• Journal of Nuclear Fuel Cycle and Waste Technology
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• v.1 no.1
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• pp.75-82
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• 2013

A large quantity of radioactive waste was generated during the decommissioning of the KRR and UCF. The radioactive waste was packed into 200 liter drums and 4m3 containers and these were temporarily stored onsite until their final disposal in the national repository facility. Some of the releasable waste was freely released and utilized for non-nuclear industries. The combustible wastes were treated by the utilization of an incinerator with a capacity of on average 20 kg/hr.

• Journal of electromagnetic engineering and science
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• v.8 no.1
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• pp.6-11
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• 2008

Advances in low power design open the possibility to harvest energy from the environment to power electronic circuits. Electrical energy can be harvested from piezoelectric transducer. Piezoelectric materials can be used as mechanisms to transfer mechanical energy usually vibrating system into electrical energy that can be stored and used to power other devices. Micro- to milli-watts power can be generated from vibrating system. We developed definitive and analytical models to predict the power generated from a cantilever beam attached with piezoelectric transducer. Analytical models are pin-force method, enhanced pin-force method and Euler-Bernoulli method. Harmonic oscillations and random noise will be the two different forcing functions used to drive each system. It has been selected the best model for generating electric power based upon the analytical results obtained.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.12 no.1
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• pp.117-125
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• 1998

In this paper, in order to develop the three phase GTO CSI of high efficiency 1M drive with low loss commutation and snubber energy, we studied the energy recovery circuit to recover stored energy in clamping capacitor and DC link inductor(VCC-l and VCC-2), and snubber capacitor(VCC-3). By using an induction motor as the load of inverter, experimental results show that dissipated DC power is decreased and capacitor voltage Vc is effectively suppressed by VCC-2 and VCC-3 system, and the validity of VCC-3 system with low loss commutation and snubber energy is proofed.roofed.

• Journal of Power Electronics
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• v.10 no.6
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• pp.733-738
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• 2010

This paper deals with a ride-through technique for permanent-magnet synchronous generator (PMSG) wind turbine systems using energy storage systems (ESS). A control strategy which consists of current and power control loops for the energy storage systems is proposed. By increasing the generator speed, some portion of the turbine power can be stored in the system inertia. Therefore, the required energy capacity of the ESS can be decreased, which results in a low-cost system. In addition, the power fluctuations due to wind speed variations can be smoothened by controlling the ESS appropriately. The effectiveness of the proposed method is verified not only by the simulation results for a 2[MW] PMSG wind turbine system, but also by the experiment results for a reduced-scale turbine simulator.

• Proceedings of the Korean Radioactive Waste Society Conference
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• 2018.11a
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• pp.343-344
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• 2018

KAERI has about 185 tons of $D-UF_6$ from 1986 and it being stored 16 48Y type cylinders inside of storage building. The $D-UF_6$ cylinders should be transported to other countries for the deconversion into stable materials such as $U_3O_8$ in order to enhance the storage safety and disposal. For the transportation to other country and loading the cylinders to the deconversion facility, the sampling process is essential. The design and procedure for the sampling are now developing, and environmental effect evaluation and risk evaluation works will be performed to acquire license for the sampling.

• The Transactions of the Korean Institute of Electrical Engineers B
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• v.48 no.7
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• pp.384-390
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• 1999

This paper describes a new ac-to-dc power converter using a multilevel converter. A conventional multilevel ac-to-dc converter has large output dc filter capacitors. When a short circuit happens in a load, the stored energy in the capacitors should be discharged through the load with a high short circuit current. The high current may cause considerable damage to the capacitors and the load. The output dc capacitors of the proposed converter do not discharge even under load short circuit condition. In the case of a load short circuit, the capacitors become a floating state immediately and remain in the state. Then the stored capacitor energy is supplied to the load again as soon as the short circuit has been cleared. Therefore, the rising time of the load voltage can be significantly reduced. This feature satisfies the requirement of a power supply for a load with frequent short circuits. The proposed converter has the characteristics of a simplified structure, a reduced cost, weight, and volume compared with conventional power supplies with frequent output short circuits. Experimental results are presented to verify the usefulness of the proposed converter.

