• Journal of Radiation Protection and Research
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• v.41 no.1
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• pp.1-6
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• 2016

Background: It is very difficult to set a regulatory guidance or criteria for the protection of non-human species from the ionizing radiation, because there are no generally or internationally accepted methods for demonstrating the compliance with such criteria. It is needed that Korea develop the primary dose rate standards for the protection of both aquatic and terrestrial biota in the near future. Materials and Methods: The potential dose rates due to both external and internal radiation exposures to marine organisms such as plaice/flounder, gray mullet, and brown seaweed collected within territorial seas around the Korean Peninsula were estimated. Results and Discussion: The total dose rates to plaice/flounder, gray mullet and brown seaweed due to $^{40}K$, a primordial radionuclide in marine environment, were found to be 0.2%, 0.08% and 0.3% of approximately the values of the Derived Consideration Reference Levels (DCRLs, i.e. $1-10mGy{\cdot}d^{-1}$), respectively, as suggested by the International Commission on Radiological Protection (ICRP) publication 124. The total dose rates to marine fishes and brown seaweed due to anthropogenic radionuclides such as $^{90}Sr$, $^{137}Cs$ and $^{239+240}Pu$ were considered to be negligible compared to the total dose rate due to $^{40}K$. The external exposure to benthic fish due to all radionuclides was much higher than that of pelagic fish. Conclusion: From this study, it is recommended that the further study is required to develop a national regulatory guidance for the evaluation of doses to non-human species.

• Advances in aircraft and spacecraft science
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• v.1 no.4
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• pp.427-441
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• 2014

Orbit-raising is an important step to place spacecraft from parking orbits into working orbits. Attitude control system design is crucial in the success of orbit-raising. Several text books have discussed this design and focused mainly on the traditional methods based on single-input single-output (SISO) transfer function models. These models are not good representations for many orbit-raising control systems which have multiple thrusters and each thruster has impact on the attitude defined by all outputs. Only one published article is known to use a more suitable multi-input multi-output (MIMO) Euler angle model in spacecraft orbit-raising attitude control system design. In this paper, a quaternion based MIMO model for the orbit-raising attitude control system design is proposed. The advantages of using quaternion based model for orbit-raising control system designs are (a) there is no need for mathematical transformations because the attitude measurements are normally given by quaternion, (b) quaternion based model does not depend on rotational sequences, which reduces the chance of human errors, and (c) the singular point of reduced quaternion model is the farthest from the operational point where linearization is performed. We will show that performance of quaternion model based design will be as good as the performance of Euler angle model based design for orbit-raising problem.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.5 no.2
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• pp.91-99
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• 1985

The acceleration levels and durations of seismic inputs for nuclear power plant design are surveyed. Among those inputs, two artificial acceleration time histories with same acceleration level and duration are selected and their characteristics are studied by calculating response spectra and spectrum intensity. The selected time histories which have the duration of 24 sec. satisfy the design response spectra of US Nuclear Regulatory Commission Regulatory Guide 1. 60. One of the selected time histories is improved to have the duration of 15 sec. without significant changes in the other characteristics. A case study of a plane model with 3 lumped masses is done using three time histories, i.e, two selected and one improved time histories. It is found that the improved curve gives almost the same results as the original one and reduces the computer time by about half, whereas two selected time histories give the results with same trend but much different magnitudes each other. It is claimed, however, that the improved time history is not the optimal one, but very economical in practical applications.

