• Nuclear Engineering and Technology
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• 제47권7호
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• pp.924-933
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• 2015

The correlation of the isotopic composition of uranium, plutonium, neodymium, and cesium with the burnup for high burnup pressurized water reactor fuels irradiated in nuclear power reactors has been experimentally investigated. The total burnup was determined by Nd-148 and the fractional $^{235}U$ burnup was determined by U and Pu mass spectrometric methods. The isotopic compositions of U, Pu, Nd, and Cs after their separation from the irradiated fuel samples were measured using thermal ionization mass spectrometry. The contents of these elements in the irradiated fuel were determined through an isotope dilution mass spectrometric method using $^{233}U$, $^{242}Pu$, $^{150}Nd$, and $^{133}Cs$ as spikes. The activity ratios of Cs isotopes in the fuel samples were determined using gamma-ray spectrometry. The content of each element and its isotopic compositions in the irradiated fuel were expressed by their correlation with the total and fractional burnup, burnup parameters, and the isotopic compositions of different elements. The results obtained from the experimental methods were compared with those calculated using the ORIGEN-S code.

• 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.

• 분석과학
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• 제16권4호
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• pp.325-332
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• 2003

고분해능질량분석기를 이용한 동위원소희석법으로 식품 중 co-planar PCBs의 분석을 시도하였다. 시료를 균질화하여 추출 후 실리카겔 및 알루미나 컬럼으로 정제를 하여 HRGC/HRMS로 분리능 10,000에서 분석하였다. 대상물질은 세계보건기구인 WHO에서 다이옥신류와 유사한 독성이 있다고 평가한 non-ortho co-planar PCB #77, #81, #126 및 #169 4종 및 mono-ortho coplanar PCBs #105, #114, #118, #123, #156, #157, #167 및 #189 8종을 포함한 12종 이었다. 대상시료는 시중에 유통 중인 우유 및 유제품을 선택하였다. 분석 결과 평균 회수율은 83~106%이었고 검출한계는 신호대잡음비 (signal/noise, S/N) >3에서 0.1 pg/g이었으며 식품시료 중 검출된 대상물질은 0.001~0.107 pgWHO-TEQ/g 수준이었다.

• 한국지하수토양환경학회지:지하수토양환경
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• 제18권3호
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• pp.1-10
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• 2013

This study was performed to summarize application of ${\delta}^{13}C$, ${\delta}^{37}Cl$ and ${\delta}D$ of trichloroethylene (TCE) to studies on environmental forensic field regarding identification of TCE sources and evaluation of contribution of TCE to groundwater using data collected from literatures. ${\delta}^{13}C$, ${\delta}^{37}Cl$ and ${\delta}D$ of TCE give some information regarding sources of TCE because they show specific value according to manufacturing method. Also, TCE do not show a significant isotopic fractionation owing to adsorption and dilution. The isotopic fractionation mainly occurs by biodegradation. In addition, isotopic fractionation factor for TCE is different according to a kind of microorganism participated in biodegradation. However, the isotopic data of TCE have to be applied with chemical compositions of TCE and other hydrogeologic factors because isotopic fractionation of TCE is influenced by various factors.

• Bulletin of the Korean Chemical Society
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• 제35권12호
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• pp.3482-3488
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• 2014

Matrix-induced mass bias and its effect on the accuracy of isotope ratio measurements have been examined for a quadrupole-based inductively coupled plasma-mass spectrometer (Q ICP-MS). Matrix-induced mass bias effect was directly proportional to % mass difference, and its magnitude varied for element and nebulizer flow rate. For a given element and conditions in a day, the effect was consistent. The isotope ratio of Cd106/Cd114 under $200{\mu}g\;g^{-1}$ U matrix deviated from the natural value significantly by 3.5%. When Cd 111 and Cd114 were used for the quantification of Cd with isotope dilution (ID) method, the average of differences between the calculated and measured concentrations was -0.034% for samples without matrix ($0.076{\mu}g\;g^{-1}$ to $0.21{\mu}g\;g^{-1}$ for the period of 6 months). However, the error was as large as 1.5% for samples with $200{\mu}g\;g^{-1}$ U. The error in ID caused by matrix could be larger when larger mass difference isotopes are used.

• Mass Spectrometry Letters
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• 제3권2호
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• pp.58-61
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• 2012

A method based on flow injection-isotope dilution-cold vapor-inductively coupled plasma mass spectrometry (FI-IDCV-ICP/MS) has been applied to determine trace level of mercury in fly ash. $^{200}Hg$ isotopic spike was added to 0.25 g of BCR176R fly ash and then decomposed by microwave digestion procedure with acid mixture A (8 mL $HNO_3$ + 2 mL HCl + 2 mL HF) and acid mixture B (8 mL $HNO_3$ + 2 mL $HClO_4$ + 2 mL HF) for applying IDMS. Mercury cold vapor was generated by using reductant solution of 0.2% (w/w) $NaBH_4$ and 0.05% (w/w) NaOH. The measurements of n($^{200}Hg$)/n($^{202}Hg$) isotope ratio was made using a quadrupole ICP/MS system. The accuracy in this method was verified by the analysis of certified reference material (CRM) of fly ash (BCR 176R). The indicative value of Hg in BCR 176R fly ash was $1.60{\pm}0.23$ mg/kg (k = 2). The determined values of Hg in BCR 176R fly ash by the method of FI-CV-ID-ICP/MS described in this paper were $1.60{\pm}0.24$ mg/kg (k = 3.18) and the analysis results were in well agreement with the indicative value within the range of uncertainty.

