• 방사성폐기물학회지
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• 제19권1호
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• pp.133-140
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• 2021

This study evaluates the radioactivity of concrete waste that occurs due to large amounts of decommissioned nuclear wastes and then determines the surface dose rate when the waste is packaged in a disposal container. The radiation assessment was conducted under the presumption that impurities included in the bio-shielded concrete contain the highest amount of radioactivity among all the concrete wastes. Neutron flux was applied using the simplified model approach in a sample containing the most Co and Eu impurities, and a maximum of 9.8×104 Bq·g-1 60Co and 2.63×105 Bq·g-1 152Eu was determined. Subsequently, the surface dose rate of the container was measured assuming that the bio-shield concrete waste would be packaged in a newly developed disposal container. Results showed that most of the concrete wastes with a depth of 20 cm or higher from the concrete surface was found to have less than 1.8 mSv·hr-1 in the surface dose of the new-type disposal container. Hence, when bio-shielded concrete wastes, having the highest radioactivity, is disposed in the new disposal container, it satisfies the limit of the surface dose rate (i.e., 2 mSv·hr-1) as per global standards.

• Nuclear Engineering and Technology
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• 제55권6호
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• pp.2158-2165
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• 2023

Marine radioactivity monitoring is critical for taking immediate action in case of unexpected nuclear accidents at nuclear facilities located near coastal areas. Especially when the level of contamination is not predictable, mobile monitoring systems will be useful for wide-area ocean radiation survey and for determination of the level of radioactivity. Here, we used a silicon photomultiplier and a high-efficiency GAGG crystal to fabricate a compact, battery-powered gamma spectroscopy that can be used in an ocean environment. The developed spectroscopy has compact dimensions of 6.5 × 6.5× 8 cm³ and weighs 560 g. We used LoRa, a low-power wireless protocol for communication. Successful data transmission was achieved within 1.4 m water depth. The developed gamma spectroscopy was able to detect radioactivity from a ¹³⁷Cs point source (3.7 kBq) at a distance of 20 cm in water. Moreover, we demonstrated an unmanned radioactivity monitoring system in a real sea by combining unmanned surface vehicle with the developed gamma spectroscopy. A hidden ¹³⁷Cs source (3.07 MBq) was detected by the unmanned system at a distance of 3 m. After successfully testing the developed mobile spectroscopy in an ocean environment, we believe that our proposed system will be an effective solution for mobile real-time marine radioactivity monitoring.

• Journal of Radiation Protection and Research
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• 제24권2호
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• pp.109-120
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• 1999

TRIGA Mark-II, III 연구로를 폐로함에 따라, 원자로를 비롯한 관련 시설로부터 작업자의 방사선피폭을 최소화하고 환경으로의 방사성물질 누출을 사전에 방지하며, 안전한 해체방법을 모색하여 해체공사시의 기술기준을 수립하기 위하여 해체대상 시설내에 잔존하고 있는 방사성물질의 방사선/능 준위를 측정 및 분석 평가하였다. 측정대상은 시설내의 바닥 및 벽면과 잔존 실험시설물의 표면, 수조내 방사화 물질의 표면, 시설내 잔존하고 있는 냉각수 등이다. 이들 측정대상에 대한 방사선량율과 표면오염도, 핵종 등을 측정, 분석 및 평가하였다. 또한 전산코드 Fispin 을 사용하여 원자로 수조내의 주요 방사화 물질에 대한 방사능양과 핵종을 평가하였다. 본 평가 결과는 해체계획서 작성시 기본자료로서 유용하게 사용되었다.

• 방사성폐기물학회지
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• 제6권1호
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• pp.11-15
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• 2008

고밀도폴리 에틸렌 고건전성용기에 담은 폐수지의 운반을 위해 원전 폐수지의 방사능 분석결과를 사용하여 운반물 등급 분류방법을 도출하였다. 원전 폐수지의 방사능 분석결과로부터 폐수지 내 핵종 존재비를 구하였고, 폐수지의 표면선량률로 핵종재고량을 평가하기 위해 MCNP 코드로 방사능대선량 환산인자를 모사하였다. 이로부터 고밀도폴리에틸렌 고건전성용기에 담은 폐수지에 대한 A형 운반물과 B형 운반물의 경계값은 1.19 TBq 이고 이를 표면선량으로 환산한 결과는 124.2 mSv/h임을 알 수 있었다.

