• Journal of Radiation Industry
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• v.4 no.3
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• pp.285-288
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• 2010

Polyimide films have excellent thermal stability, reliable mechanical properties and low dielectric constant. Therefore, this material is widely used in many industrial fields such as microelectronics, flexible circuits, semiconductor products and aerospace materials. In space applications, earth-orbiting hardware operates in environments that generally include neutral particles, charged particles such as trapped protons and electrons, solar protons, and cosmic rays. Under these conditions, polyimide films were changed in the optical, electrical and mechanical properties. Therefore, in this study, we evaluated the effects of electron beam irradiation on polyimide. The O-H functional groups were created on the polyimide film surface in the results of FT-IR spectra. And it was found that the dielectric constants were changed as a function of electron beam dose.

• Journal of Radiation Industry
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• v.6 no.3
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• pp.245-249
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• 2012

Demand of fluid flow visualization has increased in industrial processes, because medical imaging technology is highly developed. As a part of the industrial process imaging technology, industrial single photon emission computed tomography (SPECT) system was developed to measure the cross-sectional distribution of the process fluid. The SPECT consists of 36 NaI (Tl) detectors with the hexagonal configuration. Reconstructed images were acquired for various positions of radioactive source to estimate SPECT device performance. To evaluate the reliability of the experimental results, the Monte Carlo simulation results are compared with experimental results. In general, the experimental and simulation results were consistent. However, as the source position was getting far from the center of the reactor, the accuracy of reconstructed images was compromised. It seems to be due to the inconsistent spatial resolution of the collimators according to the source position.

• Journal of Radiation Industry
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• v.6 no.1
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• pp.49-54
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• 2012

Various anion exchange membranes were prepared by radiation graft copolymerization of vinylbenzyl chloride onto fluorinated films and subsequent quaternization with various tertiary amines such as trimethylamine, N,N-dimethylbuthylamine, N,N-dimethylaniline, and N-methylpiperidine. The quaternizations of the anion exchange membranes were confirmed by measuring of the ion exchange capacities of the membranes. The mechanical properties and the water uptakes were also measured. The elongation at break was found to be largely dependent on the fluorinated film, the quateranry ammonium, and the degree of grafting. The results indicate that the poly (ethylene-alt-tetrafluoroethylene) with quaternized trimethylamine moiety exhibits higher flexible property compared to the other prepared anion exchange membranes.

• Journal of Radiation Industry
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• v.7 no.1
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• pp.61-67
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• 2013

In this study, we developed ionic permselective membrane as a core material of redox flow battery using radiation grafting method. Two ionic permselective membranes, ETFE-g-PSSA and ETFE-g-PVBSA were prepared by radiation grafting with styrene and VBC followed by sulfonation, respectively. We confirmed that the prepared membranes were successfully prepared via FT-IR. The prepared ionic permselcetive membranes were characterized and the performance of the membranes were evaluated as ionic permselective membranes for vanadium redox flow battery.

• Journal of the Korean Society of Safety
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• v.36 no.5
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• pp.86-91
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• 2021

Calculating the scrutable core damage frequency (CDF) of nuclear power plants is an important component of the seismic probabilistic safety assessment (SPSA). In this work, a simple approach is developed to calculate CDF from minimal cut sets (MCSs) with non-rare events. When conventional calculation methods based on rare event approximations are employed, the CDF of industry SPSA models is significantly overestimated by non-rare events in the MCSs. Recently, quantification algorithms using binary decision diagrams (BDDs) have been introduced to prevent CDF overestimation in the SPSA. However, BDD structures are generated from a small part of whole MCSs due to limited computational memory, and they cannot be reviewed due to their complicated logic structure. This study suggests a simple approach for scrutinizing the CDF calculation based on whole MCSs in the SPSA system analysis model. The proposed approach compares the new results to outputs from existing algorithms, which helps in avoiding CDF overestimation.

