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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
Editor in Chief :
Volume & Issues
Volume 29, Issue 6 - Dec 1997
Volume 29, Issue 5 - Oct 1997
Volume 29, Issue 4 - Aug 1997
Volume 29, Issue 3 - Jun 1997
Volume 29, Issue 2 - Apr 1997
Volume 29, Issue 1 - Feb 1997
Selecting the target year
Oxidation Behavior of Unirradiated and Irradiated
in hir at
Kim, Keon-Sik ; You, Gil-Sung ; Min, Duck-Kee ; Ro, Seung-Gy ; Kim, Eun-Ka ;
Nuclear Engineering and Technology, volume 29, issue 2, 1997, Pages 93~98
Air-oxidation experiments on unirradiated and irradiated UO
were performed at temperature from 150 to 375
for investigating the long-term storage behavior of spent PWR fuel. The rate of oxidation was monitored by a thermogravimetric analyzer(TGA) and an X-ray diffraction(XRD). The correlation between the onset-time for U
formation and temperature was given as follows, logt(hr) = -12.89+7650/T(K), 423
pellet, the oxidation rate of irradiated UO
increase more rapidly at the initial stage and shows a lower saturation point at the later Stage. The Oxidation rate of high bumup UO
and gadolinia-doped UO
) were observed to be much slower than that of unirradiated UO
Development of a Mechanistic Model for Hydrogen Generation in Fuel-Coolant Interactions
Lee, Byung-Chul ; Park, Goon-Cherl ; Chung, Chang-Hyun ;
Nuclear Engineering and Technology, volume 29, issue 2, 1997, Pages 99~109
A dynamic model for hydrogen generation by Fuel-Coolant Interactions(FCI) is developed with separate models for each FCI stage, coarse mixing and stratification. The model includes the physical concept of FCI, semi-empirical heat and mass transfer correlation and the concentration diffusion equation with the general non-zero boundary condition. The calculated amount of hydrogen, which is mainly generated in stratification, is compared with the FITS experiments. The model developed in this study shows a good agreement within a range of 10 % fuel oxidation rate and predicts the controlled mechanism of the chemical reaction very well. And this model predicts more accurately than the previous works. It is shown from the sensitivity study that the higher initial temperature of fuel particle is, the larger the reaction rate is. Up to 2700 K of temperature of the particle, the reaction rate increases rapid, which can lead to metal ignition.
Development and Application of Two-Dimensional Hydrogen Mixing Model in Containment Subcompartment Under Severe Accidents
Lee, Byung-Chul ; Cho, Jae-Seon ; Park, Goon-Cherl ; Chung, Chang-Hyun ;
Nuclear Engineering and Technology, volume 29, issue 2, 1997, Pages 110~126
A two-dimensional continuum model for the hydrogen mining phenomena in the containment subcompartment under severe accident conditions has been developed to predict the spatial distribution of the hydrogen concentration. The model can predict the distribution of time-dependent hydrogen concentration for HEDL experiments well. For the simulation of these experiments, the hydrogen is mixed uniform within the test compartment. To predict the extent of non-uniform distribution, the dominant factors such as the geometrical shape of obstacle and velocity of source injection in mixing phenomena are investigated. If the obstacle disturbing the flow of gas mixture exists in the compartment, the uniform distribution of hydrogen might be not guaranteed. The convective circulation of gas flow is separately formed up and down of the obstacle position, which makes a difference of hydrogen concentration between the upper and lower region of the compartment. The recirculation flow must have a considerable mass flow rate relative to velocity of the source injection to sustain the well-mixed conditions of hydrogen. Finally, in order to account for non-uniform distribution of the hydrogen due to the geometrical configuration the maximum-to-average ratio is functionalized.
Equilibrium Concentration of Radionuclides in Cement/Groundwater/Carbon Steel System
Keum, D.K. ; Cho, W.J. ; Hahn, P.S. ;
Nuclear Engineering and Technology, volume 29, issue 2, 1997, Pages 127~137
Equilibrium concentrations of major elements in an underground repository with a capacity of 100,000 drums have been simulated using the geochemical computer code (EQMOD). The simulation has been carried out at the conditions of pH 12 to 13.5, and Eh 520 and -520 mV. Solubilities of magnesium and calcium decrease with the increase of pH. The solubility of iron increases with pH at Eh -520 mV of reducing environment while it almost entirely exists as the precipitate of Fe(OH)
(s) at Eh 520 mV of oxidizing environment. All of cobalt and nickel are predicted to be dissolved in the liquid phase regardless of pH since the solubility limit is greater than the total concentration. In the case of cesium and strontium, all forms of both ions are present in the liquid phase because they have negligible sorption capacity on cement and large solubility under disposal atmosphere. And thus the total concentration determines the equilibrium concentration. Adsorbed amount of iodide and carbonate are dependent on adsorption capacity and adsorption equilibrium constant. Especially, the calcite turns out to be a solubility-limiting phase on the carbonate system. In order to validate the model, the equilibrium concentrations measured for a number of systems which consist of iron, cement, synthetic groundwater and radionuclides are compared with those predicted by the model. The concentrations between the model and the experiment of nonadsorptive elements cesium, strontium, cobalt nickel and iron, are well agreed. It indicates that the assumptions and the thermodynamic data in this work are valid. Using the adsorption equilibrium constant as a free parameter, the experimental data of iodide and carbonate have been fitted to the model. The model is in a good agreement with the experimental data of the iodide system.
