• Journal of radiological science and technology
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• v.46 no.2
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• pp.141-149
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• 2023

The Korea Institute of Radiological and Medical Sciences plans to produce ²²⁵Ac, a therapeutic radio-pharmaceutical for precision oncology, such as prostate cancer. Radon, a radioactive gas, is generated by radium, the target material for producing ²²⁵Ac. The radon concentration is expected to be about 2000 Bq·m^-3. High-concentration radon-generating facilities must meet radioactive isotope emission standards by lowering the radon concentration. However, most existing studies concerning radon removal using activated carbon filters measured radon levels at concentrations lower than 1000 Bq·m^-3. This study measured ²²²Rn removal of coconut-based activated carbon filter under a high radon concentration of about 2000 Bq·m^-3. The ²²²Rn removal efficiency of activated carbon impregnated with triethylenediamine was also measured. As a result, the ²²²Rn removal amount of the activated carbon filter showed sufficient removal efficiency in a ²²²Rn concentration environment of about 2000 Bq·m^-3. In addition, despite an expectation of low radon reduction efficiency of Triethylenediamine-impregnated activated carbon, it was difficult to confirm a significant difference in the results. Therefore, it is considered that activated carbon can be used as a radioisotope exhaust filter regardless of whether or not Triethylenediamine is impregnated. The results of this study are expected to be used as primary data when building an air purification system for radiation safety management in facilities with radon concentrations of about 2000 Bq·m^-3.

• Journal of Radiation Protection and Research
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• v.17 no.1
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• pp.57-70
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• 1992

An excess risk of lung cancer mortality among Koreans, attributable to indoor $^{222}Rn$ daughters exposure, were quantitatively evaluated by applying a stochastic health risk projection model on the radiation exposure. The lung cancer rate in Korean males and females, based on the 1989 demographic data, were estimated to be $22.4/10^5-y\;and\;9.5/10^5-y$, respectively The lifetime baseline lung cancer risks, deduced from these rates, appeared to be 0.047 and 0.019 for males and females, respectively, and were lower than the corresponding 1984 values of 0.067 and 0.025 in the U.S.A. The excess risk coefficients, derived by modified relative risk projection model of the BEIR-IV Committee under the US National Academy of Science, per annual 1.0 WLM of exposure to indoor radon daughters were estimated to be 0.022/WLM for males, 0.009/WLM for females, and 0.017/WLM for both sexes. The resulting annual frequency of excess lung cancer mortality for the life expectancy in the Korean population appeared to be 230/10^6-WLM, which was an approximate median of $120{\sim}450/10^6-WLM$ reported so far in the world.

• Proceedings of the Korea Air Pollution Research Association Conference
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• 2000.11a
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• pp.365-366
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• 2000

라돈은 암석이나 토양 같은 지각물질에서 발생되는 우라늄($^{238}$ U) 붕괴계열인 라듐($^{226}$ Ra)의 붕괴과정에서 생성된다. 라돈($^{222}$ Rn)은 붕괴하면서 $\alpha$방사선을 방출한다. $\alpha$ 붕괴에 의하여 $^{218}$ Po, $^{214}$ Po, $^{214}$ Bi 등의 자핵종(Radon daughter)을 생성하며, 이 과정에서 인체의 세포를 죽이거나 염색체를 손상시킬 수 있으며, 폐암의 발생 위험률을 높이는 것으로 보고되었다$^{1)}$ . 라돈은 건물의 균열, 연결부위, 혹은 배수관이나 오수간, 주변의 틈을 통해서 실내로 유입된다. (중략)

• Journal of Radiation Protection and Research
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• v.14 no.2
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• pp.10-17
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• 1989