• International Journal of Contents
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• 제8권2호
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• pp.60-66
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• 2012

This study was designed to detect and measure the concentration of radioactivity of natural radionuclides ($^{238}U$, $^{232}Th$, $^{40}K$) and artificial radionuclides ($^{137}Cs$, $^{60}Co$) present in the drinking water of the city of Busan and surrounding areas in South Korea, and also to measure the absorbed dose of radiation caused by these elements in the residents so as to help better manage the risk that these radionuclides pose in the future. For the purposes of the study, a total of 42 samples of water were collected from three key water sources (19 samples of groundwater, 4 samples of tap water, and 19 samples of surface water) and their contents were analyzed for radioactivity concentration. The results revealed that two natural radionuclides, $^{238}U$ and $^{232}Th$, exist in the groundwater with an average concentration of radioactivity of 3.34 Bq/L and $8.28{\times}10^{-5}Bq/L$ respectively, while the surface water was found to contain the same two radionuclides with mean concentrations of 0.849 Bq/L and $1.103{\times}10^{-4}Bq/L$ respectively. In addition, of the 19 samples of the groundwater, $^{137}Cs$ was found in eight of them and $^{60}Co$ was detected in ten. Of the four samples of the tap water, $^{137}Cs$ was detected in all samples and $^{60}Co$ was detected in three. Both $^{137}Cs$ and $^{60}Co$ were detected in all 12 samples of surface water. As far as $^{40}K$ is concerned, this element was detected in three of the 19 groundwater samples, but was not detected in any surface or tap water sample. In addition, the absorbed dose of $^{238}U$ from the groundwater was $7.94{\times}10^{-8}Sv/y$, while the absorbed dose of $^{232}Th$ from the surface water was $9.33{\times}10^{-13}Sv/y$. The absorbed dose of $^{137}Cs$ from the tap water was $7.33{\times}10^{-5}Sv/y$, while the absorbed dose of $^{60}Co$ from the surface water was the highest at $4.23{\times}10^{-6}Sv/y$.

• 한국산업정보학회논문지
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• 제16권4호
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• pp.37-44
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• 2011

본 논문은 원자력시설내의 방사성 표면오염을 측정평가하기 위한 표변오염도 시료채취용 자동화 시료채취기 개발에 있다. 시료채취를 위한 간접법은 사람에 의한 수동적인 시료 채취방법으로서 시료를 채취하는 사람에 따라 문지르는 횟수 강도 및 면적이 다르다. 이로 인하여 표면오염도 측정치의 정확도가 저하되고 시료 채취시마다 측정치의 오차가 많이 발생한다. 개발된 장치에 의한 방법은 기존방법에 의한 표면오염도의 측정치보다 smear paper의 방사성 시료가 균일하게 채취됨을 확인하였으며, 향후 표면오염도의 평가시 측정자료의 일관성을 확보하게 되었다.

• Journal of Pharmaceutical Investigation
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• 제26권2호
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• pp.105-112
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• 1996

The surface of albumin microspheres was modified with methotrexate(MTX) by using 1,3-dicyclohexylcarbodiimide (DCC). Surface-modified albumin microspheres entrapping no MTX (SAMS), free MTX (SAMSF) and MTX-bovine serum albumin(BSA) conjugates(SAMSC) were prepared. The organ-targeting ability of free $[^3H]MTX,\;[^3H]MTX-BSA$ conjugate and the above microspheres was evaluated after i.v. administration of the preparations, equivalent to 150 nCi via the tail vein of mice. The total radioactivity in the lung increased immediately in a few minutes after i.v. injection of the microspheres, and then declined for the period of 3-4 weeks. However, the radioactivity in the liver, spleen and kidney increased slowly during the rapid decrease in radioactivity in the lung. This suggested that the microspheres could be entrapped rapidly in the lung through mechanical filtration because of their large size and slowly redistributed to the liver, spleen and kidney due to either the microspheres being degraded enough for the size to allow passage through the capillary beds of the lung and/or the release of $[^3H]MTX\;or\;[^3H]MTX-BSA$ conjugates from the microspheres. The amount of $60{sim}70%$ of the dose was targeted to the liver after the i.v. injection of SAMS, SAMSF and SAMSC, and the values of $(R_e\;^*\;_{e)liver}$ from the microspheres were $5{\sim}7$ compared to free MTX. This suggested that the liver-targeting ability from surface-modified albumin microspheres could be $5{\sim}7$ times as that of free MTX. The liver-targeted drug was accumulated in the Kupffer cells at the initial stage, thereafter the drug in the Kupffer cell was slowly transferred into the hepatocytes. The value of AUQ for liver from SAMS was higher than that from SAMSF, but much lower than that from SAMSC. This suggest that MTX bound to their surface could be eliminated slower than the entrapped free MTX, and faster than the entrapped MTX-BSA conjugates. This is consistent with the in vitro release rates order in the presence of a proteolytic enzyme. Also, surface-modified MTX was scarcely released in the absence of a proteolytic enzyme. Therefore, the surface-modified MTX nay be released (or eliminated) rapidly from SAMSC at the target site, and thereafter MTX may be released (or eliminated) slowly from the entrapped MTX-BSA conjugates in SAMSC for a long period.

