• Journal of the korean society of oceanography
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• v.36 no.1
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• pp.19-26
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• 2001

The biological pump is one of the important pumping mechanisms absorbing CO$_2$ from the atmosphere into the ocean and can be quantified by estimating new production. New production in the open ocean mostly depends on the supply of nitrate from the water below the mixed layer. While nitrate is affected by many biological processes, the helium isotope ($^3$He) is inert and has very simple physical properties. Using the $^3$He flux and the relation between $^3$He and NO${_3}\;{^-}$- within the thermocline, the nitrate flux supporting new production was estimated in the southern East Sea. The average ${\delta}^3$He within the mixed layer was -14$%_o$ and -l5.4$%_o$ in the winter and autumn, respectively. Through the year excess $^3$He occurs in the mixed layer except for a slight depletion of -17$%_o$ in summer. The $^3$He flux of 13$%_o$md$^{-1}$ associated with the concentration gradient at the air-sea interface was calculated from the product of the piston velocity and the excess $^3$He. Tritium decay within the mixed layer could support only 2$%_o$md$^{-1}$ of the flux. Thus, the remaining 11$%_o$md^{-1}$ could be attributed to the flux of tritiugenic $^3$He from the water below the mixed layer. Nitrate and $^3$He were positively correlated within the thermocline layer with the slope of 0.21 ${\mu}$mol kg$^{-1}$ $%_o\;^{-1}$. The annual nitrate flux estimated from the upward flux of $^3$He and the NO$_{3}\;{^-}$-$^3$He relation was 0.8${\pm}$0.2 mol(N) m$^{-2}$yr$^{-1}$. This flux corresponds to an annual new production of 64 g(C) m$^{-2}$yr$^{-1}$, which is consistent with that in the north-west Pacific.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.14 no.9
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• pp.4643-4651
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• 2013

In this study, we have surveyed the new technologies in the cryogenic distillation of ITER, equilibrium reactors and helium refrigeration cycle contained in the isotope separation system (ISS). We also have collected thermodynamic and transport properties for $H_2$, HD, $D_2$, HT, DT and $T_2$ components of which properties are not built in a general purpose chemical process simulators such as Aspen Plus and PRO/II with PROVISION. Verification works have been performed to compare between literature data and simulation results. For the simulation of ISS involving six hydrogen isotope components, four distillation columns and two equilibrium reactors are used for the separation of $D_2$ and DT from $T_2$.

• Bulletin of the Korean Chemical Society
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• v.34 no.6
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• pp.1689-1692
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• 2013

Food is a common source of chromium (Cr) exposure. However, it is difficult to analyze Cr in complex food matrices by using inductively coupled plasma mass spectrometry (ICP-MS) because the major isotope, $^{52}Cr$, is masked by interference generated by the sample matrix and the plasma gas. Among the systems available to minimize interference, the recently developed collision-reaction interface (CRI) has a different structure relative to that of other systems (e.g., collision cell technology, octopole reaction system, and dynamic reaction cell) that were designed as a chamber between the skimmer cone and quadrupole. The CRI system introduces collision or reaction gas directly into the plasma region through a modified hole of skimmer cone. We evaluated the use of an CRI ICP-MS system to minimize polyatomic interference of $^{52}Cr$ and $^{53}Cr$ in various foodstuffs. The $^{52}Cr$ concentrations measured in the standard mode were 2-3 times higher than the certified values. This analytical method based on an ICP-MS system equipped with a CRI of helium gas was effective for Cr analysis in complex food matrices.

• Korean Journal of Optics and Photonics
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• v.11 no.2
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• pp.114-118
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• 2000

The paper presents the effects of outpLlt-coLLpling power and small SIgnal gain of a He-Se+ laser by discharge of either $^4He$ or $^3He$. A quartz plane-plate was installed to outpLlt-coLlple the laseI beam from the resonator in the eAperimental setup. The result shows tbat compared with those of ~He, tbe outPLlt-coupling power and small-signal gain of $^4He$ increase in the most of the lines. EspeCIally, the small-signal gain of $^3He$ for the strong lines (497.6 nm, 499.3 nm, 506.9 urn, 5176 nm, 522.8 mn, 530.5 nm) lies 25% higher than Ulat of 4He, and the output-coupling power doubles oubles

