• Nuclear Engineering and Technology
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• 제48권5호
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• pp.1273-1279
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• 2016

Production of iodine-131 by neutron activation of tellurium in tellurium dioxide ($TeO_2$) material requires a target that meets the safety requirements. In a radiopharmaceutical production unit, a new lid for a can was designed, which permits tight sealing of the target by using tungsten inert gaswelding. The leakage rate of all prepared targets was assessed using a helium mass spectrometer. The accepted leakage rate is ${\leq}10^{-4}mbr.L/s$, according to the approved safety report related to iodine-131 production in the TRIGA Mark II research reactor (TRIGA: Training, Research, Isotopes, General Atomics). To confirm the resistance of the new design to the irradiation conditions in the TRIGA Mark II research reactor's central thimble, a study of heat effect on the sealed targets for 7 hours in an oven was conducted and the leakage rates were evaluated. The results show that the tightness of the targets is ensured up to $600^{\circ}C$ with the appearance of deformations on lids beyond $450^{\circ}C$. The study of heat transfer through the target was conducted by adopting a one-dimensional approximation, under consideration of the three transfer modes-convection, conduction, and radiation. The quantities of heat generated by gamma and neutron heating were calculated by a validated computational model for the neutronic simulation of the TRIGA Mark II research reactor using the Monte Carlo N-Particle transport code. Using the heat transfer equations according to the three modes of heat transfer, the thermal study of I-131 production by irradiation of the target in the central thimble showed that the temperatures of materials do not exceed the corresponding melting points. To validate this new design, several targets have been irradiated in the central thimble according to a preplanned irradiation program, going from4 hours of irradiation at a power level of 0.5MWup to 35 hours (7 h/d for 5 days a week) at 1.5MW. The results showthat the irradiated targets are tight because no iodine-131 was released in the atmosphere of the reactor building and in the reactor cooling water of the primary circuit.

• 대한안전경영과학회지
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• 제11권1호
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• pp.175-182
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• 2009

The effort for GSI based IT system consolidation has been continued due to the increase of the system and complication increase of system connection, mainly by the global company. Since successful example of GSI realization by part of developed company affect to Korea, global level IT system consolidation has been examined mainly by the domestic company that have great deal of overseas business. Although they have examined consolidation possibility mainly on R&D, finance, operation management part which is the base part of company management, there are limitation for consolidation realization because of the difference between regional business problem of huge cost needed for consolidation. To overcome these realization limitations, it is necessary to lead risk and cost reduction through stepwise part unity and decide Priority Evaluation Framework for Consolidation target and systematic consolidation strategy. For GSI realization, appropriate distributions of unification time according to target system are needed. In this study, based on easiness and usefulness of consolidation and connection between the targets, evaluation methodology for Priority Evaluation Framework of system consolidation has been developed. Priority Evaluation Framework has been decided by applying developed methodology to global production company of high tech industrial part. Through this methodology, companies can realize successful and stable GSI by investing global resources intensively by Priority Evaluation Framework of consolidation target system.

• 한국산업보건학회지
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• 제24권3호
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• pp.263-271
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• 2014

Objectives: Along with the several cases of pulmonary disorders caused by exposure to indium that have been reported in Japan, China, and the United States, cases of Korean workers involved in processes that require handling of indium compounds with potential risk of exposure to indium compounds have also been reported. We performed biological monitoring for workers in various target manufacturing processes of indium, indium oxide, and indium tin oxide(ITO)/indium zinc oxide(IZO) in domestic factories. Materials: As biological exposure indices, we measured serum concentrations of indium using inductively coupled plasma mass spectrometry, and Krebs von den Lungen 6(KL-6) and surfactant protein D(SP-D) using enzyme-linked immunosorbent assays. We classified the ITO/IZO target manufacturing process into powdering, mixing, molding, sintering, polishing, bonding, and finishing. Results: The powdering process workers showed the highest serum indium level. The mixing and polishing process workers also showed high serum indium levels. In the powdering process, the mean indium serum concentration in the workers exceeded $3{\mu}g/L$, the reference value in Japan. Of the powdering, mixing, and polishing process workers, 83.3%, 50.0%, and 24.5%, respectively, had values exceeding the reference value in Japan. We suppose that the reason of the higher prevalence of high indium concentrations in powder processing workers was that most of the particles in the powdering process were respirable dust smaller than $10{\mu}m$. The mean KL-6 and SP-D concentrations were high in the powdering, mixing, and polishing process workers. Therefore, the workers in these processes who were at greater risk of exposure to indium powder were those who had higher serum levels of indium, as well as KL-6 and SP-D. We observed significant differences in serum indium, KL-6, and SP-D levels between the process groups. Conclusions: Five among the seven reported cases of "indium lung" in Japan involved polishing process workers. Polishing process workers in Korea also had high serum levels of indium, KL-6, and SP-D. The outcomes of this study can be used as essential bases for establishing biological monitoring measures for workers handling indium compounds, and for developing health-care guidelines and special medical surveillance in Korea.