• Journal of Radiation Protection and Research
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• v.48 no.2
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• pp.84-89
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• 2023

Background: Food consumption is one of the most important routes for radionuclide intake for the public; therefore, there is the need to have a comprehensive understanding of the amount of radioactivity in food products. Consumption of radionuclide-contaminated food could increase potential health risks associated with exposure to radiation such as cancers. The present study aims to determine radioactivity levels in some food products (milk, rice, sugar, and wheat flour) consumed in Mali and to evaluate the radiological effect on the public health from these radionuclides. Materials and Methods: The health impact due to ingestion of radionuclides from these foods was evaluated by the determination of activity concentration of radionuclides ²³⁸U, ²³²Th, ⁴⁰K, and ¹³⁷Cs using gamma spectrometry system with high-purity germanium detector and radiological hazards index in 16 samples collected in some markets, mall, and shops of Bamako-Mali. Results and Discussion: The average activity concentrations were 9.8±0.6 Bq/kg for ²³⁸U, 8.7±0.5 Bq/kg for ²³²Th, 162.9±7.9 Bq/kg for ⁴⁰K, and 0.0035±0.0005 Bq/kg for ¹³⁷Cs. The mean values of radiological hazard parameters such as annual committed effective dose, internal hazard index, and risk assessment from this work were within the dose criteria limits given by international organizations (International Commission on Radiological Protection and United Nations Scientific Committee on the Effects of Atomic Radiation) and national standards. Conclusion: The results show low public exposure to radioactivity and associated radiological impact on public health. Nevertheless, this study stipulates vital data for future research and regulatory authorities in Mali.

• Journal of Radiation Protection and Research
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• v.36 no.3
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• pp.127-133
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• 2011

In 2007, the International Commission on Radiological Protection (ICRP) published Recommendations of the International Commission on Radiological Protection. Accordingly IAEA safety standards committees have reviewed and revised the BSS. The process of the implementation of the ICRP 103 into Korean radiation protection regulations has been continued. Although the new recommendations retain the fundamental protection principles, the impact of the new ICRP recommendations will necessarily be greater than ever before. ICRP recommends the application of dose constraint in planned situations and reference level in existing & emergency situations for strengthening of the principle of optimization. Dose constraints and reference level play a criterion on the level of individual dose as prospective and source-related values. Therefore it is necessary to apply dose constraints and reference levels to all nuclear and RI&RG facilities in Rep. of Korea. Dose constraints and reference level of occupational exposure will be set-up by the stakeholder itself with the cooperation of regulatory body. In this study, the implementation method was discussed to apply the dose constraints and reference level as the procedure for the optimization, not the tool of the regulation.

• Journal of the Korean Geographical Society
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• v.47 no.5
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• pp.755-774
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• 2012

The main objective of the study is to propose GIS-based methods to assess the population distribution criteria for undesirable facilities such as nuclear power plants. First of all, a review of the relevant criteria was conducted for the official documents compiled by such institutions as IAEA (International Atomic Energy Agency), U.S. NRC (Nuclear Regulatory Commission), and some national institutes including the Korea Institute of Nuclear Safety. It is informed from the review that the fundamental principle underlying the various criteria is to maximize the distance between a plant and the nearest population center. It is realized that two interrelated GIS-based techniques need to be devised to put the principle into practice; sophisticated ways of representing population distribution and identifying population centers. A dasymetric areal interpolation is proposed for the former and cell-based and area-based critical density methods are introduced. Grid-based population distributions at various spatial resolutions are created by means of the dasymetric areal interpolation. By applying the critical density methods to the gridded population distribution, some population centers satisfying the population size and density criteria can be identified. These methods were applied to the case of the Gori-1 nuclear power plant and their strengths and limitations were discussed. It was revealed that the assessment results could vary depending upon which method was employed and what values were chosen for various parameters. This study is expected to contribute to foster the applications of methods and techniques developed in geospatial analysis and modeling to the site selection and evaluation.