• Nuclear Engineering and Technology
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• v.41 no.5
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• pp.729-738
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• 2009

Given the evolution of High-Temperature Gas-cooled Reactor(HTGR) designs, the source terms for licensing must be developed. There are three potential source terms: fission products, actinides in the fuel and tritium in the coolant. It is necessary to provide first an inventory of the source terms under normal operations. An analysis of source terms has yet to be performed for HTGRs. The previous code, which can estimate the inventory of the source terms for LWRs, cannot be used for HTGRs because the general data of a typical neutron cross-section and flux has not been developed. Thus, this paper uses a combination of the MCNP, ORIGEN, and MONTETEBURNS codes for an estimation of the source terms. A method in which the HTR-10 core is constructed using the unit lattice of a body-centered cubic is developed for core modeling. Based on this modeling method by MCNP, the generation of fission products, actinides and tritium with an increase in the burnup ratio is simulated. The model developed by MCNP appears feasible through a comparison with models developed in previous studies. Continuous fuel management is divided into five periods for the feeding and discharging of fuel pebbles. This discrete fuel management scheme is employed using the MONTEBURNS code. Finally, the work is investigated for 22 isotope fission products of nuclides, 22 actinides in the core, and tritium in the coolant. The activities are mainly distributed within the range of $10^{15}{\sim}10^{17}$ Bq in the equilibrium core of HTR-10. The results appear to be highly probable, and they would be informative when the spent fuel of HTGRs is taken into account. The tritium inventory in the primary coolant is also taken into account without a helium purification system. This article can lay a foundation for future work on analyses of source terms as a platform for safety assessment in HTGRs.

• Analytical Science and Technology
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• v.15 no.1
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• pp.7-14
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• 2002

Laser ablation ion trap mass spectrometry (LAITMS) was developed for the analysis of metal and ceramic samples. For this study, XeCl excimer laser (308 nm) was used for ablating the samples and ITMS was used as a detector. Samples were introduced from outside of a ring electrode and this way of sample introduction was very effective for solid samples when laser ablation was employed. Helium gas was used as a buffer gas, and its effect on sensitivity and some parameters (buffer gas pressure, ion storage time, and cut-off RF voltage) were studied. The optimized conditions were $1{\times}10^{-4}$ Torr of buffer gas pressure, 100 ms of ion storage time and $1150V_{p-p}$ of cut-off RF voltage. From that results, copper (Cu) and molybdenum (Mo) metals were tested with LAITMS and the mass spectra of these pure metals were compared with the natural abundance of isotope ratio. We also examined ceramic samples ($Al_2O_3$, $ZrO_2$) and represented the result of elemental analysis.

• The Journal of Engineering Geology
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• v.34 no.2
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• pp.229-248
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• 2024

This investigated the hydrogeochemical and isotopic characteristics of geothermal waters, groundwaters, and surface waters in Dongrae-gu, Busan, South Korea, in order to determine the origins of the salinity components in the geothermal waters, and their formation mechanisms and heat sources The geothermal waters are Na-Cl-type, distinct from surrounding groundwaters (Na-HCO₃^- and, Ca-HCO₃^- (SO₄, Cl)-type) and surface waters (Ca-HCO₃(SO₄, Cl)-type). This indicates the geothermal waters formed at depth as compared with the groundwaters. δ¹⁸O and δD values of the geothermal waters are relatively depleted as compared with the groundwaters, due to altitude effects and deep circulation of the geothermal waters. Helium and neon isotope ratios (³ He/⁴He and, ⁴He/²⁰Ne) of the geothermal waters plot on a single mixing line between mantle (³He = 3.76~4.01%) and crust (⁴He = 95.99~96.24 %), indirectly suggesting that the heat source is due to the decay of radioactive elements in rocks. The geothermal reservoir temperatures were calculated using the silica-enthalpy and Giggenbach models, yielding values of 82~130℃, and the depth of the geothermal reservoir is estimated to be 1.7~2.9 km below the surface. The correlation between Cl/Na and Cl/HCO₃ for the Dongrae geothermal waters requires the input of salty water. The supply of saline composition is interpreted due to the dissolution of residual paleo-seawater.

