘Flow accelerated corrosion（FAC） is the main failure cause of the secondary circuit carbon steel piping in nuclear power plants.The piping failures caused by FAC have resulted in numerous unplanned outages and tragic fatalities.The existing researches focus on the main factors contributing to FAC,which include metallurgical factors,environmental factors and hydrodynamic factors. Some effective FAC management methods and programs with long term monitoring and inspection data analysis are recommended.But a comprehensive FAC management system should be developed in order to mitigate and manage FAC systematically.In this paper,the FAC influencing factors are analyzed in combination with the operating conditions of the secondary circuit piping in the Third Qinshan Nuclear Power Plant（TQNPP）,China（Third Qinshan Nuclear Power Company Limited,China）.A comprehensive FAC mitigation and management system is developed for TQNPP secondary circuit piping.The system is composed of five processes,viz.materials substitution,water chemical optimization,long-term monitor strategy for the susceptible piping,integrity evaluation of the local thinning defects,and repair or replacement.With the implementation of the five processes,the material of FAC sensitive pipe fittings are modified from carbon steel to stainless steel,N_2H_4 and NH_3 are finally selected as the water chemical regulator of secondary circuit,the secondary circuit pips are classified according to FAC susceptibility in order to conduct long term monitoring strategy,and an integrity evaluation flow for local thinning caused by FAC in carbon steel piping is developed.If the component with local thinning defects is not fit-for-service,corresponding repair or replacement should be conducted.The comprehensive FAC mitigation and management system with five interrelated processes would be a cost-effective method of increasing personnel safety,plant safety and availability.
文摘本文采用一步制粒法制备降脂宁颗粒,考察浸膏相对密度、喷液速度、进风温度、进风量、雾化压力对颗粒成品率、水分、流动性、溶化性的影响。确定了最佳的一步制粒工艺参数条件,即浸膏相对密度为1.10~1.15(50℃)时,喷液速度10~20 m L·min^(-1),进风温度70~80℃,物料温度为50~60℃,进风量110~130 m^3·h^(-1),喷液压力0.2 MPa。该工艺稳定可行,产品稳定性好,可为批量生产提供依据。
