• Journal of the Korea Safety Management & Science
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• v.17 no.4
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• pp.207-212
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• 2015

When performing Chest x-ray examination to pregnant woman, normally we shield back side of abdomen. In this situation, scattered rays made by equipment and surrounding structure can enter front side of abdomen. Therefore, in this study, we evaluate suitability of abdomen shield especially to pregnant woman. In case of One shielding material placed back of abdomen, the measured value is $0.676{\pm}0.19uSv/hr$. Two shielding material is $0.764{\pm}0.04uSv/hr$. Three is $0.685{\pm}0.16uSv/hr$. The exposure dose inferred in this study does not excess annual effective dose limit. But It is not mean absolute safety. So we have to minimize occurrence of stochastic effect of radiosensitivity by shielding front side of abdomen of pregnant woman in clinic.

• Environmental Analysis Health and Toxicology
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• v.16 no.4
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• pp.211-221
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• 2001

The purpose of this study was to investigate the acute (4 hours) and repeated-dose (6 hours a day, 5 days a week, 4 weeks) toxic effects of 1-hexene on Sprague-Dawley (SD) rats which were treated by inhalation. The results were as follows; 1. The median lethal concentration(LC$_{50}$) was estimated 52,694 ppm (confidence limit 95％; 49,494~55,447 ppm) in acute inhalation. Abnormal clinical signs related to the 1-Hexene were not observed with the acute inhalation dose. Cross findings of necropsy revealed on evidence of specific toxicity related to the 1-hexene. II. By repeated inhalation exposure the body weight of male were more or less reduced by the dose of 2,500 ppm and 5,000 ppm compared with control group. However there were no significant variation hematology and blood biochemistry for the exposed rats compared with the control rats. Abnormal clinical signs and gross findings of necropsy related to the 1-hexene were not shown. In conclusion when we exposed 1-hexene to SD rats for 4 weeks, 5 days per week, 6 hours per day, the Lowest observed effect level (LOEL) was over 2,500 ppm and Non observed effect level (NOEL) was below 500 ppm.

• Nuclear Engineering and Technology
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• v.52 no.6
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• pp.1231-1242
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• 2020

The Kori Unit 1 will be decommissioned after a permanent shutdown in June 2017. South Korea has a 0.1 mSv/yr exposure limit standard for limited or unlimited site release. This is South Korea's first commercial NPP; therefore, if the containment building is reused as a memorial hall, it will contribute to the improvement of public understanding and enhance the public's acceptance of NPPs. Also, existing Kori Unit 1 nuclear power plant manpower resources can be reused after decommissioning and resident staff and memorial hall visitors can activate nearby commercial areas. Therefore, such a reuse scenario may also prevent an economic recession. The exposure dose was calculated using the following scenarios: worker in the containment building, visitor in the containment building, and worker in buildings other than the containment building. The exposure dose in the buildings was calculated by the RESRAD-BUILD developed by the Argonne National Laboratory (ANL). The preliminary exposure dose and derived concentration guideline level (DCGL) were derived.

• Nuclear Engineering and Technology
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• v.55 no.5
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• pp.1757-1762
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• 2023

Radiological hazards from external exposure of naturally occurring radioactive materials (NORM) scales residues, generated during the extraction process of oil and gas production in southern Algeria, are evaluated. The activity concentrations of ²²⁶Ra, ²³²Th, and ⁴⁰K were measured using high-purity gamma-ray spectrometry (GeHP). Mean activity concentration of ²²⁶Ra, ²³²Th and ⁴⁰K, found in scale samples are 4082 ± 41, 1060 ± 38 and 568 ± 36 Bq kg^-1, respectively. Radiological hazard parameters, such as radium equivalent (Ra_eq), external and internal hazard indices (H_ex, H_in), and gamma index (I_γ) are also evaluated. All hazard parameter values were greater than the permissible and recommended limits and the average annual effective dose value exceeded the dose constraint (0.3 mSv y^-1). However, for occasionally exposed workers, the dose rate of 0.65 ± 0.02 mSv y^-1 is lower than recommended limit of 1 mSv y^-1 for public.

• Journal of Radiation Protection and Research
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• v.45 no.1
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• pp.16-25
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• 2020

Background: To investigate radiological effects on biota, it is necessary to assess radiation dose for flora and fauna living in a terrestrial ecosystem. This paper presents a dynamic model to assess radioactivity concentration and radiation dose of terrestrial flora and fauna after a nuclear accident. Materials and Methods: Litter, organic soil, mineral soil, trees, wild crops, herbivores, omnivores, and carnivores are considered the major components of a terrestrial ecosystem. The model considers the physicochemical and biological processes of interception, weathering, decomposition of litter, percolation, root uptake, leaching, radioactive decay, and biological loss of animals. The predictive capability of the model was investigated by comparison of its predictions with field data for biota measured in the Fukushima forest area after the Fukushima nuclear accident. Results and Discussion: The predicted radioactive cesium inventories for trees agreed well with those for evergreens and deciduous trees sampled in the Fukushima area. The predicted temporal radioactivity concentrations for animals were within the range of the measured radioactivity concentrations of deer, wild boars, and black bears. The radiation dose for the animals were, for the whole simulation time, estimated to be much smaller than the lower limit (0.1 mGy·d^-1) of the derived consideration reference level given by the International Commission on Radiological Protection for terrestrial flora and fauna. This suggested that the radiation effect of the accident on the biota in the Fukushima forest would be insignificant. Conclusion: The present dynamic model can be used effectively to investigate the radiological risk to terrestrial ecosystems following a nuclear accident.

