• 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.

• Particle and aerosol research
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• v.14 no.4
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• pp.181-189
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• 2018

In this study, the risk rates of different contamination sources of the contaminant in a minienvironment were analyzed through Computational Fluid Dynamics (CFD) simulation. The airflow pattern characteristics can only predict the qualitative variation of contaminant concentration, but cannot evaluate the quantitative variations in the risk rate of sources. From the results, the ambient contamination sources mainly affect wafers in the Front Opening Unified Pod (FOUP), whereas the internal contamination sources mainly affect wafers laid on the robot arm in the minienvironment. And the purging plenum system is very useful in protecting the wafers in the FOUP from contaminants transferred from the Fan Filter Unit (FFU). However, this system is unable to protect the wafers on the robot arm from internal contaminants and the wafers in the FOUP from sources of the interface between the FOUP and the minienvironment.

• Journal of Radiation Protection and Research
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• v.38 no.4
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• pp.234-236
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• 2013

Some of radioactive contamination is unavoidable in the facilities using the unsealed radioactive material. The primary purpose of radioactive contamination control in the workplace with contamination concern is the effects from the potential intake of radioactive material into the body. This paper provides procedures to estimate the level of internal exposure for the worker based on the conservative assumptions and simple calculations. They consist of two processes; to calculate air concentration of radioactive material and annual intake by inhalation with contaminated air and to compare each of them to Derived Air Concentration and Annual Limit on Intake mentioned in the related notification. The procedures are applicable to make a decision on practical requirements for monitoring air contamination and internal exposure of worker as follows; needs for measurement of air contamination and internal exposure and acquisition of information on the design of the ventilation system.

• Journal of Radiation Protection and Research
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• v.38 no.4
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• pp.242-245
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• 2013

Monte Carlo method was applied to discriminate the external contamination on radiation workers in nuclear power plants for internal dose assessment generally used with a bed type scanning detector whole body counter. Korean voxel model with internal contamination was used to estimate the detection patterns of whole body scanning. Also, the BOMAB model with various external contamination was assumed to compare with detection of radionuclides inside the human body. From the comparison of detection efficiency between front and back side up, external contamination was easily distinguished.

• Proceedings of the SAREK Conference
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• 2007.11a
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• pp.600-605
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• 2007

In this study, the risk rates of different contamination sources of the Foreign material in a minienvironment were analyzed through CFD simulation. From the results, the ambient contamination sources mainly affect wafers in the FOUP, whereas the internal contamination sources mainly affect wafers laid on the robot arm in the minienvironment. And the purging plenum system is very useful in protecting the wafers in the FOUP from Foreign materials transferred from the FFU. However, this system is unable to protect the wafers on the robot arm from internal Foreign materials and the wafers in the FOUP from sources of the interface between the FOUP and the minienvironment.

• Journal of Korean Academy of Nursing
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• v.3 no.2
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• pp.45-51
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• 1973

Bacterial cultures of the transfer forceps, 4"$\times$4"mesh gauze and polluted air of nursing units of general surgery, internal medicine, gynecology and pediatrics of S.N.U.H. were carried on for S consecutive days (from 17th to 21s1 August, 1972) to investigate the degree of contamination of such instruments which were used in dressing the patients. 1. The average hospitalized patients for each nursing unit were 24 persons. 2. The frequency of dressing, and using forceps and gauze in surgical nursing unit were 25,316 and 66 times respectively. Actually the forceps were used most frequently. There was no dressing in the nursing unit of internal median. 3. Most of dressing were carried on from 11 : 00 to 13 : 59 o′clock. 4. Averagely 121.5 persons passed through each nursing unit. 549 visitors dropped in the nursing unit of gynecology in maximum, and 219 visitors in the nursing of internal medicine in minimum. The visitors rushed in from 11 : 00 to 13 : 59 o′clock to he 142.5 persons for each nursing unit in average. 5. Colony counts after the bacterial cultures of the forceps and gauze disclosed 1098.44 and 704.51 per plate respectively. 6. The degree of contamination was parallel to the duration and frequency of dressings. 7. The degree of contamination of the instruments was severest in the nursing unit of internal medicine, and !east in the nursing unit of gynecology. On the matter of gauze, the contamination was most extreme in the pediatric nursing unit. 8. There was no significant daily differences in terms of contamination throughout the week. 9. It was disclosed that empty forceps jars were less contaminated than the jars with solution of any kind. 10. Bacterial cultures of the polluted air in corridor showed 73,88 colony counts per plate.

