• Proceedings of the Korean Nuclear Society Conference
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• 1997.05a
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• pp.458-463
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• 1997

A transient natural circulation behavior during a LOCA at hot-standby operation is evaluated for YGN Units 3/4. The plant initial condition is determined within the EOP limitation as suitable to hot-standby mode and the transient scenario is prepared as relevant to evaluation of transient natural circulation. A 0.4% cold leg break with loss of off-site power is calculated with RELAP5/MOD3.2, whose predictability has been verified for SBLOCA natural circulation test, S-NC-8B. Through one hour transient analysis, it is found that the plant has its own decay heat removal capability by natural circulation following a LOCA, at hot-standby mode. Additional calculation is performed to investigate an effect of HPSI flow on natural circulation.

• Nuclear Engineering and Technology
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• v.33 no.5
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• pp.457-467
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• 2001

It is well known that the performance of a fuzzy neural network strongly depends on the input features selected for its training. In its applications to sensor signal estimation, there are a large number of input variables related with an output As the number of input variables increases, the training time of fuzzy neural networks required increases exponentially. Thus, it is essential to reduce the number of inputs to a fuzzy neural network and to select the optimum number of mutually independent inputs that are able to clearly define the input-output mapping. In this work, principal component analysis (PCA), genetic algorithms (CA) and probability theory are combined to select new important input features. A proposed feature selection method is applied to the signal estimation of the steam generator water level, the hot-leg flowrate, the pressurizer water level and the pressurizer pressure sensors in pressurized water reactors and compared with other input feature selection methods.

• Proceedings of the Korean Nuclear Society Conference
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• 1996.11a
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• pp.283-288
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• 1996

Direct safety injection into the reactor vessel downcomer annulus(DVI) is a fundamental feature of the KNGR(Korean Next Generation Reactor) four-train safety injection system. The numerical analysis of thermal mixing of ECC(Emergency Core Cooling) water through DVI with the water in the RVDC(Reactor Vessel Downcomer) annulus has been performed, in order to study the impact of nozzle location on the pressurized thermal shock and safety analysis. The results of this study show that the thermal mixing due to the natural circulation induced by the limiting accident conditions is sufficient to prevent temperature in the RVDC from dropping to the level of concern for PTS. When the DVI nozzle is located right above the cold leg, the temperature distribution at the outlet of flow field is most uniform. The tool used for numerical analysis is CFDS-FLOW3D.

• Proceedings of the Korean Nuclear Society Conference
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• 1996.05b
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• pp.745-750
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• 1996

An analysis of a loss of residual heat removal system (RHRS) event during midloop operation after reactor shutdown was performed using the RELAP5/MOD3 thermal-hydraulic computer code. The experimental data of a 5% cold leg break test conducted at the ROSA-IV Large Scale Test Facility (LSTF) to simulate a main coolant pump shaft seal removal event during midloop operation of a Westinghouse-type PWR were used in the analysis. The predicted core boiling time and the peak primary system pressure showed good agreements with the measured data. Some differences between the calculational results and the experimental results were, however, found in areas of the timing of loop seal clearing and the temperature distribution in a pressurizer. Other calculational problems identified were discussed as well.

• Journal of the Korean Society of Clothing and Textiles
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• v.1 no.2
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• pp.59-64
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• 1977

The effects of skirt length on warmth retentivity were examined by measuring skin temperature on several parts of the leg warm differency length of skirts in the chamber which controlled at $-7\pm1^{\circ}C$ and $85\%$ R.H. The results were obtained as follows: 1. The high correlative efficients were found between the length of skirt and the warmth retentivity. Little warmth retentivity was found in a mini-skirt. 2. The skin temperature was dropped gradually lower nearing the ankle. 3. The skin temperature was also dropped immediately when the skin was exposed to the cold air, and showed a gradual fall.

• Nuclear Engineering and Technology
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• v.40 no.5
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• pp.419-428
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• 2008

During the overhaul period of nuclear power plants in Korea, an ROV(Remotely Operated Vehicle) enters the cold-leg pipes connected with the reactor to examine the state of the thermal sleeves and their positions in the safety injection nozzles. To measure the positions of the thermal sleeves or scratches with video images recorded during the examination, time-varying camera parameters should be known, such as the focal length and principal points used for the capturing each video image. In this paper, we propose a camera calibration and measurement scheme by using a single image containing two circular grooves of a cylindrical nozzle whose radius and distance are known.

• Nuclear Engineering and Technology
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• v.41 no.6
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• pp.775-784
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• 2009

This paper summarizes the tests performed in the ATLAS facility during its first two years of operation (2007${\sim}$2008). Two categories of tests have been performed successfully: (a) the reflood phase of the large-break loss-of-coolant accidents in a cold leg, and (b) the breaks in one of four direct vessel injection lines. Those tests contributed to understanding the unique thermal-hydraulic behavior, resolving the safety-related concerns and providing an evaluation of the safety analysis codes and methodology for the advanced pressurized water reactor, APR1400. Several important and interesting phenomena have been observed during the tests. In most cases, the ATLAS shows reasonable accident characteristics and conservative results compared with those predicted by one-dimensional safety analysis codes. A wide variety of small-break LOCA tests will be performed in 2009.

