|
KMID : 1039220180280030283
|
|
Journal of Korean Society of Occupational and Environmental Hygiene
2018 Volume.28 No. 3 p.283 ~ p.291
|
|
|
Evaluation of Effective Dose and Exposure Level of Radon in Process Handling NORM
|
|
Chung Eun-Kyo
Jang Jae-Kil
Kim Jong-Kyu
Kim Jooon-Beom
Kwon Ji-Woon
|
|
|
Abstract
|
|
|
Objectives: To monitor the radon concentration level in plants that handle phosphorus rock and produce gypsum board and cement, and evaluate the effective dose considering the effect of radon exposure on the human body.
Methods: Airborne radon concentrations were measured using alpha-track radon detectors (α-track, Rn-tech Co., Korea) and continuous monitors (Radon Sentinel 1030, Sun Nuclear Co., USA). Radon concentrations in the air were converted to radon doses using the following equation to evaluate the human effects due to radon.
H (m㏜/yr) = Radon gas concentration x Equilibrium factor x Occupancy factor x Dose conversion factor. The International Commission on Radiological Protection (ICRP) used 8 n㏜/(㏃·hr/㎥) as the dose conversion factor in 2010, but raised it by a factor of four to 33 n㏜/(㏃·hr/㎥) in 2017.
Results: Radon concentrations and effective doses in fertilizer manufacturing process averaged 14.3 (2.7) ㏃/㎥ (2.0-551.3 ㏃/㎥), 0.11-0.54 m㏜/yr depending on the advisory authority and recommendation year, respectively. Radon concentrations in the gypsum-board manufacturing process averaged 14.9 ㏃/㎥ at material storage, 11.4 ㏃/㎥ at burnability, 8.1 ㏃/㎥ at mixing, 10.0 ㏃/㎥ at forming, 8.9 ㏃/㎥ at drying, 14.7 ㏃/㎥ at cutting, and 10.5 ㏃/㎥ at shipment. It was low because it did not use phosphate gypsum. Radon concentrations and effective doses in the cement manufacturing process were 23.2 ㏃/㎥ in the stowage area, 20.2 ㏃/㎥ in the hopper, 16.8 ㏃/㎥ in the feeder and 11.9 ㏃/㎥ in the cement mill, marking 0.12-0.63 m㏜/yr, respectively.
Conclusions: Workers handling phosphorous gypsum directly or indirectly can be assessed as exposed to an annual average radon dose of 0.16 to 2.04 mSv or 0.010 to 0.102 WLM (Working Level Month).
|
|
|
KEYWORD
|
|
|
Dose conversion factor, ICRP, NORM
|
|
|
FullTexts / Linksout information
|
|
|
|
|
|
Listed journal information
|
|
|
|