• Nuclear Engineering and Technology
• /
• v.31 no.4
• /
• pp.375-384
• /
• 1999

The credibility of CHECWORKS FAC model analysis was evaluated for plant application in a model plant chosen for demonstration. The operation condition at each pipe component was defined before the wear rate analysis by plant data base, water chemistry analysis, and network flow analysis. The predicted wear was compared with the measured wear for 57 sample components selected from 43 susceptible line groups analysed. The inspected 57 locations represent components of highest predicted wear in each line group. Both absolute value and relative ranking comparisons indicated reasonable correlations between the predicted and the measured values. Four components showed much higher measured wear rates than the predicted ones in the feed water train from main feed water pump discharge to steam generator, probably due to high hydrazine concentration operation the effect of which had not been incorporated into the CHECWORKS model. The measured wear was higher than the predicted one consistently for components with least susceptibility to FAC. It is believed that the conservatism maintained during UT data analysis dominated the measurement accuracy. A great deal of enhancement is anticipated over the current plant pipe management program when a comprehensive plant pipe management program is implemented based on the model analysis.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
• /
• v.23 no.12
• /
• pp.83-89
• /
• 2009

The environment of electrical power industry is now faced on problems such as electric rates, an increasing sensitivity in society with environmental issues and energy factors. Up to now, reliability is greatly influenced by maintenance and environmental factors that are unique to the electric utilities. The reliability is a characteristic assigned to the electric power systems's function which is related to the concept of installment of equipment. Therefore this reports's key finding is that it is important that the utilities track their individual components' value over investment expense of their installed components. This can be accomplished to consider the cases of foreign electric power companies and take into account the various possible installment ways of equipment in Korea. These results are expected to be used as a reference material for design underground distribution facilities and future applications.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.21 no.12
• /
• pp.52-59
• /
• 2020

Currently, the domestic electricity rates for houses are charged by applying a progressive level according to monthly electricity usage. Electricity rates rise sharply wWhen the amount of electricity used is large, electricity rates rise sharply. The standardized electricity rate progressive system has limitations in that it lacks consideration of the consumers' power usage patterns and limits consumers' their options. Accordingly, the Ministry of Trade, Industry and Energy and the Korea Electric Power Corporation have been demonstrating the basis of a rate system for housing, which is a method of charging electricity according to the amount of electricity used by season and time. In this paper, 10 electricity usage patterns were derived through from AMI data analysis for 5 five years of 362 apartment complexes located in metropolitan cities. The patterns were, and then applied to the existing domestic electricity rate and time-by-time rates applied to demonstrations, and by time-by-time rates in the US and Australia. The effect of the optional rate by pattern was compared and analyzed. As a result, it was confirmed that benefits occurred in five5 patterns compared to existing rate plans, and the electricity rates increased in 5 five patterns, and t. This phenomenon shows the same phenomenon withis the same as the overseas rates, including domestic rates being demonstrated.

• Progress in Superconductivity and Cryogenics
• /
• v.2 no.1
• /
• pp.19-23
• /
• 2000

We are developing a small-sized superconducting magnetic energy storge ($\mu$SMES) magnet with the storage capacity of a few megajoules, which provides electric power with high quality to sensitive electric loads. A kA class superconductor with a high coppe $r^erconductor ratio was selected as a candidate conductor. The superconductor was tested in two points of view, which are basic and important in development of the $\mu$SMES magnet. First, stabilities of the superconductor against localized disturbances such as wire motions were estimated by using a wire heater. Second, the quench current characteristics for different charge rates were also tested. The stability data showed that the short heat pulses made the conductor more unstable. The superconductor had relatively high recovery currents ranging between 40% and 50% of its critical currents. The quench tests indicated that the quench currents of the conductor were independent of current ramp rates up to 3000 A/s and nearly equal to its cuitical current data.ta.

• Proceedings of the Korean Nuclear Society Conference
• /
• 1997.05b
• /
• pp.123-128
• /
• 1997

The effects of heat treatment on fatigue crack growth rates (FCGRs) of Inconel 690 have been investigated in terms of carbide morphology and grain size. Cycling tests in air at room temperature have shown that FCGR in low stress intensity factor range (ΔK) region can be effectively reduced by increasing the grain boundary carbide precipitate size and grain size. Decrease in FCGR is attributed to the crack tip blunting at the precipitates of grain boundary chromium carbides.

