• 한국지하수토양환경학회지:지하수토양환경
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• 제15권6호
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• pp.9-16
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• 2010

Groundwater sampling was performed at 38 wells where they are located in the areas with high uranium and radon (marked as A and B, respectively) concentrations, which were based on the previous research results. In-situ parameters (temperature, pH, EC, Eh, DO) and natural radionuclides (uranium and radon) were analyzed to figure out the characteristics of groundwater environments. In-situ data did not show any relations to natural radionuclide data, which could be caused by groundwater mixing, depths of wells, and geological settings, etc. But the highest radon well presented relatively low temperature value and the highest uranium well presented relatively low pH values The highest uranium concentration ranging $1.14{\sim}188.19{\mu}g/L$ showed in the area of A region consisted of Jurassic two-mica granite. The areas of Jurassic biotite granite and Cretaceous granite in the A region have the uranium concentrations ranging $0.10{\sim}49.78{\mu}g/L$ and $0.36{\sim}3.01{\mu}g/L$, respectively. The uranium values from between wells of community water systems (CWSs) penetrating fractured bed-rock aquifers and personal boreholes settled in shallow aquifers near the wells of CWSs show big differences. It implies that the groundwaters of the two areas have evolved from different water-rock interaction paths that may caused by various types of wells having different aquifers. High radon activities in the area of B region composed of Precambrian gneiss showed ranging from 6,770 to 64,688 pCi/L. Even though the wells are located in the same geological settings, their rodon concentration presented different according to depth and distance.

• Nuclear Engineering and Technology
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• 제55권2호
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• pp.523-529
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• 2023

Cemented uranium tailings backfill created from alkali-activated slag (CUTB) is an effective method of disposing of uranium tailings. Using some environmental functional minerals with ion exchange, adsorption, and solidification abilities as backfill modified materials may improve the leaching resistance of the CUTB. Natural zeolite, which has good ion exchange and adsorption characteristics, is selected as the backfill modified material, and it is added to the backfill materials with cementitious material proportions of 4%, 8%, 12%, and 16% to prepare CUTB mixtures with environmental functional minerals. After the addition of natural zeolite, the uniaxial compressive strength (UCS) of the CUTB decreases, but the leaching resistance of the CUTB increases. When the natural zeolite content is 12%, the UCS reaches the minimum value of 8.95 MPa, and the concentration of uranium in the leaching solution is 0.28-8.07 mg/L, the leaching rate R₄₂ is 9.61×10^-7 cm/d, and cumulative leaching fraction P₄₂ is 8.53×10^-4 cm, which shows that the alkali-activated slag cementitious material has a good curing effect on the CUTB, and the addition of environmental functional minerals helps to further improve the leaching resistance of the CUTB, but it reduces the UCS to an extent.

• Nuclear Engineering and Technology
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• 제2권4호
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• pp.273-278
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• 1970

국내에서 채광한 자연방사능광물의 분석의뢰를 계기로 이에 관심을 갖고 Uranium와Thorium 의 함유량을 원광으로부터 비파괴적이고 간단한 ${\gamma}$-선 분광법으로 측정 분석하여 보았다. Ge(Li) 측정기를 ${\gamma}$-선 분광에 이용한 결과는 재래식방법에 비하여 분석정도를 훨씬 높일 수 있었으며, 자연방사능측정법과 원자로중성자로 조사시킨 activation법으로 Uranium와 Thorium의 함유량을 분석하였던바 하나의 시료(인천에서 채광)에서는 약 0.5%의 Uranium, 또 다른 시료에서는 2%의 Th와 0.1%의 U이 포함되어 있음이 확인되었다. 우리가 처음 시도한 이 분석법은 경제적이고 간편.신속하게 분석할수 있어 핵연료물질조사에 널러 이용할 수 있음을 입증한다.

