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REFERENCE LINKING PLATFORM OF KOREA S&T JOURNALS
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Nuclear Engineering and Technology
Journal Basic Information
Journal DOI :
Korean Nuclear Society
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Volume & Issues
Volume 32, Issue 6 - Dec 2000
Volume 32, Issue 5 - Oct 2000
Volume 32, Issue 4 - Aug 2000
Volume 32, Issue 3 - Jun 2000
Volume 32, Issue 2 - Apr 2000
Volume 32, Issue 1 - Feb 2000
Selecting the target year
A Study on the Applicability of MELCOR to Molten Core-Concrete Interaction Under Severe Accidents
Kim, Ju-Youl ; Chung, Chang-Hyun ; Lee, Byung-Chul ;
Nuclear Engineering and Technology, volume 32, issue 5, 2000, Pages 425~432
It has been an essential part for the safety assessment of nuclear power plants to understand various phenomena associated with the molten core-concrete interaction(MCCI) under severe accidents. In this study, the severe accident analysis code MELCOR was used to simulate the MCCI experiments such as SWISS and SURC test series which had been performed in Sandia National Laboratories(SNL). The calculation results were compared with corresponding experimental data such as melt temperature, concrete ablation distance, gas generation rate, and aerosol release rate. Good agreements were observed between MELCOR calculation and experimental data. The melt pool was sustained within the range of high temperature and the concrete ablation occurred continuously. The gas generation and aerosol release were under the influence of melt temperature and overlying water pool, respectively.
Development of the Interfacial Area Concentration Measurement Method Using a Five Sensor Conductivity Probe
Euh, Dong-Jin ; Yun, Byong-Jo ; Song, Chul-Hwa ; Kwon, Tae-Soon ; Chung, Moon-Ki ; Lee, Un-Chul ;
Nuclear Engineering and Technology, volume 32, issue 5, 2000, Pages 433~445
The interfacial area concentration (IAC) is one of the most important parameters in the two-fluid model for two-phase flow analysis. The IAC can be measured by a local conductivity probe method that uses the difference of conductivity between water and air/steam. The number of sensors in the conductivity probe may be differently chosen by considering the flow regime of two-phase flow. The four sensor conductivity probe method predicts the IAC without any assumptions of the bubble shape. The local IAC can be obtained by measuring the three dimensional velocity vector elements at the measuring point, and the directional cosines of the sensors. The five sensor conductivity probe method proposed in this study is based on the four sensor probe method. With the five sensor probe, the local IAC for a given referred measuring area of the probe can be predicted more exactly than the four sensor probe. In this paper, the mathematical approach of the five sensor probe method for measuring the IAC is described, and a numerical simulation is carried out for ideal cap bubbles of which the sizes and locations are determined by a random number generator.
The Application of a Laser to the Chemical Characterization of Radionuclides
Park, Y.J. ; Park, K.K. ; M/Y. Suh ; S.K. Yoon ; Park, Y.S. ; Kim, D.Y. ; Kim, W.H. ;
Nuclear Engineering and Technology, volume 32, issue 5, 2000, Pages 446~456
Laser induced photoacoustic, fluorescence, and photon correlation spectroscopies were applied to the chemical characterization of radionuclides in connection with the radiowaste treatment and disposal. Their measuring principles and systems were briefly described together with their advantages over conventional spectroscopies. Also, other applications of lasers are introduced. Laser induced photoacoustic spectra were measured for a P
solution with a very low molar absorptivity. The detection sensitivity was 4.3
and was 100 times better than that of a UV/VIS spectrophotometer. The Eu(III) excitation spectra(
transition) were measured for Eu(III)-phthalate complexes using laser fluorescence spectroscopy, showing that only two species, 1:1 and 1:2 complexes, are present in the Eu(III)-phthalic acid system. The size and size distribution for colloidal humic acids and Eu(III)-humate colloids was determined using photon correlation spectroscopy. The presence of Eu(III) enhanced the aggregation of humic acids.s.
