• Journal of the Computational Structural Engineering Institute of Korea
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• v.17 no.4
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• pp.405-412
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• 2004

During the irradiation tests of material and fuel rod, all components of the cylindrical structure with multiple holes act like heat sources due to high gamma heat and fission heat. The objective of this study is to formulate the general solution for the temperature distribution to estimate the thermal integrity of structure during irradiation tests. For the temperature distribution analysis, the two-dimensional heat conduction theory is used. The unmerical analysis is performed by the commercial finite element analysis code, ANSYS 6.1. If the cylindrical structure with hole number would not exceed three holes, the analysis results and finite element results are good agreement together. For the structure with four holes, the discrepancy between FE results and analysis results of the structural temperature distribution is increased.

• Corrosion Science and Technology
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• v.7 no.2
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• pp.77-84
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• 2008

Based upon the good compatibility to neutron irradiation and high temperature water environment, austenitic stainless steels are widely used for core internal structural materials of light water reactors. But, recently, intergranular cracking was detected in the stainless steels for the core applications in some commercial PWR plants. Authors studied on the root cause of the intergranular cracking and developed the countermeasure including the alternative materials for these core applications. The intergranular cracking in these core applications are defined as an irradiation assisted mechanical cracking and irradiation assisted stress corrosion cracking. In this paper, the root cause of the intergranular cracking and its countermeasure are summarized and discussed.

• Korean Membrane Journal
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• v.7 no.1
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• pp.19-27
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• 2005

PP hollow fiber membrane was hydrophilized by EVOH dip coating followed by low temperature plasma treatment and UV irradiation. EVOH coating attained high water flux without any prewetting but its stability did not guaranteed at high water permeation rate. At high water permeation rate, water flux declined gradually due to swelling and delamination of the EVOH coating layer causing pore blocking effect. However, plasma treatment reduces the swelling, which suppress delamination of the EVOH coating layer from PP support result in relieving the flux decline. Also, UV irradiation helped the crosslinking of the EVOH coating layer to enhance the performance at low water permeation rate. FT-IR and ESCA analyses reveal that EVOH dip coating performed homogeneously through not only membrane surface but also matrix. Thermogram of EVOH film modified plasma treatment and W irradiation show that crosslinking density of EVOH layer increased. Chemical modification by plasma treatment and UV irradiation stabilized the hydrophilic coating layer to increase the critical flux of the submerged membrane.

• Preventive Nutrition and Food Science
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• v.2 no.1
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• pp.23-28
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• 1997

Physicohemical properties of corn starches isolated from non-glutinous and corn grains fol-lowing γ-irradiation up to 10kGy were investigated. Blue value, water binding capacity and swelling power decreased, while alkali number ad solubility increased by γ-irradiation , which was more pronounced in glu-tinous corn starch than in non-glutinous corn starch. The optical transmittance increased with an increment of heating temperature and applied irradiation doses. No significant difference was observed in Hunter's color value between both starches isolated from non- irradiated and irradiated and irradiated corn grains. Amylograph viscosities decreased remarkably as dose levels increased. The overall effects of γ-irradiation was more distinguished in glutinous starch than in non-glutinous starch.

• Journal of the Korean Society of Food Science and Nutrition
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• v.27 no.1
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• pp.63-68
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• 1998

Irradiation can be utilized to inhibit sprouting of onions and garlic. Thermoluminescence(TL) is a potential method to detect post-irradiation of onions and garlic because they are irradiated with soil or dusts on them, from which minerals can be isolated for TL analysis. This study was to determine whether TL can be applied for the detection of post-irradiation of onions and garlic. Onions and garlic produced in Korea were irradiated in the range of 0.01~0.6kGy. Minerals isolated from the samples using sodium polytrungstate solution were used for TL analysis. The onions and garlic irradiated at 0.15kGy or higher could be detected with little errors. Minimum dose for the 2nd glow could be applied since the dose for the 2nd glow did not affect the results. The TL intensities of the temperature ranges of 229~295$^{\circ}C$ and 229~361$^{\circ}C$ and the maximum intensity provided more accurate information for the determination of the post-irradiation of onions and garlic.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2009.06a
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• pp.220-220
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• 2009

