• Mass Spectrometry Letters
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• 제5권1호
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• pp.12-15
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• 2014

Thermal ionization mass spectrometry (TIMS) was used to determine the concentration and isotope ratio of uranium contained in samples of soil and groundwater collected from Korea. Quantification of uranium in ground water samples was performed by isotope dilution mass spectrometry. A series of chemical treatment processes, including chemical separation using extraction chromatography, was applied to the soil samples to extract the uranium. No treatments other than filtration were applied to the groundwater samples. Isotopic analyses by TIMS showed that the isotope ratios of uranium in both the soil and water samples were indistinguishable from those of naturally abundant uranium. The concentration of uranium in the groundwater samples was within the U.S. acceptable standards for drinking water. These results demonstrate the utility of TIMS for monitoring uranium in environmental samples with high analytical reliability.

• Mass Spectrometry Letters
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• 제1권1호
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• pp.17-20
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• 2010

As background significantly affects measurement accuracy and a detection limit in determination of the trace amounts of uranium, it is necessary to minimize the impurities in the filaments used for thermal ionization mass spectrometry (TIMS). We have varied the degassing condition such as the heating currents and duration times to reduce the backgrounds from the filaments prepared with zone-refined rhenium tape. The most efficient degassing condition of the heating current and the duration time was determined as 3.5 A and 60 min, respectively. The TIMS measurement combined with the isotope dilution mass spectrometry (IDMS) technique showed that the uranium backgrounds were determined to be in a few fg level from blank rhenium filaments. The background minimized filaments were utilized to measure the uranium isotope ratios of a U030 (NIST) standard sample. The excellent agreement of the measurement with the certified isotope ratios showed that the degassing procedure optimized in this study efficiently reduced the impurity signals of uranium from blank rhenium filaments to a negligible level.

• Mass Spectrometry Letters
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• 제3권2호
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• pp.54-57
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• 2012

Mass spectrometric analysis was carried out using multicollector inductively coupled plasma mass spectrometry (MC-ICP-MS) for the precise and accurate determination of the isotope ratios of ultratrace levels of uranium dissolved in 3% $HNO_3$. We used the certified reference material (CRM) 112-A at a trace level of 100 pg/mL for the uranium isotopic measurement. Multiple collectors were utilized for the simultaneous measurement of uranium isotopes to reduce the signal uncertainty due to variations in the ion beam intensity over time. Mass bias correction was applied to the measured U isotopes to improve the precision and accuracy. Furthermore, elemental standard solution with certified values of platinum, iridium, gold, and thallium dissolved in 3% $HNO_3$ were analyzed to investigate the formation rates of the polyatomic ions of $Ir^{40}$ $Ar^+$, $Pt^{40}$ $Ar^+$, $Tl^{40}$ $Ar^+$, $Au^{40}$ $Ar^+$ for the concentration range of 50-400 pg/mL. Those polyatomic ions have mass-to-charge ratios in the 230-245 m/z region that it would contribute to the increase of background intensity of uranium, thorium, plutonium, and americium isotopes. The effect of the polyatomic ion interference on uranium isotope measurement has been estimated.

• 분석과학
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• 제16권6호
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• pp.450-457
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• 2003

사용후핵연료 내 U 및 동위원소 정량분석을 동위원소 희석 질량분석법 (isotope dilution mass spectrometry, IDMS)으로 수행하였다. 시료는 산화우라늄 사용후핵연료 시료를 $HNO_3$(1+1) 또는 이 용액과 14 M $HNO_3-0.05M$ HF 혼합용액으로 용해한 후 막 거르게 ($1.2{\mu}m$)로 여과하여 준비하였다. 시료 및 스파이크를 첨가한 시료 중의 U은 AG lX8 음이온교환 수지관에서 0.1 M HCl 용액으로 용리하였다. 시료 중의 총 U 량과 성분 동위원소 ($^{234}U$, $^{235}U$, $^{236}U$ 및 $^{238}U$)의 조성은 $^{233}U$을 스파이크로 이용하는 동위원소 희석 질량분석법으로 정량하였다. 제조한 U-233 스파이크 용액은 천연 및 감손 U을 이용한 역동위원소 희석 질량분석법 (reverse isotope dilution mass spectrometry, R-IDMS)으로 표정하였다. 동위원소 희석 질량분석법에 의한 핵연료시료 중의 총 U 량 측정결과를 전위차 적정으로 측정한 결과와 비교하였을 때 0.34% 평균 상대오차 범위에서 일치하였다.

