• Nuclear Engineering and Technology
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• 제56권5호
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• pp.1880-1886
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• 2024

To elucidate the mechanism of damage caused by hyphae and organic acids produced by Aspergillus Niger on the surface and internal structure of uranium ore, direct uranium leaching, indirect uranium leaching and semidirect uranium leaching were conducted, and the surface morphology, strength, mineral crystallinity, porosity, and permeability of the ore were analyzed. The results demonstrated that the combination of biomechanical forces exerted by hyphae and the complexation effects of organic acids led to the dissolution of SiO₂ and other substances on the surface of ore, resulting in exfoliation from the exterior to the interior, thereby promoting uranium recovery. Furthermore, the proton exchange involving H⁺ and the complexation of organic acids resulted in the dissolution of cations within the ore, causing destruction to the crystal lattice structure of minerals and increasing the porosity and permeability inside the ore. The dominant factor contributing to ore damage during recovery was organic acids.

• 자원환경지질
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• 제27권6호
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• pp.601-609
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• 1994

Uranium resources of Mongolia are generally confined to sediments deposited during Jurassic to Cretaceous volcanism. Territory of Mongolian uranium deposits is divided into four districts as follows; Mongol-Priargun, Gobi-Tamtsag, Hentii-Dauer, North-Mongolian. Potential uranium deposits were discovered by Airborne Gamma ray Spectrometric Survey(AGSM). One of them, Haraat deposit, which was interested to us, has been under detailed survey for exploitation by one of American companies, Concord company. The Erdes uranium mine is partly operated by about hundred Russian staffs at the open pit, while underground mining facilities such as the main hoist are almost closed. Ore minerals of the Erdes Mine are coffinite and pitchblende. Uranium content in ore ranges from 0.06% to 1%, averaging 0.2%. Ore reserves of uranium ore in the Dornod deposit including the Erdes Mine accounts 29,000 ton. It is reported that Uranium resources of Mongolia are 1,471,000 ton.

• KSBB Journal
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• 제11권3호
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• pp.353-359
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• 1996

Thiobacillus ferrooxidans를 이용한 보다 효율적이고 현장에 직접 응용할 수 있는 우라늄 침출공정을 개발하기 위하여 배양조건의 확립과 교반 반응기 및 이중기포탑 반융기에서의 우라늄 침출에 대한 연구 를 수행하였다. 배지의 초기 $Fe^{2+}$ 농도는 원광석 40g/L에 대하여 16.2g/L를 이용하는 것이 적합하였으며, 원광석의 업자는 작을수록 우라늄 침출율이 증가하였다. 또한 원광석의 첨가량이 많을수록 우라늄의 침출속도는 증가하였으나 침출율은 약간씩 감소하였다. 교반 반 응기 빛 이중기포탑 반응기에서의 우라늄 침출에 대한 실험을 최적조건에서 수행한 결과 교반 반응기에 서는 진탕배양기에서와 통일하게 12일 배양시 39.3%의 침출율로 5.5mgjL의 우라늄을 얻었다. 반면 이중기포탑 반응기에서는 교반 반응기에 비하여 세 균수가 2.4배 증가하였으며, 우라늄의 침출율과 침출된 우라늄 농도도 각각 91.4%와 12.8mgjL으로 교반 반응기 보다 2.3배 증가하였다. 이러한 결과는 이중기포탑 반응기에서는 충분한 양의 산소와 이산 화탄소의 공급과 원광석의 혼합이 잘됨으로써 세균 의 활성이 크게 증가하여 우라늄 침출이 향상된 것으로 추정된다.

• 자원리싸이클링
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• 제22권1호
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• pp.3-10
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• 2013

본 발표는 국내 흑색 점판암으로부터 우라늄 및 바나듐 회수의 일반적인 현황 및 연구개발에 관한 내용이다. 우라늄 화합물(yellow cake)의 세계적인 수급 및 향후 전망뿐만 아니라, 국내 우라늄광의 매장량, 품위 및 특성에 대해 설명하였다. 그리고 국내 우라늄광의 기술개발에 관한 기 연구 실적 및 수행중인 연구과제의 개략적인 내용에 대해 기술하였다. 또한, 우라늄 및 바나듐 성분이 함유된 국내 흑색 점판암을 대상으로 하여 침출, 분리정제 및 회수에 관한 기술을 하였다.

• 자원환경지질
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• 제56권5호
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• pp.547-555
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• 2023

분석 기기의 발달과 더불어 자연 우라늄 동위원소 비(²³⁸U/²³⁵U)와 분별작용에 대한 연구가 점차 증가하고 있다. MC-ICP-MS을 이용한 우라늄 동위원소의 정밀한 분석이 가능해지면서 137.88의 고정된 값으로 여겨졌던 자연 물질의 ²³⁸U/²³⁵U 비가 우라늄 동위원소 분별작용에 의해 최대 수 퍼밀까지 변화할 수 있다는 것이 밝혀졌다. 본 고찰에서는 우라늄 동위원소의 분석과 표기에 대해 간략하게 설명한 후, 지구 상 주요 물질들의 우라늄 동위원소 값(δ²³⁸U)의 변화와 지구화학적 특징을 살펴본다. 특히, 우라늄 광상의 유형과 특징에 따른 우라늄 동위원소 조성 연구 사례를 소개하고, 상대적으로 큰 δ²³⁸U 범위를 야기하는 우라늄 동위원소 분별작용에 대해 논의한다. 이를 바탕으로 고준위 방사성 폐기물 처분장의 모의 실험을 위한 자연 유사 모델로서 우라늄 광상이 갖는 연구 의의에 대해 고찰한다.

