The triple-to-double coincidence ratio （TDCR） method of liquid scintillation count- ing is an absolute measurement method of radioactivity. The formulation of the TDCR method and the established TDCR liquid scintill...The triple-to-double coincidence ratio （TDCR） method of liquid scintillation count- ing is an absolute measurement method of radioactivity. The formulation of the TDCR method and the established TDCR liquid scintillation counter are presented in this paper. The NIST standard reference material （SRM） of tritium water was measured to verify the performance of the TDCR liquid scintillation counter.展开更多
Transient separation behavior in tritiated water distillation tower packed with materials having ability to adsorb water is investigated analytically and experimentally for nuclear reactor safety. Analytical equations...Transient separation behavior in tritiated water distillation tower packed with materials having ability to adsorb water is investigated analytically and experimentally for nuclear reactor safety. Analytical equations based on the stage model are set up for simulation of the transient behavior of tritium (T) separation from wastewater. It is found that a dimensionless time defined in terms of the inside vapor flow rate and the liquid holdups in tower, reboiler and condenser can correlate variations over time to achieve a steady-state T concentration. However, when mixing with different T concentrations at a feed point occurs, the transition time period becomes longer than expected. Effects of the reflux ratio, the stage separation factor and the total stage number on the transient and steady-state T concentrations are numerically calculated. Variations over time to achieve each steady-state value are compared with experimental data using a small-scale tower. Long time distillation experiment for one month has been completed, and it is confirmed that a distillation column packed with ceramic Raschig rings coated with zeolite 13X adsorbent is hardly affected by water corrosion.展开更多
In this work, tritium concentration was determined in different D2O enrichment in heavy water samples. Samples were prepared from Arak Heavy Water Production Plant. Tritium concentration was determined utilizing liqui...In this work, tritium concentration was determined in different D2O enrichment in heavy water samples. Samples were prepared from Arak Heavy Water Production Plant. Tritium concentration was determined utilizing liquid scintillation detector (LSC) system based on β-decay of tritium isotope. In this work instead of simple distillation, the azeotropic distillation method was used. Absorbed spectra and fluorescence spectra were registered by Shimadz spectrometer UV-2100 model and fluorescence spectrometer LS50B model respectively. Tritium concentration was obtained from 1.75 ± 0.80 up 6.16 ± 1.01 Bq/L for 0.35% to 77.50% enrichment of D2O concentration in heavy water samples. Coefficient correlation between tritium concentration and D2O concentration in heavy water R2 = 0.853 was derived. For 99.8% enriched D2O in heavy water, deviation was observed from direct line that caused decreasing of R2.展开更多
Results of environmental radioactivity monitoring around Qinshan Nuclear Power Plant (QNPP) are reported in this paper. From 1992 to 2005, concentrations of 90Sr, 137Cs and 3H in terrestrial freshwater are (4.4±1...Results of environmental radioactivity monitoring around Qinshan Nuclear Power Plant (QNPP) are reported in this paper. From 1992 to 2005, concentrations of 90Sr, 137Cs and 3H in terrestrial freshwater are (4.4±1.7) mBq·L-1, (0.3±0.1) mBq·L-1 and (1.6±0.5) Bq·L-1, respectively, and (2.8±2.4) Bq·L-1 of 3H in rainwater. Concentrations of 90Sr, 137Cs and 3H in the seawater samples collected from sea area nearby QNPP are (5.4±4.1) mBq·L-1, (0.7±0.2) mBq·L-1 and (1.0±0.5) Bq·L-1, respectively. Concentrations of 90Sr, 137Cs and 3H in the total waste water discharged from NPP-I are (4.0±1.8) m Bq·L-1, (1.0±0.5) mBq·L-1 and (2.8±2.2) Bq·L-1, respectively, and (1.4±0.4) Bq·L-1 of 3H in seawater sampled from No.1 outlet. Atomspheric 3H concentration in 1993～2005 at two monitoring sites is (78.9±96.3) and (64.2±40.2) mBq·m-3, respectively, with an increasing trend after 2003. Atmospheric 14C concentrations at the two sites are in the same levels as the background and data of the reference site.展开更多
The present work studies the environmental isotopes assess groundwater characteristics of the different parts of the main aquifer in the northeast Missan Province in south of Iraq. Water samples of groundwater and sur...The present work studies the environmental isotopes assess groundwater characteristics of the different parts of the main aquifer in the northeast Missan Province in south of Iraq. Water samples of groundwater and surface water were collected for two dry and wet seasons during the water year of 2011-2012. The study shows that most of the groundwater in the aquifer falls above the global meteoric water line, and all the samples fall below the Mediterranean meteoric water line, indicating that these samples are a mixture of two water types. The tritium content of these samples supports this conclusion. The overall conclusion of this study indicates that there are two sources of groundwater recharge in the studied area： the ephemeral streams （Teeb and Dewerge） and major precipitation sources. According to the tritium levels at or below one tritium unit （TU） obtained from the water, supply wells are highly confined or ＂not vulnerable＂. Overall, the 3^H results imply that recent recharge has taken place during the last four to five decades. In the recharge area, the high tritium content in the southern part of the Teeb area suggests that the recharge originates from rapid infiltration of surface runoff. Therefore, the groundwater resources in the study area should be protected from contamination, because it will influence the aquifer in a relatively short period of time if any contamination enters the recharge areas of the aquifer.展开更多
