• Journal of the Korea Safety Management & Science
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• v.21 no.4
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• pp.45-49
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• 2019

The basalt fiber is expected to become a trend for industrial fibers as they have better properties of heat-resistant, non-combustion, absorbent, soundproof, moistureproof, lightweight, corrosion resistant, and high strength properties. Also, the fiber is found to be non-toxic and harmless to the human body. Therefore, in this study, we analyzed the chemical and mineral compositions of powdered sludge of basalt produced at seven sites on Jeju Island for the development of fire resistance insulating material for a building. The results showed that the basalt stone sludge is made from only sodium calcium aluminum silicate and ferridioside components unlike the basalt rock.

• Nuclear Engineering and Technology
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• v.52 no.8
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• pp.1871-1880
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• 2020

Round robin analyses for vessel failure probabilities due to PTS events are proposed for plant-specific analyses of all types of reactors developed in Korea. Four organizations, that are responsible for regulation, operation, research and design of the nuclear power plant in Korea, participated in the round robin analysis. The vessel failure probabilities from the probabilistic fracture mechanics analyses are calculated to assure the structural integrity of the reactor pressure vessel during transients that are expected to initiate PTS events. The failure probabilities due to various parameters are compared with each other. All results are obtained based on several assumptions about material properties, flaw distribution data, and transient data such as pressure, temperature, and heat transfer coefficient. The realistic input data can be used to obtain more realistic failure probabilities. The various results presented in this study will be helpful not only for benchmark calculations, result comparisons, and verification of PFM codes developed but also as a contribution to knowledge management for the future generation.

• Proceedings of the Korean Nuclear Society Conference
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• 1996.05a
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• pp.571-576
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• 1996

Currently most nuclear power plants(NPPs) are adopted the mid-loop operation to minimize the overhaul period and save the operating cost. For mid-loop operation it is essential to install nozzle dam between RCS pipe and steam generator(SG). Because SG remains more highly contaminated with radioactive material than any other parts of the NPPs, the repairmen are very reluctant to carry out installing nozzle dam inside the SG. Until now, unfortunately, it appears that no practically applicable device was developed to provide the longstanding demand. Also the accidents have been reported by licenser event report during this operation mode due to loss of residual heat removal(RHR). The purpose of this paper is to conduct remotely blocking and disintegration of nozzle of a SG which has the highest radiation exposure during the maintenance in NPPs. The remote nozzle blocking device of a SG includes three bladders, hubs, air controller provisions to supply and contact air pressure into the bladders. This remote nozzle block device will give the larger operation margin to prevent the loss of RHR and minimize the radiation exposure dose to the repairman and shorten the overhaul periods.

• Journal of the Korean Society of Radiology
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• v.14 no.3
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• pp.193-201
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• 2020

The purpose of this study is to evaluate the photon characteristics according to the material and thickness of the electrons incidented through a linear accelerator. The computer simulation design is a linear accelerator target consisting of a 2 mm thick tungsten single material and a 1.8 mm and 2.3 mm thick tungsten and copper composite material. In the research method, First, the behavior of primary particles in the target was evaluated by electron fluence and electron energy deposition. Second, photons occurring within the target were evaluated by photon fluence. Finally, the photon angle-energy distribution at a distance of 1 m from the target was evaluated by photon fluence. As a result, first, electrons, which are primary particles, were not released out of the target for electron fluence and energy deposition in the target of a single material and a composite material. Then, electrons were linearly attenuated negatively according to the target thickness. Second, it was found that the composite material target had a higher photon generation than the single material target. This confirmed that the material composition and thickness influences photon production. Finally, photon fluence according to the angular distribution required for shielding analysis was calculated. These results confirmed that the photon generation rate differed depending on the material and thickness of the linear accelerator target. Therefore, this study is necessary for designing and operating a linear accelerator use facility for container security screening that is being introduced in the country. In addition, it is thought that it can be used as basic data for radiation protection.