• Nuclear Engineering and Technology
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• 제30권6호
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• pp.518-530
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• 1998

A natural analogue study has been performed for the Koongarra uranium ore deposit in Australia as an international agreement of the Analogue Studies in the Alligator Rivers Region (ASARR). Rocks obtained from the Koongarra deposit, Northern Territory of Australia, were examined in order to understand uranium migration processes of primary and secondary ore-body in both weathered and unweathered zones. Total alpha activities of rock samples were measured to compare the relative amount of uranium in the sample. Uranium distributions have been investigated by means of both the alpha-autoradiography and the fission track registration technique after irradiation in a flux of thermal neutrons (~10$\times$$10^{13}$nㆍ$cm^{-2}$ㆍs$^{-1}$) for 2 minutes. The mineral phases corresponding to the registered alpha-tracks and fission tracks were identified by petrological observation with optical microscope as well as X-ray diffraction and electron microprobe analysis (EPMA). Uranium was found mostly inside of the fracture of the quartzite and its mineral phase was identified as sklodowskite. The mineral phase associated with high uranium concentration was found as illeminite by petrological observation with optical microscope as well as EPMA.

• Nuclear Engineering and Technology
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• 제53권12호
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• pp.4033-4041
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• 2021

To better understand the permeability of uranium sandstone, improve the leaching rate of uranium, and explore the change law of pore structure characteristics and blocking mechanism during leaching, we systematically analyzed the microstructure of acid-leaching uranium sandstone. We investigated the variable rules of pore structure characteristics based on nuclear magnetic resonance (NMR). The results showed the following: (1) The uranium concentration change followed the exponential law during uranium deposits acid leaching. After 24 h, the uranium leaching rate reached 50%. The uranium leaching slowed gradually over the next 4 days. (2) Combined with the regularity of porosity variation, Stages I and II included chemical plugging controlled by surface reaction. Stage I was the major completion phase of uranium displacement with saturation precipitation of calcium sulfate. Stage II mainly precipitated iron (III) oxide-hydroxide and aluminum hydroxide. Stage III involved physical clogging controlled by diffusion. (3) In the three stages of leaching, the permeability of the leaching solution changed with the pore structure, which first decreased, then increased, and then decreased.

• The Korean Journal of Ecology
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• 제5권4호
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• pp.137-142
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• 1982

From 1975 to 1981, the survey was carried out to find out radioecological effects of uranium ore deposits on natural vegetation in Koisan, Korea. The symptoms of spotty and mosaic chlorosis, and necrosis were observed in flowering plants in the areas of uranium ore deposits at Deok-Peung-Ri A, B, and C in Koisan. Although 13 species were found to be chlorosis and necrosis, foliages observed are small and very rare. The features of these symptoms closely resemble those occured by the effects of heavy meetals. The amount of transparent radiation throughout the depth of soils from uranium radiation sources decreases exponentially. The mean contents in leaves of spotty and mosaik chlorotic plants, and soils were 1.36~1.53 and 5.3~7.4 ppm, respectively.

• Nuclear Engineering and Technology
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• 제7권4호
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• pp.295-310
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• 1975

고리원자로의 핵연로비 추정을 위한 가격 모델을 수립하고 이를 기초로 MITCOST-II 전자계산 code를 써서 고리 발전소의 전수명에 걸친 핵연료주기비를 계산하였다. 사용후 연료를 재처리 하지 않는다는 간단한 핵주기를 가정하였는데 평균 단위 핵연료비는 7.332 mills/Kwhe으로 추정되었으며 이중 우라늄 원광비와 농축비가 85% 이상을 차지하고 있음을 알아내었다. 또한 원광가격과 농축가격의 변동 및 발전소 가동율의 변화에 따른 영향을 계산했으며 그 결과 핵연료비가 원광가격 변동에 매우 민감하게 변화한다는 사실도 알아내었다. 따라서 경제적으로 전력을 생산하기 위해서는 적기에 염가로 우라늄을 확보할 수 있도록 노력을 기울여 야 한다고 제안하였다.

• Nuclear Engineering and Technology
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• 제29권4호
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• pp.327-335
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• 1997

The correlation of isotope composition of uranium, plutonium and neodymium with the burnup in M uranium dioxide fuel has been investigated experimentally. The total and fractional($^{235}$ U) burnup were determined by Nd-148 and, U and Pu mass spectrometric method respectively. The isotope compositions of these elements, after their separation from the fuel samples were measured by mass spectrometric. The content of the elements in the irradiated fuel ore determined by isotope dilution mass spectrometric method using $^{233}$ U, $^{242}$ Pu and $^{150}$ Nd as spikes. The content of plutonium in the irradiated fuel was expressed by the correlation with uranium isotopes. The correlations between isotope compositions themselves and the total and fractional burnup ore compared with those calculated from ORIGEN2 code.