A Design of the Thickness Gauge Using the Compton Gamma-ray Backscattering
B.S. Moon ; Kim, Y.K. ; Kim, J.Y. ; Kim, J.T. ; C.E. Chung ; S.B. Hong ;
Nuclear Engineering and Technology, volume 32, issue 5, 2000, Pages 457~464
In this paper, we describe the results of various calculations performed for a design of the thickness gauges that use the gamma-ray backscattering method. The radiation source is assumed to be the
1Am(60keV gamma-ray) and the detector is a single crystal scintillator in a cylindrical form. The source is located at the center of the detector with the collimator of a cylindrical shape. First, when gamma-rays are incident on a material with a constant angle, we compute the variations of the spectrum for the photons scattered into different angular intervals. Next, we compute for an optimal size for the collimator cylinder for a fixed detector size and an optimal distance from the detector to the material. Finally, we compute the number of observed photons for different thickness of two different materials, a plastic film and an Al foil.
Evaluation of Plugging Criteria on Steam Generator Tubes and Coalescence Model of Collinear Axial Through-Wall Cracks
Lee, Jin-Ho ; Park, Youn-Won ; Song, Myung-Ho ; Kim, Young-Jin ; Moon, Seong-In ;
Nuclear Engineering and Technology, volume 32, issue 5, 2000, Pages 465~476
In a nuclear power plant, steam generator tubes cover a major portion of the primary pressure-retaining boundary. Thus very conservative approaches have been taken in the light of steam generator tube integrity According to the present criteria, tubes wall-thinned in excess of 40% should be plugged whatever causes are. However, many analytical and experimental results have shown that no safety problems exist even with thickness reductions greater than 40%. The present criterion was developed about twenty years ago when wear and pitting were dominant causes for steam generator tube degradation. And it is based on tubes with single cracks regardless of the fact that the appearance of multiple cracks is more common in general. The objective of this study is to review the conservatism of the present plugging criteria of steam generator tubes and to propose a new coalescence model for two adjacent through-wall cracks existing in steam generator tubes. Using the existing failure models and experimental results, we reviewed the conservatism of the present plugging criteria. In order to verify the usefulness of the proposed new coalescence model, we performed finite element analysis and some parametric studies. Then, we developed a coalescence evaluation diagram.
Evaluation of Daily Intake of
in a Korean Mixed Diet Sample Using RNAA
Chung, Yong-Sam ; Moon, Jong-Hwa ; Kim, Sun-Ha ; Park, Kwang-Won ; Kang, Sang-Hoon ; Cho, Seung-Yeon ;
Nuclear Engineering and Technology, volume 32, issue 5, 2000, Pages 477~484
To estimate the degree of intake of
Th through daily diet, a Korean mixed diet sample was prepared after the investigation of the amount of consumption of the daily diet which corresponds to the age of 20 to 60 years. For the analysis of U and Th, the RNAA method was applied. Two standard reference materials were used for quality control and assurance and the analytical results were compared with a certified value. The determination of U and Th in the Korean mixed diet sample was carried out under the same analytical conditions and procedures with SRM. It is found that the concentration of U and Th in a Korean mixed diet was about 35.4 ppb and 3.4 ppb. From these results, the daily intake of
Th by diet is evaluated to be 6.98 and 0.67
per day, respectively. Radioactivities related to the intake of
Th were estimated to be about 86 mBq and 27 mBq per person per day and the annual dose equivalents from
Th revealed as 3.18
Sv and 0.29
Sv per person, respectively.
A Fuzzy Neural Network Combining Wavelet Denoising and PCA for Sensor Signal Estimation
Na, Man-Gyun ;
Nuclear Engineering and Technology, volume 32, issue 5, 2000, Pages 485~494
In this work, a fuzzy neural network is used to estimate the relevant sensor signal using other sensor signals. Noise components in input signals into the fuzzy neural network are removed through the wavelet denoising technique . Principal component analysis (PCA) is used to reduce the dimension of an input space without losing a significant amount of information. A lower dimensional input space will also usually reduce the time necessary to train a fuzzy-neural network. Also, the principal component analysis makes easy the selection of the input signals into the fuzzy neural network. The fuzzy neural network parameters are optimized by two learning methods. A genetic algorithm is used to optimize the antecedent parameters of the fuzzy neural network and a least-squares algorithm is used to solve the consequent parameters. The proposed algorithm was verified through the application to the pressurizer water level and the hot-leg flowrate measurements in pressurized water reactors.