• 한국안전학회지
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• 제35권2호
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• pp.28-33
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• 2020

Recently, the overseas construction market has been actively promoted for about 10 years, and overseas dam construction has been continuously performed. For the economic and safe construction of the dam, it is important to prepare the main dam construction plan considering the design frequency of the diversion tunnel and the cofferdam. In this respect, the prediction of river level during the rainy season is significant. Since most of the overseas dam construction sites are located in areas with poor infrastructure, the most efficient and economic method to predict the water level in dam construction is to use the upstream water level. In this study, a linear regression model, which is one of the simplest statistical methods, was proposed and examined to predict the downstream level from the upstream level. The Pyeongchang River basin, which has the characteristics of the upper stream (mountain stream), was selected as the target site and the observed water level in Pyeongchang and Panwoon gaging station were used. A regression equation was developed using the water level data set from August 22th to 27th, 2017, and its applicability was tested using the water level data set from August 28th to September 1st, 2018. The dependent variable was selected as the "level difference between two stations," and the independent variable was selected as "the level of water level in Pyeongchang station two hours ago" and the "water level change rate in Pyeongchang station (m/hr)". In addition, the accuracy of the developed equation was checked by using the regression statistics of Root Mean Square Error (RMSE), Adjusted Coefficient of Determination (ACD), and Nach Sutcliffe efficiency Coefficient (NSEC). As a result, the statistical value of the linear regression model was very high, so the downstream water level prediction using the upstream water level was examined in a highly reliable way. In addition, the results of the application of the water level change rate (m/hr) to the regression equation show that although the increase of the statistical value is not large, it is effective to reduce the water level error in the rapid level rise section. Accordingly, this is a significant advantage in estimating the evacuation water level during main dam construction to secure safety in construction site.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2007년도 추계학술대회 논문집
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• pp.719-728
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• 2007

Recently the assurance of railroad safety is very important issue in KOREA because there are lots of changes in the railroad industries. The Railway Safety Act was established in order to cope with these changes effectively and prevent the railroad transportation accidents. According to this law, Korea Transportation Safety Authority (KOTSA) has been entrusted with 'Integrated Railroad Safety Audit (IRSA)' and has implemented the safety audit to the railroad operation agencies such as Korea Railroad (KORAIL) and the railroad facility management organization such as the Korea Rail Network Authority (KR Network). The target of IRSA is to establish the effective rail safety management system and to raise the safety level of the railroad operation and facility agencies by checking synthetically their performance of safety duties with sincerity according to the Railway Safety Act. The purpose of this paper is to improve the efficiency of IRSA by the comparative research between IRSA and other similar safety audit system. To study the efficiency of IRSA, we investigated the rail safety audit systems of EU system specially France, England where the big changes have happened for the rail operation concepts and Japan where government entity control the railroad safety. The international standards of Occupational Health & Safety Assessment Series (OHSAS 18001), Quality Management System (ISO 9001) and Guidelines for Quality and/or Environmental Management Systems Auditing (ISO 19011) are investigated.