Flare Test and Stress Analysis of Alloy 600/690 Tubes
Kim, W. G. ; J. Jang ; I. H. Kuk ;
Nuclear Engineering and Technology, volume 29, issue 2, 1997, Pages 138~147
Korean-made alloys 600 and 690 tubes were evaluated by flare tests according to ASTM standards, and acting stresses during the test ore analyzed. All the tubes, including alloys 600 and 690 tubes with various heat treatment conditions, satisfied the requirement with 30 or 35750.D expansion. Axial stresses in alloy 690 tubes were higher than those in alloy 600 ones and the gap increased gradually with flaring percentage(F.P, %). Assuming the tubes as the rigid-perfectly plastic body, a stress equation was obtained using modified Tresca's yield criterion. Also microstructural change of the flared tubes was discussed with the acting stresses.
Design of a New Capsule Controlling Neutron Flux and Fluence and Temperature of lest Specimen
Choo, Kee-Nam ; Kang, Young-Hwan ; Taiji Hoshiya ; Motoji Niimi ; Takashi Saito ;
Nuclear Engineering and Technology, volume 29, issue 2, 1997, Pages 148~157
A new capsule that has a unique structure in which the test environments including neutron flux and fluence, and irradiation temperature can be controlled precisely during irradiation, was conceptually designed. The capsule structure and instrumentation were successfully designed according to the JMTR's standard procedures of capsule design. Based on the target irradiation, the details of the irradiation such as neutron fluence and irradiation temperature ore calculated and the related capsule safety was evaluated. In addition, the effects of design parameters including the changes in inner-capsule configuration, heater capacity, and Helium gas pressure on the specimen temperature were analyzed with a computer program. Through these thermal and strength evaluations, this capsule was proved to be safe during the irradiation in the JMTR.
Numerical Analysis on Letdown System Performance Test for YGN 3
Seo, Ho-Taek ; Sohn, Suk-Whun ; Seo, Jong-Tae ; Boo, Jung-Sook ;
Nuclear Engineering and Technology, volume 29, issue 2, 1997, Pages 158~166
Integrated performance test of Chemical and Volume Control System was successfully performed in 1994. However, an extensive effort to correct hardware and software problems in the letdown line was required mainly due to the lack of adequate simulation code to predict the test accurately. Although the LTC computer code was used during the YGN 3'||'&'||'4 NSSS design process, the code can not satisfactorily predict the test due to it insufficient letdown line modeling. This study developed a numerical model to simulate the letdown test by modifying the current LTC code, and then verified the model by comparing with the test data. The comparison shows that the modified LTC computer code can predict the transient behavior of letdown system lese very well. Especially, the model was verified to be able to predict the "Stiction (composition of stick and friction)" phenomena which caused instantaneous fluctuations in the letdown backpressure and flowrate. Therefore, it is concluded that the modified LTC computer code with the ability of calculating the "Stiction" phenomena will be very useful for future plant design and test predictions.predictions.
Closed-Loop Timing Controller Design for Control Rod Drive Mechanism (CRDM) Control System in Pressurized Water Reactor
Kim, Byeong-Moon ; Joon Lyou ;
Nuclear Engineering and Technology, volume 29, issue 2, 1997, Pages 167~174
The method that the operating condition of Control Rod Drive Mechanism (CRDM) can be monitored without mounting sensors within CRDM housing was developed, and by using this developed method the closed-loop controller for the CRDM was designed which can optimize the performance and maximize the reliability of CRDM operation. Neural network is utilized as pattern recognition engine in detecting CRDM actuation. In this paper, most problems in previous open loop system are resolved. The control algorithms for closed-loop system ore developed and implemented within the hardware of timing controller based on microprocessor. All functions in the timing controller ore verified by means of real time CRDM simulator. The results show that the timing controller performs its intended functions properly.
Water-Side Oxide Layer Thickness Measurement of the Irradiated PWR Fuel Rod by ECT Method
Park, Kwang-June ; Chun, Yong-Bum ;
Nuclear Engineering and Technology, volume 29, issue 2, 1997, Pages 175~180
It has been known that eater-side corrosion of fuel rods in nuclear reactor is accompanied with the metallic loss of wall thickness and hydrogen pickup in the fuel dadding tube. The fuel dad corrosion is one of the major factors to be controlled to maintain the fuel integrity during reactor operation. An oxide later thickness measuring device equipped with ECT probe system was developed by KAERI, and whose performance test was carried out in NDT(Non-destructive Test) hot-cell or PIE(Post Irradiation Examination) Facility. At first, the calibration/performance test was executed for the unirradiated standard specimen rod fabricated with several kinds of plastic thin films whose thickness ore predetermined, and the result of which showed a good precision within 10% of discrepancy. And then, hot test us peformed for the irradiated fuel rod selectively extracted from J44 fuel assembly discharged from Kori Unit-2. The data obtained with this device were compared with the metallographic result obtained from destructive examination in PIEF hot-cell on the same fuel rod to verify the validity of the measurement data.