일개 대학 강의실의 실내 라돈농도 및 연간유효선량 평가 (Assessment of Indoor Radon Concentration and Annual Effective Dose in a University Lecture Room)

서지정보

· 발행기관 : (사)한국방사선산업학회
· 수록지 정보 : 방사선산업학회지 / 12권 / 3호 / 223 ~ 231페이지
· 저자명 : 이재승, 양성환, 권대철

초록

The purpose of this study is to evaluate the effective dose of radon by radon exposureby measuring the concentration of radon in university lecture room. The measurement of radonconcentration was made in two lecture rooms on the first floor of reinforced concrete structurefrom March to May, 2018. On weekends when there was no use of the lecture room, it wasmeasured for 24 hours in a closed state for 12 hours before measurement, and continued for 12hours in 12 hours and 12 hours in continuous for 5 weeks. The indoor radon concentration wasmeasured by a radon meter and an analysis program, and the indoor radon concentration per unittime was converted in real time. The annual effective dose and the continuously measured radonconcentration due to radon inhalation were analyzed for mean and standard deviation, coefficientof variation, indoor radon concentration range, and quartile range. The closed lecture room radonconcentration was estimated to be 67~81.8 Bq·m-3 (mean 74.5±6.65 Bq·m-3) and the effectivedose per year was 0.289~0.353 mSv·y-1. The average radon concentration in normal operationwas 26.6~54 Bq·m-3 (mean 40.2±8.34 Bq·m-3), which was 54% lower than the closed room. Themean radon concentration was 48.3±5.94 Bq·m-3 before the start of the academic year, 31.3±6.64Bq·m-3, the average radon concentration was 41.9±9.64 Bq·m-3, 0.115~0.233 mSv·y-1. Radonconcentration 32.2~54 Bq·m-3 (average 45.7±5.2 Bq·m-3) at 18:00 o’clock without the lecture at09:00 the following day, quaternary range 43.9~48.8 Bq·m-3, annual effective dose 0.190~0.211mSv·y-1 respectively. Radon concentration was 26.6~40 Bq·m-3 (average 31.3±6.64 Bq·m-3) from09:00 am to 18:00 pm, which was reduced by 68.5% compared to the classroom without class, andthe quartile range was 28.3~33.8 Bq·m-3, and annual effective dose was 0.122~0.146 mSv·y-1.
The average radon concentration in the lecture room was 10 min resting time (31.8±6.54 Bq·m-3)after lecture 50 minutes, 10 minutes resting time (32.3±7.18 Bq·m-3) after 1 hour and 50 minuteslecture, and 0.008~0.013 mSv·y-1. The average indoor radon concentration of 40.2±8.92 Bq·m-3 for 2 hours and 50 minutes of continuous use in classroom, the annual effective dose of 0.01~0.016mSv·y-1 for 50 minutes or 1 hour 50 minutes, indoor radon concentration and annual effectivedose of about 30% respectively. The radon concentrations in the lecture room were measured atlower levels than the indoor radon concentration control standards, and the hazard coefficientsfrom the radon inhalation in these environments were evaluated to be lower than the populationmean life time cancer risk.

영어초록

The purpose of this study is to evaluate the effective dose of radon by radon exposureby measuring the concentration of radon in university lecture room. The measurement of radonconcentration was made in two lecture rooms on the first floor of reinforced concrete structurefrom March to May, 2018. On weekends when there was no use of the lecture room, it wasmeasured for 24 hours in a closed state for 12 hours before measurement, and continued for 12hours in 12 hours and 12 hours in continuous for 5 weeks. The indoor radon concentration wasmeasured by a radon meter and an analysis program, and the indoor radon concentration per unittime was converted in real time. The annual effective dose and the continuously measured radonconcentration due to radon inhalation were analyzed for mean and standard deviation, coefficientof variation, indoor radon concentration range, and quartile range. The closed lecture room radonconcentration was estimated to be 67~81.8 Bq·m-3 (mean 74.5±6.65 Bq·m-3) and the effectivedose per year was 0.289~0.353 mSv·y-1. The average radon concentration in normal operationwas 26.6~54 Bq·m-3 (mean 40.2±8.34 Bq·m-3), which was 54% lower than the closed room. Themean radon concentration was 48.3±5.94 Bq·m-3 before the start of the academic year, 31.3±6.64Bq·m-3, the average radon concentration was 41.9±9.64 Bq·m-3, 0.115~0.233 mSv·y-1. Radonconcentration 32.2~54 Bq·m-3 (average 45.7±5.2 Bq·m-3) at 18:00 o’clock without the lecture at09:00 the following day, quaternary range 43.9~48.8 Bq·m-3, annual effective dose 0.190~0.211mSv·y-1 respectively. Radon concentration was 26.6~40 Bq·m-3 (average 31.3±6.64 Bq·m-3) from09:00 am to 18:00 pm, which was reduced by 68.5% compared to the classroom without class, andthe quartile range was 28.3~33.8 Bq·m-3, and annual effective dose was 0.122~0.146 mSv·y-1.
The average radon concentration in the lecture room was 10 min resting time (31.8±6.54 Bq·m-3)after lecture 50 minutes, 10 minutes resting time (32.3±7.18 Bq·m-3) after 1 hour and 50 minuteslecture, and 0.008~0.013 mSv·y-1. The average indoor radon concentration of 40.2±8.92 Bq·m-3 for 2 hours and 50 minutes of continuous use in classroom, the annual effective dose of 0.01~0.016mSv·y-1 for 50 minutes or 1 hour 50 minutes, indoor radon concentration and annual effectivedose of about 30% respectively. The radon concentrations in the lecture room were measured atlower levels than the indoor radon concentration control standards, and the hazard coefficientsfrom the radon inhalation in these environments were evaluated to be lower than the populationmean life time cancer risk.

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