• Journal of radiological science and technology
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• v.37 no.2
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• pp.143-150
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• 2014

This study was designated to investigate the bremsstrahlung and radiation dose by beta rays. Radiation attenuation from I-131 treatment ward was analyzed using radio protective apron. Shielding materials which is included lead or water were simulated in Monte Carlo Simulation then the spectrum on interaction was analyzed. The shielding materials were categorized according to the thickness. 0.25mm and 0.5mm thick lead and 0.1mm and 0.2mm thick water shielding materials were configured in Monte Carlo Simulation for this study. Only lead shielding method and water plus lead shielding method were carried. As a results, when 0.5mm thick lead shielding method was performed, the radiation dose was similar to the results with water plus lead shielding method. In case of using 0.25mm thick lead shielding, the shielding effect was somewhat less. However, that shielding method cause dose reduction of about 60% compare with non-shielding material.

• Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
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• v.6 no.3
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• pp.233-244
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• 2008

A conceptual design study for a pyroprocesing facility, has been carried out in this study, which is available for the recovery of uranium and transuranic elemental group(TRU), that is, reusable as a nuclear fuel especially in a next generation-type reactor. The scale of this facility has been chosen as 20 kg HM/batch, comparatively small engineering size in order to collect scale-up data for the design of a commercial facility as well as to get operational experience. The spent fuel to be handled in this process is as follows : 3.5 % enriched uranium fuel, 35,000MWd/tU and 5-year cooled. The major items considered in the conceptual study are a building lay-out including various hot cells, safety management of the process operation in conjunction with material balance control, radiation safety, inert atmosphere control in shielded hot cells, and criticality control of uranium and TRU products.

• Nuclear Engineering and Technology
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• v.45 no.2
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• pp.211-218
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• 2013

Large quantities of irradiated graphite waste from graphite-moderated nuclear reactors exist and are expected to increase in the case of High Temperature Reactor (HTR) deployment [1,2]. This situation indicates the need for a graphite waste management strategy. Of greatest concern for long-term disposal of irradiated graphite is carbon-14 ($^{14}C$), with a half-life of 5730 years. Fachinger et al. [2] have demonstrated that thermal treatment of irradiated graphite removes a significant fraction of the $^{14}C$, which tends to be concentrated on the graphite surface. During thermal treatment, graphite surface carbon atoms interact with naturally adsorbed oxygen complexes to create $CO_x$ gases, i.e. "gasify" graphite. The effectiveness of this process is highly dependent on the availability of adsorbed oxygen compounds. The quantity and form of adsorbed oxygen complexes in pre- and post-irradiated graphite were studied using Time of Flight Secondary Ion Mass Spectrometry (ToF-SIMS) and Xray Photoelectron Spectroscopy (XPS) in an effort to better understand the gasification process and to apply that understanding to process optimization. Adsorbed oxygen fragments were detected on both irradiated and unirradiated graphite; however, carbon-oxygen bonds were identified only on the irradiated material. This difference is likely due to a large number of carbon active sites associated with the higher lattice disorder resulting from irradiation. Results of XPS analysis also indicated the potential bonding structures of the oxygen fragments removed during surface impingement. Ester- and carboxyl-like structures were predominant among the identified oxygen-containing fragments. The indicated structures are consistent with those characterized by Fanning and Vannice [3] and later incorporated into an oxidation kinetics model by El-Genk and Tournier [4]. Based on the predicted desorption mechanisms of carbon oxides from the identified compounds, it is expected that a majority of the graphite should gasify as carbon monoxide (CO) rather than carbon dioxide ($CO_2$). Therefore, to optimize the efficiency of thermal treatment the graphite should be heated to temperatures above the surface decomposition temperature increasing the evolution of CO [4].

• Journal of the Korea Safety Management & Science
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• v.11 no.1
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• pp.27-33
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• 2009

A study of fracture to material is getting interest in nuclear and aerospace industry as a viewpoint of safety. Acoustic emission (AE) is a non-destructive testing and new technology to evaluate safety on structures. In previous research continuously, all tensile tests on the pre-defected coupons were performed using the universal testing machine, which machine crosshead was move at a constant speed of 5mm/min. This study is to evaluate an AE source characterization of SM45C steel by using k-nearest neighbor classifier, k-NNC. For this, we used K-means clustering as an unsupervised learning method for obtained multi -variate AE main data sets, and we applied k-NNC as a supervised learning pattern recognition algorithm for obtained multi-variate AE working data sets. As a result, the criteria of Wilk's $\lambda$, D&B(Rij) & Tou are discussed.