• Journal of Animal Science and Technology
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• v.65 no.1
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• pp.69-95
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• 2023

In order to evaluate the effects of ARG sources (arginine [ARG] and Guanidinoacetic acid [GAA]) and phenylalanine (PHE) supplementation on performance, susceptibility to ascites, intestinal morphology, and nutrient digestibility in the cold-stressed broilers fed a canola meal (CM)-based diet, a 2×2 factorial experiment with four treatments was conducted. The dietary treatments included CM-based diet + 2.57 g/kg ARG, CM-based diet + 2.57 g/kg ARG + 1.5 g/kg PHE, CM-based diet + 1.8 g/kg GAA and CM-based diet + 1.8 g/kg GAA + 1.5 g/kg PHE. The corn-CM diet without supplementation was used as a negative control (NC) group in the fifth treatment that excluded the factorial arrangement. The results showed that adding ARG to diets without PHE supplement increased (p < 0.05) feed intake. Also, birds fed diets containing ARG had higher (p < 0.05) body weight gain (BWG) compared to those fed GAA added diets. Supplementation of PHE improved (p < 0.05) the FCR compared to groups fed diets without added PHE. Further, ARG addition increased (p < 0.05) plasma nitric oxide (NO) concentration, carcass, breast and leg yields, duodenal, jejunal, and ileal villus height (VH) to crypt depth (CD, and dry matter digestibility, while decreasing (p < 0.05) ascites mortality and right ventricle (RV) to total ventricle (TV) ratio compared to GAA added groups. Supplementation of PHE also declined susceptibility to ascites by reducing (p < 0.01) RV to TV ratio while increasing (p < 0.05) plasma NO level. The digestibility of ether extract also increased (p < 0.05) in broilers fed GAA supplemented diets versus those fed ARG added diets. The findings suggested that ARG may improve BWG and lower ascites incidence in broilers fed a diet based on CM under cold stress because of its antihypertensive effects. Moreover, the findings of this study demonstrated the importance of including PHE formulation in ARG-deficient diets to attenuate the adverse effects of cold stress on broilers. It was also concluded that GAA could be efficaciously used in cold-stressed broilers fed an ARG-deficient diet.

• The Journal of the Society of Korean Medicine Diagnostics
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• v.16 no.1
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• pp.27-34
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• 2012

Objectives The purpose of this study was to find out whether if there is correlation between the pattern differentiation questionnaire and edema index of body composition analysis. Methods The authors obtained results of pattern differentiation Questionnaires and body composition analysis tests from 195 female patients who visited the Oriental gynecology department in Kyung Hee university Oriental medicine hospital at Gang-dong. The authors conducted correlation analysis between indicators of Body composition analysis and each part of the pattern differentiation Questionnaire. Pearson correlation analysis was performed on SPSS version 13.0 for windows. Results There was negative correlation between the Phlegm Questionnaire and right arm ECF, left arm ECF, and left arm ECW of the Body composition index. There was no correlation between Yin-deficiency Questionnaire and Body composition index. There was no correlation between Heat pattern Questionnaire and Body composition index. There was positive correlation between the Cold pattern Questionnaire and right leg ECF, and right leg ECW of the body composition index. There was no correlation between degree of edema self-awareness and Body composition index. Conclusions The result showed that each Questionnaire score has different correlation or even no correlation with Body composition index and degree of edema self-awareness. Further studies are needed for a better understanding and interpretation of the relationship between edema index on Body composition analysis and Questionnaires.

• Nuclear Engineering and Technology
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• v.44 no.7
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• pp.735-744
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• 2012

In order to quantify the flow distribution characteristics of APR+ reactor, a test was performed on a test facility, ACOP ($\underline{A}$PR+ $\underline{C}$ore Flow & $\underline{P}$ressure Test Facility), having a length scale of 1/5 referring to the prototype plant. The major parameters are core inlet flow and outlet pressure distribution and sectional pressure drops along the major flow path inside reactor vessel. To preserve the flow characteristics of prototype plant, the test facility was designed based on a preservation of major flow path geometry. An Euler number is considered as primary dimensionless parameter, which is conserved with a 1/40.9 of Reynolds number scaling ratio. ACOP simplifies each fuel assembly into a hydraulic simulator having the same axial flow resistance and lateral cross flow characteristics. In order to supply boundary condition to estimate thermal margins of the reactor, the distribution of inlet core flow and core exit pressure were measured in each of 257 fuel assembly simulators. In total, 584 points of static pressure and differential pressures were measured with a limited number of differential pressure transmitters by developing a sequential operation system of valves. In the current study, reactor flow characteristics under the balanced four-cold leg flow conditions at each of the cold legs were quantified, which is a part of the test matrix composing the APR+ flow distribution test program. The final identification of the reactor flow distribution was obtained by ensemble averaging 15 independent test data. The details of the design of the test facility, experiment, and data analysis are included in the current paper.