• Nuclear Engineering and Technology
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• v.49 no.3
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• pp.549-555
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• 2017

A lead slowing-down spectrometer (LSDS) system is under development to analyze isotopic fissile content that is applicable to spent fuel and recycled material. The source neutron mechanism for efficient and effective generation was also determined. The source neutron interacts with a lead medium and produces continuous neutron energy, and this energy generates dominant fission at each fissile, below the unresolved resonance region. From the relationship between the induced fissile fission and the fast fission neutron detection, a mathematical assay model for an isotopic fissile material was set up. The assay model can be expanded for all fissile materials. The correction factor for self-shielding was defined in the fuel assay area. The corrected fission signature provides well-defined fission properties with an increase in the fissile content. The assay procedure was also established. The assay energy range is very important to take into account the prominent fission structure of each fissile material. Fission detection occurred according to the change of the Pu239 weight percent (wt%), but the content of U235 and Pu241 was fixed at 1 wt%. The assay result was obtained with 2~3% uncertainty for Pu239, depending on the amount of Pu239 in the fuel. The results show that LSDS is a very powerful technique to assay the isotopic fissile content in spent fuel and recycled materials for the reuse of fissile materials. Additionally, a LSDS is applicable during the optimum design of spent fuel storage facilities and their management. The isotopic fissile content assay will increase the transparency and credibility of spent fuel storage.

• Journal of Radiation Protection and Research
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• v.49 no.1
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• pp.19-28
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• 2024

Background: This study aims to analyze radiation safety management and regulatory perceptions, focusing on companies that must report radiation sources. The intent is to reduce the gap between regulation measures and addressing real concerns while improving practical safety management measures and regulations for all stakeholders. Materials and Methods: Radiation safety officers at a total of 244 reporting companies using radiation generators (79.8%) and sealed radioisotopes (15.1%) were surveyed using a questionnaire. Results and Discussion: The perception that regulation is stronger than the actual risk of the radiation source used was 3.47 points (out of 5 points), indicating a score above average. The most important factors and considerations were education and training (48%) as a human factor, safety devices of the radiation source (71.3%) as a hazardous material factor, the use of radiation (50.8%) as an organizational environment, and the radiation effect of nearby facilities (67.2%) as a physical environment. Radiation safety management educational experience (F= 5.030, p< 0.01), the group with high subjective knowledge (t= 6.017, p< 0.001), and the group with high objective knowledge (t= 1.989, p< 0.05) was found to be better at radiation safety management. Conclusion: It is necessary to standardize the educational experience regarding radiation safety management because each staff member has individual differences in educational experience. It is necessary to provide more information on how to solve radiation accidents via educational content. Applying radiation safety regulations based on the factors that significantly affect radiation safety management shown in this survey will help improve safety.

• Nuclear Engineering and Technology
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• v.46 no.5
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• pp.667-674
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• 2014

One of the largest problems for tokamak devices such as Kazakhstan Tokamak for Material Testing (KTM) is the operation scenarios' development and execution. Operation scenarios may be varied often, so a convenient hardware and software solution is required for scenario management and execution. Dozens of diagnostic and control subsystems with numerous configuration settings may be used in an experiment, so it is required to automate the subsystem configuration process to coordinate changes of the related settings and to prevent errors. Most of the diagnostic and control subsystems software at KTM was unified using an extra software layer, describing the hardware abstraction interface. The experiment sequence was described using a command language. The whole infrastructure was brought together by a universal communication protocol supporting various media, including Ethernet and serial links. The operation sequence execution infrastructure was used at KTM to carry out plasma experiments.