Hydraulic Conductivity of Bentonite-Sand Mixture for a Potential Backfill Material for a High-level Radioactive Waste Repository
Cho, Won-Jin ; Lee, Jae-Owan ; Kang, Chul-Hyung ;
Nuclear Engineering and Technology, volume 32, issue 5, 2000, Pages 495~503
The hydraulic conductivities in the bentonite-sand mixtures with high density were measured, and the effects of sand content and dry density on the hydraulic conductivity were investigated. The hydraulic conductivities of the bentonite-sand mixtures with a dry density of 1.6 Mg/㎥ and 1.8 Mg/㎥ are less than 10
m/s when the sand content is not higher than 70 wt%. However at the sand content of 90 wt%, the hydraulic conductivity increases rapidly At the same dry density, the logarithm of hydraulic conductivity increases linearly with increasing sand content. The hydraulic conductivity of the bentonite-sand mixture can be explained by the concept of effective clay dry density, and using this concept, the hydraulic conductivities for the mixtures with various sand contents and dry densities can be estimated.
Adsorption and Desorption Characteristics of Methyl iodide on Silver ion-Exchanged Synthetic Zeolite at High Temperature
Park, Geun-Il ; Park, Byung-Sun ; Cho, Il-Hoon ; Kim, Joon-Hyung ; Ryu, Seung-Kon ;
Nuclear Engineering and Technology, volume 32, issue 5, 2000, Pages 504~513
The adsorption characteristics of methyl iodide generated from the simulated off-gas stream on various adsorbents such as silver ion-exchanged zeolite (AgX), zeocarbon and activated carbon were investigated. An extensive evaluation was made on the optimal silver ion-exchanged level for the effective removal of methyl iodide at temperature up to 38
. The degree of adsorption efficiency of methyl iodide on silver ion-exchanged zeolite is strongly dependent of silver ion-amount and process temperature. The influence of temperature, methyl iodide concentration and silver ion-exchanged level on the adsorption efficiency is closely related to the pore characteristics of adsorbents. It would be facts that the effective silver ion-exchanged level was about 10 wt%, based on the degree of silver utilization for the removal of methyl iodide.
Determination of Chemical Compositions and Oxidation States for Corrosion Products in LiCl Molten Salts
Park, Yong-Joon ; Pyo, Hyung-Ryul ; Kim, Do-Yang ; Jee, Kwang-Yong ; Kim, Won-Ho ;
Nuclear Engineering and Technology, volume 32, issue 5, 2000, Pages 514~520
The mechanism of corrosion behavior has to be understood clearly to select an optimum material for handling molten salts to be used in the oxide reduction process of PWR spent fuel. In this study, the oxidation states of corrosion products on the surface of Inconel 600 and 800H as well as their chemical compositions and structural informations were determined by using XPS, ICP-AES, AAS, EPMA and XRD after the corrosion experiment with lithium molten salts at 75
for 25 hours. Nickel and oxygen were detected from the corrosion products on the surface of Inconel plates and chromium was found to be dissolved out into lithium molten salts leaving cracks on the surface. The corrosion products were identified as metal oxides such as Fe
, NiO, NiFe
and MnO by using XPS and XRD.
Evaporation of a Water Droplet in High-Temperature Steam
Ban, Chang-Hwan ; Kim, Yoo ;
Nuclear Engineering and Technology, volume 32, issue 5, 2000, Pages 521~529
A modified interfacial heat transfer correlation between a dispersed water droplet and ambient superheated steam is proposed and compared with available experimental data and other correlations. Modified one overcomes the inherent deficiencies of Lee and Ryley's interfacial heat transfer correlation that ignored the effects of steam superheating which can not be neglected especially in the reflood situation of a loss-of-coolant accident. Modified one is represented by (equation omitted) In the present correlation the effect of possible subcooling of a water droplet is not taken into consideration. Comparison of the above correlation with currently available measurement data for a water droplet in high temperature gas flow shows that the proposed one correlates well with the measurement data where the degree of superheating is negligible and considerable.