• Journal of Radiation Protection and Research
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• v.38 no.2
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• pp.91-99
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• 2013

There are many reasons for decommissioning of cyclotron such as not only age-related deficiency, any serious wear or damage but also relocation, upgrade and changing mission. Decommission of cyclotron in USA and EU give rise to a lot of low-level radioactive waste and costs. Various research on decommissioning of particle accelerator have been carried to reduce the cost of decommissioning in USA and EU. In USA, the NRC require DFP (Decommissioning Funding Plan) to authorized licenser by 10 CFR Part 30.35. To resolve radioactive waste problem and reduce the estimated cost of cyclotron decommissioning, we should consider technical aspects (decommissioning procedures, decontamination techniques, etc.) and safety aspects(residual radioactivity, the expected dose, etc) for decommissioning. In this study, we analyzed practical information on the decommissioning of cyclotron in ANL (Argonne National Laboratory) and Belgium (EU). And we investigated the experience on the cyclotron relocation from SNUH (Seoul National University Hospital) to SKKU (Sungkyunkwan University). From these results, we provide the basic data for establishing of relevant standards on domestic cyclotron decommissioning. It is necessary to adopt the DFP for safe and economic decommissioning and waste recycling. These result could be utilized for the establishment on the standards and useful requirements.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2013.04a
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• pp.589-595
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• 2013

A reactor vessel internals comprehensive vibration assessment program(RVI CVAP) of an advanced power reactor 1400(APR1400) is being verified on the integrity of RVI for the design life of the plant by performing the non-prototype category-2 type on the US Nuclear Regulatory Commission Guide(NRC RG) 1.20, for which consists of a vibration and stress analysis program, a limited vibration measurement program, an inspection program, and the correlation of these programs. The aim of this paper is to describe the plan for the vibration measurement, test and acceptance criteria portion, and documentation and results of the APR1400 RVI CVAP. We will conduct the limited vibration measurement program of the APR1400 RVI CVAP according to the measurement plan and the vibration measurement testing in this paper.

• Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
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• v.16 no.4
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• pp.455-472
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• 2018

It is important to study how to manage dry storage casks of spent nuclear fuels (SNF), because wet storage spaces for SNF will shortly be at full capacity in the Republic of Korea. The US has operated a dry storage cask system for several decades, and has carried out significant studies into how to successfully manage dry storage cask for SNF. This type of expertise and experience is currently lacking in the Republic of Korea. The degradation of dry casks is an important issue that must be considered. In particular, chloride-induced stress corrosion cracking (CISCC) is known to lead to the release of radioisotopes from canisters. The U.S. Department of Energy, U.S. Nuclear Regulatory Commission, and the Electric Power Research Institute have undertaken research into the CISCC mechanism. In addition, Sandia National Laboratories (SNL) has extensively researched CISCC and how to manage it in dry storage canisters. In this review paper, the probabilistic model proposed by the SNL is analyzed and, based on this model, US-based CISCC research is reviewed in detail. This paper will inform the management of dry cask storage of SNF from light water reactors in austenite stainless steel canisters in the Republic of Korea.

• Journal of radiological science and technology
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• v.33 no.3
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• pp.269-276
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• 2010

This study attempts to propose ways to optimize and improve the period of hospitalization for the radioiodine treatment by calculating the dose rate of patients treated with high-dose radioiodine by distance and time slot. As a result, 24 hours after the patient was treated with 100 mCi high-dose iodine, the dose rate was attenuated to $1,035{\mu}Sv/hr$ at the navel, to $109{\mu}Sv/hr$ at 50 cm, and to $33{\mu}Sv/hr$ at 100 cm. 24 hours after the patient was treated with 150 mCi high-dose iodine, the dose rate was attenuated to $637{\mu}Sv/hr$ at the navel, to $100{\mu}Sv/hr$ at 50 cm, and to $40{\mu}Sv/hr$ at 100 cm. 24 hours after the patient was treated with 180 mCi high-dose iodine, the dose rate was attenuated to $1,251{\mu}Sv/hr$ at the navel, $140{\mu}Sv/hr$ at 50 cm, and to $56{\mu}Sv/hr$ at 100 cm. In light of the current criterion for discharge recommended by the US Nuclear Regulatory Commission being $70.4{\mu}Sv/hr$, the present study indicates earlier discharge is feasible by applying a new scheme. This suggests that the proposed scheme in this study will help to solve the problem of shortage of treatment beds with the increasing trend of patients with thyroid cancer taken into consideration.