• Proceedings of the Korean Nuclear Society Conference
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• 1995.05b
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• pp.853-858
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• 1995

$^{152}$EU, $^{241}$Am 및 $^{241}$Np를 선정하여 추출제 di-(2-ethylhexyl)phosphoric acid (DEHPA)로 이들 세가지 핵종의 상호 분리공정에 대해 연구하였다. 추출공정에서 질산농도는 0.IM이고 추출 제DEHPA/n-dodecane 농도가 IM 일때, $^{152}$Eu 및 $^{241}$Am, $^{241}$Np 핵종 모두 99.9% 이상 추출되었다. $^{241}$Am 핵종의 역추출을 위한 제 1 역추출공정에서 역추출제인 0.05M di-ethylenetriamine pentaacetic acid (DTPA)와 1.5M 젖산 (lactic acid) 혼합용액의 pH가 3.6 일때 $^{152}$Eu과 $^{241}$Am의 상호분리비와 역추출율이 가장 좋았다. $^{152}$Eu의 역추출을 위한 제 2 역추출단계에서 역추출제인 질산용액의 최적농도는 6M이며, 이때 $^{152}$Eu은 99%가 역추출되었다.$^{241}$Np 핵종의 역추출을 위한 제 3 역추출공정에서 역추출제는 0.5M 옥살산이며, 이때 $^{241}$Np은 92%가 역추출되었다.

• Proceedings of the Korean Nuclear Society Conference
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• 1998.10a
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• pp.278-278
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• 1998

• Nuclear Engineering and Technology
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• v.51 no.2
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• pp.526-532
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• 2019

In this study, an in-house $^{152}Eu$ calibration source was produced from a custom epoxy matrix with a density of ${\rho}=1.14g\;cm^{-3}$, which is chemically stable and durable form after its solidification. The homogeneity of $^{152}Eu$ in matrix was obtained better than 98%. For a Marinelli beaker geometry, an efficiency calibration procedure was applied to a n-type, coaxial, 78.5% relative efficient HPGe detector in the energy range of 121.7-1408.0 keV by using in-house $^{152}Eu$ calibration source. Then the measured efficiencies for Marinelli geometry were compared with the results calculated by MEFFTRAN and ANGLE softwares for the validation. Although MEFFTRAN and ANGLE have two different efficiency transfer algorithms to calculate the efficiencies, they usually need to use a reliable and accurate reference efficiency values as input data. Hence, reference efficiency values were obtained experimentally from a multinuclide standard source for the same detector-Marinelli geometry. In the present source characterization, the corrections required for self-absorption and true coincidence summing effects for $^{152}Eu$ gamma-rays were also obtained for a such close counting geometry condition. The experimental results confirmed the validity of efficiency calculations obtained by MEFFTRAN and ANGLE softwares that are calculation tools.

• Applied Chemistry for Engineering
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• v.7 no.1
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• pp.153-161
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• 1996

Several main nuclides($^{241}Am$, $^{152}Eu$ and $^{237}Np$) in radioactive waste solution were selected and examined to mutual separation with di-(2-ethylhexyl) phosphoric acid by solvent extraction technique. $^{237}Np$ was extracted more than 99.9% adding the $H_2O_2$ that was a good reductant for the oxidation state control of $^{237}Np$. $^{241}Am$, $^{152}Eu$ and $^{237}Np$ could be fairly well separated one another during the different sequence stripping stages, but about 7~9.6% of the other nuclides were still remained for the $^{241}Am$ stripping solution. This result shows that the product of $^{152}Eu$ and $^{237}Np$ was good, but $^{241}Am$ may be needed to further purification process. It was also discussed on the cause of the third phase formation phenomenon that was found in the solvent regeneration.