• Nuclear Engineering and Technology
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• 제50권1호
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• pp.140-144
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• 2018

Isotopic analyses of plutonium and low-enriched uranium mixtures with particle sizes of $0.6-3.3{\mu}m$ were performed using thermal ionization mass spectrometry with a continuous heating method to verify its effectiveness for the accurate analysis of minor isotopes without sample pretreatment. The mixed particles used in this study were prepared from a mixed solution of plutonium (SRM 947) and uranium (U010, $^{235}U$ 1% enriched) reference materials. The isotope ratios for plutonium in the individual mixed particles, including $^{238}Pu/^{239}Pu$, $^{241}Pu/^{239}Pu$ as well as $^{240}Pu/^{239}Pu$, and $^{242}Pu/^{239}Pu$, were in good agreement with the certified values despite the isobaric interference of $^{238}U$ and $^{241}Am$. The isotope ratios for uranium in the mixed particles also agreed well with the certified values within the range of error. However, the isotope ratios for minor isotopes, such as $^{234}U$ and $^{236}U$, in the particles with diameters of less than approximately $1.8{\mu}m$ could not be measured because numbers of $^{234}U$ and $^{236}U$ atoms in analyzed particles are too low. These results indicate that thermal ionization mass spectrometry with a continuous heating method is applicable for the analysis of trace amounts of plutonium isotopes, including $^{238}Pu$ and $^{241}Pu$, despite the presence of the respective isobars $^{238}U$ and $^{241}Am$ in the microsamples.

• 분석과학
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• 제25권2호
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• pp.146-151
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• 2012

액체섬광계수기를 이용한 지하수 내 우라늄 동위원소의 최적 측정방법에 대한 연구를 수행하였다. 용매추출법을 이용해 우라늄을 추출하였고, 시료량과 pH에 따른 추출효율을 조사하였다. 우라늄 추출효율에 미치는 영향을 조사하기 위해 표준용액을 사용하여 100 mL~1 L 범위에서 시료량을 변화 시켰으며 pH는 0.5~10 범위에서 측정하였다. 실험결과 우라늄의 추출효율은 pH에 매우 민감한 것으로 나타났으며 pH 2 에서 최고치를 나타냈다. 이에 반해 시료량은 추출효율에 큰 영향을 미치지 않는 것으로 나타났다. 우라늄 표준시료를 이용한 실험 결과 추출효율은 $95.93{\pm}0.77%$ 이었고, 계측시간 5시간을 기준으로 한 우라늄의 검출한계는 0.018 Bq/L 이었다. 본 연구결과로부터 지하수에 함유된 우라늄의 최적추출 및 측정법을 확립할 수 있었고 본 방법의 검증을 위해서 지하수 중 우라늄의 분석에 일반적으로 사용되는 ICP-MS 측정결과와의 비교분석도 함께 수행하였다. 본 연구에서 개발된 분석법을 대전 주변 지역 네 곳의 지하수를 대상으로 우라늄 함량 및 동위원소 비의 측정에 적용한 결과 우라늄의 농도는 0.59~6.69 Bq/L 그리고 $^{234}U/^{238}U$의 방사성 비는 0.88~1.40 범위로 나타내었다.

• 한국방사성폐기물학회:학술대회논문집
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• 한국방사성폐기물학회 2018년도 추계학술논문요약집
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• pp.608-609
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• 2018

• 한국방사성폐기물학회:학술대회논문집
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• 한국방사성폐기물학회 2017년도 춘계학술논문요약집
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• pp.67-68
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• 2017

• Journal of Radiation Protection and Research
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• 제24권1호
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• pp.1-7
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• 1999

기존의 TBP 용매 추출법을 토대로 간단하고 정밀한 환경시료중 우라늄 동위원소 분석법을 개발했다. 질산-불화수소를 가해 토양시료를 분해하였고 TBP와 $CCl_4$등의 유기용매 혼합비율을 조절하여 우라늄을 수층에서 유기 층으로 추출하였으며 8 M HCl를 사용하여 토륨성분을 제거한 후 1 M HCl로 우라늄성분을 유기 층에서 수층으로 역 추출하여 우라늄만을 순수분리하였다. 기존의 전기전착 용액에 DTPA 착화제를 첨가한 새로운 전기전착 용액을 개발하여 최적의 우라늄 전착조건을 설정하였다. 수립된 우라늄 동위원소 분석법을 IAEA Reference 시료에 적용하여 개발된 분석법에 대한 신뢰성을 검증하였다.

• 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.