• 한국산업융합학회 논문집
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• 제10권1호
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• pp.47-54
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• 2007

Bridge decks are one of the main structural components that are most suitable for utilizing the advantages of FRP materials due to the high strength weight ratio of FRP materials. Design codes for the design of FRP bridge decks should be established to apply FRP materials for bridge decks effectively. At present, design codes are relatively well established for the use of FRP materials as reinforcements in concrete structures. However, design codes have not yet been provided for the structures made of FRP as a main construction material. In this study, for the purpose of preparing design code provisions, reliability analyses were performed to evaluate target level of safety and serviceability on GFRP decks. Based on the results, several guidelines for the development of design codes are suggested.

• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2012년도 추계 학술논문 발표대회
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• pp.195-196
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• 2012

Because of the high level of the safety and durability, a lot of reinforcing bars is placed in the concrete structure of the Nuclear Power Plant. But the overcrowding re-bars cause some problems during the construction as the diseconomy, construction delay, quality deterioration, and so on. These problems can be solved by applying the high-strength reinforcing bars to NPP structure. To achieve this, after analysing the structural target performance like the control of cracks, adherence, shear, torsion, development of reinforcement and earthquake-resistance, the results of the analysis will be reflected in the structural performance evaluation test.

• 대한인간공학회지
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• 제28권4호
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• pp.71-76
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• 2009

Effects of dark adaptation have large safety implications. This study was aimed to investigate the effects of varying illuminance and the size of critical detail on visual performance (i.e., time-to-detect) in a dark room environment. While adapting to the dark environment, ten subjects were asked to detect and answer simple numerical expressions under 9 experimental conditions (3 illuminance level $\times$ 3 target size). The ANOVA results revealed that the time-to-detect was significantly affected by both of the illumination level and the size of critical detail. As illumination increased from 10 lux to 20 lux, the time-to-detect was significantly declined. For the size of critical detail, 0.5/min size (i.e., equal to 2 minutes of visual angle) resulted in a shorter time-to-detect, as compared to 0.7/min size (i.e., equal to 1.6 minutes of visual angle). Potential applications of this research include the development of design guidelines for illumination and warning signs in poorly illuminated viewing environments.

• 한국지진공학회논문집
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• 제18권3호
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• pp.141-150
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• 2014

A methodology to evaluate the seismic performance of interface piping systems that cross the isolation interface in the seismically isolated nuclear power plant (NPP) was developed. The developed methodology was applied to the safety-related interface piping system to demonstrate the seismic performance of the target piping system. Not only the seismic performance for the design level earthquakes but also the performance for the beyond design level earthquakes were evaluated. Two artificial seismic ground input motions which were matched to the design response spectra and two historical earthquake ground motions were used for the seismic analysis of piping system. The preliminary performance evaluation results show that the excessive relative displacements can occur in the seismically isolated piping system. If the input ground motion contained relatively high energy in the low frequency region, we could find that the stress response of the piping system exceed the allowable stress level even though the intensity of the input ground motion is equal to the design level earthquake. The structural responses and seismic performances of piping system were varied sensitively with respect to the intensities and frequency contents of input ground motions. Therefore, for the application of isolation system to NPPs and the verification of the safety of piping system, the seismic performance of the piping system subjected to the earthquake at the target NPP site should be evaluated firstly.

• 한국수산과학회지
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• 제55권6호
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• pp.836-843
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• 2022

In the present study, exposure to heavy metals by consumption of edible seaweeds (green laver, laver, hijiki, sea tangle, and sea mustard) was assessed based on their concentrations of lead (Pb), cadmium (Cd), arsenic (As), and mercury (Hg). The mean of heavy metal concentrations were 0.006-0.023 mg/kg for Pb, 0.037-0.156 mg/kg for Cd, 1.117-15.928 mg/kg for As, and 0.008-0.021 mg/kg for Hg. In multivariate analysis, the correlations were high between Pb levels in sea mustard, Cb levels in laver, and As and Hg level in Hijiki. However, the estimated daily intake and target hazard quotient (THQ) of the heavy metals in edible seaweeds were below their approved limits suggesting no health risks associated with seaweed consumption by Koreans.