Beishan region in Gansu was the preselected area for China's high-level radioactive waste(HLW) repository. In selecting and evaluating a new dump site, the tritium study is of great significance. The Xinchang-Xian...Beishan region in Gansu was the preselected area for China's high-level radioactive waste(HLW) repository. In selecting and evaluating a new dump site, the tritium study is of great significance. The Xinchang-Xiangyangshan preselected area in the Beishan area was taken as an example. This paper selects typical unit and tries to use the distribution characteristics of tritium in the soil to study the atmospheric precipitation infiltration recharge in this area. The results show: In this region, the spatial variability of the tritium content in surface soil is large; it is feasible to use bound tritium tracer method to study the theory of atmospheric precipitation infiltration recharge; the atmospheric precipitation infiltration has close relationship with the soil particle composition, salt content, mineral composition, water content and organic matter content. These results can provide important basis for developing the atmospheric precipitation infiltration recharge, groundwater numerical simulation, nuclide migration study and so on.展开更多
To characterize the groundwater in the Ejina Basin,surface and groundwater samples were collected in May and October of 2002.On-site analyses included temperature,electrical conductance(EC),total alkalinity(as HCO 3) ...To characterize the groundwater in the Ejina Basin,surface and groundwater samples were collected in May and October of 2002.On-site analyses included temperature,electrical conductance(EC),total alkalinity(as HCO 3) by titration,and pH.Chemical analyses were undertaken at the Geochemistry Laboratory of the Cold and Arid Region Environmental and Engineering Institute,Chinese Academy of Sciences,Lanzhou,China.The pH of the groundwater ranged from 7.18 to 8.90 with an average value of 7.72,indicating an alkaline nature.The total dissolved solids(TDS) of the groundwater ranged from 567.5 to 5,954.4 mg/L with an average of 1,543.1 mg/L and a standard deviation of 1,471.8 mg/L.According to the groundwater salinity classification of Robinove et al.(1958),47.4 percent of the samples were brackish and the remainder were fresh water.The ion concentration of the groundwater along the riverbed and near the southern margin of the basin were lower than those farther away from the riverbed.The groundwater in the study area was of Na +-HCO 3 type near the bank of the Heihe River and in the southern margin of the basin,while Na +-SO 4 2-Cl type samples were observed in the terminal lake region.In the desert area the groundwater reached a TDS of 3,000-6,000 mg/L and was predominantly by a Na +-Cl chemistry.Br/Cl for the water of Ejina Basin indicates an evaporite origin for the groundwater with a strongly depleted Br/Cl ratio(average 0.000484).The surface water was slightly enriched in Br/Cl(average 0.000711) compared with groundwater.The calculated saturation index(SI) for calcite and dolomite of the groundwater samples range from 0.89 to 1.31 and 1.67 to 2.67 with averaged 0.24 and 0.61,respectively.About 97 percent of the groundwater samples were kinetically oversaturated with respect to calcite and dolomite,and all the samples were below the equilibrium state with gypsum.Using isotope and hydrochemical analyses,this study investigated the groundwater evolution and its residence time.The groundwater content was mainly determined by the dissolutions of halite,gypsum,and Glauber’s salt(Na 2 SO 4),as well as Na + exchange for Ca 2+,and calcite and dolomite precipitation.With the exception of a few locations,most of the groundwater samples were suitable for irrigation uses.Most of the stable isotope compositions in the groundwater sampled plotted close to the Global Meteoric Water Line(GMWL),indicating that the groundwater was mainly sourced from meteoric water.There was evidence of enrichment of heavy isotopes in the groundwater due to evaporation.Based on the tritium content in atmospheric precipitation and by adopting the exponential-piston model(EPM),the mean residence time of the unconfined aquifer groundwater was evaluated.The results show that these groundwaters have low residence time(12 to 48 years) and are renewable.In contrast,the confined groundwater had 14 C ages estimated by the Pearson model between 4,087 to 9,364 years BP.Isotopic signatures indicated formation of deep confined groundwaters in a colder and wetter climate during the late Pleistocene and Holocene.展开更多
文摘The triple-to-double coincidence ratio （TDCR） method of liquid scintillation count- ing is an absolute measurement method of radioactivity. The formulation of the TDCR method and the established TDCR liquid scintillation counter are presented in this paper. The NIST standard reference material （SRM） of tritium water was measured to verify the performance of the TDCR liquid scintillation counter.
