• Title, Summary, Keyword: radon chamber

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The Determination of Radon Progeny Concentration in Controlled Radon Environment (라돈을 제어하는 환경에서 라돈 자핵종의 농도 결정)

  • Seo, Kyung-Won;Lee, Byung-Kee
    • Journal of Radiation Protection and Research
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    • v.18 no.1
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    • pp.37-51
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    • 1993
  • A standard radon chamber and a radon generator adjusted by ventilation system which had used in this research were assumed to calculate theoretically the concentration of radon progeny using Jacobi model theory. On the one hand, the filter sampled from the radon standard chamber and the radon generator was measured and analysed by the alpha spectrometry method. It is clear that measured result shows a good agreement with theoretical result. Therefore, it is observed that this research can made a great contribution to more accurate internal dose assessment by alpha emission of radon progeny in indoor radon environment, and fast individual measurement and determination of concentration for radon progeny.

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Effect of Black Charcoal and Activated Carbon for Reduction of Radon Radioactivity that Emitted from Building Materials (건축재료로부터 방출되는 라돈방사능 감소를 위한 흑탄과 활성탄 효과)

  • Cho, Yun-Min;Lee, Hwa-Hyung
    • Journal of the Korea Furniture Society
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    • v.22 no.1
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    • pp.13-17
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    • 2011
  • Recently, interest in indoor air quality is increasing. Especially, radon radioactivity among the indoor air is a well-known risk factor for lung cancer because of ionizing radiation in the form of ${\alpha}$-particles. This study was carried out to investigate effect of black charcoal and activated carbon for reduction of radon radiation that emitted from building materials. Black charcoal and activated carbon were used as a barrier which was against the infiltration of radon. The source of radon was gypsum board. Two types of charcoal barrier were powder- and board-type with 5 mm, 10 mm thickness respectively. The method for this determination is evaluated radon concentration in chamber. The measurements were performed with radon detector, SARAD3120. Results of this study are as following: Black charcoal and activated carbon confirmed the highly efficient barrier. Radon concentration was reduced from 72% to 85% as compared the control chamber. Radon reduction capability, however, was no difference as barrier's types. Results obtained in ventilation condition, radon concentration shows 5.93 pCi/L on average in the closed condition and shows 2.69 pCi/L in the opened condition.

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CONSTRUCTION OF AN ENVIRONMENTAL RADON MONITORING SYSTEM USING CR-39 NUCLEAR TRACK DETECTORS

  • AHN GIL HOON;LEE JAI-KI
    • Nuclear Engineering and Technology
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    • v.37 no.4
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    • pp.395-400
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    • 2005
  • An environmental radon monitoring system, comprising a radon-cup, an etching system, and a track counting system, was constructed. The radon cup is a cylindrical chamber with a radius of 2.2 cm and a height of 3.2 cm in combination with a CR-39 detector. Carbon is impregnated in the bodies of the detector chamber to avoid problem of an electrostatic charge. The optimized etching condition for the CR-39 exposed to a radon environment turned out to be a 6 N NaOH solution at 70^{\circ}$ over a 7hour period. The bulk etch rate under the optimized condition was $1.14{\pm}0.03\;{\mu}m\;h^{-1}$. The diameter of the tracks caused by radon and its progeny were found to be in the range of $10\~25\;{\mu}m$ under the optimized condition. The track images were observed with a track counting system, which consisted of an optical microscope, a color charged couple device (CCD) camera, and an image processor. The calibration factor of this system is obtained to be $0.105{\pm}0.006$ tracks $cm^2$ per Bq $m^{-3}$ d.