• Nuclear Engineering and Technology
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• v.56 no.3
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• pp.866-872
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• 2024

Design Extension Conditions (DEC)-A assessments of the operating nuclear power plants are generally considered for the purpose of getting additional safety demonstrations of their capability to undergo conditions that are generally more severe than DBAs by features implemented in the design and accident management measures. The pursued methodology is generally based upon Best Estimate approaches aiming at verifying that the safety limits in terms of integrity of the barriers against eventual large or early releases of radioactive material are fulfilled. These aspects are nowadays being experimentally and analytically addressed within the OECD/NEA experimental projects like the ATLAS and PKL series where a set of DEC-A experiments are considered. In this paper, experiments related to SBLOCA at the vessel upper head of the pressurized vessel of ATLAS and PKL are analytically assessed using the CATHARE code. These experiments includes issues related to common cause failure of the safety injection system and operator actions for preventing core excessive overheating. It is shown that, on the one hand, the safety features embedded in the design together with the operator actions are capable to prevent the progression towards a severe accident state and on the other hand, the code prediction capabilities for such scenario are generally good but still to be enhanced.

• Journal of the Korean Society of Radiology
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• v.14 no.4
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• pp.455-465
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• 2020

The purpose of this study is to evaluate the photoneutron characteristics generated by the linear accelerator target and collimator. The computer simulation design firstly, consisted of a target, a single material target and a composite material target. Secondly, it consisted of a cone beam and a fan beam depending on the type of the collimator. Finally, the material of the fan beam collimator is composed of a single material composed of only lead (Pb) and a composite material collimator composed of tungsten (W) and lead (Pb). The research method calculated the photoneutron production rate and energy spectrum using F2 tally from the surface of a virtual sphere at a distance of 100 cm from the target. As a result, firstly the photoneutron production rate was 20% difference, depending on the target. Secondly, depending on the type of the collimator, there was a 10% difference. Finally, depending on the collimator material, there was a 40% difference. In the photoneutron energy spectrum, the average photoneutron flux tended to be similar to the photoneutron production rate. As a result, it was confirmed that the 9 MeV linear accelerator photoneutron are production increased more by the collimator than by the target, and by the material, not the type of the collimator. Selecting and operating targets and collimator with low photoneutron production will be the most active radiation protection. Therefore, it is considered that this research can be a useful data for introducing and operating and radiation protection of a linear accelerator for container security inspection.

• The Korean Journal of Nuclear Medicine Technology
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• v.13 no.3
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• pp.110-122
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• 2009

Purpose: Nowadays, A medical institution assesment could get more interest about a quality of medical services from many hospitals that developed the active activities for improving medical services. Also, there is an other additional issue which is the patients risk management. Uijeongbu ST. Mary's hospital Nuclear Medicine department has been changed many work process after PET-CT introduction and renovation of its place since 2008. Therefore, modified structure and the way of existing work process have contained risk factors. The purpose of this study would be the appropriate risk management process while imaging examination process, the removal risk factors and improved activities through the analysis risk factors. Materials and Methods: Nuclear Medicine department new process should analysis through many-sided, Firstly, make and trained risk management manual after then apply an actual work. Result analysis showed the number of risk accident occurrence that comparing the last year and after the improved activities. Secondly, producing risk management public relations film has been showed an applicable patient after then the customer service measurement checked for a hundred patient by questionnaire. Lastly, Risk factors were eliminated through the facilities participation improving activities which could change for the better risk factors. Results: The number of safety accident occurrence(medication error, fall and collision) were checked as zero after the improving activities both PET-CT and gamma camera examination. The results of questionnaire showed as follows; 74% marked as understanding of the test process and 81% checked "satisfaction" after the public relations film showing. The question "Did you consider about the risk factors?", both PET-CT and gamma camera checked as 94% and 89% respectively. Customer risk management could be accomplished effectively through the improving activities at the nuclear medicine department. Conclusions: The study would be an opportunity that spread risk factors were systematically showed and analyzied. Also, It showed the possibility of the minimized safety accident and its feedback, if application of the response manuel that could be a standard of radiology technician's work method to react safety accident. It was the more effective that visual material could be easy to approach as a methodology of risk factors. As far as I have concerned that It could help the safety and convenience through continuous and detailed activities that offer to patients.