文摘Transient separation behavior in tritiated water distillation tower packed with materials having ability to adsorb water is investigated analytically and experimentally for nuclear reactor safety. Analytical equations based on the stage model are set up for simulation of the transient behavior of tritium (T) separation from wastewater. It is found that a dimensionless time defined in terms of the inside vapor flow rate and the liquid holdups in tower, reboiler and condenser can correlate variations over time to achieve a steady-state T concentration. However, when mixing with different T concentrations at a feed point occurs, the transition time period becomes longer than expected. Effects of the reflux ratio, the stage separation factor and the total stage number on the transient and steady-state T concentrations are numerically calculated. Variations over time to achieve each steady-state value are compared with experimental data using a small-scale tower. Long time distillation experiment for one month has been completed, and it is confirmed that a distillation column packed with ceramic Raschig rings coated with zeolite 13X adsorbent is hardly affected by water corrosion.
文摘In this work, tritium concentration was determined in different D2O enrichment in heavy water samples. Samples were prepared from Arak Heavy Water Production Plant. Tritium concentration was determined utilizing liquid scintillation detector (LSC) system based on β-decay of tritium isotope. In this work instead of simple distillation, the azeotropic distillation method was used. Absorbed spectra and fluorescence spectra were registered by Shimadz spectrometer UV-2100 model and fluorescence spectrometer LS50B model respectively. Tritium concentration was obtained from 1.75 ± 0.80 up 6.16 ± 1.01 Bq/L for 0.35% to 77.50% enrichment of D2O concentration in heavy water samples. Coefficient correlation between tritium concentration and D2O concentration in heavy water R2 = 0.853 was derived. For 99.8% enriched D2O in heavy water, deviation was observed from direct line that caused decreasing of R2.
文摘Results of environmental radioactivity monitoring around Qinshan Nuclear Power Plant (QNPP) are reported in this paper. From 1992 to 2005, concentrations of 90Sr, 137Cs and 3H in terrestrial freshwater are (4.4±1.7) mBq·L-1, (0.3±0.1) mBq·L-1 and (1.6±0.5) Bq·L-1, respectively, and (2.8±2.4) Bq·L-1 of 3H in rainwater. Concentrations of 90Sr, 137Cs and 3H in the seawater samples collected from sea area nearby QNPP are (5.4±4.1) mBq·L-1, (0.7±0.2) mBq·L-1 and (1.0±0.5) Bq·L-1, respectively. Concentrations of 90Sr, 137Cs and 3H in the total waste water discharged from NPP-I are (4.0±1.8) m Bq·L-1, (1.0±0.5) mBq·L-1 and (2.8±2.2) Bq·L-1, respectively, and (1.4±0.4) Bq·L-1 of 3H in seawater sampled from No.1 outlet. Atomspheric 3H concentration in 1993～2005 at two monitoring sites is (78.9±96.3) and (64.2±40.2) mBq·m-3, respectively, with an increasing trend after 2003. Atmospheric 14C concentrations at the two sites are in the same levels as the background and data of the reference site.
基金supported by Selcuk University Scientific Research Projects(BAP)under Grant no.12201045 for the Doctoral Program of Higher Education of Turkey(Konya)
文摘The present work studies the environmental isotopes assess groundwater characteristics of the different parts of the main aquifer in the northeast Missan Province in south of Iraq. Water samples of groundwater and surface water were collected for two dry and wet seasons during the water year of 2011-2012. The study shows that most of the groundwater in the aquifer falls above the global meteoric water line, and all the samples fall below the Mediterranean meteoric water line, indicating that these samples are a mixture of two water types. The tritium content of these samples supports this conclusion. The overall conclusion of this study indicates that there are two sources of groundwater recharge in the studied area： the ephemeral streams （Teeb and Dewerge） and major precipitation sources. According to the tritium levels at or below one tritium unit （TU） obtained from the water, supply wells are highly confined or ＂not vulnerable＂. Overall, the 3^H results imply that recent recharge has taken place during the last four to five decades. In the recharge area, the high tritium content in the southern part of the Teeb area suggests that the recharge originates from rapid infiltration of surface runoff. Therefore, the groundwater resources in the study area should be protected from contamination, because it will influence the aquifer in a relatively short period of time if any contamination enters the recharge areas of the aquifer.
