• Journal of Korean Society of Environmental Engineers
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• v.36 no.6
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• pp.387-395
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• 2014

A highly sensitive analytical method based on stir bar sorptive extraction (SBSE) technique and gas chromatography/tandem mass spectrometry (GC-MS/MS) has been developed, allowing the simultaneous multi-analyte determination of 11 synthetic fragrances (SFs) in water samples. The stir bar coated with polydimethylsiloxane (PDMS) was added to 40 mL of water sample at pH 3 and stirred at 1,100 rpm for 120 min. Other SBSE parameters (salt effect and presence of organic solvent) were optimised. The method shows good linearity (coefficients > 0.990) and reproducibility (RSD < 10.9%). The extraction efficiencies were above 83% for all the compounds. The limits of detections (LOD) and limits of quantification (LOQ) were 2.1~4.1 ng/L and 6.6~12.9 ng/L, respectively. The developed method offers the ability to detect 11 SFs at ultra-low concentration levels with only 40 mL of sample volume. Matrix effects in tap water, river water, wastewater treatment plant (WWTP) final effluent water and seawater were investigated and it was shown that the method is suitable for the analysis of trace level of 11 SFs. The method developed in the present study has the advantage of being rapid, simple, high-sensitive and both user and environmentally friendly.

• The Transactions of the Korean Institute of Electrical Engineers B
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• v.51 no.3
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• pp.107-115
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• 2002

This parer presents the analysis of hot gas flow in puffer-type circuit breakers using FVFLIC method. For the analysis of arc-flow interaction, the flow field is analyzed from the equations of conservation for mass, momentum and energy with the assumption of local thermodynamic equilibrium state. The arc is represented as the energy source term composed of ohmic heating and radiation term in the energy conservation equation. Ohmic heating is computed by the electric field analysis only within the conducting plasma region. An approximate radiation transport model is employed for the evaluation of emission and absorption of the radiation. The analysis method was applied to the real circuit breaker model and simulation results such as pressure rise and arc voltage were compared with the experimental ones.

• Nuclear Engineering and Technology
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• v.25 no.2
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• pp.248-254
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• 1993

The purpose of this study is to evaluate the thermal safety for dry transport of a shipping cask. Analysis condition was based on an ambient temperature of 38$^{\circ}C$ for normal heat condition. The cask was designed to carry 4PWR spent fuel assemblies with a burnup of 38,000 MWD/MTU and 3 years of cooling time. Thermal analysis was carried out by using the COBRA-SFS code. The fuel cavity was considered to be filled with air, nitrogen or helium gas for dry transport. The results of analysis showed that the maximum temperatures of fuel rod cladding in air and helium cavity would be 277$^{\circ}C$ and 226$^{\circ}C$, respectively, for 3 years of cooling time. These values were less than the specified temperature to maintain the thermal integrity of fuel assembly for dry transport.

• Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
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• v.19 no.2
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• pp.205-214
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• 2021

Currently, the interim storage pools of spent fuels in South Korea are expected to become saturated from 2024. It is required to prepare an operation plan of a domestic dry storage facility during a long-term period, with the researches on safety evaluation methods. This study modified the FRAPCON code to predict the spent fuel integrity evaluation such as the axial cladding temperature, the hoop stress and hydrogen distribution in dry storage. The cladding temperature in dry storage was calculated using the COBRA-SFS code with the burnup information which was calculated using the FRAPCON code. The hoop stress was calculated using the ideal gas equation with spent fuel information such as rod internal pressure. Numerical analysis method was used to calculate the degree of hydrogen diffusion according to the hydrogen concentration and temperature distribution during a dry storage period. Before 50 years of dry storage, the cladding temperature and hoop stress decreased rapidly. However, after 50 years, they decreased gradually and the cladding temperature was below 400 K. The initial temperature distribution and hydrogen concentration showed a parabolic line, but hydrogen was transferred by the hydrogen concentration and temperature gradient over time.