• Nuclear Engineering and Technology
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• v.48 no.3
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• pp.785-794
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• 2016

The Argonne National Laboratory of the United States and the Kharkov Institute of Physics and Technology of the Ukraine have been collaborating on the design, development and construction of a neutron source facility at Kharkov Institute of Physics and Technology utilizing an electron-accelerator-driven subcritical assembly. The electron beam power is 100 kW using 100-MeV electrons. The facility was designed to perform basic and applied nuclear research, produce medical isotopes, and train nuclear specialists. The biological shield of the accelerator building was designed to reduce the biological dose to less than 5.0e-03 mSv/h during operation. The main source of the biological dose for the accelerator building is the photons and neutrons generated from different interactions of leaked electrons from the electron gun and the accelerator sections with the surrounding components and materials. The Monte Carlo N-particle extended code (MCNPX) was used for the shielding calculations because of its capability to perform electron-, photon-, and neutron-coupled transport simulations. The photon dose was tallied using the MCNPX calculation, starting with the leaked electrons. However, it is difficult to accurately tally the neutron dose directly from the leaked electrons. The neutron yield per electron from the interactions with the surrounding components is very small, ~0.01 neutron for 100-MeV electron and even smaller for lower-energy electrons. This causes difficulties for the Monte Carlo analyses and consumes tremendous computation resources for tallying the neutron dose outside the shield boundary with an acceptable accuracy. To avoid these difficulties, the SOURCE and TALLYX user subroutines of MCNPX were utilized for this study. The generated neutrons were banked, together with all related parameters, for a subsequent MCNPX calculation to obtain the neutron dose. The weight windows variance reduction technique was also utilized for both neutron and photon dose calculations. Two shielding materials, heavy concrete and ordinary concrete, were considered for the shield design. The main goal is to maintain the total dose outside the shield boundary less than 5.0e-03 mSv/h during operation. The shield configuration and parameters of the accelerator building were determined and are presented in this paper.

• Journal of Radiation Protection and Research
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• v.45 no.2
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• pp.81-87
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• 2020

Background: Kori unit #1 is permanently shut down after a 40-year lifetime. The Nuclear Safety and Security Commission recommends establishing initial decommissioning plans for all nuclear and radwaste treatment facilities. Therefore, the Korea Atomic Energy Research Institute (KAERI) must establish an initial and final decommissioning plan for radwaste-treatment facilities. Radiation safety assessment, which constitutes one chapter of the decommissioning plan, is important for establishing a decommissioning schedule, a strategy, and cost. It is also a critical issue for the government and public to understand. Materials and Methods: This study provides a method for assessing external radiation dose to workers during decommissioning. An external dose is calculated following each exposure scenario, decommissioning strategy, and working schedule. In this study, exposure dose is evaluated using the deterministic method. Physical characterization of the facility is obtained by both direct measurement and analysis of the drawings, and radiological characterization is analyzed using the annual report of KAERI, which measures the ambient dose every month. Results and Discussion: External doses are calculated at each stage of a decommissioning strategy and found to increase with each successive stage. The maximum external dose was evaluated to be 397.06 man-mSv when working in liquid-waste storage. To satisfy the regulations, working period and manpower must be managed. In this study, average and cumulative exposure doses were calculated for three cases, and the average exposure dose was found to be about 17 mSv/yr in all the cases. Conclusion: For the three cases presented, the average exposure dose is well below the annual maximum effective dose restriction imposed by the international and domestic regulations. Working period and manpower greatly affect the cost and entire decommissioning plan; hence, the chosen option must take account of these factors with due consideration of worker safety.

• Journal of radiological science and technology
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• v.18 no.2
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• pp.49-59
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• 1995

Recently, general radiography became to variety because of the continuous development of Inverter type generator and ortho chromatic system. Therefore, we must re-evaluate about patient exposure dose and image quality. I studied about chest radiography which has frequency among general radiography being used during FEB. to AUG., 1994 over 151 medical facilities from medical facilities that are located in Seoul area. The result obtained were as follows ; 1) The rectification method of the generator were employing mainly single phase full wave in 82.8 %, three phase full wave in 11.26 % and Inverter type in 4.64 % and condenser type is 1.32 %. 2) Exposure kV was used below 80 kV in most medical facilities and 21.8 % of the medical facilities was using high tube voltage higher than 120 kV. 3) The exposure time was used below the 0.05 sec in 28.4 %, in 29.8 % of the medical facilities used above 0.1 sec. 4) The usage frequency of the added filter is 15.3 %, and among them compound filter was used only 4 %. 5) Rare earth screen was used in 37.7 %. 6) The average skin entrance dose was 0.25 mSv, the range of dose is $0.05{\sim}0.79\;mSv$ in each medical facilities. 7) The average density of the lung field is 1.76, 0.49 in lung side, 0.30 in mediastinum and 0.37 in heart shadow. Therefore it is required to improve all of these for increasing image quality and reducing patient exposure dose as soon as possible.

• Journal of radiological science and technology
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• v.39 no.3
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• pp.385-390
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• 2016

Radioactive iodine treatment that uses the 2 people isolation room is to cause unnecessary radiation exposure between patients. This research is to be tested safety of 2 people Isolation treatment room and dose-rate through conservative perspective except physiology characteristic and biology information on the assumption that patient have iodine without excretion in 2 people isolation treatment room. This research shows that 364 keV gamma rays emitted by the radioiodine was to determine that the air layer about 30 cm or lead shield 3 mm a half-layer. In addition, In addition, patients in the distance, and lead shielding, length of hospital stay (48 hours) for external radiation exposure that is received from the other patients, two of treatment as appears to be lower than the legal isolation standard dose less than 5 mSv isolation room effective analyzed that manageable.