• Proceedings of the Korean Institute Of Construction Engineering and Management
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• autumn
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• pp.115-122
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• 2002

There is various points that should be improved in Fairness such as our contract practice to propose construction projects, project managing and the stakeholders' way of thinking and culture. We consider that the revision of construction related provisions and systems is required but even more, an overall change in business management through the implementation of Integrated Construction Information Management System that will enable the owner, which drives the project, and contractor sharing construction information is required. To mange construction related information in an integrated manner, designing information should be smoothly transferred to purchasing information, and changes are required in order to move ahead to process-oriented work system. Finally information created from various construction organizations should be delivered in an aligned and standardized manner as well. The domestic Nuclear Power Plant Construction has been accepting various technology transfers from U.S, France, Canada and UK, which enabled us to self-support technology and recently even proceeded to the phase exporting our technology to others. However, continuous effort is required to improve internal business efficiency and to respond to external environmental change such aselectricity market deregulation. Recently, in accordance with the result in number of CEO's intention to make progress in IT and improve business efficiency, the number of enterprises introducing Enterprise Resource Planning is increasing. ERP is an innovative tool which changes the way of performing work from organization and department orientation to process-orientation in order to optimize the resources, such as human and material resources, through out the Enterprise by performing BPR which will maximize overall business efficiency of the enterprise, such includes not only construction management, but also business management. KHNP continued to performing large scaled construction projects such as nuclear power plant construction for past 30 years and took the initiatives of large scale project management and Quality management ability in domestic industry by having independent capability of over all construction planning, purchasing and, construction and start up management etc. To maintain our leading position of improving construction management technology based on our accumulated project management experience and technology, KHNP included construction into our ERP project in purpose of innovating construction business. We would like to discuss the characteristics of nuclear construction business, project management system, information system infrastructure and information sharing system among construction related entities, and implementation practices for information system, and consider how to resolve our practice that should be improved in this thesis.

• Journal of Radiation Industry
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• v.12 no.4
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• pp.303-310
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• 2018

Since Roentgen discovered X-rays, radiation sources have been utilized for many areas such as agriculture, industry, medicine and fundamental chemical research. As a result, human society has gained lots of benefits. However, if a radioactive material is used for the malicious purpose, it causes serious consequences to humanity and environment. Consequently, international organizations including International Atomic energy Agency (IAEA) have been emphasizing establishment and implementation of security management to prevent sabotage and illicit trafficking of radioactive materials. For this reason, the rule of technical standards of radiation safety management was revised and the public notice of security management regarding radioisotope was legislated in 2015 by Nuclear Safety and Security Commission (NSSC). Several radioactive sources which have to be regulated under the above rule and the public notice have been utilized in Advanced Radiation Technology Institute (ARTI) of Korea Atomic Energy Research Institute (KAERI). In order to control them properly, security management system such as access control and physical protection has been adapted since 2015. In this paper, we have analyzed the public notice of NSSC and its field application case. Based on the results, we are going to draw improvement on the public notice of NSSC and security system.

• Journal of Families and Better Life
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• v.20 no.4
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• pp.149-164
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• 2002

The purpose of this study was to identify the types of social networks of urban housewives according to different network composition patterns and to analyze the structural and functional characteristics of identified types. The data used in this study were collected from 589 full-time housewives residing in Taejeon city. The major findings are as follows: 1) The social networks of housewives in urban nuclear families were classified into eight types: the kin network, the non-kin network, the kin-centered network, the friend-centered network, the neighbor-centered network, the associate-centered network, the parallel network, and the decentralized network. 2) The structual characteristics (size, density, homogeneity, duration, proximity, frequency, closeness, direction) varied according to the type. The kin network type and the non-kin network type showed extreme degrees in network characteristics. The parallel network type and the decentralized network type showed an average level of network characteristics. The kin-, friend-, neighbor-, and the associate-centered types showed network characteristics of an intermediate level between the single-category types and the decentralized type. 3) The average levels of function of social network types were different in only two(service support, interference) of the six function areas(emotional support, service support, material support, information support, social companionship support, interference). The average level of service support by the non-kin network type was higher than other types. The average level of interference by the kin-centered network type was higher than other types, and that of the neighbor-centered network type was lower than other types. On the other hand, the total amount of function performance of social network types was different in all function areas. The total amount of social support given by the decentralized network type was greater than the other types. The total amount of interference given by the non-kin network type was smaller than the other types.

