With the global warming and sea level rising, it is widely recognized that there is an increasing tendency of typhoon occurrence frequency and intensity. The defenses code against typhoon attacks for nuclear power pla...With the global warming and sea level rising, it is widely recognized that there is an increasing tendency of typhoon occurrence frequency and intensity. The defenses code against typhoon attacks for nuclear power plant should be calibrated because of the increasing threat of typhoon disaster and severe consequences. This paper discusses the probabilistic approach of definitions about ＂probable maximum typhoon＂ and ＂probable maximum storm surge＂ in nuclear safety regulations of China and has made some design code calibrations by use of a newly proposed Double Layer Nested Mtdti-objective Probability Model （DLNMPM）.展开更多
This work presents a new velocity search algorithm for designing a condenser of a 1200 MWe large-scale nuclear power plant situated in tropical region.For this,the condenser pressure was considered in the range of 7.5...This work presents a new velocity search algorithm for designing a condenser of a 1200 MWe large-scale nuclear power plant situated in tropical region.For this,the condenser pressure was considered in the range of 7.5-15 kPa while its tube inner diameter was taken as 28 mm with 1 mm tube wall thickness.Both longitudinal and transverse condensers with multiple shell tanks and varied shell tank lengths from 8-14 m have been considered in this work.Three different tertiary coolant temperature rises were chosen as 4°C,8°C and 12°C by considering tropical region average reservoir water temperature range of 28°C to 32°C during summer.Velocity of tertiary coolant was kept within 0.75-1.5 m/s to ensure sufficient turbulence to avoid erosion-corrosion of the tubes.Numerical simulation has been employed to obtain tube-side pressure drop and convection heat transfer coefficient directly from tertiary coolant inlet velocity using κ-ω turbulent flow model.A new iterative“Velocity-search algorithm”has been developed that focuses on finding the correct tertiary coolant velocity instead of overall heat transfer coefficient.Results revealed that velocity-search algorithm yielded very close to the important physical and thermal parameters of condenser compared to the existing design data in large scale nuclear power plants.Velocity-search algorithm has given less number of condenser design physical parameters that meets the velocity acceptance criteria for longitudinal condenser compared to the transverse condenser.Finally,velocity-search algorithm is found to be more reliable,robust,and consistent for condenser design compared to the conventional design algorithm used in Log-Mean Temperature Difference method.展开更多
随着全球气候变暖和海平面上升,台风发生的频次和强度呈逐年增大的趋势。由台风引发的灾害及带来的后果促使人们必须重新评估核电站的海岸防护标准。文中对核电安全规定中的"可能最大台风"(Probable Maximum Typhoon)、"...随着全球气候变暖和海平面上升,台风发生的频次和强度呈逐年增大的趋势。由台风引发的灾害及带来的后果促使人们必须重新评估核电站的海岸防护标准。文中对核电安全规定中的"可能最大台风"(Probable Maximum Typhoon)、"可能最大暴潮"(Probable Maximum Storm Surge)、"设计基准洪水"(Design Basic Flood)进行了概率分析,并用"双层嵌套多目标概率模式"(DLNMPM)对设计规范计算结果进行了修正。展开更多
基金supported by the Nationam Natural Science Foundation of China(Grant No.50679076)Office of State Flood Control and Drought Relief Headquarters of China(Grant No.20060120)
文摘With the global warming and sea level rising, it is widely recognized that there is an increasing tendency of typhoon occurrence frequency and intensity. The defenses code against typhoon attacks for nuclear power plant should be calibrated because of the increasing threat of typhoon disaster and severe consequences. This paper discusses the probabilistic approach of definitions about ＂probable maximum typhoon＂ and ＂probable maximum storm surge＂ in nuclear safety regulations of China and has made some design code calibrations by use of a newly proposed Double Layer Nested Mtdti-objective Probability Model （DLNMPM）.
基金The authors would like to thank Department of Nuclear Engineering,University of Dhaka for providing necessary laboratory facilities.This work has not received any sort of grant or funding from any individual or organization.
文摘This work presents a new velocity search algorithm for designing a condenser of a 1200 MWe large-scale nuclear power plant situated in tropical region.For this,the condenser pressure was considered in the range of 7.5-15 kPa while its tube inner diameter was taken as 28 mm with 1 mm tube wall thickness.Both longitudinal and transverse condensers with multiple shell tanks and varied shell tank lengths from 8-14 m have been considered in this work.Three different tertiary coolant temperature rises were chosen as 4°C,8°C and 12°C by considering tropical region average reservoir water temperature range of 28°C to 32°C during summer.Velocity of tertiary coolant was kept within 0.75-1.5 m/s to ensure sufficient turbulence to avoid erosion-corrosion of the tubes.Numerical simulation has been employed to obtain tube-side pressure drop and convection heat transfer coefficient directly from tertiary coolant inlet velocity using κ-ω turbulent flow model.A new iterative“Velocity-search algorithm”has been developed that focuses on finding the correct tertiary coolant velocity instead of overall heat transfer coefficient.Results revealed that velocity-search algorithm yielded very close to the important physical and thermal parameters of condenser compared to the existing design data in large scale nuclear power plants.Velocity-search algorithm has given less number of condenser design physical parameters that meets the velocity acceptance criteria for longitudinal condenser compared to the transverse condenser.Finally,velocity-search algorithm is found to be more reliable,robust,and consistent for condenser design compared to the conventional design algorithm used in Log-Mean Temperature Difference method.
文摘随着全球气候变暖和海平面上升,台风发生的频次和强度呈逐年增大的趋势。由台风引发的灾害及带来的后果促使人们必须重新评估核电站的海岸防护标准。文中对核电安全规定中的"可能最大台风"(Probable Maximum Typhoon)、"可能最大暴潮"(Probable Maximum Storm Surge)、"设计基准洪水"(Design Basic Flood)进行了概率分析,并用"双层嵌套多目标概率模式"(DLNMPM)对设计规范计算结果进行了修正。
