• Journal of the Korean Society of Safety
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• v.27 no.5
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• pp.219-223
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• 2012

For an off-site consequence analysis at nuclear power plant, MELCOR Accident Consequence Code System(MACCS) II code is widely used as a software tool. In this study, the algorithm of web-based off-site consequence analysis program(OSCAP) using the MACCS II code was developed for an Integrated Leak Rate Test (ILRT) interval extension and Level 3 probabilistic safety assessment(PSA), and verification and validation(V&V) of the program was performed. The main input data for the MACCS II code are meteorological, population distribution and source term information. However, it requires lots of time and efforts to generate the main input data for an off-site consequence analysis using the MACCS II code. For example, the meteorological data are collected from each nuclear power site in real time, but the formats of the raw data collected are different from each site. To reduce the efforts and time for risk assessments, the web-based OSCAP has an automatic processing module which converts the format of the raw data collected from each site to the input data format of the MACCS II code. The program also provides an automatic function of converting the latest population data from Statistics Korea, the National Statistical Office, to the population distribution input data format of the MACCS II code. For the source term data, the program includes the release fraction of each source term category resulting from modular accident analysis program(MAAP) code analysis and the core inventory data from ORIGEN. These analysis results of each plant in Korea are stored in a database module of the web-based OSCAP, so the user can select the defaulted source term data of each plant without handling source term input data.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.35 no.11
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• pp.1445-1451
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• 2011

Pneumatic valves are widely used parts that have the ability to control the air supplied to automation systems. However, if failure occurs in a pneumatic valve, it may affect the entire system and could lead to huge losses, depending on the characteristics of the system at the time of failure. Because of this significant risk and the level of consumer demand for reliability, there has been much study on ensuring the reliability of products by predicting valve lifetime distributions and degradation characteristics. In this paper, in order to determine the main factors useful for predicting the lifetime of a pneumatic valve, the scale parameter and $B_{10}$ life time value of the widely used plug-in-type pneumatic manifold valves were measured using complete observational data on the valve lifetimes. And also the property of life distribution has been distribution-suitabilityreviewed by correlation coefficients, the degradation characteristics of valve has been presented by the result of analysis through dynamic response time test and leakage test.

• Journal of Radiation Protection and Research
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• v.22 no.4
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• pp.251-261
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• 1997

A package to transport the high level radioactive materials is required to withstand the hypothetical accident conditions as well as normal transport conditions according to IAEA standards and domestic regulations. The regulations require that the package should maintain the shielding, thermal and structural integrities to release no radioactive material. In general, safety evaluation of packages is performed by experimental methods using scale model and/or analytical methods using computer codes. This paper presents the safety evaluation of package to transport the radioisotopes produced in the HANARO to the radioisotope production facility. Radiation shielding, thermal and structural analyses were peformed using the computer codes. It has been verified that the package is safe under hypothetical accident conditions as well as normal transport conditions.

• Journal of the Korean Society of Marine Environment & Safety
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• v.10 no.1 s.20
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• pp.51-54
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• 2004

In recently days, the breed fish farm is increased in the beach side for farming fish. In such a farm, the heater is requested for preventing freezing in cold season. The heating material are requested high corrosion resistance and strength for endurance high corrosive salt and pressure. In case of low corrosion resistance and/or strength, the heating element shall be broke down and eventually make spillage or leaking contaminated salt. In the most cases, crevice corrosion is localized form of corrosion usually associated with a stagnant solution on the micro-environmental level. In this study, the crevice corrosion of Ferritic type 430 stainless steel is investigated. The size of specimen is $15{\times}20{\times}3mmt$. Test solution is 1N H2SO4 + 0.05N NaCl. The artificial crevice gap size is $0.24{\times}3{\times}15mmL$. Crevice corrosion is measured under applied voltage 300mV(SCE) to the external surface. the result of this study showed that 1) the induced time for initiation of crevice is 750seconds, 2) potential is dropped in the crevice from the top of gap opening from -320 to -399mV. The result confirmed that the potential drop(IR mechanism) in the crevice is one of mechanism for crevice corrosion.

• Proceedings of the KIEE Conference
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• 2003.07b
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• pp.1003-1005
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• 2003

In this paper, 3-D nonlinear electromagnetic analysis of a single phase 1MVA 22.9 kV/6.6 kV high temperature superconducting(HTS) transformer with double pancake windings was accomplished. The characteristics of 1MVA HTS transformer such as The efficiency, voltage regulation and % impedance voltage drop were obtained by the 3-D non-linear electromagnetic analysis. And in order to verify the 3-D non-linear electromagnetic analysis of a single phase 1MVA HTS transformer, a 1MVA test transformer with windings made of copper tapes with the same size as BSCCO-2223 HTS tape was manufactured. The energy conservation method to perform the analysis of leakage impedances of both a 1MVA HTS transformer and test transformer was used. The characteristic analysis such as efficiency, voltage regulation and % impedance voltage drop of transformer was performed. And the obtained values of both 1MVA HTS transformer and test transformer were compared.