• Proceedings of the KIEE Conference
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• 1997.07f
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• pp.2033-2036
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• 1997

In this paper, we proposed a novel current-fed DC-DC converter with multi-output. It has two winding reactor in series with the input source of the converter. By using the 2nd winding recycling the energy stored in the reactor to the input, the double-outputs DC-DC converter can be created, which makes it a good choice for a multi-output power supply with more outputs and has savings in cost and space. The steady state and dynamic characteristics of the converter are analyzed in detail by using the state space averaging method. It is found that the maximum value of $V_{o2}$ exists in the 2nd output and also during the MOSFET off period, the energy stored in the magnetizing inductance is reset through auxiliary winding $N_3$, so the duty cycle is restricted to 50%. Theoretical and experimental results were taken from the converter rated at switching frequency 50kHz. input voltage 50V. output voltage 5V. 12V and output power 65W. As a result, both results were well consistent. Therefore, it is varified the validity of the proposed converter in this paper.

• Tunnel and Underground Space
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• v.5 no.4
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• pp.363-375
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• 1995

Critical literature review in this study revealed that there can be a significant influence of the residual stress on the engineering properties of rock. The review also showed that few number of research works on the quantification of the influence was attributed to the limitation of the two classical measurement techniques, viz, X-ray diffraction and mechanical relaxation method. In this study, a new way of approach was sought based on the assumption that residual stress up to the failure. A series of hoop tests conducted onthe samples from the limb of Carboniferous Limestone in Clevedon, England, revealed that (i) there is no preferential orientations of microcracks and minerals which have been widely believed as the main source of the strength anisotropy of rock; (ii) the anisotropy of the tensile strength of the limestone results from the influence of the residual stress; (iii) since jointing commenced within the fold, residual stored strain energy has been released preferentially in the direction perpendicular to the major joints(o$^{\circ}$ and 90$^{\circ}$); (ⅳ) during the hoop test making it much easier to create tensile fracture in these directons, viz 45$^{\circ}$ and 135$^{\circ}$)was released during the hoop test making it much easier to create tensile fracture in these directions, viz 45$^{\circ}$and 135$^{\circ}$;(v) the direction in which the stored strain energy may be presumed to be the least, required the greatest work to cause failure.

• Journal of Biosystems Engineering
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• v.15 no.2
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• pp.123-133
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• 1990

Thermal performance of a solar heating plastic greenhouse designed for a hydroponic system was studied. The system was constructed with the air-water heat exchanger and thermal storage tank that were combined with hydroponic water beds. Experiments were carried out to investigate the daily average heat stored and released in thermal storage tank, average solar energy collection efficiency, average coefficient of performance, average oil reduction factor of thermal storage system, and the heat transfer coefficient during the nighttime in plastic greenhouse. The results obtained in the present study are summarized as follows. 1. Daily average heat stored in thermal storage tank and released from the thermal storage tank was 1,259 and $797KJ/m^2$ day, respectively. 2. The average solar energy collection efficiency of thermal storage tank was 0.125 during the experiment period. And the average coefficient of performance of thermal storage system in plastic greenhouse was 3.6. 3. The average oil reduction factor of thermal storage system and the heat transfer coefficient during the nighttime in plastic greenhouse were found to be 0.52 and $4.3W/m^2\;hr\;^{\circ}C$, respectively.

• Journal of Nutrition and Health
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• v.27 no.9
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• pp.923-929
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• 1994

The effects of vitamin B6 deficiency on energy utilization during fasting or underfeeding were studied in rats. Fifteen rats were fed a vitamin B6 deficient(-B6) diet and another 15 rats wee fed a control (+B6) diet. These rats were fed for 5 weeks with respective diet, and then subdivided into 3 groups : non-fasted group, fasted group, underfed group. Rats of the fasted group were fasted for 3 days and those of underfed group for 6 days. At the respective time (non-fast, 3 day-fast, 6 day-underfeed at 5 weeks), animals were sacrificed. Feed efficiency ratio of - B6 rats was significantly lower than that of +B6 rats. In - B6 rats, the liver and kidney weights were significantly heavier than those of +B6 rats but spleen and heart weights were not. In non-fasted group, liver protein and triglyceride level of - B6 rats were significantly higher than that of +B6 rats. After - B6 rats were fasted for 3 days, plasma free fatty acid level was significantly lower but liver glycogen level was higher than that of +B6 rats and muscle protein level of +B6 was decreased while that of - B6 was not changed. Vitamin B6 deficiency had little effect on the energy utilization with 6 days underfeeding. These results suggest that vitamin B6 deficiency may impair the utilization of stored fuel during fasting.