• Economic and Environmental Geology
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• v.40 no.4
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• pp.361-374
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• 2007

Rare earth elements(REEs) have been used as an useful tool in understanding the various geological processes such as evolution and differentiation in the crust. The REEs also have been used as an analog of actinides for radioactive wastes at the water-rock interactions. Using physicochemical properties of the REEs and actinides, we have shown that Eu is an optimum analogue for understanding the behavior of Am in subsurface environments. Factors affecting sorption behavior of radioactive nuclides in groundwater were investigated by batch experiments. Four nuclides such as $^{241}Am,\;^{152}Eu,\;^{160}Tb\;and\;^{60}Co$ were selected to test our hypothesis, and $^{160}Tb$ and $^{60}Co$ were specifically used to compare to the sorption behavior between $^{241}Am-^{152}Eu$ and other radioactive nuclides. Four different rock samples and one groundwater were used in the batch experiments where solution pH for all experiments was fixed at 5.5. Our results demonstrate that $^{241}Am,\;^{152}Eu,\;and\;^{160}Tb$ show similar sorption behavior whereas $^{60}Co$ is different in sorption behavior at the mineral-water interface, suggesting that the sorption behavior of $^{60}Co$ is affected by different rock types. Our results also show that 1) Eu in REEs is optimum analogue of fate and transport of Am in subsurface environments, and 2) mineral compositions such as $SiO_2,\;TiO_2,\;P_2O_5$ and distribution of REEs such as Eu anomaly play key roles in affecting sorption behavior of radioactive nuclides even though physicochemical properties of geological materials such as specific surface area and cation exchange capacity can not be ruled out.

• Nuclear Engineering and Technology
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• v.52 no.6
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• pp.1266-1270
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• 2020

A code is developed to correct for the coincidence summing effect in detecting a voluminous gamma source, and this code is applied to a¹⁵²Eu standard source as a test case. The source is 1000 mL of liquid in a cylindrical shape. To calculate the coincidence summing effect, the cylindrical source is considered as 10(radial) × 8(height) sectional sources. For each sectional source, the peak efficiency and total efficiency are obtained by Monte Carlo simulation at each energy for 10 energies between 50 keV and 2000 keV. The efficiencies of each sector are then expressed as polynomials of gamma energy. To calculate the correction coefficients for the coincidence summing effect, the KORSUM code is used after modification. The magnitudes of correction are 4%-17% for the standard ¹⁵²Eu source measured in this study. The relative deviation of 4.7% before the coincidence correction is reduced to 0.8% after the correction is applied to the efficiency based on the measured gamma line. Hence, this study has shown that a new method has been developed that is applicable for correcting the coincidence effect in a voluminous source, and the method is applied to the measured data of a standard ¹⁵²Eu cylinder source.

• Proceedings of the Korean Vacuum Society Conference
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• 2015.08a
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• pp.152-152
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• 2015

최근에 백색 발광체 개발에 많은 관심이 고조되고 있다. 본 연구에서는 고상반응법을 사용하여 활성제 이온 $Dy^{3+}$의 함량을 0.05 mol로 고정하고, $Eu^{3+}$ 이온의 함량을 각각 0, 0.5, 1, 5, 10, 15 mol%로 변화시켜 $Y_2WO_6:Dy^{3+}$, $Eu^{3+}$ 형광체 분말을 합성하였다. $Dy^{3+}$ 이온만 도핑된 $Y_2WO_6$ 형광체의 흡광 수펙트럼은 전하 전달 밴드 ($Dy^{3+}-O^{2-}$)에 의한 250~350 nm에 존재 하는 밴드폭이 넓은 전이 신호와 360~500 nm 영역에 걸쳐 있는 상대적으로 흡광 세기가 약한 다수의 $Dy^{3+}$ 이온의 전이 신호가 관측 되었다. $Dy^{3+}$와 $Eu^{3+}$가 동시 도핑된 $Y_2WO_6$ 형광체의 발광 스펙트럼의 경우에, $Eu^{3+}$ 이온의 몰 비가 증가함에 따라 $Dy^{3+}$ 이온에 의한 577 nm에 주 피크를 갖는 황색 발광 파장의 세기는 감소하였고, $Eu^{3+}$ 이온에 의해 발생하는 612 nm의 적색 발광 파장의 세기는 순차적으로 증가하였다. 이 결과는 $Dy^{3+}$와 $Eu^{3+}$ 이온의 몰 비를 적절히 조절함으로써 최적의 백색 발광 형광체를 제조할 수 있음을 제시한다.

