• Korean Journal of Environmental Biology
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• v.24 no.4
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• pp.387-391
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• 2006

Computational and experimental dosimetry of Henschke applicator with respect to high dose rate brachytherapy using the MIRD phantom and a remote control afterloader were performed. A comparison of computational dosimetry was made between the simulated Monte Carlo dosimetry and GAMMADOT brachytherapy Planning system's dosimetry. Dose measurements was performed using ion chamber in a water phantom. Dose rates are calculated using Monte Carlo code MCNP4B and the GAMMADOT. Thecomputational models include the detailed geometry of Ir-192 source, tandem tube, and shielded ovoids for accurate estimation. And transit dose delivered during source extension to and retraction from a given dwell position was estimated by Monte Carlo simulations. Point doses at ICRU bladder/rectal pointswhich have been recommened by ICRU 38 was assessed. Calculated and measured dose distribution data agreed within 4% each other. The shielding effect of ovoids leads to 19% and 20% dose reduction at bladder surface and rectal points.

• Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
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• v.18 no.2
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• pp.157-167
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• 2020

Removing radioactive concrete is crucial in the decommissioning of nuclear power plants. However, this process generates radioactive aerosols, exposing workers to radiation. Although large amounts of radioactive concrete are generated during decommissioning, studies on the internal exposure of workers to radioactive aerosols generated from the cutting of radioactive concrete are very limited. In this study, therefore, we calculate the internal radiation doses of workers exposed to radioactive aerosols during activities such as drilling and cutting of radioactive concrete, using previous research data. The electrical-mobility-equivalent diameter measured in a previous study was converted to aerodynamic diameter using the Newton-Raphson method. Furthermore, the specific activity of each nuclide in radioactive concrete 10 years after nuclear power plants are shut down was calculated using the ORIGEN code. Eventually, we calculated the committed effective dose for each nuclide using the IMBA software. The maximum effective dose of ¹⁵²Eu constituted 83.09% of the total dose; moreover, the five highest-ranked elements (¹⁵²Eu, ¹⁵⁴Eu, ⁶⁰Co, ²³⁹Pu, ⁵⁵Fe) constituted 99.63%. Therefore, we postulate that these major elements could be measured first for rapid radiation exposure management of workers involved in decommissioning of nuclear power plants, even if all radioactive elements in concrete are not considered.

• 대한방사선방어학회:학술대회논문집
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• 2010.04a
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• pp.220-221
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• 2010

• Journal of Radiation Protection and Research
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• v.29 no.2
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• pp.141-150
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• 2004

Dose rate characteristics of cosmic radiation field at flight altitudes were analyzed and the route doses to the personnels on board due to cosmic-ray were calculated for Korean-based commercial international airline routes using CARI-6. Annual individual doses to aircrew and the collective effective dose of passengers were estimated by applying the calculated route doses to the flight schedules of aircrew and the air travel statistics of Korea. The result shows that the annual doses to aircrew, around 2.62 mSv, exceed the annual dose limit of public and are comparable to doses of the group of workers occupationally exposed. Therefore it is necessary to consider the frequent flyers as well as the aircrew as the occupational exposure group. The annual collective dose to 11 million Korean passengers in 2001 appeared to be 136 man-Sv. The results should be modified when the dose rates of cosmic radiation at high altitude are revised by taking into account the changes in the radiation weighting factors for protons and neutrons as given in ICRP 92.

• Journal of Radiation Protection and Research
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• v.34 no.3
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• pp.129-136
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• 2009

During the maintenance period at Korean nuclear power plants, internal exposure of radiation workers occurred by the inhalation of $^{131}I$ released to the reactor building when primary system opened. The internal radioactivity of radiation workers contaminated by $^{131}I$ was measured using a whole body counter. Intake estimation and the calculation of committed effective dose were also conducted conforming to the guidance of internal dose assessments from publications of International Commission on Radiological Protection. Because the uptake and excretion of $^{131}I$ in a body occur quickly and $^{131}I$ is accumulated in the thyroid gland, the estimated intakes showed differences depending on the counting time after intake. In addition, since ICRP publications do not provide the intake retention fraction (IRF) for whole body of $^{131}I$, the IRF for thyroid was substitutionally used to calculate the intake and subsequently this caused more error in intake estimation. Thus, intake estimation and the calculation of committed effective dose were conducted by manual calculation. In this study, the IRF for whole body was also calculated newly and was verified. During this process, the estimated intake and committed effective dose were reviewed and compared using several computer codes for internal dosimetry.

• The Journal of the Korea Contents Association
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• v.10 no.2
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• pp.258-267
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• 2010

This interest in radiation exposure makes increasing doctor's awareness and knowledge of radiation dose in patients during X-ray test important in reducing patient's uneasiness. However, very few facilities are equipped with measurement instruments. Therefore, an intensive study to find out patient dose using computational method has been initiated. This study used special features of the bit system and NDD-M and directly measured the output dose of diagnostic X-ray instruments used in Korea to create tables. Two different methods were found to be adequate when applied to cases when X-ray outputs were both known and unknown, and comparative experiments with real measurement doses were carried out. Presented methods were found to provide more accurate results compared to the bit system and NDD-M. Therefore, patient dose during clinical trials were found to be more easily acceptable to medical personnel in the radiation field in terms of radiation exposure and reduction of medical X ray dose.

• 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.17 no.2
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• pp.15-23
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• 1992

Transport behaviors of Cs-137 and Sr-90 were analyzed and ingestion doses were calculated using dynamic model for rice field-rice-man pathway. Cs-137 binding strongly to soil remain longer in rice field than Sr-90. Foliar deposition on rice plant during growing period is the main contamination mechanism.

• Proceedings of the Korean Nuclear Society Conference
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• 1995.05b
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• pp.867-873
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• 1995

개방수조형 연구로인 하나로에서 가상적인 채널유동 차단사고에 따른 방사능 방출시의 환경영향을 부지 기상자료 측정결과를 이용하여 고공방출과 지표 면방출의 두가지 경로에 대해 평가하였다. 계산 결과, 지표면방출이 고공방출보다 피폭선량이 크게 나타났으나, 두 경우 모두 제한구역(EAB) 및 저인구지역(LPZ) 경계에서의 피폭선량 허용기준치를 만족하였다. 그리고 비상계획구역은 800 m로 설정하면 적절함을 입증하였다.

• Proceedings of the Korean Nuclear Society Conference
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• 1996.05a
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• pp.269-274
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• 1996

월성원자력발전소 2호기와 같은 CANDU 6형 원자로의 반응도제어기구 설치대에는 여러 반응도제어기구가 삽입되기때문에 원자로심으로부터의 방사선흐름현상으로 인한 방사선피폭이 예상될 수 있는 위치이다. 좁고 긴 반응도제어기구 도관에서의 방사선 흐름으로 인한 반응도제어기구 설치대에서의 방사선량을 예측하기 위해 몬테 칼로 MCNP 코드를 1차원 각분할법 코드인 ANISN과 연계하여 사용하였다. 월성원자력2호기의 상단차폐해석을 위한 ANISN 계산, 도관의 방사선흐름을 평가하기 위한 MCNP 계산, 그리고 반응도제어기구 설치대에서의 방사선량율 평가를 위한 MCNP 계산등 3단계 계산 기법의 적응이 시도되었다.