An in-house code,CONTHAC-3D,was developed to calculate and analyze thermal-hydraulic phenomena in containments during severe accidents.CONTHAC-3D is a three-dimensional computational fluid dynamics code that can be ap...An in-house code,CONTHAC-3D,was developed to calculate and analyze thermal-hydraulic phenomena in containments during severe accidents.CONTHAC-3D is a three-dimensional computational fluid dynamics code that can be applied to predict gas flow,diffusion,and steam condensation in a containment during a severe hypothetical accident,as well as to obtain an estimate of the local hydrogen concentration in various zones of the containment.CONTHAC-3D was developed using multiple models to simulate the features of the proprietary systems and equipment of HPR1000 and ACP100,such as the passive cooling system,passive autocatalytic recombiners and the passive air cooling system.To validate CONTHAC-3D,a GX6 test was performed at the Battelle Model Containment facility.The hydrogen concentration and temperature monitored by the GX6 test are accurately predicted by CONTHAC-3D.Subsequently,the hydrogen distribution in the HPR1000 containment during a severe accident was studied.The results show that the hydrogen removal rates calculated using CONTHAC-3D for different types of PARs agree well with the theoretical values,with an error of less than 1%.As the accident progresses,the hydrogen concentration in the lower compartment becomes higher than that in the large space,which implies that the lower compartment has a higher hydrogen risk than the dome and large space at a later stage of the accident.The amount of hydrogen removed by the PARs placed on the floor of the compartment is small;therefore,raising the installation height of these recombiners appropriately is recommended.However,we do not recommend installing all autocatalytic recombiners at high positions.The study findings in regard to the hydrogen distribution in the HPR1000 containment indicate that CONTHAC-3D can be applied to the study of hydrogen risk containment.展开更多
Microcystis blooms are an environmental and ecological concern that has received a serious attention. Hydrogen peroxide(H_2O_2) is an environment-friendly cyanocide that is commonly used to control Microcystis blooms....Microcystis blooms are an environmental and ecological concern that has received a serious attention. Hydrogen peroxide(H_2O_2) is an environment-friendly cyanocide that is commonly used to control Microcystis blooms. While the ecological safety of H_2O_2 has been previously studied, its influence on bacterioplankton has not been investigated to date. In this study, we used mesocosm experiments to determine the influence of H_2O_2 on the dynamic changes of the community structure of bacterioplankton. By using deep-sequencing and metagenomics strategy we determined the community structures of phytoplankton and bacterioplankton assemblages that were dominated by M icrocystis at a highly eutrophic Dianchi Lake, China. The results showed that M icrocystis was more sensitive to H_2O_2 than other eukaryotic algae. More interestingly, application of H_2O_2 changed the community structure of bacterioplankton, evidenced by the emergence of F irmicutes as the dominant species in place of B acteroidetes and Proteobacteria. The H_2O_2 treatment resulted in the community of bacterioplankton that was primarily dominated by E xiguobacterium and Planomicrobium. Our results show that the abundance changed and the bacterioplankton diversity did not recover even after the concentration of H_2O_2 reached to the background level. Thus, the response of bacterioplankton must be considered when assessing the ecological risks of using H_2O_2 to control Microcystis blooms, because bacterioplankton is the key player that forms the basis of food web of aquatic environment.展开更多
在加氢裂化装置超期服役面临腐蚀风险加重的背景下,对多个重要标准进行了研究,包括加氢裂化装置典型的腐蚀机理如氢腐蚀、湿硫化氢腐蚀、铵盐腐蚀及开停工期间的连多硫酸应力腐蚀开裂等涉及到的典型标准,如API RP 941,API RP 939C,NACE ...在加氢裂化装置超期服役面临腐蚀风险加重的背景下,对多个重要标准进行了研究,包括加氢裂化装置典型的腐蚀机理如氢腐蚀、湿硫化氢腐蚀、铵盐腐蚀及开停工期间的连多硫酸应力腐蚀开裂等涉及到的典型标准,如API RP 941,API RP 939C,NACE 8X194,NACE RP0472,NACE MR0103,API RP932B及NACE SP0170。通过对历年不同版本的对比分析,梳理出超期服役的加氢裂化装置需要重点关注的腐蚀风险点,并根据标准提出相应的腐蚀防控措施,保障装置的长期安全运行。展开更多
