• Journal of Radiation Protection and Research
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• v.22 no.1
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• pp.35-46
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• 1997

A simple and precise method of $^{14}C$ was developed to analyze $^{14}C$ in the environment samples using a commercially available $^{14}CO_2$ absorbent and a liquid scintillation counter. An air sampler and a combustion system were developed to collect HTO and $^{14}CO_2$ in the air and the biological samples simultaneously. The collection yield of $^{14}CO_2$ by the air sampler was in the range of 73-89% . The yield of the combustion system was 97%. In preparing samples for counting, the optimum ratio of $CO_2$ absorbent to the scintillator for mixing was 1:1. No variation of the specific activity of $^{14}C$ in the counting sample was observed up to 70 days after preparation of the samples. The detection limit for$^{14}C$ was 0.025 Bq/gC, which is the level applicable to the natural level of $^{14}C$. The analytical result of $^{14}C$ obtained by the present method were within ${\pm}6%$ of the relative error from the one by the benzene synthesis. The specific activity of $^{14}C$ in the air collected at Taejon during the period of October 1996 ranged from 0.26 to 0.27 Bq/gC. The specific activity of $^{14}C$ in the air collected at 1km from the Wolsong nuclear power plant a 679 MWe PHWR, was $0.54{\pm}0.03$ Bq/gC. The ranges of specific activities of $^{14}C$ in the pine needles and the vegetations from the areas around the Wolsong nuclear power plant were 0.56-0.67 Bq/gC and 0.23-1.41 Bq/gC, respectively.

• Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
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• v.14 no.3
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• pp.253-266
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• 2016

In accordance with the classification system of radioactive waste in Korea, all the disused sealed radioactive sources (DSRSs) fall under the category of EW, VLLW or LILW, and should be managed in compliance with the restrictions for the disposal method. In this study, the management and disposal method are drawn in consideration of half-life of radionuclides contained in the source and A/D value (i.e. the activity A of the source dividing by the D value for the relevant radionuclide, which is used to provide an initial ranking of relative risk for sources) in addition to the domestic classification scheme and disposal method, based on the characteristic analysis and review results of the management practices in IAEA and foreign countries. For all the DSRSs that are being stored (as of March 2015) in the centralized temporary disposal facility for radioisotope wastes, applicability of the derivation result is confirmed through performing the characteristic analysis and case studies for assessing quantity and volume of DSRSs to be managed by each method. However, the methodology derived from this study is not applicable to the following sources; i) DSRSs without information on the radioactivity, ii) DSRSs that are not possible to calculate the specific activity and/or the source-specific A/D value. Accordingly, it is essential to identify the inherent characteristics for each of DSRSs prior to implementation of this management and disposal method.

• Korean Journal of Environmental Agriculture
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• v.23 no.1
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• pp.52-58
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• 2004

This work was conducted to provide the reference data of radioactivity in the foodstuffs at a radiological emergency situation in Jeju Island The sampled foodstuffs were agricultural (31), livestock (6), marine (12) and forest products (4), and processed foods (3) consumed by Jeju Islanders. $^{137}Cs$ and $^{40}K$ activities were determined by HPGe r-ray spectromety. The activity ranges of $^{137}Cs$ was ${\sim}650\;mBq/kg$ fresh in the agricultural products, ${\sim}131\;mBq/kg$. fresh in the livestock, ${\sim}834\;mBq/kg$ fresh in the forest, ${\sim}253\;mBq/kg$ fresh in the marine and $32.0{\sim}483\;mBq/kg$. fresh in the processed foods (tea). In case of $^{40}K$ the activity was $16.6{\sim}542\;Bq/kg$. fresh in the agricultural products, $39.1{\sim}294\;Bq/kg$ fresh in the livestock, $85.5{\sim}116\;Bq/kg$ fresh in the forest, $50.1{\sim}657\;Bq/kg$ fresh in the marine, and $33.6{\sim}1,065\;Bq/kg$ fresh in the processed foods (tea). The highest activity of $^{137}Cs$, 834mBq/kg fresh was observed in oak mushroom and $^{40}K$ 1,065 Bq/kg fresh in coffee. Annual effective doses of $^{137}Cs$ and $^{40}K$ by intake of foodstuffs per capita were the following order; agricultural products (66,543 nSv) > livestock products (19,311 nSv) > processed foods (6,648 nSv) > marine products (6,579 nSv) > forest products (860 nSv). Therefore, total annual effective dose was summed 99,941 nSv which is quite low level comparing to the annual effective dose by external exposure, 2,400,000 nSv. The data obtained in this study can be useful for monitoring whether the foodstuffs are contaminated or not at an emergency radiation accident, and showed that the foodstuffs consumed in Jeju are safe in terms of annual effective dose of $^{137}Cs$ and $^{40}K$

• Proceedings of the Korean Society of Soil and Groundwater Environment Conference
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• 2005.04a
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• pp.300-303
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• 2005