• Nuclear Engineering and Technology
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• v.31 no.5
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• pp.498-505
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• 1999

Trivalent actinide-lanthanide group separation is difficult to perform on an industrial scale, because of the many drawbacks of the available chemical process. In this paper, picolinamide(C$_{8}$H$_{17}$) is synthesized and characterized, and extraction yields of Am-241, Eu-152 and Nd are determined in batch extraction experiments. In particular, the influence of the solvent is described. The extraction yields of Am-241, Eu-152 and Nd depended on the LiNO$_3$ concentration, the picolinamide(C$_{8}$H$_{17}$) concentration and the acidity. A favorable picolinamide(C$_{8}$H$_{17}$) concentration was found to be about 2M. The appropriate nitric acid concentration and LiNO$_3$ concentration were confirmed to be about 0.125M and 3M, respectively. The separation factor of Am and Eu was about 9.9 at optimum conditions. The picolinamide(C$_{8}$H$_{17}$) is a very promising extractant for the actinide(III)-lanthanides(III) separation.aration.aration.

• Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
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• v.18 no.2
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• pp.157-167
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• 2020

Removing radioactive concrete is crucial in the decommissioning of nuclear power plants. However, this process generates radioactive aerosols, exposing workers to radiation. Although large amounts of radioactive concrete are generated during decommissioning, studies on the internal exposure of workers to radioactive aerosols generated from the cutting of radioactive concrete are very limited. In this study, therefore, we calculate the internal radiation doses of workers exposed to radioactive aerosols during activities such as drilling and cutting of radioactive concrete, using previous research data. The electrical-mobility-equivalent diameter measured in a previous study was converted to aerodynamic diameter using the Newton-Raphson method. Furthermore, the specific activity of each nuclide in radioactive concrete 10 years after nuclear power plants are shut down was calculated using the ORIGEN code. Eventually, we calculated the committed effective dose for each nuclide using the IMBA software. The maximum effective dose of ¹⁵²Eu constituted 83.09% of the total dose; moreover, the five highest-ranked elements (¹⁵²Eu, ¹⁵⁴Eu, ⁶⁰Co, ²³⁹Pu, ⁵⁵Fe) constituted 99.63%. Therefore, we postulate that these major elements could be measured first for rapid radiation exposure management of workers involved in decommissioning of nuclear power plants, even if all radioactive elements in concrete are not considered.

• Proceedings of the Korean Nuclear Society Conference
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• 1997.05b
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• pp.301-306
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• 1997

추출제 di-(2-ethylhexyl)phosphoric acid건의 Zr 염으로 $^{241}$Am 및 $^{152}$Eu의 상호분리를 위한 용매추출공정에 대한 화학적 특성을 규명하였다. 추출공정에서 질산농도 0.5M, Zr 농도 8.7g/L, 추출제 HDEHP/n-dodecane 농도가 1M 일때 Am 및 Eu은 각각 92.3%와 99.1%가 추출되었으며, Zr 농도에 비례하여 Am, Eu의 추출율이 증가하는 상승효과를 나타내었다. pH가 3인 0.05M DTPA와 1M lactic acid 혼합 역추출용액으로 Am을 선택적으로 역추출한 결과 Am의 역추출율은 38.1% 이며, 이때 Am과 Eu의 상호분리비는 14.2 였다. 그리고 유기상에 남아 있는 Eu은 6M 질산용액으로 역추출한 결과 94.4%의 Eu가 역추출되었다.