Radon Exhalation from Five Wood Species

  • Lee, Ju Yong;Choi, Gyu Woong;Kang, Seog Goo
    • Journal of the Korean Wood Science and Technology
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    • v.46 no.6
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    • pp.735-747
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    • 2018
  • Radon radiation exposures in home have been posed as a potential cancer hazard. This research aims to present the basic data of the indoor radon concentration level by examining the radon exhalation rates of wood species. Radon exhalation rates from five commonly used wood species in Korean wood building construction were measured with Continuous Radon Monitor (CRM), Model 1028 (Sun Nuclear Co., USA) using the Closed Chamber Method (CCM). The mass exhalation rate was observed to vary from $0.00089Bq{\cdot}kg^{-1}{\cdot}h^{-1}$ to $0.00181Bq{\cdot}kg^{-1}{\cdot}h^{-1}$, whereas the surface exhalation rate was observed to be $0.00677-0.01517Bq{\cdot}m^{-2}{\cdot}h^{-1}$. The radon exhalation rate of Quercus accutissima Carruth (white oak) which has the highest density showed the highest figure among the five wood species, on the other hand, the rest of four species showed similar results which were similar to the radon exhalation rates of wood in the U.S.A. and Canada. The average of the concentration measured by the CCM represented well up to the second half-life period (7.7 days). Because result of these small quantities seems to indicate that radon exhalation from the tested wood species has almost negligible impact, the main culprit of the high indoor radon concentration is clearly derived from the background of surrounding wood house. Therefore, as a safety precaution, infrastructures made of wood materials should be designed with the consideration of influx of radon and built accordingly. Furthermore, it is highly desirable that wood will be needed to use for furniture and interior finishing material in indoor environment.

A study on the Prediction of Indoor Concentration due to Radon Exhalation from Domestic Building Materials (건축자재 라돈 방출에 의한 실내공기 중 라돈농도 예측에 관한 연구)

  • Lee, Cheolmin;Gwak, Yoonkyung;Lee, Donghyun;Lee, Dajeong;Cho, Yongseok
    • Journal of Environmental Science International
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    • v.24 no.9
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    • pp.1131-1138
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    • 2015
  • Radon exhalation rates have been determined for samples of concrete, gypsum board, marble, and tile among building materials that are used in domestic construction environment. Radon emanation was measured using the closed chamber method based on CR-39 nuclear track detectors. The radon concentrations in apartments of 100 households in Seoul, Busan and Gyeonggi Provinces were measured to verify the prediction model of indoor radon concentration. The results obtained by the four samples showed the largest radon exhalation rate of $0.34314Bq/m^2{\cdot}h$ for sample concrete. The radon concentration contribution to indoor radon in the house due to exhalation from the concrete was $31.006{\pm}7.529Bq/m^3$. The difference between the prediction concentration and actual measured concentration was believed to be due to the uncertainty resulting from the model implementation.

Effects of radon on soil microbial community and their growth

  • Lee, Kyu-Yeon;Park, Seon-Yeong;Kim, Chang-Gyun
    • Environmental Engineering Research
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    • v.25 no.1
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    • pp.29-35
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    • 2020
  • The aim of this study was to estimate the microbial metabolic activity of indigenous soil microbes under the radon exposure with different intensity and times in the secured laboratory radon chamber. For this purpose, the soil microbes were collected from radon-contaminated site located in the G county, Korea. Thereafter, their metabolic activity was determined after the radon exposure of varying radon concentrations of 185, 1,400 and 14,000 Bq/㎥. The average depth variable concentrations of soil radon in the radon-contaminated site were 707, 860 and 1,185 Bq/㎥ from 0, 15, and 30 cm in deep, respectively. Simultaneously, the soil microbial culture was mainly composed of Bacillus sp., Brevibacillus sp., Lysinibacillus sp., and Paenibacillus sp. From the radon exposure test, higher or lower radiation intensities compared to the threshold level attributed the metabolic activity of mixed microbial consortium to be reduced, whereas the moderate radiation intensity (i.e. threshold level) induced it to the pinnacle point. It was decided that radon radiation could instigate the microbial metabolic activity depending on the radon levels while they were exposed, which could consequently address that the certain extent of threshold concentration present in the ecosystem relevant to microbial diversity and population density to be more proliferated.