• Corrosion Science and Technology
• /
• v.14 no.1
• /
• pp.33-39
• /
• 2015

Pipe wall-thinning by flow-accelerated corrosion and various types of erosion is significant damage in secondary system piping of nuclear power plants(NPPs). All NPPs in Korea have management programs to ensure pipe integrity from degradation mechanisms. Ultrasonic test(UT) is widely used for pipe wall thickness measurement. Numerous UT measurements have been performed during scheduled outages. Wall-thinning rates are determined conservatively according to several evaluation methods developed by Electric Power Research Institute(EPRI). The issue of reliability caused by measurement error should be considered in the process of evaluation. The reliability analysis method was developed for single and multiple measurement data in the previous researches. This paper describes the application results of reliability analysis method to real measurement data during scheduled outage and proved its benefits.

• Journal of the Korea Institute of Military Science and Technology
• /
• v.23 no.3
• /
• pp.237-245
• /
• 2020

In this paper, I introduce Phase-Change Cooling for thermal management of high power devices that can be applied to High Power Laser and Electric Propulsion Systems which are composed of multiple distributed superheat sources. Phase-Change Cooling can be good used to efficient cooling of their heat sources. Phase-Change Cooling has extremely high efficiency of two-phase heat transport by utilizing heat of vaporization, relatively low flow rates and reduced pumps power. And I suggest TPI(Thermal Performance Index) which is a quantitative performance index of Phase-Change Cooling for thermal management. I quantify the performance of Phase-Change Cooling by introducing TPI. I present the test results of TPI's changing refrigerant, heat sink and flow rate of the Phase-Change Cooling system through the experiments and analyze these results.

• Proceedings of the KIEE Conference
• /
• 1993.07a
• /
• pp.82-85
• /
• 1993

The load forecasting has been essential in planning and operation of power systems. The load composition rata is also needed to analyze power-systems - load flow calculation and system stability. This paper proposes the monthly peak load forecasting methods for load groups in residential class using load composition rate and electric consumption characteristics. The proposed methods were applied to a real-scale power system and the effectiveness was turned out.

• Journal of Radiation Protection and Research
• /
• v.32 no.2
• /
• pp.45-50
• /
• 2007

In this study, uptake rates of internal organs and daily urinary excretion rates were measured to get more reliable estimation results for Korean. Radioactive iodine($^{131}I$) of $100{\mu}Ci$ was administered by ingestion to 28 adult males for the experiment and then the radioactivity in thyroid gland, liver, stomach, small intestine, kidneys, and urine was measured after time intervals of 2, 4, 6 and 24 hours. Uptake rates of each organ and daily urinary excretion rates were calculated on the basis of these experimental results. As a result, uptake rates of 19.70% for thyroid and daily urinary excretion rates of 71.12%, on the average, were indicated. The maximum of uptake rates and daily urinary excretion rates were recorded after 2 hours of administration of $^{131}I$, but those rates were decreased gradually later. It was also found that uptake rates were the highest in stomach, followed by the left kidney, liver, small intestine and right kidney except for thyroid gland. In this experiment, the calculated uptake change rate in thyroid gland after 24 hours of administration of $^{131}I$ was different from that of ICRP-54/67(30%) and ICRP-78(25%). Thus, it is necessary to apply more reliable approach, reflecting the characteristic of Korean physiology and to obtain the basic data of results using this approach for calculation of the internal adsorbed dose. In the future, this approach can be helpful for the internal dose assessment of radiation workers in a nuclear power plant or in a hospital.

• Proceedings of the IEEK Conference
• /
• 2001.10a
• /
• pp.443-447
• /
• 2001

A laboratory-scale electrodewatering system for enhancing conventional filter pressure dewatering by an electric field has been developed to decrease the water content of sludge generated in the wastewater treatment. It consists of a piston-typed filter press, a power supply and data acquisition system. The offset of electrodewatering is investigated as a function of applied pressure, applied voltage, sludge type and filtration time. Also the optimal conditions for maximizing the dewatering efficiency in the eletrodewatering system are investigated. Electric field strength and mechanical pressure are in the range of from 0 to 120 V/cm and from 98.1 to 392.4 kPa. The dewatering rates increased with increasing electric strength. These experiments produced a final sludge cake with water content of 60 wt% using electrodewatering technology, compared with a 80 wt% using pressure filtration alone. The conventional filtration system using the electrodewatering shows the potential to be effective method for improving dewatering Sludge.