In case of favourable irradiation conditions, the ratio of irradiation to the total irradiation went up and then the irradiation increased in the area with high angle of inclination. The study showed that on a clear day with the irradiation of more than $800[W/m^2]$, the pattern of alternating current power change in the fixed system was similar with that in the single-axis tracker. On the contrary, in case of unfavourable irradiation conditions, the ratio of diffuse irradiation to the total irradiation went up and then the horizontal irradiation increased. In the demo system, the fixed system, the single-axis tracker and the dual-axis tracker all had low generation power and similar generation pattern with each other. The study showed the generation power varied with the irradiation in the fixed system, while in the single-axis tracker and the dual-axis tracker, the amount of the generation power variation was much more than the irradiation variation. The demo system was operated from 11:00 AM to 2:00 PM for generating power, during which time, 46[%] to 56[%] of the total generation power was produced. In this study. the generation power was increased by 147[%] in the fixed system, by 136[%] in the single-axis tracker, and by 164[%] in the dual-axis tracker, and the pattern of generation power was similar with the generation power variation in the situation where the irradiation increased by 140[%] in the spring with plenty of insolation. The alternating current power was more sensitive to variation of the irradiation than to that of the surface temperature of a module. The variation of the irradiation had a more positive effect on the generation power than the type of array.

• Nuclear Engineering and Technology
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• v.52 no.6
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• pp.1213-1221
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• 2020

Chromium-nickel alloy 42XNM (XHM-1, Bochvalloy) is considered as a promising material for future generations of nuclear reactors, primarily as a material for the fuel elements shells in the development of accident tolerant fuel. However, as with most nickel-based alloys, 42ХNМ is characterized by a sharp decrease in plastic properties in the temperature range of (500-900)℃. This effect is enhanced by neutron irradiation. Preliminary tests of ring samples of 42XNM alloy (after irradiation as a part of the VVER-1000 control system) in the temperature range of ductility failure showed that the standard technique for processing tensile diagrams does not allow to evaluate the plastic properties correctly at low strains. Therefore, in this work, the alternative method for testing ring samples from materials with low plastic characteristics was developed. It was shown that the minimum value of the permanent strain of the irradiated 42XNM alloy in the temperature range of (500-1100)℃, determined by the alternative method, was ~1.6% at 750 ℃.

• Journal of Korean Society on Water Environment
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• v.30 no.5
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• pp.486-490
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• 2014

Industrial use of microwave heating as an alternative to conventional heating is becoming popular mainly due to dramatic reductions in reaction time. Therefore, this work experimentally determined the effect of microwave irradiation on ammonia nitrogen removal in wastewater. The effects of air flow rate (0.3~0.9 L/min), treatment temperature ($70{\sim}100^{\circ}C$), and initial pH (9~11) were characterized. As the air flow rate increased from 0.3 to 0.9 L/min, the ammonia removal rate constant (k) increased from -0.6642 to $-1.0755min^{-1}$. As the temperature increased from 70 to $100^{\circ}C$, k increased -0.0338 to $-1.0755min^{-1}$. As the pH increased from 9 to 11, k increased -0.2443 to $-1.0755min^{-1}$. Ammonia removal was strongly dependent on temperature and pH rather than air flow rate. The results show that microwave irradiation is effective in ammonia nitrogen removal in wastewater due to advantages of fast and effective processing.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.10
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• pp.73-77
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• 1971

The experiment was carried out to investigate post-irradiation storage effect which was related to temperature(i.e. at 2$^{\circ}C$, 17$^{\circ}C$ and 4$0^{\circ}C$) on wheat seeds; Weibull's Svenno, treated with gamma-ray and fast neutron. Results obtained showed that the seedling height in both radiation sources was decreased with prolongation of storage period, especially when the seeds were treated with high dosage and stored at high temperature(4$0^{\circ}C$). The results of this trial, however, showed that storage effect was influenced by irradiation dose, temperature and storage time.

• Journal of the Korean Society of Food Science and Nutrition
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• v.32 no.6
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• pp.864-869
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• 2003

In order to expand the acceptability of irradiated foods by public, substantial basic data about the change of nutrient contents during irradiation are needed. The nutrient contents and digestibility of macronutrients such as carbohydrates, proteins and lipids in foods are known to be not significantly influenced by irradiation treatment. However, some of the vitamins among micronutrients are susceptible to irradiation to a large extent depending upon the food composition, food process and storage condition. This study was conducted to investigate change of thiamin in chicken breast, and vitamin C in strawberry and mandarine orange after irradiation. The effects of irradiation at frozen or refrigerated state and the effects of cooking such as heating or micron ave on thiamin contents in chicken breast were observed. Irradiation reduced the thiamin content, however, temperature condition during irradiation was much more important factor to the loss of thiamin contents. In strawberry, vitamin C content was significantly affected by original content or the variety rattler than treatments such as irradiation, heating or microwave. These results indicated that the losses of water-soluble vitamins, especially thiamin or vitamin C, are affected by food temperature during irradiation process and variety or composition of foods rallier than irradiation itself, within an acceptable range of irradiation.