• 통합자연과학논문집
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• 제6권2호
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• pp.104-110
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• 2013

1-Aza-12-crown-4 macrocyclic ligand was combined with styrene (2th petroleum in 4th class hazardous materials) divinylbenzene copolymer having 1%, 2%, 3%, and 6% crosslinks by a substitution reaction, in order to synthesize resin. These synthetic resins were confirmed by chlorine content, elementary analysis and IR-spectrum. As the results of the effects of pH, equilibrium arrival time, crosslink of synthetic resin, and dielectric constant of a solvent on uranium ion adsorption for resin adsorbent, the uranium ion showed high adsorption at pH 3 or over and adsorption equilibrium of uranium ion was about 2 hours. In addition, adsorption selectivity for the resin in methanol solvent was the order of uranium ($UO_2{^{2+}}$) > iron ($Fe^{3+}$) > lutetium ($Lu^{3+}$) ions, adsorbability of the uranium ion was in the crosslinks order of 1%, 2%, 3%, and 6% was increased with the lower dielectric constant.

• Nuclear Engineering and Technology
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• 제52권12호
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• pp.2867-2873
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• 2020

In reprocessed uranium, derived from an impoverished fuel of light-water moderated reactors, there are isotopes of ^{232, 234, 236}U, which make its recycling remarkably difficult. A method of concentration of ²³⁵U target isotope in cascade's additional product was proposed to recover the isotopic composition of reprocessed uranium. A general calculation procedure is presented and a parameters' optimization of multi-flow cascades with additional products. For the first time a numeric model of a cascade that uses the cuts of partial flows of stages with relatively high separation factors was applied in this procedure. A novel computing experiment is carried out on separation of reprocessed uranium hexafluoride with providing a high concentration of ²³⁵U in cascade's additional product with subsequent dilution. The parameters of cascades' stages are determined so as to allow reducing the ^{232, 234, 236}U isotope content up to the acceptable. It was demonstrated that the dilution of selected products by the natural waste makes it possible to receive a low enriched uranium hexafluoride that meets the ASTM C996-15 specification for commercial grade.

• 방사성폐기물학회지
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• 제4권2호
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• pp.179-186
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• 2006

원자력을 이용하는 시설 및 그와 관련한 연구개발실험실로부터 각종 화학폐수가 다량으로 발생되고 있으며 이들 폐수를 화학폐수 전용처리시설로 처리하고 있으나 최종 건조 케이크내에 함유된 우라늄의 농도가 규제면제농도인 10 Bq/g을 약간 초과하므로서 방사성폐기물로 분류하여 별도로 저장하고 있다. 화학폐수 처리후 침전된 슬러지내의 우라늄 농도를 분석한 결과 우라늄이 용액상이 아닌 침전물상에 존재함을 알았으며, 이들 우라늄을 침전물로부터 용액상으로 용해하기 위하여 강질산으로 용해시켰다. 그 결과 대부분의 우라늄이 슬러지의 침전물로부터 용액상으로 용출되었으며, 용해후 얻어진 슬러지 산용해액에 대해 IRN-77과 비드형으로 새로 제조한 다이포실 수지를 실 폐액처리에 적용하기 위한 흡착실험을 수행하였다. IRN-77과 다이포실 비드를 단독, 혼합 또는 단계적으로 사용한 결과, 80%이상의 우라늄 흡착효율을 얻기 위해서는 산용해액과 동등량 또는 그 이상의 다량의 수지가 소요되었다. 한편 침전 슬러지를 압착하여 부피가 더욱 축소된 탈수케이크를 산용해한 결과, 탈수케이크 대 질산의 비율이 3:2에서 우라늄의 함량을 최대 11 mg/L을 얻었으며 슬러지 용해시보다 적은 양으로 산용해가 가능하였다. 탈수 케이크 산용해액의 방사능 농도는 6.97E-01 Bq/ml 로서 기존의 자연증발처리시설에서 처리가 가능한 수준이었으며, 건조케이크의 비방사능은 11.2 Bq/g로서 최종 폐기물로 발생될 폐증발천의 비방사능이 4.3 Bq/g으로 평가되어 우라늄 동위원소의 규제면제치인 10 Bq/g 미만이므로 자체처분이 가능한 수준이었다. 결론적으로 화학폐수를 처리한 후 부피가 최소화된 탈수케이크에서 우라늄을 산용해시키고 최종 산용해액은 기존의 자연증발시설로 증발처리하면 방사성 건조케이크의 발생 없이 또한 자연증발천도 자체처분이 가능한 최적의 방안을 도출하였다.