文摘An in-house code,CONTHAC-3D,was developed to calculate and analyze thermal-hydraulic phenomena in containments during severe accidents.CONTHAC-3D is a three-dimensional computational fluid dynamics code that can be applied to predict gas flow,diffusion,and steam condensation in a containment during a severe hypothetical accident,as well as to obtain an estimate of the local hydrogen concentration in various zones of the containment.CONTHAC-3D was developed using multiple models to simulate the features of the proprietary systems and equipment of HPR1000 and ACP100,such as the passive cooling system,passive autocatalytic recombiners and the passive air cooling system.To validate CONTHAC-3D,a GX6 test was performed at the Battelle Model Containment facility.The hydrogen concentration and temperature monitored by the GX6 test are accurately predicted by CONTHAC-3D.Subsequently,the hydrogen distribution in the HPR1000 containment during a severe accident was studied.The results show that the hydrogen removal rates calculated using CONTHAC-3D for different types of PARs agree well with the theoretical values,with an error of less than 1%.As the accident progresses,the hydrogen concentration in the lower compartment becomes higher than that in the large space,which implies that the lower compartment has a higher hydrogen risk than the dome and large space at a later stage of the accident.The amount of hydrogen removed by the PARs placed on the floor of the compartment is small;therefore,raising the installation height of these recombiners appropriately is recommended.However,we do not recommend installing all autocatalytic recombiners at high positions.The study findings in regard to the hydrogen distribution in the HPR1000 containment indicate that CONTHAC-3D can be applied to the study of hydrogen risk containment.
基金Supported by the Major Science and Technology Program for Water Pollution Control and Treatment(No.2013ZX07102005)the National Natural Science Foundation of China(No.41561144008)the State Key Laboratory of Freshwater Ecology and Biotechnology(No.2016FBZ07)
文摘Microcystis blooms are an environmental and ecological concern that has received a serious attention. Hydrogen peroxide(H_2O_2) is an environment-friendly cyanocide that is commonly used to control Microcystis blooms. While the ecological safety of H_2O_2 has been previously studied, its influence on bacterioplankton has not been investigated to date. In this study, we used mesocosm experiments to determine the influence of H_2O_2 on the dynamic changes of the community structure of bacterioplankton. By using deep-sequencing and metagenomics strategy we determined the community structures of phytoplankton and bacterioplankton assemblages that were dominated by M icrocystis at a highly eutrophic Dianchi Lake, China. The results showed that M icrocystis was more sensitive to H_2O_2 than other eukaryotic algae. More interestingly, application of H_2O_2 changed the community structure of bacterioplankton, evidenced by the emergence of F irmicutes as the dominant species in place of B acteroidetes and Proteobacteria. The H_2O_2 treatment resulted in the community of bacterioplankton that was primarily dominated by E xiguobacterium and Planomicrobium. Our results show that the abundance changed and the bacterioplankton diversity did not recover even after the concentration of H_2O_2 reached to the background level. Thus, the response of bacterioplankton must be considered when assessing the ecological risks of using H_2O_2 to control Microcystis blooms, because bacterioplankton is the key player that forms the basis of food web of aquatic environment.
文摘在加氢裂化装置超期服役面临腐蚀风险加重的背景下,对多个重要标准进行了研究,包括加氢裂化装置典型的腐蚀机理如氢腐蚀、湿硫化氢腐蚀、铵盐腐蚀及开停工期间的连多硫酸应力腐蚀开裂等涉及到的典型标准,如API RP 941,API RP 939C,NACE 8X194,NACE RP0472,NACE MR0103,API RP932B及NACE SP0170。通过对历年不同版本的对比分析,梳理出超期服役的加氢裂化装置需要重点关注的腐蚀风险点,并根据标准提出相应的腐蚀防控措施,保障装置的长期安全运行。