• Journal of Radiation Protection and Research
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• v.38 no.4
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• pp.189-193
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• 2013

Annual dose on the containment building wall of the interim storage facility at normal condition was calculated to estimate the dose rate transition of the facility of PWR spent nuclear fuel. In this study, source term was generated by ORIGEN-ARP with 4.5 wt% initial enrichment, 45,000 MWd/MTU burnup and 10 years cooling time. Modeling of the storage facility and the containment building and radiation shielding evaluations were conducted by MCNP code depending on the distance between the wall and the facility in the building. In the case of the centralized storage system, the distance required for the annual dose rate limit from 10CFR72 was estimated to be 50 m.

• Journal of radiological science and technology
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• v.44 no.5
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• pp.489-494
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• 2021

In this study, radioactivity quantitative analysis was performed on radon contained in cigarette, and the effective dose was calculated using the result value to determine the amount of exposure caused by smoking. A total of 5 types of cigarettes were sampled. Cigarette smoke was collected by using activated carbon, and tobacco were measured by homogenizing for quantitative analysis. For each sample, Bi-214 and Pb-214 were subjected to gamma nuclide analysis to observe the uranium-based radioactive material contained in cigarette, and a measurement time of 30,000 seconds was set for the sample based on the results of previous studies. As a result of measuring the radioactivity of tobacco, a maximum of 0.715 Bq/kg was derived, and in the case of cigarette smoke measured using activated carbon, a maximum of 3.652 Bq/kg was derived. Using this measurement, the average effective dose to the lungs is 0.938 mSv/y, and it was found that there is a possibility of receiving exposure up to 1.099 mSv/y depending on the type of tobacco. It was found that the exposure dose due to cigarette occupies a large proportion of the annual effective dose limit for the general public. Therefore, more diverse studies on radioactive substances in cigarette are needed, and measures to monitor and reduce the incidental exposure to radon should be established.

• Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
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• v.21 no.3
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• pp.371-381
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• 2023

Evaluating the effectiveness of the radiation protection measures deployed at the Centralized Radioactive Waste Management Facility in Ghana is pivotal to guaranteeing the safety of personnel, public and the environment, thus the need for this study. Radiagem^TM 2000 was used in measuring the dose rate of the facility whilst the personal radiation exposure of the personnel from 2011 to 2022 was measured from the thermoluminescent dosimeter badges using Harshaw 6600 Plus Automated TLD Reader. The decay store containing scrap metals from dismantled disused sealed radioactive sources (DSRS), and low-level wastes measured the highest dose rate of 1.06 ± 0.92 µSv·h^-1. The range of the mean annual average personnel dose equivalent is 0.41-2.07 mSv. The annual effective doses are below the ICRP limit of 20 mSv. From the multivariate principal component analysis biplot, all the personal dose equivalent formed a cluster, and the cluster is mostly influenced by the radiological data from the outer wall surface of the facility where no DSRS are stored. The personal dose equivalents are not primarily due to the radiation exposures of staff during operations with DSRS at the facility but can be attributed to environmental radiation, thus the current radiation protection measures at the Facility can be deemed as effective.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.11 no.6
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• pp.2118-2123
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• 2010

Korean individual occupational exposure control is focused on the retrospective service to the over-exposed person by the reading of personal dosimeter. Since the radiophamaceuticals using in the nuclear medicine department are uncontained radiation sources, the potential exposure at working environment is very high. Moreover, a patient remains radioactive for hours or even days after the administration of a radiopharmaceutical for diagnosis or treatment. Thus, the proper working environmental exposure control must be established and executed to protect not only the affiliated employees, but also guardians accompanying patients and temporarily visiting public from the exposure by the patients. Japanese radiation protection law regulates working environmental radiation exposure by regularly measuring and filing the environmental dose for years. This study was aimed at measuring working environmental radiation dose in the nuclear medicine department of an university hospital located in Daejeon, Korea. We measured the accumulation radiation dose in air at 8 locations in the nuclear medicine department by using the same method as in Japan with glass dosimeters. The highest dose rate, 0.23 mSv per month, was measured at the waiting room, and the second one is at reception desk. Even though the doses were lower than the Korean constraint dose rate (0.3 mSv/week) at the boundary of the radiation controlled area, it was over the dose limit of public (1 mSv/y) and environment (0.25 mSv/y). Conclusionally, it was found that the new or additional procedure was necessary to less the exposure dose to the receptionist and guardians by the environmental radiation dose in the nuclear medicine department.

• Journal of the Korean Society of Radiology
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• v.9 no.7
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• pp.449-457
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• 2015

In this study, to evaluate the usefulness of the treatment plan of tomotherapy and volumetric modulated arc therapy (VMAT) in the radiotherapy for prostate cancer, the absorbed dose, dose volume histogram (DVH), treatment efficiency, and the results of dose verification accuracy using MapCHECK2 were compared and analyzed. Of the prostate cancer patients who underwent tomotherapy treatment in the Radiologic Oncology of H University Hospital between July 2014 and December 2014, 12 patients were randomly selected. As a result of analyzing the absorbed dose and DVH, both radiologic treatment plans showed slight differences in the treatment of the cancer tissues and the bladder, but the difference was in the error range of -5% to +3%, and did not exceed the side effect guideline or the tolerance dose limit. VMAT showed higher treatment efficiency than tomotherapy with a 2.5 times shorter treatment time and a 10.3 times less monitor unit (MU). Both showed 95% or higher dose accuracy satisfying the standard. VMAT showed 2.3% higher efficiency than tomotherapy. In both tomotherapy and VMAT, appropriate doses were absorbed for cancer tissues, and did not exceed the tolerance dose for normal tissues showing no significant difference in dose distribution. However, considering the shorter treatment time, lower total MU, and better treatment efficiency and dose verification accuracy, VMAT may be more useful than tomotherapy in cancer treatments.