• Journal of radiological science and technology
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• v.11 no.1
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• pp.63-69
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• 1988

In case of occuring the atomic energy accidents the proper medical treatments should be necessary. As the aim of the basic data for protective actions, the present studies were carried out to evaluate the decontamination of radioiodine by the administration of the antithyroid drugs (KI, NaI) and isotonic saline. Some recommended methods of decorporating radioiodine were investigated using 450, NIH-GP mice, each injected intraperitoneally with $1{\mu}Ci$ of $NaI^{131}$ as the internal contamination and treated with 2mg/0.2ml-saline of NaI and 2.6mg/0.2ml-saline of KI as the antithyroid drugs. Accordingly, effects of antithyroid drugs for internal contamination were: 1. Administration of NaI and KI caused to rapidly excrete internal radioiodine as the antithyroid drugs and decrease in whole body retention was reduced than in the saline group. 2. After internal contamination NaI and KI were to be administered for radioprotective effects as quickly as possible. 3. Decrease in body-retention made temporary shifts with enough fluids (water), however, as far as radioprotective effects is concerned, saline was not more significant than in the other group (NaI and KI). 4. Regarding to thyroid protective effects NaI, KI and saline were significant in effectively order.

• Journal of Radiation Protection and Research
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• v.41 no.2
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• pp.133-140
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• 2016

Backgrounds: The accident at Fukushima Daiichi Nuclear Power Plant (NPP), March 2011, caused serious radioactive contamination over wide area in east Japan. Therefore, it is important to know the effect of the accident and the status of NPP. Materials and Methods: This paper provides a review on the status of radiation dose and radioactive contamination caused by the accident on the basis of publicized information. Results and Discussion: Monitoring of radiation dose and exposure dose of residents has been conducted extensively by the governments and various organizations. The effective dose of general residents due to the accident proved to be less than a mSv both for external and internal dose. The equivalent committed dose of thyroid was evaluated to be a few mSv in mean value and less than 50 mSv even for children. Monitoring of radioactivity concentration has been carried out on food ingredients, milk and tap water, and actual meal. These studies indicated the percentage of foods above the regulation standard was over 10% in 2011 but decreasing steadily with time. The internal dose due to foods proved to be tens of ${\mu}Sv$ and much less than that due to natural $^{40}K$ even in the Fukushima area and decreasing steadily, although high level concentration is still observed in wild plants, wild mushrooms, animals and some kind of fishes. Conclusion: According to extensive studies, not only the effect of the accident but also the pathway and countermeasures against radioactive contamination have been revealed, and they are applied very effectively for restoration of environment and reconstruction of the area.

• Journal of The Korean Society of Clinical Toxicology
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• v.9 no.2
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• pp.39-48
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• 2011

In mass casualty situation due to radiological accidents, it is important to start aggressive management with rapid triage decisions. External contamination needs immediate decontamination and internal contamination should be treated with special expertise and equipment to prevent the rapid uptake of radionuclides by target organs. Acute radiation syndrome shows a sequence of events that varies with the severity of the exposure. More severe exposures generally lead to more rapid onset of symptoms and severe clinical findings. After the massive exposure, various systems of the body reflect their severe damages that can lead to death within hours or up to several months. The disease progression has classically been divided into four stages: prodromal, latent, manifest illness, and recovery or death. Three characteristic clusters of symptoms including the hematopoietic syndrome, the gastrointestinal syndrome and the cerebrovascular syndrome are all associated with the acute radiation syndrome. The standard medical management of the patients with a potentially survivable radiation exposure includes good medical, surgical and supportive measures. Specific treatment with cytokines and bone marrow transplantation should be considered. The management of internal contamination is much the same as the treatment of poisoning. The standard decontamination should be applied to reduce uptake, and the chelating agents can be administered to enhance the clearance of radioisotopes. Radioactive iodine ($^{131}I$) as one of the nuclear fission products can increase the incidence of thyroid cancer in children. Potential benefit of potassium iodide prophylaxis is greater especially in neonates, infants and small children.

• International Journal of Precision Engineering and Manufacturing
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• v.6 no.3
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• pp.51-55
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• 2005

This study addresses the contamination sensitivity test of a typical fuel pump for an automotive vehicle. The objective of the study is to find the contamination sensitivity coefficient of a fuel pump on specific contaminant particle sizes so that an optimal fuel filter could be selected. To achieve the objective, the degradation of discharge flow rate of the fuel pump is measured under the experiments of various contaminants size ranges of ISO test dust up to $80\;{\mu}m$. The fundamental theory of contamination sensitivity is introduced and the contamination sensitivity coefficients are estimated using the experimental data. Maximum contamination sensitivity coefficient of $5\chi\;10^{-6}\;L/min{\cdot}Ea$ is found in the contaminant size range of $40\;{\mu}m\~50\;{\mu}m$. The magnified picture of the surface of vane disc reveals that the abrasive wear is the principal cause of discharge flow rate degradation. Hence, this study reveals that a high efficiency filter for contaminant particles especially in the size range of $30\;{\mu}m\~70\;{\mu}m$ especially should be used to maintain the service life of the fuel filter.