• Journal of Radiation Protection and Research
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• v.20 no.4
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• pp.285-296
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• 1995

The site of Korea Final Repository, KFR, to collect and dispose of radioactive wastes produced in nuclear power plants will be selected to seaside. As all the radwastes stored temporarily in the site of power plants should be transported by the sea, Nuclear Environmental Management Center, NEMAC, of Korea Atomic Energy Research Institute, KAERI, has been developing the sea transport system to secure safe and efficient transportation of the radwastes from the power plant sites to the final repository. Investigating the status of advanced techniques of foreign countries for transport vessels and considering inland circumstances, the technical criteria of the transport vessel have been suggested in this study. Therefore, all the radwastes will be transported safely by the sea, without releasing any radioactive material to environment even in the case of accident.

• Journal of Radiation Protection and Research
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• v.41 no.3
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• pp.291-300
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• 2016

Background: It is necessary to assess radiation dose to workers due to inhalation of airborne particulates containing naturally occurring radioactive materials (NORM) to ensure radiological safety required by the Natural Radiation Safety Management Act. The objective of this study is to develop an internal dose assessment procedure for workers at industries using raw materials containing natural radionuclides. Materials and Methods: The dose assessment procedure was developed based on harmonization, accuracy, and proportionality. The procedure includes determination of dose assessment necessity, preliminary dose estimation, airborne particulate sampling and characterization, and detailed assessment of radiation dose. Results and Discussion: The developed dose assessment procedure is as follows. Radioactivity concentration criteria to determine dose assessment necessity are $10Bq{\cdot}g^{-1}$ for $^{40}K$ and $1Bq{\cdot}g^{-1}$ for the other natural radionuclides. The preliminary dose estimation is performed using annual limit on intake (ALI). The estimated doses are classified into 3 groups ( < 0.1 mSv, 0.1-0.3 mSv, and > 0.3 mSv). Air sampling methods are determined based on the dose estimates. Detailed dose assessment is performed using air sampling and particulate characterization. The final dose results are classified into 4 different levels ( < 0.1 mSv, 0.1-0.3 mSv, 0.3-1 mSv, and > 1 mSv). Proper radiation protection measures are suggested according to the dose level. The developed dose assessment procedure was applied for NORM industries in Korea, including coal combustion, phosphate processing, and monazite handing facilities. Conclusion: The developed procedure provides consistent dose assessment results and contributes to the establishment of optimization of radiological protection in NORM industries.

• Journal of the Korean Society of Radiology
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• v.14 no.5
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• pp.563-575
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• 2020

The purpose of this study is to evaluate the activation characteristics that occur in a linear accelerator for container security inspection. In the computer simulation design, first, the targets consisted of a tungsten (Z=74) single material target and a tungsten (Z=74) and copper (Z=29) composite target. Second, the fan beam collimator was composed of a single material of lead (Z=82) and a composite material of tungsten (Z-74) and lead (Z=82) depending on the material. Final, the concrete in the room where the linear accelerator was located contained magnetite type and impurities. In the research method, first, the optical neutron flux was calculated using the MCNP6 code as a F4 Tally for the linear accelerator and structure. Second, the photoneutron flux calculated from the MCNP6 code was applied to FISPACT-II to evaluate the activation product. Final, the decommissioning evaluation was conducted through the specific activity of the activation product. As a result, first, it was the most common in photoneutron targets, followed by a collimator and a concrete 10 cm deep. Second, activation products were produced as by-products of W-181 in tungsten targets and collimator, and Co-60, Ni-63, Cs-134, Eu-152, Eu-154 nuclides in impurity-containing concrete. Final, it was found that the tungsten target satisfies the permissible concentration for self-disposal after 90 days upon decommissioning. These results could be confirmed that the photoneutron yield and degree of activation at 9 MeV energy were insignificant. However, it is thought that W-181 generated from the tungsten target and collimator of the linear accelerator may affect the exposure when disassembled for repair. Therefore, this study presents basic data on the management of activated parts of a linear accelerator for container security inspection. In addition, When decommissioning the linear accelerator for container security inspection, it is expected that it can be used to prove the standard that permissible concentration of self-disposal.