대전지역 화강암지대에 존재하는 75개 지하수를 5개 지역구에서 채취하였으며, 상ㅁ하반기 동안 2차례 시료를 채취하여 건기와 우기후의 라돈 및 우라늄 농도를 분석하였다. 5개 지역에 대한 라돈과 우라늄의 평균 농도는 유성구에서 270.9 Bq/L, $43.8{\mu}g/L$ 였으며, 동구의 경우 41.3 Bq/L, $4.9{\mu}g/L$, 대덕구는 131.8 Bq/L, $54.3{\mu}g/L$, 중구의 경우 44.0 Bq/L, $8.1{\mu}g/L$ 그리고 서구는 112.9 Bq/L, $0.4{\mu}g/L$ 이었다. 라돈과 우라늄의 함량은 건기가 우기후에 비해 대체로 높게 나타났으며 건기시의 평균값은 라돈은 $253{\pm}14\;Bq/L$ 우라늄은 $63{\mu}g/L$ 이었으며, 우기시는 $195{\pm}11\;Bq/L,\;45.4{\mu}g/L$ 이었다.

• Proceedings of the Korean Nuclear Society Conference
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• 1995.05b
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• pp.827-832
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• 1995

한국원자력연구소 실증소각시설의 성능 및 운전성을 입증하기 위하여 방사성동위원소를 포함한 모의폐기물 및 원자력발전소 발생 방사성폐기물에 대한 시험소각을 실시하였다. 비휘발성인 $^{60}$Co 및 $^{54}$Mn의 거동은 비산재의 거동과 거의 유사하였으며 각각의 제염계수는 4.7 x $10^{5}$및 6.2 x $10^{5}$이었다. 반휘발성인 $^{137}$Cs의 경우에는 8$50^{\circ}C$ 및 $700^{\circ}C$의 다른 소각온도에서 각각 2.8 $\times$ $10^4$, 2.6 $\times$ $10^3$으로 소각온도의 의존성을 보여주었다. 원자력발전소에서 운반된 건조 방사성폐기물(DAW)에 대한 시험소각은 성공적으로 수행되었다. 총 베타/감마 방사능에 대한 제염계수가 1.1 $\times$ $10^{5}$이었으며 결과적인 연돌에서의 배출농도는 0.019 Bq/N㎥으로 기체상 배출물에 대한 최대허용농도를 만족시킬 수 있었다.수 있었다.

• Journal of Radiation Protection and Research
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• v.27 no.1
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• pp.11-19
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• 2002

The seasonal variation of $^7Be$ and $^{137}Cs$ concentrations in airborne dust, precipitation and dry fallout collected at Daejeon during the period of 1998 - 1999 has been studied. The annual mean values of 7Be concentrations in airborne dust, precipitation and dry fallout were in the range of $3.80{\sim}4.29\;mBq\;m^{-3},\;1.25{\sim}1.67\;Bq\;l^{-1},\;19.7{\sim}22.3 MBq\;km^{-2}$, respectively. The annual mean values of $^{137}Cs$ concentrations in airborne dust, precipitation and dry fallout ranged $1.08{\sim}1.28{\mu}Bq\;m^{-3},\;0.44{\sim}2.66 mBq\;l^{-1}\;\;0.036{\sim}0.0455\;MBq\;km^{-2}$, respectively. While the concentrations of $^7Be$ and $^{137}Cs$ in airborne dust and dry fallout were relatively higher in the spring and autumn when the amount of dry fallout increased than in other season, their concentrations in precipitation were relatively lower in the summer when the rainfall increased. The total depositions of $^7Be$ and $^{137}Cs$ due to dry fallout and precipitation were in the range of $80.7{\sim}137MBq\;km^{-2}$ and $0.059{\sim}0.060MBq\;km^{-2}$, respectively. More than 80% of $^7Be$ deposition resulted from precipitation, whereas about 60% of $^{137}Cs$ deposition was due to dry fallout.

• Proceedings of the Korean Radioactive Waste Society Conference
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• 2004.06a
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• pp.399-406
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• 2004

본 연구에서는 국내 원전이 위치한 지역의 토양에서 $Cs^{137}$의 축적 경향을 파악하기 위하여 원전이 위치한 영광군 관내의 평지와 고산지대인 금정산, 불갑산 및 영광원전으로부터 원거리에 위치한 내장산 등을 대상으로 토양 중 $Cs^{137}$의 화학적인 특성과 고도에 따른 $Cs^{137}$의 축적 경향을 평가하기 위하여 실험을 통한 연구를 수행하였다. 일반적으로 국내 토양 중 $Cs^{137}$의 농도는 불검출 - 2523q/kg-dry의 범위 내에 포함되었으며 본 연구에서 수행한 평지부분과 고산지대인 원전으로부터 2km 떨어진 금정산, 약 20km 떨어진 불갑산 및 원거리에 위치한 내장산에서도 지금까지의 $Cs^{137}$ 농도 범위에 들었다. 그러나 고산지대는 평지에서와는 다르게 고도가 증가함에 따라 $Cs^{137}$ 농도도 증가하는 경향을 보이고 있고, 정상 부분보다 $Cs^{137}$의 농도가 하부 부분보다 더 높게 나타났고 영광원전 인근 일반평지부분보다는 $Cs^{137}$의 방사능 농도가 2~6배 정도의 높은 경향을 나타내었다. 연구결과 $Cs^{137}$의 분포는 지형적 요인(고도, 강수량 등)과 토양의 화학적 요인(양이온치환용량)과 상관성이 근 것으로 나타났다. 지형적 요인으로는 주로 고도를 들수가 있는데 높은 고도의 산의 경우 대기중 $Cs^{137}$이 토양에 침투되는 기회가 커짐으로 동일한 토질 조건의 평지 토양에 비해 높은 $Cs^{137}$ 준위를 나타내었다. 토양의 화학적 요인으로는 양이온치환용량이 주요 인자임이 규명되었다. 양이온치환용량은 침적된 $Cs^{137}$을 토양에 고정시키는 능력을 나타내며 같은 지형조건에서 높은 양이온치환용량을 가진 시료가 낮은 양이온치환용량을 가진 토양에 비해 $Cs^{137}$ 농도가 높은 값을 보였다.

