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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 35, Issue 6 - Dec 2003
Volume 35, Issue 5 - Oct 2003
Volume 35, Issue 4 - Aug 2003
Volume 35, Issue 3 - Jun 2003
Volume 35, Issue 2 - Apr 2003
Volume 35, Issue 1 - Feb 2003
Selecting the target year
Estimation of Beam Mode Frequencies of Co-axial Cylinders Immersed in Fluid by Equivalent Mass Approach
Kim, Tae-Wan ; Park, Suhn ; Park, Keun-Bae ;
Nuclear Engineering and Technology, volume 35, issue 1, 2003, Pages 1~13
In this study, an effective method to estimate the fundamental frequencies of co-axial cylinders immersed in fluid is proposed. The proposed method makes use of the equivalent mass or density that is derived from the added mass matrix caused by the fluid-structure interaction (FSI) phenomenon. The equivalent mass is defined from the added mass matrix based on a 2-D potential flow theory. The theory on two co-axial cylinders extended to the case of three cylinders. To prove the validity of the proposed method, the eigenvalue analyses upon coaxial cylinders coupled with fluid gaps are peformed using the equivalent mass. The analyses results upon various fluid gap is conditions reveal that the present method could provide accurate frequencies and be suitable for expecting the fundamental frequencies of fluid coupled cylinders in beam mode vibration.
Sintering Behavior of
Kim, Keon-Sik ; Song, Kun-Woo ; Yang, Jae-Ho ; Kang, Ki-Won ; Jung, Youn -Ho ; Kim, Gil-Moo ;
Nuclear Engineering and Technology, volume 35, issue 1, 2003, Pages 14~24
This work investigates the effects of Cr
and oxygen potential on grain growth and densification of UO
pellets. Powder mixtures of UO
and 0.03-0.4wt% Cr
were pressed and sintered in 3 different gas atmospheres: the
ratios were 5
In the first gas atmosphere the Cr
contents below 0.2 wt% have an insignificant effect on grain size, but the Cr
contents more than 0.3 wt% promote grain growth in the inner zone of a pellet but not in the outer zone. In both the second and third atmospheres, the grain size increases with the Cr
content. With the same level of Cr
content the grain size is larger in the second atmosphere than in the third. Sintering behavior and developed microstructure are discussed in terms of the reduction of C
to Cr, the dissolution of C
, and liquid phase sintering.
Development of Acoustic Emission Monitoring System for Fault Detection of Thermal Reduction Reactor
Pakk, Gee-Young ; Yoon, Ji-Sup ; Park, Byung-Suk ; Hong, Dong-Hee ; Kim, Young-Hwan ;
Nuclear Engineering and Technology, volume 35, issue 1, 2003, Pages 25~34
The research on the development of the fault monitoring system for the thermal reduction reactor has been performed preliminarily in order to support the successful operation of the thermal reduction reactor. The final task of the development of the fault monitoring system is to assure the integrity of the thermal
reduction reactor by the acoustic emission (AE) method. The objectives of this paper are to identify and characterize the fault-induced signals for the discrimination of the various AE signals acquired during the reactor operation. The AE data acquisition and analysis system was constructed and applied to the fault monitoring of the small- scale reduction reactor, Through the series of experiments, the various signals such as background noise, operating signals, and fault-induced signals were measured and their characteristics were identified, which will be used in the signal discrimination for further application to full-scale thermal reduction reactor.
Evaluation of Neutron Cross Sections for Eu-153, Gd-155 and Gd-157
Lee, Y. D. ; J. H. Chang ;
Nuclear Engineering and Technology, volume 35, issue 1, 2003, Pages 35~44
The neutron induced nuclear data for Eu-153, Gd-155 and Cd-157 are calculated and evaluated in the high energy region. The evaluation procedure for deformed nuclei is setup by using Ecis-Empire codes. The energy dependent optical model potential parameters are searched based on the recent experimental data and applied up to 20 MeV. Optical model, full featured Hauser-Feshbach model and multistep direct and multistep compound model are used in the calculation. The direct-semidirect capture model and the direct coupled-channels contribution to discrete levels are introduced to improve the capture and inelastic scattering cross sections. The theoretically calculated cross sections are compared with the experimental data and the evaluated files. The model-calculated total and capture cross sections are in good agreement with the reference experimental data. The evaluated cross section results are compiled to ENDF-6 format and are expected to improve the ENDF/B-Vl.
Application of Hyperbolic Two-fluids Equations to Reactor Safety Code
Hogon Lim ; Lee, Unchul ; Kim, Kyungdoo ; Lee, Won-Jae ;
Nuclear Engineering and Technology, volume 35, issue 1, 2003, Pages 45~54
A hyperbolic two-phase, two-fluid equation system developed in the previous work has been implemented in an existing nuclear safety analysis code, MARS. Although the implicit treatment of interfacial pressure force term introduced in momentum equation of the hyperbolic equation system is required to enhance the numerical stability, it is very difficult to implement in the code because it is not possible to maintain the existing numerical solution structure. As an alternative, two-step approach with stabilizer momentum equations has been selected. The results of a linear stability analysis by Von-Neumann method show the equivalent stability improvement with fully-implicit solution method. To illustrate the applicability, the new solution scheme has been implemented into the best-estimate thermal-hydraulic analysis code, MARS. This paper also includes the comparisons of the simulation results for the perturbation propagation and water faucet problems using both two-step method and the original solution scheme.
Simulation of Pore Interlinkage in the Rim Region of High Burnup
Koo, Yang-Hyun ; Oh, Je-Yong ; Lee, Byung-Ho ; Cheon, Jin-Sik ; Joo, