• Korean Journal of Fisheries and Aquatic Sciences
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• v.48 no.2
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• pp.193-199
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• 2015

We observed that the growth and physiological change in Haliotis discus discus by low-dose irradiation with gamma ray.Irradiation with gamma ray was undertaken by using the low-level irradiation facility ($^{60}CO$) in cooperation with the Institute of Nuclear Science and Technology at Jeju National University. The parent abalones were attached one by one and then fixed by using the rubber band to the front side of the fabricated case for irradiation with gamma ray. The experimental plots of irradiation with gamma ray were set as 10, 15, 20 and 25 Gy and the 25 female abalones and 10 male abalones were utilized for each experimental plot. The sperms and eggs were fertilized by setting an interval for each dose to prevent mixing with other experimental plots when fertilizing the sperms and eggs for each dose of irradiation with gamma ray. As for the fertility, it was confirmed to be 85% the control and 10 Gy groups, whereas it was found to be 80%, 65% and 50% in the 15 Gy, 20 Gy and 25 Gy groups, respectively. As a conclusion, the hatching rate and attachment rate were higher at 10 and 15 Gy than the other experimental plots, and the growth rate was higher at 20 Gy than the other experimental plots. Also the changes in lysozyme activity in accordance with the stress of water temperature were found to have a significant increase in the other experimental plots as compared with the control plot at the end of 0 h. The changes in lysozyme activity have remained constant in all the experimental plots at the end of 12 h. These results allowed us to confirm that lysozyme was undertaking the biodefense action by reacting sensitively to the stress of water temperature in the control experimental plot. As for the other experimental plots, they are believed to avoid the biodefense mechanism due to the high degree of anti-parasite mechanism and anti-viral mechanism. Thus, it is believed that it would be imperative to conduct development and research on breeds that were potent for environmental tolerance by applying the method of irradiation with gamma ray to other marine animals and plants.

• Nuclear Engineering and Technology
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• v.54 no.11
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• pp.4084-4094
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• 2022

The Advanced Fuels Campaign Fission Accelerated Steady-state Test (FAST) at Idaho National Laboratory (INL) completed its first irradiation cycle within the Advanced Test Reactor (ATR). The test focused on the irradiation of alloy fuel forms for use in sodium fast reactors. The first cycle of FAST testing was completed and four rodlets were removed for the initial post irradiation examination (PIE). The rodlet design and irradiation conditions were evaluated using Monte Carlo N-Particle (MCNP) for as-run power history and COMSOL for temperature analysis. These rodlets include a set of low burnups (~2.5 % fissions per initial metal atoms [%FIMA]), control rodlets, and a helium-bonded annular rodlet (4.7 %FIMA). Nondestructive PIE has been completed and includes visual inspection, neutron radiography and gamma scanning of the FAST capsules and rodlets. Radiography confirmed the integrity of the experiments, revealed that the annulus in the annular fuel was filled at a modest burnup (4.7 %FIMA), and indicated potential slumping of the cooler rodlets at lower burnup. Precision gamma scanning indicated mostly usual fission product behavior, except for cesium in the He-bonded annular fuel. Future destructive PIE will be necessary to fully interpret the effects of accelerated irradiation on U-Zr metallic fuel behavior.

• Horticultural Science & Technology
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• v.19 no.4
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• pp.515-520
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• 2001

To observe the stimulating effect of low dose ${\gamma}$ radiation on the dormancy breaking and growth, microtubers of two potato cultivars (Solanum tuberosum L. cv. Dejima and cv. Superior) were irradiated at the dose of 0.5-30 Gy. Though it varied with cultivars and storage duration, sprouting rate, plant growth and tuber yield were promoted by 2-8 Gy irradiation in microtuber of 'Dejima' stored at low temperature. On the other hand, in microtuber of 'Superior', sprouting rate was promoted by 2 and 4 Gy irradiation, and the growth and tuber yield by 4 Gy irradiation. These results suggest that low dose of ${\gamma}$ radiation could have stimulating effects on the dormancy breaking of microtuber and potato growth.

• Macromolecular Research
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• v.12 no.1
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• pp.112-118
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• 2004

With the goal of enhancing the creep resistance of ultra-high molecular weight polyethylene (UHMWPE), we performed gamma irradiation and post-irradiation annealing at a low temperature, and investigated the crystalline structures and mechanical properties of the samples. Electron spin resonance spectra reveal that most of the residual radicals are stabilized by annealing at 100$^{\circ}C$ for 72 h under vacuum. Both the melting temperature and crystallinity increase after increasing the dose and by post-irradiation annealing. When irradiated with the same dose, the quenched sample having a higher amorphous fraction exhibits a lower swell ratio than does the slow-cooled sample. The measured tensile properties correlate well to the crystalline structure of the irradiated and annealed samples. For enhancing creep resistance, high crystallinity appears to be more critical than a high degree of crosslinking.

• 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.

• Journal of Dairy Science and Biotechnology
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• v.23 no.2
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• pp.93-98
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• 2005

Effects of heat and gamma irradiation on chemical, microbiological, and immunological changes of raw milk were compared. Free fatty acid content of milk showed increasing tendency according to the increase of heating temperature and irradiation dose, and showed similarity in UHT (ultra high temperature) and 5 kGy irradiation. Total bacterial counts and coliforms were not detected after treatment of LTLT (low temperature long time), HTST (high temperature short time), UHT, and irradiation from 1 to 10 kGy in the milk with initial microbial load at $10^3$ CFU/mL initially, but after 7 day storage, were not detected in UHT milk and that irradiated at 3 kGy or above. Heat treatment decreased (p<0.05) arginine, asparate, iso-leucine, lysine, and methionine content compared to raw milk while irradiation decreased (p<0.05) asparate, histidine, iso-luecine, leucine, and lysine content, which means irradiation could change primary structure of milk proteins. It was concluded that f kGy gamma irradiation treatment of raw milk could give a similar effect to UHT treatment in chemical and microbiological viewpoint, and may reduce allergenicity of raw milk.

• Applied Biological Chemistry
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• v.51 no.2
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• pp.148-152
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• 2008

This study was to elucidate the effect of low dose gamma (${\gamma}$)-ray irradiation on the germination, seedling growth and antioxidant activity in sunflower seeds. The seed germination was stimulated in the range of 2.7${\sim}$8.0% by low dose ${\gamma}$-ray irradiation compared with that of the control; however, the germination of seeds stored for 4 months after irradiated was decreased at all low dose ${\gamma}$-ray irradiation groups. Especially, the germination rate of 32 Gy-irradiated seed group was much lower than that of the other groups and 8 Gy was the optimal radiation dose for germination at room temperature. Though there was variation with storage time and temperature, seedling growth stored at 10$^{\circ}C$ for 4 months after irradiated was promoted at the 1 Gy ${\gamma}$-ray irradiation group compared to seed stored at 25$^{\circ}C$. For the antioxidant activity of ${\gamma}$-ray irradiated seeds extract, 4 Gy and 32 Gy groups were significantly increased by 68.83% and 95.44%, respectively, compared to control at the concentration of 100 ${\mu}g$/ml.

• Nuclear Engineering and Technology
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• v.54 no.3
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• pp.991-996
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• 2022

Microstructures of monolithic high purity SiC and SiC with sintering additives after neutron irradiation to a fluence of 2.0-2.5 × 10²⁴ n/m² (E > 0.1 MeV) at 333-363 K and after post-irradiation annealing up to 1673 K were observed using a transmission electron microscopy. Results showed that no black spot defects or dislocation loops in SiC grains were found after the neutron irradiation for all of the specimens owing to the moderate fluence at low irradiation temperature. Thus, it is confirmed that these specimens were swelled mostly by the formation of point defects. Black spots and small dislocation loops were discovered only after the annealing process in PureBeta-SiC and CVD-SiC, where the swelling almost diminished. Anomalous-shaped YAG grains were found in SiC ceramics containing sintering additives. These grains contained dense black spots defects and might lose crystallinity after the neutron irradiation, while these defects may annihilate by recrystallization during annealing up to 1673 K. Amorphous grain boundary phase was also presented in this ceramic, and a large part of it was crystallized through post-irradiation annealing and could affect their recovery behavior.

• Journal of IKEEE
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• v.15 no.2
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• pp.143-148
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• 2011

MOS (Metal-Oxide Semconductor) devices among the most sensistive of all semiconductors to radiation, in particular ionizing radiation, showing much change even after a relatively low dose. The necessity of a radiation dosimeter robust enough for the working environment has increased in the fields of aerospace, radio-therapy, atomic power plant facilities, and other places where radiation exists. The power MOSFET (Metal-Oxide Semiconductor Field-Effect Transistor) has been tested for use as a gamma radiation dosimeter by measuring the variation of threshold voltage based on the quantity of dose, and a maximum total dose of 30 krad exposed to a $^{60}Co$ ${\gamma}$-radiation source, which is sensitive to environment parameters such as temperature. The gate oxide structures give the main influence on the changes in the electrical characteristics affected by irradiation. The variation of threshold voltage on the operating temperature has caused errors, and needs calibration. These effects can be overcome by adjusting gate oxide thickness and implanting impurity at the surface of well region in MOSFET.

• Nuclear Engineering and Technology
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• v.53 no.5
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• pp.1602-1611
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• 2021

A varying degree of eccentricity always exists in the initial configuration of a nuclear fuel rod. Its impact on traditional LWR fuel is limited as the radial gap closes relatively early during irradiation. However, the effect of misalignment is expected to be more relevant in rods with highly conductive fuels, large initial gaps and low conductivity filling gases. In this paper, we study similar characteristics in the experimental setup of two fuel disc irradiation campaigns carried out in the OECD Halden Boiling Water Reactor. Using the multi-dimensional fuel performance code OFFBEAT, we combine 2-D axisymmetric and 3-D simulations to investigate the effect of eccentricity on the fuel temperature distribution. At the same time, we illustrate how the advent of modern tools with multi-dimensional capabilities might further improve the design and interpretation of in-pile separate-effect tests and we outline the potential of such an analysis for upcoming experiments.