A study for the assessment of dose given by outdoor radon to respiratory system has been carried out by making use of radon-cups containing CR-39 plastic track detectors. Detection efficiencies were determined by irradiation of the radon-cups in a standard radon chamber of known concentration. Thus determined detection factors of CR-39 plastic track detector in bare, open cup and filtered cup geometry are found to be 0.273, 0.0813 and 0.0371 $trmm^{-2}$/(37$Bqm^{-3}{\cdot}d$), respectively, which are chemically etched in 30% NaOH solution of $70^{\circ}C$ for 220 minutes. The outdoor radon concentrations measured at Taejeon(Chungnam National University) from May 1988 to March 1989 are in the range of 27.4 - 135.8 Bq/$m^3$(0.74 - 3.67pCi/l)by open cup and 16.7 - 143.9 Bq/$m^3$(0.45 - 3.89 pCi/l) by filtered cup, which yield overall annual average value of outdoor radon concentration of $70.8Bq/m^3$(1.91 pCi/l). Corresponding effective dose equivalent rate to respiratory system of ICRP standard man is assessed to be 520 nSv /h.

• Journal of Radiation Protection and Research
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• v.37 no.3
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• pp.149-158
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• 2012

In this paper, we measured the variations of radon concentrations in groundwater using low-level Liquid Scintillation Counter (LSC), an instrument for analyzing the alpha and beta radionuclides at its 10 sites around the Kumjung-Gu, north-western of Busan. Optimization of Pulse Shape Analyzer (PSA) to determinate the highest value of figure of merit (FM) was decided using Quantulus 1200 LSC with radium-226 source, the optimal PSA level was shown in the range of 100 to 110. The results show that the Minimum Detectable Activity (MDA) of radon concentrations is 0.61 $Bq{\cdot}L^{-1}$ for 20 minutes in PSA level. We find that the average radon concentration in groundwater is high in granitic rock area and low in volcanic rock area. (Biotite granite : 191.39 $Bq{\cdot}L^{-1}$, Micro graphic granite : 141.88 $Bq{\cdot}L^{-1}$, Adamellite : 92.94 $Bq{\cdot}L^{-1}$, Andesite (volcanic) : 35.35 $Bq{\cdot}L^{-1}$). No significant seasonal variation pattern is observed from the long-term variation analysis from 10 selected sites. We have not seen the significant correlation of radon concentration to groundwater temperature, atmospheric temperature, atmospheric pressure and rainfall. The concentration variation is probably caused by more complex factors and processes.

• Proceedings of the Korea Water Resources Association Conference
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• 2022.05a
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• pp.383-383
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• 2022

기존 큰 지진을 대상으로 한 많은 연구결과들을 살펴보면, 큰 지진이 발생하기 전에 토양 속에 존재하는 다양한 인자들 중에 라돈(²²²Rn, 반감기=3.82일) 농도가 비정상적으로 증가하는 현상을 나타낸다. 이러한 결과들은 라돈발생의 경향성을 분석한다면, 지진발생에 대한 전조증상이나 예측이 가능함을 나타낸다. 본 연구에서는 포항지역을 중심으로 지진발생에 대한 전조증상이나 모니터링을 분석하기 위해 지하수 관측소에 설치된 라돈 관측기기에서 라돈 관측자료를 수집하고 이를 활용하는 연구를 수행하였다. 라돈 관측자료 기간은 2019년 11월부터 2020년 9월까지의 자료이며, 라돈인자 뿐만 아니라 지하수위, 강수량, 수온인자를 같이 분석하였으며, 동일기간 동안 발생한 진도 2 이상의 지진사례 6개(E1(M_L 3.5): 2019.12.30.; E2(M_L 3.2): 2020.01.30.; E3(M_L 2.4): 2020.02.09.; E4(M_L 2.7): 2020.02.16.; E5(M_L 2.8): 2020.05.27.; E6(M_L 2.1): 2020.09.22.)를 대상으로 하였다. 지진발생의 전조증상이 나타나는 지역을 분석하기 위해 Dobrovolsky radius values (Dobrovolsky et al., 1979)와 Harversine 관계식을 적용하였다. 적용결과, 시간적 분석에서 라돈의 증감 경향성이 지진발생의 전조증상과 유의미한 상관성이 있음을 확인하였으며, 공간적인 분석에서도 유의미하지는 않으나 상관성이 나타났다. 그 외 지하수위는 상관성이 어느 정도 나타났으나 강수량은 유의미한 결과를 나타내지는 않았다. 따라서 라돈을 활용한다면 지진발생의 전조증상을 시공간적으로 파악할 수 있음을 확인하였다.