• Journal of the Korean Society of Radiology
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• v.6 no.1
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• pp.27-37
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• 2012

From Jan 2002 to June 2011, we evaluated 4419 cases of radiation dose of 323 radiation related individuals consist of physician, nurses, technician and others in local C national university hospital. On annual analysis, year 2003 ranked the highest and 2007 the lowest dose. Dose was relatively higher in male than female. Dose was highest in 30s on age basis analysis. Dose was high in order of physician, nurse, and technician. Average radiation dose was high in order of cardiovascular center, radiologic intervention ceter, radiologist individuals, and fluoroscopic contrast study room. Those doses did not excess the standard dose recommended by ICRP (20mSv/year). However unlike average dose, there are wide variations of dose in individuals. Therefore radiation related workers should do one's best in personal radiation exposure dose management for achievement of minimum dose of radiation.

• Proceedings of the Korean Radioactive Waste Society Conference
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• 2003.11a
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• pp.671-675
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• 2003

In accordance with the KRR-1 & 2 decommissioning project, the decontamination and dismantling activities of the KRR-2 auxiliary facilities, radioisotope production facilities, were completed from Aug 2001 to Dec 2002. The auxiliary facilities were composed of the concrete hot-cell, lead hot-cells and several laboratories for the radioisotope production. The dismantling objects are home hoods, experimental desks, sinks, and contaminated inner facilities. For the purpose of the safe decommissioning activity, the method statements and working procedures were set up. The manpower of the total 20,933 man-hour was required and several dismantling equipments were also. The maximum surface contamination is: 9.24 Bq/$\textrm{cm}^2$ in removable contamination and 350,000 cpm in fixed contamination. The total amount of 62.146 Ton was raised as dismantled waste with kinds of the concretes, wood, steels, etc. The collective dose was evaluated as 0.33 mam-mSv during this period.

• Journal of Radiation Protection and Research
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• v.28 no.1
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• pp.75-78
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• 2003

The organically bound tritium(OBT) concentrations of the marine organisms(seaweed and shellfish) around Wolsung nuclear power plants were measured. The OBT concentrations of seaweeds were in the range of $0.372{\sim}2.72$ Bq/kg-fresh. The OBT concentrations of shellfish were in the range of $0.239{\sim}2.02$ Bq/kg-fresh. The internal dose due to the OBT concentration of seaweed was estimated as $3.4{\times}10^{-7}$ mSv/year.

• The Journal of Korea Institute of Information, Electronics, and Communication Technology
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• v.1 no.3
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• pp.33-40
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• 2008

The TMO may contain two types of methods, time-triggered methods(also called the spontaneous methods of SpMs) which are clearly separated from the conventional service methods (SvMs). The SpM executions are triggered upon design time whereas the SvM executions are triggered by service request message from clients. In this paper, we describes the application environment as the patient monitor telemedicine system with TMO structure. Vital sign information web viewer systems is also the standard protocol for medical image and transfer. In order to embrace new technologies as telemedicine service, it is important to develope the standard protocol between different systems in the hospital, as well as the communication with external hospital systems. It is able to apply to remote medical examination and treatment. Through the proper data exchange and management of patient vital sign information, real time vital sign information management will offer better workflow to all hospital employee.

• Nuclear Engineering and Technology
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• v.32 no.5
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• pp.477-484
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• 2000

To estimate the degree of intake of $^{238}$ U and $^{232}$ Th through daily diet, a Korean mixed diet sample was prepared after the investigation of the amount of consumption of the daily diet which corresponds to the age of 20 to 60 years. For the analysis of U and Th, the RNAA method was applied. Two standard reference materials were used for quality control and assurance and the analytical results were compared with a certified value. The determination of U and Th in the Korean mixed diet sample was carried out under the same analytical conditions and procedures with SRM. It is found that the concentration of U and Th in a Korean mixed diet was about 35.4 ppb and 3.4 ppb. From these results, the daily intake of $^{238}$ U and $^{232}$ Th by diet is evaluated to be 6.98 and 0.67 $\mu\textrm{g}$ per day, respectively. Radioactivities related to the intake of $^{238}$ U and $^{232}$ Th were estimated to be about 86 mBq and 27 mBq per person per day and the annual dose equivalents from $^{238}$ U and $^{232}$ Th revealed as 3.18 $\mu$Sv and 0.29 $\mu$Sv per person, respectively.

• Journal of Radiation Industry
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• v.8 no.2
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• pp.123-132
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• 2014

After the nuclear accident of the Fukushima Dai-ichi Nuclear Power Plants (FDNPPs) on 11 March 2011, a large amount of radioactive materials has been released into the atmosphere and the ocean. A compartment model is used to evaluate the circulation characteristics and the spatiotemporal concentration distributions of radionuclides in the ocean. In the comparison with observed concentrations of $^{137}Cs$ in seawater, calculated concentrations by the compartment model were well agreed with them. On the basis of these results, we performed evaluation of the effective dose and the cancer risk. In the early stage of the accident, the effective doses from ingestion of the seafood near the Fukushima region were much higher than 1 mSv which is the value of the annual effective dose limit to individual recommended by the International Commission on Radiological Protection (ICRP). However, the effective doses by ingestion of the seafood decreased below 1 mSv as distance from the FDNPPs increased and time passed. In addition, it was estimated that the cancer risks by intake of the contaminated marine products were less than natural occurrence probability of cancer. Consequently, it was inferred that the health risk due to the $^{137}Cs$ was low after since mid-term period of the accident.