• Journal of Radiation Industry
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• v.6 no.3
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• pp.267-272
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• 2012

This study evaluated the change in anti-allergy activity of ${\beta}-glucan$ by electron beam irradiation. ${\beta}-Glucan$ was irradiated at dose of 50 kGy and then orally pre-treated with electron beam irradiated and non irradiated ${\beta}-Glucan$ for 7 days. After pre-treatment, allergy was induced by injection of ovalbumin (OVA). Serum total immunoglobulin E (IgE) and OVA-specific IgE levels in the allergic mice was significantly increased but the mice pre-treated 50 kGy electron beam irradiated ${\beta}-glucan$ was significantly decreased the levels of total IgE and OVA-specific IgE, respectively. Moreover, cytokine production (interleukin-4) was also decreased in the 50 kGy electron beam irradiated ${\beta}-Glucan$ pre-treated mice. These results indicate that pre-treatment of 50 kGy electron beam irradiated ${\beta}-glucan$ may elevate the anti-allergy activity. Therefore, electron beam-irradiated ${\beta}-glucan$ could be used for nutraceutical foods in food industry.

• Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
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• v.4 no.4
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• pp.401-409
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• 2006

Regulatory systems for decommissioning of nuclear power plants in several countries, such as Japan, United States of America, Germany, United Kingdom, France, and Republic of Korea, are surveyed. In the survey, regulatory policies, legislations, licensing process, inspection and public involvements for decommissioning are identified and compared. Afterwards, the survey results will be utilized as a reference to establish the improvement directions of domestic regulatory system.

• Journal of the Korean Society for Marine Environment & Energy
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• v.18 no.3
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• pp.157-165
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• 2015

This study investigated and compared sediment properties and macrobenthic community structures within heated effluent plumes at the discharge areas of Kori Nuclear Power Plant (KNPP) and Sinkori Nuclear Power Plant (SNPP) in Korea, which have different thermal effluent discharge systems. There were significant differences in sand, clay and organic carbon contents between sediments at the two discharge areas. Species richness and abundance of macrobenthos were higher at the SNPP discharge area than at that of the KNPP, although the values at both areas were comparable to previous studies in coastal areas of eastern Korea.

• Journal of Radiation Industry
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• v.4 no.1
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• pp.59-64
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• 2010

This study was conducted to evaluate the microbial (Total aerobic count, Coliform, Coagulase positive Staphylococci, Salmonella, Yeast/Mold, Escherichia coli, Bacillus cereus), Hunter'color values ($L^*$, $a^*$, $b^*$) and organoleptic quality of freeze-dried Miyeokguk, Korean seaweed soup in space food. Bacillus cereus was 1 log level while not detected in the sample irradiated at 10 kGy. Hunter's color values of the samples irradiated less than 10 kGy was not significantly different (p>0.05). The sensory evaluation result showed that the preference scores in all the sensory properties decreased when it was irradiated over 10 kGy, but sensory score of less than 10 kGy samples was similar in all terms. Therefore, it was considered that gamma irradiation at 10 kGy was enough to sterilize the freeze-dried Miyeokguk without deterioration of sensory quality.

• Journal of Radiation Industry
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• v.4 no.3
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• pp.233-237
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• 2010

This study evaluated the change in whitening activity of ${\beta}-glucan$ by gamma-irradiation. Tyrosinase inhibition was significantly increased in the samples with 30, 50, 100 kGy irradiated ${\beta}-glucan$. Melanin synthesis of irradiated ${\beta}-glucan$ was measured from B16BL6 melanoma cell line treated with ${\alpha}-melanin$ stimulating hormone. Melanin synthesis was increased in the ${\alpha}-melanin$ stimulating hormone added group. However, it was decreased in the groups of 30, 50 and 100 kGy gamma-irradiated ${\beta}-glucan$ treated with ${\alpha}-melanin$ stimulating hormone. These results indicate that gamma irradiated ${\beta}-glucan$ may elevate the whitening activity. Therefore, gamma-irradiated ${\beta}-glucan$ could be used for nutraceutical foods in cosmetic industry.