The Environmental program of the Cernavoda NPP （nuclear power plant） is based on the analysis of environmental samples： airborne, TLDs （thermoluminescence dosimeters）, water, deposition, soil, grass, sediment, fi...The Environmental program of the Cernavoda NPP （nuclear power plant） is based on the analysis of environmental samples： airborne, TLDs （thermoluminescence dosimeters）, water, deposition, soil, grass, sediment, fish, milk, meat, eggs, grains, fruits and vegetables, using determination of 3H and 14C, gross alpha/beta and gamma spectrometry measurement techniques. This Program is a legal constraint for nuclear utilities and it is approved and supervised by the regulatory body. Besides, the actual legal requirements, Cernavoda NPP participates in a CANDU （Canadian Deuterium Uranium） Owners Group Project （COG HS ＆ E-304） in order to implement the new standard CAN-CSA 288.1-08 for derived emission limits using results of measurements for OBT （organically bound tritium） concentrations in plant and animal products. The method for determination of 3H and 14C in organic samples after separation through non-catalytic combustion by flame oxidation is performed in Sample Oxidizer 307 equipment. Average values for total tritium activity concentration in fish samples of 21 ± 2 Bq/kg fresh weight were determined. Results for 14C have an average value of 327 ± 26 Bq/kg-C in fish from Danube-River and 315 ± 25 Bq/kg-C in fish from lakes. The average values for 14C activity concentration in vegetables samples from Cernavoda and Seimeni areas are about 338 ± 27 Bq/kg-C.展开更多
Serious fouling and slagging problems are associated with the combustion of Chinese Zhun-Dong coal due to its high content of sodium （Na）. Understanding the release characteristic of Na during the combustion is esse...Serious fouling and slagging problems are associated with the combustion of Chinese Zhun-Dong coal due to its high content of sodium （Na）. Understanding the release characteristic of Na during the combustion is essential to viable utilization of this coal. In this work, coal samples were treated with a sequence of solvents： water （H2O）, ammonium acetate （NH4Ac）, hydrochloric acid （HC1）, and the release characteristics of various classes of Na during coal combustion were investigated using the technique of laser-induced breakdown spectroscopy. The relative contribution of various Na classes to the Na release during each combustion stage was found to be similar, in the order of H2O-soluble Na 〉 NHaAcsoluble Na 〉 HCl-soluble Na 〉 insoluble Na. Sodium released during the devolatilization stage can be attributed to each of the sodium classes. After the devolatilization stage, H2O-soluble Na and NHaAc-soluble Na dominated the Na release during both char and ash stages. Over 64 % of the total Na released during combustion comes from the H2O-soluble Na, which suggests that the Na release during the combustion of Zhun-Dong coal can be reduced effectively after treatment by H2O washing.展开更多
文摘The Environmental program of the Cernavoda NPP （nuclear power plant） is based on the analysis of environmental samples： airborne, TLDs （thermoluminescence dosimeters）, water, deposition, soil, grass, sediment, fish, milk, meat, eggs, grains, fruits and vegetables, using determination of 3H and 14C, gross alpha/beta and gamma spectrometry measurement techniques. This Program is a legal constraint for nuclear utilities and it is approved and supervised by the regulatory body. Besides, the actual legal requirements, Cernavoda NPP participates in a CANDU （Canadian Deuterium Uranium） Owners Group Project （COG HS ＆ E-304） in order to implement the new standard CAN-CSA 288.1-08 for derived emission limits using results of measurements for OBT （organically bound tritium） concentrations in plant and animal products. The method for determination of 3H and 14C in organic samples after separation through non-catalytic combustion by flame oxidation is performed in Sample Oxidizer 307 equipment. Average values for total tritium activity concentration in fish samples of 21 ± 2 Bq/kg fresh weight were determined. Results for 14C have an average value of 327 ± 26 Bq/kg-C in fish from Danube-River and 315 ± 25 Bq/kg-C in fish from lakes. The average values for 14C activity concentration in vegetables samples from Cernavoda and Seimeni areas are about 338 ± 27 Bq/kg-C.
基金supported by the National Natural Science Foundation of China(51406178)China Postdoctoral Science Foundation(2014M551732)+1 种基金National Basic Research Program of China(2012CB214906)Specialized Research Fund for the Doctoral Program of Higher Education of China(20130101110095)
文摘Serious fouling and slagging problems are associated with the combustion of Chinese Zhun-Dong coal due to its high content of sodium （Na）. Understanding the release characteristic of Na during the combustion is essential to viable utilization of this coal. In this work, coal samples were treated with a sequence of solvents： water （H2O）, ammonium acetate （NH4Ac）, hydrochloric acid （HC1）, and the release characteristics of various classes of Na during coal combustion were investigated using the technique of laser-induced breakdown spectroscopy. The relative contribution of various Na classes to the Na release during each combustion stage was found to be similar, in the order of H2O-soluble Na 〉 NHaAcsoluble Na 〉 HCl-soluble Na 〉 insoluble Na. Sodium released during the devolatilization stage can be attributed to each of the sodium classes. After the devolatilization stage, H2O-soluble Na and NHaAc-soluble Na dominated the Na release during both char and ash stages. Over 64 % of the total Na released during combustion comes from the H2O-soluble Na, which suggests that the Na release during the combustion of Zhun-Dong coal can be reduced effectively after treatment by H2O washing.