• 방사성폐기물학회지
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• 제5권2호
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• pp.113-122
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• 2007

본 연구에서는 타당한 지하조건을 모사하기 위한 실험장치를 글로버박스(Glove-box) 내에 설치하고 천연지하수 및 자연균열을 가진 화강암 시추코어를 이용하여 핵종이동 실험을 수행하였다. 암반코어의 균열을 통한 지하수 유동을 해석하기 위하여 비수착성 음이온 핵종인 Br로 지하수 유동실험을 수행하였다. 암반 균열을 통한 우라늄 이동 실험결과에서 유출된 우라늄의 파과곡선이 비수착성 핵종인 Br와 유사한 거동을 보여주었는데, 이는 주어진 지하수 조건에서 우라늄이 주로 탄산염과 결합된 음이온 복합체로 이동하기 때문인 것으로 추정된다. 아울러 균열충전광물에 대한 우라늄의 회분식 수착실험을 수행한 결과, 균열충전광물에 대한 우라늄의 분배계수 $K_d$는 약 2.7 mL/g로 낮게 나타났다. 이러한 우라늄 수착실험 결과는 빠른 유출을 보인 우라늄 이동실험 결과와 일치한다. 균열암반을 통한 우라늄 이동의 지 연 특성을 보다 자세히 분석하기 위하여 회분식 수착실험으로 부터 구한 $K_d$값을 이용해 지연인자 $R_d$값 $({\sim}16.2)$를 구하고 이동실험 결과로부터 구한 $R_d$값 $({\sim}14.3)$과 비교한 결과, 서로 매우 유사한 지연인자 값을 가진다는 것을 알 수 있었다. 이는 화강암 코어의 균열을 통한 우라늄의 이동 지연이 주로 균열충전광물에 의해 이루어지고 있음을 의미하는 것이라고 하겠다.

• Advances in materials Research
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• 제2권2호
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• pp.93-98
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• 2013

Objective of this study is to calculate gamma buildup factors for pointed and isotropic gamma sources in depleted uranium, uranium dioxide, natural uranium, tin, water and concrete using MCNP4C code. The thickness of the media ranges from 0.5 to 10 mean-free-path (mfp) and gamma energy ranges from 0.5 to 10 MeV. Owing to the outstanding accuracy of MCNP in calculation involving gamma interaction, results fairly match those reported previously. The maximum relative error is 2%.

• Nuclear Engineering and Technology
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• 제38권4호
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• pp.353-358
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• 2006

Alpha track analysis for the determination of the trace amount of alpha emitting nuclides in a very small particle was performed as an efficient and powerful technique during safeguard inspection. Metal particles with well-defined spherical shape, size and isotopic compositions as a reference material were used to correlate the number of tracks or track diameter with an isotopic composition eventually to identify the uranium enrichment in the environmental swipe samples. Slopes in the number of tracks versus the exposure time curve provide a simple insight into the uranium enrichment of an unknown particle. Low enriched uranium metal particles result in slopes still steeper than the depleted or natural uranium metal particles. In addition, a linear relationship between track diameter and particle size Is thought to be a useful first stage analytical tool as an efficient and convenient inspection guide. The significance of the simple linear model was also judged using the usual statistical tests.

• 한국의류학회지
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• 제14권2호
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• pp.98-103
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• 1990

Fibrous adsorbents containing amidoxime group which make chelate complexes with uranyl ions are studied for the recovery of uranium from sea water. Acrylic fibers are used as base Polymer. The adsorption properties of uranium are carried out to examine pH effect, concen-tration dependence, adsorption rate, separation, and chelate complex. The results obtained are as follows; 1. Metal capacity of U (VI) ion is in the range of pH $2\~10.2$. Amidoxime group-containing fiber recover U (VI) ions existed in sea water or waste water in extremely small quantities. 3. Using amidoxime group-containing fiber Cu (II) and U (VI) are separated with each other in dilute nitric acid solution (pH 2.3). 4. U (VI) chelate complexes are conformed by tridendate ligands, which are coordinated with one nitrogen and two oxygens onto amidoxime group-containing fiber.