• Economic and Environmental Geology
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• v.45 no.3
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• pp.277-294
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• 2012

The characteristics of temporal spacial radon variation in soil according to parent rock type and affecting factors were studied in Busan, Korea. The concentration of $^{222}Rn$ in soils and their parent elements ($^{226}Ra$,$^{228}Ra$, U and Th) in rocks and soils were measured at 24 sites in Busan area. The distribution and transportation behavior of these parent elements were analyzed and their correlations to radon concentration in soil were determined. Topographic effects were also evaluated. Two in-situ radon measurement (soil probe and buried tube) methods were applied to measure radon concentration in soil and their accuracies were evaluated. The spatial variation of radon in soil generally reflected U concentration in the parent rock. Average radon concentrations were higher in plutonic rocks than in volcanic rocks and were decreased in the order of felsic>intermediate>mafic rock. However, the radon concentrations were significantly varied in soils developed from same parent rocks due to the disequilibrium of U and $^{226}Ra$ between rock and soil. As results, the correlation of these element concentrations between rocks and soils was very low and radon concentrations in soils had highly co-related to the concentrations of these elements in soils. Th and $^{228}Ra$ show complex enrichment characteristics, differing significantly with U, in soils developed from same parent rock because the geochemical behavior of these elements during weathering and soil developing process was different with U. The radon concentrations in the same depth of soil in slope area were also different according to positions. The radon concentrations in soils developed from same parent rocks (19 sites at Pusan National University) varied 6.8~29.8Bq/L range because of small scale topographic variation. The opposite seasonal variation pattern of radon were observed according to soil properties. It was determined that buried tube method is more accurate method than soil probe method and was very advantageous application for the analysis for the characteristics of temporal spacial radon variation in soil.

• Journal of radiological science and technology
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• v.40 no.4
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• pp.633-638
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• 2017

The amount of radioactive waste has been rapidly increased with development of radiation treatment in medical field. Recently, it has been a common practice to use I-131 for thyroid cancer, F-18 for PET/CT and Tc-99m for diagnosis of nuclear medicine. All the wastes concerned have been disposed of by means of the self-disposal method, for example incineration, after storage enough to decay less than clearance level. IAEA proposed criteria for clearance level of waste which depends on the individual ($10{\mu}Sv/y$) and collective dose (1 man-Sv/y), and concentration of each nuclide (IAEA Safety Series No 111-P-1.1, 1992 and IAEA RS-G-1.7, 2004). In this study, specific radioactivity of radioactive waste contaminated with Re-186 was measured to confirm whether it meets the clearance level. Re-186 has long half life of 3.8 days relatively and emits beta and gamma radiation, therefore it can be applied in treatment and imaging purposes. The specific radioactivity of contaminated gloves weared by radiation workers was measured by MCA(Multi-channel Analyzer) which was calibrated by reference materials in accordance with the measuring procedure. As a result, comparison evaluation of decay storage period between the half-life which was calculated by attenuation curve based on real measurement and physical half-life was considered, and it is showed that the physical half-life is longer than induced half-life. Therefore, the storage period of radioactive waste for self-disposal may be curtailed in case of application of induced half-life. The result of this study will be proposed as ISO standard.

• The Korean Journal of Nuclear Medicine
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• v.12 no.1
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• pp.29-35
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• 1978

인슈린-$^{125}I$를 클로라민-T법을 써서 $30{\sim}35%$의 표지 수율로 얻었으며 그 비방사능은 대략 100uCi/ug이었다. 생성물을 방사면역 측정용으로 표준화하기 위해 최적 표지부분을 전분젤 전기영동, 래디오오토그래피 및 인슈린 항체와의 인큐베이션등으로 선정하였다. 선정된 표지 인슈린으로 표준화한 결과 $50{\mu}U/ml$까지의 인슈린농도에 대해 항체와의 결합 인슈린-$^{125}I$(B)와 미결합 인슈린-$^{125}I$ (F)와의 비 (B/F)가 $0.2{\sim}1.6$으로써 매우 가파른 표준 dose-response곡선을 보여 주었다. 인슈린 방사면역 측정킷트를 만들어 그 사용 가능기간을 측정하였으며 일상 생산방법을 확립하였다.