• Economic and Environmental Geology
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• v.40 no.5
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• pp.635-649
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• 2007

Geochemical composition, stable isotopes $({\delta}^{18}O,\;{\delta}D,\;{\delta}^{34}S)$ and noble gases(He, Ne and Ar) of nine hot spring water and three groundwater for five hot springs(Jukam, Hwasun, Dokog, Jirisan, Beunsan) from the Honam area were analyzed to investigate the hydrogeochemical characteristics and the hydrogeochemical evolution of the hot spring waters, and to interpret the source of sulfur, helium and argon dissolved in the hot spring waters. The hot spring waters show low water temperature ranging from 23.0 to $30.5^{\circ}C$ and alkaline characteristics of pH 7.67 to 9.98. Electrical conductivity of hot spring waters is $153{\sim}746{\mu}S/cm$. Groundwaters in this area were characterized by the acidic to neutral pH range$(5.85{\sim}7.21)$, the wide electrical conductivity range $(44{\sim}165{\mu}S/cm)$. The geochemical compositions of hot spring and groundwaters can be divided into three water types: (1) $Na-HCO_3$ water type, (2) Na-Cl water type and (3) $Ca-HCO_3$ water type. The hot spring water of $Ca-HCO_3$ water type in early stage have been evolved through $Ca(Na)-HCO_3$ water type into $Na-HCO_3$ type in final stage. In particular, Jurim alkaline(pH 9.98) hot spring water plotted at the end point of $Na-HCO_3$ type in the Piper diagram is likely to arrive into the final stage in geochemical evolution process. Hydrogen and oxygen isotopic data of the hot spring water samples indicate that the hot spring waters originated from the local meteoric water showing latitude and altitude effects. The ${\delta}^{34}S$ value for sulfate of the hot spring waters varies widely from 0.5 to $25.9%o$. The sulfur source of most hot spring waters in this area is igneous origin. However, The ${\delta}^{34}S$ also indicates the sulfur of JR1 hot water is originated from marine sulfur which might be derived ken ancient seawater sulfates. The $^3He/^4He\;and\;^4He/^{20}Ne$ ratios of the hot spring waters range from $0.0143{\times}10^{-6}\;to\;0.407{\times}10^{-6}\;and\;6.49{\sim}584{\times}10^{-6}$, respectively. The hot spring waters are plotted on the mixing line between air and crustal components. It means that the He gas in the hot spring waters was mainly originated from crustal sources. However, the JR1 hot spring water show a little mixing ratio of the helium gas of mantle source. The $^{40}Ar/^{36}Ar$ ratios of hot spring water are in the range from $292.3{\times}10^{-6}\;to\;304.1{\times}10^{-6}$, implying the atmospheric argon source.

• The Journal of Engineering Geology
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• v.26 no.4
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• pp.515-529
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• 2016

In this study, geochemical composition, CFCs (Chlorofluorocarbons), ${\delta}^{18}O$, ${\delta}D$, ${\delta}^{13}C$ isotopes and noble gases isotopes (He, Ne) were analyzed to determine their recharge age, source of $CO_2$ gas and noble gases of carbonated hot spring water and carbonated-water samples collected in the Seoqwipo of the Jeju. The pH of the carbonated waters ranges from 6.21 to 6.84, and the high electrical conductivity range ($1,928{\sim}4,720{\mu}S/cm$). Their chemical composition is classified as $Mg(Ca,\;Na)-HCO_3$ and $Na(Ca,\;Mg)-HCO_3$ types. As a result of the calculation of groundwater age using CFCs concentrations as an environmental tracer, the carbonated water and groundwater were estimated to be about 47.5~57.2 years and about 30.3~49.5 years, respectively. The ${\delta}^{13}C$ values of carbonated water range from -1.77 to -7.27‰, and are plotted on thr deep-seated field or the mixing field of the deep-seated and inorganic origin. Noble gases isotopic ($^3He/^4He$, $^4He/^{20}Ne$) ratio shows that helium gas of carbonated hot waters comes from deep-seated magma origin.