• 분석과학
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• 제27권6호
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• pp.269-276
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• 2014

후 컬럼 동위원소 희석법의 불확도를 HPLC-ICP/MS에서 Selenomethionine을 분석할 경우에 대하여 간단히 연구하였다. 주요하다고 생각한 오차의 원인으로 셀레늄 동위원소 용액의 농도와 흐름속도, 스파이크 용액과 시료 용액에서의 셀레늄 원자량, 그리고 스파이크된 시료용액에서 측정된 동위원소의 비를 선택하였다. 각 요인에 따른 불확도를 구하고 전체 농도의 불확도에 미치는 요인을 계산한 결과, 각각에 대하여 54.4%와 0.61%, 0.0072%와 0.018%, 그리고 45.0%를 얻었다. 가장 큰 요인은 스파이크 동위원소 용액의 농도이며 두 번째는 스파이크가 첨가된 시료용액에서의 동위원소비이었다. 스파이크 용액의 질량흐름속도와 원자량의 불활도는 크게 영향을 끼치지 못하였다. 계산된 전체불확도는 $126.30ng{\cdot}g^{-1}$ SeMet 표준용액에 대하여 $1.46ng{\cdot}g^{-1}$으로서 실험결과는 $127.09ng{\cdot}g^{-1}$을 얻었고 상대불확도는 1.20%이었다.

• 분석과학
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• 제23권3호
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• pp.312-321
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• 2010

7개 indicator PCBs (IUPAC nos 28, 52, 101, 118, 138, 153, 180)는 2006년부터 2007년까지 한국인의 대표식품을 중심으로 곡류(백미), 육류, 알류, 우유와 유가공품, 수산물 및 그 가공품을 대상으로 동위원소희석법을 이용하여 분석하였다. 모든 식품들 중 어류(평균 39.8 ng/g)에서 가장 높게 검출되었고, 그 다음으로 우유 및 유가공품 (1.4 ng/g), 육류 (0.9 ng/g)이였다. 어류 중 갈치 15.4 ng/g, 삼치 5.4 ng/g, 조기 4.5 ng/g 및 고등어 4.4 ng/g가 검출되었다. 모든 식품에서 indicator PCBs의 비율은 PCB-153 35.8%, PCB-138 16.2%, PCB-101 16.1%, PCB-118 13.4%, PCB-180 8.8%, PCB-52 6.9% 및 PCB-28 2.9% 이었다. PCB-153과 138은 hexa-CB로서 분포가 가장 많았고, 다음으로는 penta-CB인 PCB-101과 118 이었다. 식품을 통한 indicator PCBs에 의한 인체의 평균 및 극단 노출량은 수산물 및 그 가공품이 50%를 차지하였다. 그러나 이 수준은 한국인의 건강에 위해를 끼치지 않은 수준으로 평가되었다.

• 한국지역사회생활과학회지
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• 제23권3호
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• pp.255-263
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• 2012

Polybrominated diphenyl ethers (PBDEs) are a group of brominated flame retardants (BFRs), which are used in a variety of consumer products. Several of those are produced in large quantities. Their chemical structure similarities to polychlorinated dibenzo-p-dioxins and polychlorinated biphenyls (PCBs), as well as their toxicity, has been studied. PBDEs are persistent and lipophilic, which results in their bioaccumulation in the fatty tissues of organisms and enrichment throughout food chains. In addition, a number of studies also reported high levels of PBDEs in animals and food resulting from the use of contaminated animal feed Public concern about PBDEs levels in animals and food has been raised. Feed contamination by toxic chemicals has been the cause of the contamination of poultry products. The purpose of this study was to evaluate PBDEs in pig feed to search the origin chase of POPs in pigs. Feed samples were obtained wheat from East Europe, corn from South America and America, soybean meal from Korea, America, South America and India and tallow from Korea. The preparation of samples was based on the EPA method 1614. Instrumental analysis was based on the use of high resolution gas chromatography coupled to high resolution mass spectrometry (HRGC/HRMS). Quantification was carried out by the isotopic dilution method. The analysis of ${\Sigma}PBDEs$ involved 22 PBDE congeners, including BDE-17, 28, 47, 49, 66, 71, 77, 85, 99, 100, 119, 126, 138, 153, 154, 156, 183, 184, 190, 191, 196 and 197.

• 분석과학
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• 제22권6호
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• pp.449-457
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• 2009

국내에 유통 중인 식품을 대상으로 PCBs 62종 동족체를 동위원소희석법으로 분석하고 노출평가를 실시하였다. 시료에 $^{13}C$-labeled된 회수율 측정용 표준용액을 가하여 추출하고 다층 칼럼 크로마토그래피로 정제하여 HRGC/MSD로 분석하였다. 식품 중 평균 검출량(ng/g)은 쌀 0.13, 육류 1.8~3.4, 우유 및 유가공품 0.3~3.7, 계란 10.0, 수산물 0.8~34.4 이었다. 식품군별 검출분포는 수산물(94.4%) >육류 (2.3%) >알류(1.7%) > 우유 및 유가공품(1.3%) >쌀(0.3%) 순이었다. 식품을 통한 총 PCBs의 1일 노출량은 14.5 ng/kg bw/day로 건강상 안전한 것으로 평가되었다.