• Journal of Radiation Protection and Research
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• v.36 no.2
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• pp.64-70
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• 2011

The intercomparison exercise on internal dose assessment has been carried out for the purpose of the evaluation for harmonization of internal dosimetry between the nuclear-related institutes in Korea. The exercises of 9 items on internal dose assessment have been developed for the unknown internal dosimetric parameters such as the intake pathway, absorption type, AMAD, and intake time of a radionuclide. Solutions to these exercises were reported by 7 participants from 5 institutes. The range of the ratio between the individual values and the geometric mean value of the evaluated doses for the exercises was $5.75{\times}10^{-4}$ ~ 9.81. But without the extreme partial solution, the range of the ratio was 0.216 ~ 3.12.

• Journal of Radiation Protection and Research
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• v.32 no.3
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• pp.111-115
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• 2007

A deuterium oxide leakage accident occurred on October 4, 1999, at nuclear power plant in Korea. The concentration of tritium in air increased and 22 workers were exposed by tritium at that time. It is well known that tritium causes internal exposure. Therefore, we examined complete blood cell count, physical and biological dosimetry fur 13 workers among whole 22 workers to check the health effect and to evaluate the dose estimation of tritium exposure. The leukocyte count test, one of general blood test, was normal. The estimated doses were 0 - 4.44 mSv by physical dosimetry and 0-37 mGy by biological dosimetry. This dose does not exceed radiation dose limit, and the clinical symptoms of the exposed workers were not shown. The consistency between clinical sign and estimated dose means that physical and biological dosimetry were very useful especially in accident evaluation.

• Journal of Radiation Protection and Research
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• v.34 no.1
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• pp.37-42
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• 2009

Whole body counters (WBCs) are used to monitor radiation workers for internal contamination of radionuclides at domestic nuclear power plants (NPPs). A WBC is a scintillation detector using sodium iodide (NaI) and provides the identification of inhaled radionuclide and the measurement of its internal radioactivity in a short time. However, it is often possible to estimate external contamination as internal contamination due to radionuclides attached to the skin of radiation workers and this leads to an excessively conservative estimation of radioactive contamination. In this study, several experiments using a WBC and the Korean humanoid phantom were performed to suggest the more systematic method of discrimination between external and internal contamination. Furthermore, a WBC geometry experiment was conducted to suggest the optimal WBC geometry in consideration of deposited areas inside the body for dominant radionuclides at NPPs. The procedure of measurement and estimation of internal radioactivity for radiation workers at NPPs was improved on the basis of experimental results. Thus, it is expected to prevent from estimating internal exposure dose conservatively owing to the application of accurate whole body counting program to NPPs.

• Journal of Radiation Protection and Research
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• v.29 no.2
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• pp.97-104
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• 2004

MIRD-type Korean adult male phantom, 'KMIRD' was constructed to calculate Korean-specific dosimetric quantities for radiation protection consideration. The external shape of KMIRD was based on national physical standard data of Korean. KMIRD has thicket trunk than MIRD5 and arm models divided from trunk. The height and weight of the KMIRD are 171 cm and 63.8 kg. ICRP23 data were referred to constitute organs and tissues of KMIRD. However nine organs were constructed based on Korean reference data provided by Radiation Health Research Institute. In the present study, the MCNPX2.3 Monte Carlo transport code was combined with KMIRD to calculate dose conversion coefficients for photon in the energy range from 0.05 to 10 MeV. The simulated irradiation geometries are broad parallel photon beams in AP, PA, LLAT and RLAT direction. Absorbed dose conversion coefficients were compared with data calculated with MIRD5, MIRD-type phantom based on ICRP23 reference man. In some organs, the discrepancies between two phantoms amount up to nearly 30%. The effective doses conversion coefficients of KMIRD are lower than those of MIRD5. The dose discrepancies between two MIRD-type phantoms ate because of physical differences between Korean and Western, also geometric differences between two phantoms. KMIRD should be revised using the full set of Korean reference data of all organs. The developed MIRD-type Korean adult male phantom can be applied to dose assessment of internal exposure.

• Journal of Radiation Protection and Research
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• v.40 no.4
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• pp.216-222
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• 2015

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 $0.01{\mu}m$ sized particulates were higher than doses due to $100{\mu}m$ sized particulates by factors of about 100 and 50 for $^{238}U$ and $^{230}Th$, 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 $11g{\cdot}cm^{-3}$ and $0.7g{\cdot}cm^{-3}$ resulted in dose difference by about 60 %. For $^{238}U$, inhalation doses were higher for absorption type of S, M, and F in that sequence. Committed effective dose for absorption type S of $^{238}U$ was about 9 times higher than dose for absorption F. For $^{230}Th$, inhalation doses were higher for absorption type of F, M, and S in that sequence. Committed effective dose for absorption type F of $^{230}Th$ 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.

• Proceedings of the Korean Nuclear Society Conference
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• 1998.10a
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• pp.333-333
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• 1998

• Radioisotope journal
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• v.16 no.4
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• pp.16-27
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• 2001

• Radioisotope journal
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• v.16 no.4
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• pp.2-6
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• 2001

• Radioisotope journal
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• v.16 no.4
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• pp.7-15
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• 2001

• Radioisotope journal
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• v.12 no.4
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• pp.63-68
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• 1997