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REFERENCE LINKING PLATFORM OF KOREA S&T JOURNALS
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Nuclear Engineering and Technology
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Journal DOI :
Korean Nuclear Society
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Volume & Issues
Volume 24, Issue 3 - Sep 1992
Volume 24, Issue 2 - Jun 1992
Volume 24, Issue 1 - Mar 1992
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Dynamic Characteristics of Spacer Grid Impact Loads for SSE
Jhung, Myung-Jo ; Song, Heuy-Gap ; Park, Keun-Bae ;
Nuclear Engineering and Technology, volume 24, issue 2, 1992, Pages 111~120
This paper investigates the dynamic characteristics of spacer grid impact loads and the effects of variations in the amplitude and frequency of the core plate motions on the resultant impact loads. A model of the longest row (15 fuel assemblies) across the core is analyzed using the input motions generated from safe shutdown earthquake. Input excitations consist of time history motions applied to the core support plate, fuel alignment plate and core shroud. The responses are determined for a set of four parameter runs with respect to the amplitude and frequency changes. Spacer grid impact loads and normalized input values for all cases are presented. The results show that changing the natural frequency has negligible effect but changing the amplitude of the input motions has a significant effect on the grid impact loads Therefore, time history analysis is not necessary for a shifted case to get the core responses under the seismic excitation.
Absorption and Accumulation of Sr-90 by Rice and Soybean and Its Soil-to-Plant Transfer Coefficients
Park, Yong-Ho ; Lee, Chang-Woo ; Lee, Kang-Suk ; Lee, Jeong-Ho ; Jo, Jae-Seong ; Chung, Kyu-Hoi ;
Nuclear Engineering and Technology, volume 24, issue 2, 1992, Pages 121~129
Radio-tracer experiments on the Sr-90 absorption by rice and soybean from a sandy-loam soil of pH 6.35 treated with 5.2 and 31.2Bq Sr-90 per g-soil were carried out through pot cultivations. Sr-90 absorption rates of both crops increased till the mature stage when the rates were about 1.0%. Concentrations in their whole tops, however, decreased or changed little as they grew. Sr-90 concentrations in plant parts of both crops increased with the increase of those in soil. Soil-to-plant transfer coefficients of Sr-90 for rice and soybean at mature stages ranged, on the dry weight basis, from 0.07(unpolished seed) to 3.67(lean and from 0.86(seed) to 9.26(leaf), respectively. Only the unpolished rice seed showed a significant difference in the coefficient with 0.17 in 5.2Bq treatment and 0.07 in 31.2Bq treatment. Sr-90 retention rates of the upper 15cm soil after crop harvests were about 80% Sr-90 absorptions had no effect on the plant growth and yield of the crops.
An Analysis on Direct-Contact Condensation in Horizontal Cocurrent Stratified How of Steam and Cold Water
Lee, Sukho ; Kim, Hho-Jung ;
Nuclear Engineering and Technology, volume 24, issue 2, 1992, Pages 130~140
The physical benchmark problem on the direct-contact condensation under the horizontal occurrent stratified flow was analyzed using the RELAP5/MOD2 and /MOD3 one-dimensional model. Analysis was peformed for the Northwestern experiments, which involved condensing steam/water flow in a rectangular channel. The study showed that the RELAP5 interfacial heat transfer model, under the horizontal stratified flow regime, predicted the condensation rate well though the interfacial heat transfer area was underpredicted. However, some discrepancies in water layer thickness and local heat transfer coefficient with experimental results were found especially when there is a wavy interface, and those were satisfied only within the range.
A Study on Electrolysis of Heavy Water and Interaction of Hydrogen with Lattice Defects in Palladium Electrodes
Ko, Won-Il ; Yoon, Young-Ku ; Park, Yong-Ki ;
Nuclear Engineering and Technology, volume 24, issue 2, 1992, Pages 141~153
Excess tritium analysis was peformed to verify whether or not cold fusion occurs during electrolysis of heavy water in the current density range of 83~600 mA/
for a period of 24 ~ 48 hours with use of palladium electrodes of seven different processing treatments and geometries. The extent of recombination of D
gases in the electrolytic cell was measured for the calculation of accurate enthaplpy values. The behavior and interaction of hydrogen atoms with defects in Pd electrodes were examined using the Sieverts gas charging and the positron annihilation(PA) method. Slight enrichment of tritium observed was attributed to electrolytic enrichment but not to the formation of a by-product of cold fusion. The extent of recombination of D
gases was 32%. Hence the excess heat measured during the electrolysis was considered to be due to the exothermic reaction of recombination but not to nuclear fusion. Lifetime results from the PA measurements on the Pd electrodes indicated that hydrogen atoms could be trapped at dislocations and vacancies in the electrodes and that dislocations were slightly more preferred sites than vacancies. It was also inferred from R parameters that the formation of hydrides was accompanied by generation of mostly dislocations. Doppler broadening results of the Pd electrodes indicated that lattiec defect sites where positrons were trapped first increased and then decreased, and this cycle was repeated as electrolysis continued. It can be inferred from PA measurements on the cold-rolled Pd and the isochronally annealed Pd hydride specimens that microvoid-type defects existed in the hydrogen-charged electrode specimen.