• Korean Journal of Environmental Agriculture
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• v.31 no.1
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• pp.9-15
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• 2012

BACKGROUND: A preliminary investigation of the radon ($^{222}Rn$) concentration has been conducted, employing solid-state nuclear-track detectors (SSNTD) and a continuous radon monitor (CRM), for fourteen randomly selected agricultural greenhouses in Jeju Island, where the underground-air was used for air conditioning and $CO_2$ supplement. METHODS AND RESULTS: The SSNTD was used to measure the average radon concentration for three months and the CRM was used for an instantaneous measurement. In order to obtain the radon concentration of a greenhouse, the SSNTDs were placed at a number of evenly distributed points inside the greenhouse and the mean of the measured values was taken. In addition, in order to assess the radon concentration of the underground-air itself, measurement was also made at the borehole of the underground-air in each agricultural facility, employing both the SSNTD and CRM. It is found that the radon concentration of the greenhouses ranges higher than those not using the underground-air and the average of Korean dwellings. While the radon concentration of most agricultural facilities is still lower than the reference level (1,000 Bq/$m^3$) recommended by the International Radiation Protection Committee (ICRP), three facilities at one site show higher concentrations than the reference level. The three-month-averaged radon concentration and the instantaneous radon concentration of the underground-air itself ranges 1,228- 5,259 and 3,322-17,900 Bq/$m^3$, respectively, and regional variation is more significant. CONCLUSION: From this results, radon concentration of the underground-air is assumed that it is associated with the geological characteristics and the boring depth of the region located of their.

• Analytical Science and Technology
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• v.25 no.1
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• pp.7-13
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• 2012

The real-time monitoring of radon ($^{222}Rn$) concentrations has been carried out to evaluate the background concentration level of atmospheric radon in Gosan site, Jeju Island. The mean concentration of radon for the recent 10 years was 2831 $mBq/m^3$ (0.077 pCi/L), which was 19.5 time lower than that of indoor radon in Korea. The seasonal concentrations were 2657, 2071, 3249, 3384 $mBq/m^3$ respectively for spring, summer, fall, and winter seasons. In monthly comparison, the radon concentrations were high in October and low in July. The hourly concentrations have increased during the nighttime, showing 3666 $mBq/m^3$ at 7 a.m., and decreased relatively during the daytime, showing 2755 $mBq/m^3$ at 2~3 p.m. From the back trajectory analysis, the radon concentrations showed higher values when the air mass was moved from the Asia continent to Jeju area, on the other hand, it showed low values when it was moved from the North Pacific Ocean.

• The Journal of Engineering Geology
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• v.22 no.1
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• pp.95-111
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• 2012

This study investigated the relationship between the geochemical environment and the occurrence of natural radioactive materials (uranium and Rn-222) in borehole groundwater at an Icheon site. The drill core recovered from the study site consists mainly of biotite granite with basic dykes. The groundwater samples were collected at four different depths in the borehole using the double-packed system. The pH range of the groundwater was 6.5~8.6, and the chemical type was Ca-$HCO_3$. The ranges of uranium and Rn-222 concentrations in the groundwater were 8.81~1,101 ppb and 5,990~11,970 pCi/L, respectively, and concentrations varied greatly with depth and collection time. The ranges of uranium and thorium contents in drill core were 0.53~18.3 ppm and 6.66~17.5 ppm, respectively. Microscope observations and electron microprobe analyses revealed the presence of U and Th as substituted elements for major composition of monazite, ilmenite, and apatite within K-feldspar and biotite. Although the concentration of uranium and thorium in the drill core was not high, the groundwater contained a high level of natural radioactive materials. This finding indicates that physical factors, such as the degree of fracturing of an aquifer and the groundwater flow rate, have a greater influence on the dissolution of radioactive materials than does the geochemical condition of the groundwater and rock. The origin of Rn-222 can be determined indirectly, using an interrelationship diagram of noble gas isotopes ($^3He/^4He$ and $^4He/^{20}Ne$).

• 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.