• Applied Biological Chemistry
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• 제41권3호
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• pp.253-257
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• 1998

사양토성 lysimeter에서 살균제 $^{14}C-propiconazole$의 행방을 조사하고자 하였다. 벼 이앙 15일 후 $^{14}C-propiconazole$을 0.12 kg/10a 수준으로 lysimeter 토양표면에 처리한 후 시기별로 용탈수, 토양 및 휘발성분중 방사능을 조사하였다. 약제처리 후 16주간 lysimeter토양에서 용탈된 방사능은 처리 방사능의 4.4%였으며, 대부분의 방사능은 모화합된 형태이었다. 약제처리 16주 후 토양에 잔류하는 방사능은 처리 방사능의 76.5%였으며 97% 이상이 토양표층 깊이 20 cm 이내에 존재하였다. Lysimeter 토양에서 생성된 $^{14}CO_2$는 처리 방사능의 7.8%였다. 벼 수확 후 볏짚에 잔류하는 방사능은 처리량의 7.2%였으며 지엽, 벼이삭, 왕겨 그리고 현미에서는 각각 0.1% 이하를 나타내었다.

• 대한방사성의약품학회지
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• 제8권2호
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• pp.95-101
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• 2022

Microfluidic radioimmunoassay (RIA) platform called µ-RIA spends less reagent and shorter reaction time for the analysis compared to the conventional tube-based radioimmunoassay. This study reported the design of µ-RIA chips optimized for the gamma counter which could measure the small samples of radioactive materials automatically. Compared with the previous study, the µ-RIA chips developed in this study were designed to be compatible with conventional RIA test tubes. And, the automatic gamma counter could detect radioactivity from the ¹²⁵I labeled anti-PSA attached to the chips. Effects of the multi-layer microchannels and two-phase flow in the µ-RIA chips were investigated in this study. The measured radioactivity from the ¹²⁵I labeled anti-PSA was linearly proportional to the number of stacked chips, representing that the radioactivity in µ-RIA platform could be amplified by designing the chips with multi-layers. In addition, we designed µ-RIA chip to generate liquid-gas plug flow inside the microfluidic channel. The plug flow can promote binding of the biomolecules onto the microfluidic channel surface with recirculation in the liquid phase. The ratio of liquid slug and air slug length was 1 : 1 when the ¹²⁵I labeled anti-PSA and the air were injected at 1 and 35 µL/min, respectively, exhibiting 1.6 times higher biomolecule attachment compared to the microfluidic chip without the air injection. This experimental result indicated that the biomolecular reaction was improved by generating liquid-gas slugs inside the microfluidic channel. In this study, we presented a novel µ-RIA chips that is compatible with the conventional gamma counter with automated sampler. Therefore, high-throughput radioimmunoassay can be carried out by the automatic measurement of radioactivity with reduced radiowaste generation. We expect the µ-RIA platform can successfully replace conventional tube-based radioimmunoassay in the future.

• Nuclear Engineering and Technology
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• 제15권2호
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• pp.110-116
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• 1983

육상식물인 대두(Glycine max)에 있어서 Sr-90의 흡수 및 이행과정을 온실조건하에서 실험하여 다음과 같은 결과를 얻었다. 엽면처리한 Sr-90은 식물체의 다른 부위로 일부분만이 이행하였고 대부분은 잎에 그대로 잔류하여 낙엽에 의한 토양오염의 원인이 되고 있었다. 토양처리한 Sr-90은 뿌리를 통하여 흡수된 다음 잎, 줄기, 종자, 뿌리등 각 부위로 널리 분포되는데 식물의 생육단계에 따라 그 패턴이 달리 나타났다.