Electrochemical and Sludge Dissolution Behavior During a Copper Removal Process for Chemical Cleaning on the Secondary Side of Nuclear Steam Generators
Hur, Do-Haeng ; Chung, Han-Sub ; Kim, Uh-Chul ; Chae, Sung-Ki ; Park, Kwang-Kyoo ; Kim, Jae-Pyong ;
Nuclear Engineering and Technology, volume 24, issue 2, 1992, Pages 154~162
Two major goals for chemical cleaning on the secondary side of nuclear steam generators are to remove sludge effectively and to minimize corrosion of base metals. In this work, electrochemical and sludge dissolution behaviors have been investigated in order to find out which parameters are critical and important during a copper removal process for chemical cleaning and to evaluate safety aspects and effectiveness of two major copper removal processes developed commercially in foreign countries. Hydrogen peroxide is vert effective for the process to use EDTA, NH
OH and EDA at 38
to control the potential of copper in a potential range sood for copper sludge removal. Corrosion rates for carbon steel SA 285 Gr.C and Alloy 600 are very small during this process if it is controlled properly. However, the corrosion rate of SA 285 Gr.C will be increased greatly if its corrosion potential is maintained below -450mV. The process to use EDA and ammonium carbonate is effective at 6
to dissolve copper sludge if the corrosion potential of copper can be controlled above -200mV. However, it is very difficult to raise the corrosion potential of copper to this range by air blowing and stirring.
Determination of Trace Impurities in High Purity Aluminum by Instrumental Neutron Activation Analysis
Cho, Seung-Yeon ; Kim, Young-Kuk ; Chung, Yong-Sam ;
Nuclear Engineering and Technology, volume 24, issue 2, 1992, Pages 163~167
Nondestructive neutron activation analysis of copper in high purity Aluminum samples which can be used as a parameter of impurity is investigated and determined. Other 23 trace impurity elements in the samples are also determined. In the analysis of copper, the new irradiation method using thermal column was applied to reduce the interfering activity of 24Na produced by 27Al(n,
)24Na reaction induced by fast neutron. As a result, the interference can be reduced to 100 times more than other activation methods. Also the influence by activity of 24Na is found in the range of 2~3 %. It has been observed that the copper contents in so-ratted“six nine”class standard aluminum samples are about 0.54
0.08 ppm. By the comparison with other values re-ported, our results are reasonable and can be available as a improved routine analysis.
A Study on the Measurement of Local Void Fraction
B.J. Yun ; Kim, K.H. ; Park, G.C. ; C.H. Chung ;
Nuclear Engineering and Technology, volume 24, issue 2, 1992, Pages 168~177
The importance of the study of two phase flow phenomena has increased for both fuel performance and safety analysis of nuclear power plants. In the analysis of two phase flow system, an accurate prediction of local void fractions is very important. In this study, a vertical rectangular subchannel having 4 electrically heated rods is constructed for the measurement of local void fraction under two phase flow. The measurement has been conducted by electrical conductivity probes and signal processing circuit which are known to be adequate to measuring local void fraction. Also experiments are performed with varying the inlet flow rate to search for radial void fraction profile accordingly to the different flow rate even with the same averaged void fraction. From the result of experiments, the validity of electrical conductivity probe and electrical circuit is confirmed.
Burnup Evaluation of Spent PWR Fuel by Measuring Gamma-Ray of Fission Product Cs-137
Lee, Young-Gil ; Eom, Sung-Ho ; Park, Kwang-June ; Hong, Kwon-Pyo ; Ro, Seung-Gy ;
Nuclear Engineering and Technology, volume 24, issue 2, 1992, Pages 178~182
Spent PWR fuel rods have been scanned axially and sectionally to measure the relative gamma-ray intensity of Cs-137 and then bumups of the scanned rods determined by measuring Nd-148 which has been chemically separated. From these experimental results, a linear relation(LR) between the gamma-ray intensity of Cs-137 and the bumup in the range of 10∼35 GWD/MTU was obtained. In order to validate the LR, the Cs-137 gamma-ray intensity of unknown sample was nondestructively measured and the bumup obtained by the LR was compared with that of the Nd-148 method. It is revealed that the results from both methods are in good agreement, and thus it seems to be possible to estimate the bumup of spent PWR fuel rod by measuring nondestructively gamma-ray of fission product Cs-137.
Advanced Load Follow Operation Mode for Korean Standardized Nuclear Power Plants
Park, Jung-In ; Oh, Soo-Youl ; Song, In-Ho ; Hah, Yung-Joon ; Kuh, Jung-Eui ; Lee, Un-Chul ;
Nuclear Engineering and Technology, volume 24, issue 2, 1992, Pages 183~192
An advanced load-follow operation mode, Mode K, is presented for the Korean Standardized Nuclear Power Plants. The Mode K utilizes a heavy worth bank dedicated to axial shape control independent of the existing regulating banks. In Mode K, the heavy bank provides a wide range of axial shape control and a monotonic relationship between its motion and the axial shape change, which makes it easy to automate axial shape control. The achievement of full automatic reactor power control both for the reactivity and power shape would reduce the burden due to load-follow operation on the operator. Also, it can accommodate the frequen-cy control, which requires the plant to respond to the unexpected demand. The Mode K design concepts were tested using simulation responses of Yonggwang Units 3&4, the reference plants for the Korean Standardized Nuclear Power Plants. The results illustrate that the Mode K is an adequate operation mode to provide practical load-follow capabilities for the Korean Standardized Nuclear Power Plants.
원자력 노형전략과 CANDU 원자로
Nuclear Engineering and Technology, volume 24, issue 2, 1992, Pages 195~202
CANDU 원전의 건설과 인허가
Nuclear Engineering and Technology, volume 24, issue 2, 1992, Pages 203~212
개량형 및 피동형 CANDU의 개발 현황
Nuclear Engineering and Technology, volume 24, issue 2, 1992, Pages 213~218