• Journal of the Korean Institute of Gas
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• v.6 no.1 s.17
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• pp.10-16
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• 2002

This paper introduces developed prototype intelligent pig which detects corrosion on pipeline by using Magnetic Flux Leakage technology. The 8 inch developed MFL(Magnetic Flux Leakage) pig is composed of 5 yokes which magnetize pipeline wall and 45 Hall sensors which detect MFL signal. The designed MFL modules are analyzed by using magnetic circuit method in order to confirm whether pipeline wall is fully saturated. A variety of artificial defects are manufactured on 8 inch diameter steel pipeline in order to acquire MFL signals. So leakage flux of the axial, radial and circumferential component was acquired as defects. The results of this paper show that design technique for 8 inch MFL pig can be applied to large diameter MFL pig and 0.5mm defect depth can be detected.

• Fire Science and Engineering
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• v.32 no.6
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• pp.15-21
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• 2018

This study examined the flow characteristics of fire smoke under pressurized air ventilation conditions by carrying out fire simulations on multi-compartment enclosure, including room, ancillary room and stair case. Fire simulations were conducted for the air-leakage test facility, which was constructed to measure the effective leakage area and aimed to improve the understandings of fire and smoke movement by analyzing the overall behaviors of fire smoke flow and pressure distributions of each compartment. The simulation results showed that the heat release rate of the fires was controlled sensitively by the amount of air supplied by the ventilation system. An analysis of the velocity distributions between the room and ancillary room showed that fire smoke could be leaked to the ancillary room through the upper layer of the door, even under pressurized air supply conditions. From these results, it was confirmed that the fire size and spatial characteristics should be considered for the design and application of a smoke control system by a pressurized air supply.

• Journal of the Korean Society of Propulsion Engineers
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• v.24 no.6
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• pp.61-68
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• 2020

7-tonf turbopump real-propellant tests in Naro Space Center were conducted and high-frequency signals from an accelerometer and pressure sensors installed on the casing and the inlet/outlet pipeline of LOX pump were analyzed to estimate the structural and hydrodynamic stabilities. Waterfalls, frequency spectrums and RMS(Root Mean Square) values of the measured signals were calculated and characteristic instability frequencies by the rotating cavitation and the rear floating ring seal(F.R.S) were investigated. Static pressures of the inlet/outlet pipeline and an acceleration of the pump casing are strongly affected on pressure fluctuation induced by the rear floating ring seal in the leakage path. Despite the acceleration RMS value seems totally small, the rotating-speed-related synchronous frequency affecting the shaft instability is distinctly observed in the frequency contour.

• KOREAN JOURNAL OF PACKAGING SCIENCE & TECHNOLOGY
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• v.25 no.3
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• pp.79-87
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• 2019

The degree of cosmetic's oxidation depends on the storage conditions and external conditions when using the product. The microbial contamination and oxygen exposure often results in the quality deterioration of cosmetics. In addition, the problem is that consumers often use cream-type cosmetics, which have short expiration period (6-12 months), even after the product is expired. When using the deteriorated cosmetics, it can be fatal to consumers' safety including some symptoms such as folliculitis, rashes, edema, and dermatitis. Therefore, it is necessary to develop sealed smart packaging for cosmetics to prevent the deterioration of cosmetics and improve consumer safety. In this study, we have developed smart packaging design for cosmetics that can measure the surrounding environment and expiration date for the cosmetics in the real time. In addition, the smart packaging includes sensor, which are linked to the mobile application. Users can find out the measurement results through the application. Also, the packaging design and functions were set up based on the survey results by the user and feasible model can be produced based on user choice. The measurement in the three environment has been done after manufactured the sensor, PCB, and mobile application. As a result, it works normally within a certain range under all three environmental conditions. It is believed that the information on expiration dates and storage environment can be efficiently delivered to the consumers through developed cosmetics smart packaging and applications. The development of UI/UX design for consumer is further studied. The UX/UI design of the application plays an essential role in achieving this goal through the commercialization the cosmetic products in the wide range.

• Fire Science and Engineering
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• v.31 no.3
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• pp.63-72
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• 2017

This study fabricated a low-voltage 10 circuit distribution board based on the KEMC (Korea Electrical Manufacturers Cooperative) 2102-610 standard and performed a characteristics assessment of the developed 10 circuit distribution board to secure product stability. The developed 10 circuit distribution board is designed to have the characteristics of insulation materials, as well as resistance to corrosion ultraviolet radiation and mechanical impact. The developed distribution board is fabricated to have an appropriate protection class of enclosure, electric shock prevention and protection circuits, switchgear and its components, internal electrical circuits and connectors, external conduct terminal, insulation characteristics, temperature rise test, heat resistance, etc. The developed 10 circuit distribution board consists of a single phase circuit and 3-phase circuits. It is possible to measure in real time the leakage current generated from the load distribution line by installing a sensor module at the load side of each of the branched switchgears. In addition, it is possible to increase a circuit according to the use and purpose of the load and to also manage and check the load in real time. Temperature rise tests were performed on the developed 10 circuit distribution board at 18 places including the inlet connection, main circuit and distribution circuit bus bars and bus bar supports, etc. The highest temperature of $65.3^{\circ}C$ was measured at the R-Phase of the connection of the MCCB power supply for the branch circuit bus bar and a temperature rise of $61.6^{\circ}C$ was measured at the T-Phase of the load side. When applying thermal stress to an MCCB for 6 hours at $180^{\circ}C$ using a heat resistant experimental device, it was found that the actuator lever was transformed and moved in the tripped state.