基金supported by special project on decommission of nuclear facilities and disposal of radioactive wastes(SASTIND No.2 Department No.[2014]305)
文摘Beishan region in Gansu was the preselected area for China's high-level radioactive waste(HLW) repository. In selecting and evaluating a new dump site, the tritium study is of great significance. The Xinchang-Xiangyangshan preselected area in the Beishan area was taken as an example. This paper selects typical unit and tries to use the distribution characteristics of tritium in the soil to study the atmospheric precipitation infiltration recharge in this area. The results show: In this region, the spatial variability of the tritium content in surface soil is large; it is feasible to use bound tritium tracer method to study the theory of atmospheric precipitation infiltration recharge; the atmospheric precipitation infiltration has close relationship with the soil particle composition, salt content, mineral composition, water content and organic matter content. These results can provide important basis for developing the atmospheric precipitation infiltration recharge, groundwater numerical simulation, nuclide migration study and so on.
基金supported by grants from the National Social Science Foundation (No. 08XJY009)the National Natural Science Foundation of China (Nos. 40701054,Yo11391001 and 40801001)the China Postdoctoral Science Foundation (No. 20090450850)
文摘To characterize the groundwater in the Ejina Basin,surface and groundwater samples were collected in May and October of 2002.On-site analyses included temperature,electrical conductance(EC),total alkalinity(as HCO 3) by titration,and pH.Chemical analyses were undertaken at the Geochemistry Laboratory of the Cold and Arid Region Environmental and Engineering Institute,Chinese Academy of Sciences,Lanzhou,China.The pH of the groundwater ranged from 7.18 to 8.90 with an average value of 7.72,indicating an alkaline nature.The total dissolved solids(TDS) of the groundwater ranged from 567.5 to 5,954.4 mg/L with an average of 1,543.1 mg/L and a standard deviation of 1,471.8 mg/L.According to the groundwater salinity classification of Robinove et al.(1958),47.4 percent of the samples were brackish and the remainder were fresh water.The ion concentration of the groundwater along the riverbed and near the southern margin of the basin were lower than those farther away from the riverbed.The groundwater in the study area was of Na +-HCO 3 type near the bank of the Heihe River and in the southern margin of the basin,while Na +-SO 4 2-Cl type samples were observed in the terminal lake region.In the desert area the groundwater reached a TDS of 3,000-6,000 mg/L and was predominantly by a Na +-Cl chemistry.Br/Cl for the water of Ejina Basin indicates an evaporite origin for the groundwater with a strongly depleted Br/Cl ratio(average 0.000484).The surface water was slightly enriched in Br/Cl(average 0.000711) compared with groundwater.The calculated saturation index(SI) for calcite and dolomite of the groundwater samples range from 0.89 to 1.31 and 1.67 to 2.67 with averaged 0.24 and 0.61,respectively.About 97 percent of the groundwater samples were kinetically oversaturated with respect to calcite and dolomite,and all the samples were below the equilibrium state with gypsum.Using isotope and hydrochemical analyses,this study investigated the groundwater evolution and its residence time.The groundwater content was mainly determined by the dissolutions of halite,gypsum,and Glauber’s salt(Na 2 SO 4),as well as Na + exchange for Ca 2+,and calcite and dolomite precipitation.With the exception of a few locations,most of the groundwater samples were suitable for irrigation uses.Most of the stable isotope compositions in the groundwater sampled plotted close to the Global Meteoric Water Line(GMWL),indicating that the groundwater was mainly sourced from meteoric water.There was evidence of enrichment of heavy isotopes in the groundwater due to evaporation.Based on the tritium content in atmospheric precipitation and by adopting the exponential-piston model(EPM),the mean residence time of the unconfined aquifer groundwater was evaluated.The results show that these groundwaters have low residence time(12 to 48 years) and are renewable.In contrast,the confined groundwater had 14 C ages estimated by the Pearson model between 4,087 to 9,364 years BP.Isotopic signatures indicated formation of deep confined groundwaters in a colder and wetter climate during the late Pleistocene and Holocene.
