| 천연방사성물질을 함유한 공기 중 부유입자 흡입 시 입자의 물리화학적 특성에 따른 호흡방사선량 민감도 평가 |
| 김시영1, 최철규1, 박일1, 김용건1, 최원철1,2, 김광표1 |
1경희대학교
2한국원자력안전기술원 |
| Assessment of Inhalation Dose Sensitivity by Physicochemical Properties of Airborne Particulates Containing Naturally Occurring Radioactive Materials |
| Si Young Kim1, Cheol Kyu Choi1, Il Park1, Yong Geon Kim1, Won Chul Choi1,2, Kwang Pyo Kim1 |
1Kyung Hee University
2Korea Institute of Nuclear Safety |
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Received: October 30, 2015; Revised: November 24, 2015 Accepted: November 24, 2015. |
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| ABSTRACT |
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Facilities processing raw materials containing naturally occurring radioactive materials (NORM) may give rise to enhanced radiation dose to workers due to chronic inhalation of airborne particulates. Internal radiation dose due to particulate inhalation varies depending on particulate properties, including size, shape, density, and absorption type. The objective of the present study was to assess inhalation dose sensitivity to physicochemical properties of airborne particulates. Committed effective doses to workers resulting from inhalation of airborne particulates were calculated based on International Commission on Radiological Protection 66 human respiratory tract model. Inhalation dose generally increased with decreasing particulate size. Committed effective doses due to inhalation of 0.01 μm sized particulates were higher than doses due to 100 μm sized particulates by factors of about 100 and 50 for 238U and 230Th, respectively. Inhalation dose increased with decreasing shape factor. Shape factors of 1 and 2 resulted in dose difference by about 18 %. Inhalation dose increased with particulate mass density. Particulate mass densities of 11 g·cm-3 and 0.7 g·cm-3 resulted in dose difference by about 60 %. For 238U, inhalation doses were higher for absorption type of S, M, and F in that sequence. Committed effective dose for absorption type S of 238U was about 9 times higher than dose for absorption F. For 230Th, inhalation doses were higher for absorption type of F, M, and S in that sequence. Committed effective dose for absorption type F of 230Th was about 16 times higher than dose for absorption S. Consequently, use of default values for particulate properties without consideration of site specific physiochemical properties may potentially skew radiation dose estimates to unrealistic values up to 1-2 orders of magnitude. For this reason, it is highly recommended to consider site specific working materials and conditions and use the site specific particulate properties to accurately access radiation dose to workers at NORM processing facilities. |
| Keywords:
Naturally occurring radioactive material, Human respiratory tract model, Particulate physicochemical property, Inhalation dose, Sensitivity to particulate properties |
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