• Journal of the Korean Chemical Society
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• v.38 no.1
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• pp.34-40
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• 1994

First observation of uranium using a diode laser was published recently. The experiment was performed by the optogalvanic spectroscopy using diode lasers. A laser source causes the current change in a hollow cathode discharge lamp when metal atoms in plasma absorb the diode laser light. The optogalvanic signal is collected by detecting the current change. This work is the extended investigation of our previous research, the uranium detection using a diode laser. New electronic transitions of uranium and thorium in 775∼850 nm were investigated using diode lasers. In addition, the Rb(Ⅰ) optogalvanic spectra at 780.02 nm and 794.76 nm were studied. The Rb(Ⅰ) spectrum at 780.02 nm showed the isotopic features and hyperfine splittings. This work provides a key idea that the diode lasers are useful in the specrochemical analysis of the radioactive actinides that have a rich spectrum with transitions which can be easily reached with AlGaAs diode lasers. Also, this study shows that the diode lasers can be an important tool to find the spectroscopic parameters of actinides and rare earth elements which have not known.

• Applied Chemistry for Engineering
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• v.10 no.7
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• pp.996-1002
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• 1999

The oxalate precipitation of lanthanide and actinide by oxalic acid was investigated in the simulated radioactive liquid waste, which was composed of 17 elements of alkali, alkaline earth(Cs, Rb, Ba, Sr), transition metal(Zr, Fe, Mo, Ni, Pd, Rh), lanthanide(La, Y, Nd, Ce, Eu) and actinide(Np, Am) in nitric acid solution. The effect of concentrations of nitric acid and ascorbic acid on the precipitation yield of each element in the simulated solution was examined at 0.5 M oxalic acid concentration. The precipitation yields of the elements were usually decreased with nitric acid concentration, nevertheless, the precipitation yields of lanthanide and actinide were more than 99%. Palladium was precipitated due to the reduction of Pd(II) into Pd metal by the addition of ascorbic acid in the oxalate precipitation and then, the precipitation yields of Mo, Fe, Ni, Ba decreased by 10~20% with concentration of ascorbic acid. The reductive precipitation of Pd(II) into Pd metal by the addition of ascorbic acid into the simulated radwaste occurred at below 1 M nitric acid concentration and its yield showed maximum at the ascorbic acid concentration of 0.01~0.02 M. The hydrazine suppressed the reductive precipitation of Pd by the ascorbic acid.

• Proceedings of the Optical Society of Korea Conference
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• 2002.07a
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• pp.236-237
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• 2002

원자력 발전소에서 사용되는 연료의 효율을 증가시키기 위해서는 반응로에서 연소된 연료에 잔존하는 미량의 란탄족 (lanthanide)과 악티늄족 (actinide) 원소를 측정하고, 동위원소 성분비를 분석하는 작업이 필요하다. 이러한 미량원소 측정에는 흡수분광학 (absorption spectroscopy) 방법이 주로 사용되고 있다. 최근 들어 단일 종 모드 (single-longitudinal mode) 반도체 레이저가 개발되면서 미량원소 분석을 위한 분광 기술이 급속히 발전하고 있다. 반도체 레이저는 동작시킬 때 전력소모가 적고, 설치 공간이 작다는 점 때문에 현장 적용이 용이하므로 미량원소 측정 연구의 광원으로 많이 활용되고 있다. (중략)

• Proceedings of the Korean Radioactive Waste Society Conference
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• 2009.11a
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• pp.198-199
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• 2009

킬레이팅 고분자를 메조기공 탄소 표면 위에 흡착시킴으로써 금속이온과 착물을 형성할 수 있는 기능성 나노구조체를 제조하였다. 악티늄족 원소를 단일입자 내에 영구처분을 위한 예비연구로서 Eu을 대용물(surrogate)로 사용하여 기능성 나노 구조체에 주입한 후 메조기공 입구를 고분자반응을 통해 봉쇄함으로써 Eu의 단일입자 내 고정화를 시도하였다. 시간에 따라 침출현상을 분석한 결과, 고분자로 메조기공을 blocking 하였을 때 Eu의 침출현상이 크게 완화되는 것을 확인하였다. 이는 시멘트화나 유리화 등과 같은 고비용 공정을 거치지 않고도 단일입자 내 유해 금속의 영구처분이 가능하다는 것을 의미한다. 더 나아가, 이러한 접근방법은 지지체로 메조기공 탄소에 국한되지 않고 실리카와 같은 다른 메조기공 금속산화물에 적용될 수 있다는 점에서 큰 강점이 있다.

• Proceedings of the Korean Radioactive Waste Society Conference
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• 2010.10a
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• pp.291-292
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• 2010

• Proceedings of the Korean Radioactive Waste Society Conference
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• 2007.11a
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• pp.300-301
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• 2007

• Proceedings of the Korean Radioactive Waste Society Conference
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• 2016.05a
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• pp.139-140
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• 2016

• Journal of the Korean Society of Marine Environment & Safety
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• v.18 no.2
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• pp.67-83
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• 2012

In order to evaluate die geochemical characteristics of sediment in a semi-enclosed bay used as shellfish and fish farming area, the concentrations of metallic(V, Cr, Mn, Fe, Co. Ni, Cu, Zn, Ag, Cd, Hg, Ph, As) and non-metallic(P, Se) elements and uranium were measured in the surface sediment samples collected from 19 stations of Gamak Bay in April 2010. Metal contamination status in the sediments were also evaluated using the sediment quality guidelines(SQGs) proposed by the National Oceanic and Atmospheric Administration(NOAA) and the enrichment factor(EF). The concentrations of elements in sediment were mainly controlled by quartz-dilution effect(V, Cr, Fe, Co and Ni), the dilution effect of organic matter(Cd and U), and metal redistribution by the decomposition of organic matter(Mn, Ag, As, and Se). The concentrations of metals, except As and Ni, in sediments from all sampling stations were lower than ERL values of NOAA. Conclusively, the surface sediment of Gamak Bay was slightly polluted with Ni, Ag, Cd, and Cd but was not polluted with other elements on the basis of EF results. Our results suggest that the surface sediment in Gamak Bay is not polluted by metallic elements.

• Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
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• v.8 no.1
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• pp.1-7
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• 2010

In the present work, an electrowinning process in the LiCl-KCl/Cd system is considered to model and analyze the electrotransport of the actinide and rare-earth elements. A simple dynamic modeling of this process was performed by taking into account the material balances and diffusion-controlled electrochemical reactions in a diffusion boundary layer at an electrode interface between the molten salt electrolyte and liquid cadmium cathode. The proposed modeling approach was based on the half-cell reduction reactions of metal chloride occurring on the cathode. This model demonstrated a capability for the prediction of the concentration behaviors, a faradic current of each element and an electrochemical potential as function of the time up to the corresponding electrotransport satisfying a given applied current based on a galvanostatic electrolysis. The results of selected case studies including five elements (U, Pu, Am, La, Nd) system are shown, and a preliminary simulation is carried out to show how the model can be used to understand the electrochemical characteristics and provide better information for developing an advanced electrowinner.

• Proceedings of the Korean Radioactive Waste Society Conference
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• 2009.06a
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• pp.305-306
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• 2009