Theoretical Calculation on Alpha Track Density by Using an Electrostatic Ion Spectrometer (정전기분광분석방법에 의한 알파입자비적밀도의 이론적 계산연구)

  • Yoon, Suk-Chul;Ha, Chung-Woo
    • Journal of Radiation Protection and Research
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    • v.18 no.1
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    • pp.25-35
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    • 1993
  • To develop a technique of theoretical alpha track density calculation for comparison with measured track density, an electrostatic ion spectrometer was specially designed and fabricated. The mobility spectrum of first radon daughter(Po-218) in the range of $0.07{\sim}5.0cm^2/V\;s$ from the radon chamber was measured using-the electrostatic ion spectrometer. Measurement was taken in a radon chamber operated using dry particle free air passed through silica gel, activated charcoal and molecular sieve filters. The mobility of a new-born Po-218 ion measured by the electrostatic ion spectrometer was determined to be $1.92cm^2/V\;s$. A comparison of the theoretical and measured alpha track densities was completed and uncertainties concerning the shape of the spectrum were analyzed. It was found that the discrepancies in track densities are primarily Que to the neglect of wall loss of ions in the theoretical track density calculation.

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A Study on Radon Emission Reduction of Construction Materials using Radon-reducing Agent (라돈 저감제를 이용한 건축자재의 라돈 방출 저감 연구)

  • Park, Kyung-Buk;Lee, Sang-Houck
    • Journal of Environmental Health Sciences
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    • v.40 no.6
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    • pp.484-491
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    • 2014
  • Objectives: A radon emission reducing agent was prepared using charcoal and zeolite, and the amount was measured after coating construction materials with the agent. The availability of the radon emission reducing agent was evaluated. Methods: Construction materials (red brick, cement brick, and gypsum board) coated with reducing agent were placed in a chamber to measure radon emissions. The construction materials were coated one through three times. The spread volume for brick and gypsum board was 50 mL and 75 mL per application, respectively. The amount of radon emitted was measured by RAD-7 after 48 hours. Results: The reduction ratio increased with the number of coatings, and the reduction ratios for red brick, cement brick, and gypsum board were 63.3, 73.6, and 58%, respectively, in the case of three coatings of RA-1. The reduction ratios for red brick, cement brick, and gypsum board were 42.8, 58.1, and 26.2%, respectively in the case of three coatings with RA-2. RA-1 was slightly better than RA-2 in radon emission reduction. Conclusions: Radon emissions from construction materials decreased according to the concentration of reducing agent coating, and it was more effective than existing methods.

Performance Evaluation of Several Radon Detectors in the Standard Chamber and Dwellings (라돈 표준실과 가옥 내에서 일부 라돈검출기에 대한 성능 평가)

  • Yoon, Seok-Won;Kim, Yong-Jae;Chang, Byung-Uck;Byun, Jong-In;Yun, Ju-Yong
    • Journal of Radiation Protection and Research
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    • v.33 no.4
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    • pp.173-181
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    • 2008
  • To ensure the performance of radon detectors, three passive radon detectors ($RadTrak^{(R)}$, $Radopot^{(R)}$, and $E-PERM^{(R)}$)have been reviewed. The difference ratios of RadTrak and Radopot tested in the radon standard chamber were -13.2% and -6.0%, respectively, which were in good accordance within 20% of the value measured by $AlphaGUARD^{(R)}$. To ensure the performance of the long term measurement, the 3 detectors were installed at the same position of approximately one hundred of dwellings for one year. The correlation curve between RadTrak and Radopot shows good agreement with a correlation coefficient ($R^2$) of 0.91. However, The correlation curve between E-PERM and Radopot shows bad agreement ($R^2$ = 0.021). In addition, the distribution map of annual mean indoor gamma dose rate measured with E-PERM was not in accordance with the distribution map of outdoor gamma dose rate measured by Portable Ion Chamber. According to the results, some requisites for the selection of the radon passive detectors in the large-scale indoor radon survey were discussed.

The KRISS Radon Chamber

  • Ahn, Gil-Hoon;Lee, Jong-Man;Park, Tae-Soon
    • Proceedings of the Korean Nuclear Society Conference
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    • pp.942-943
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    • 2005
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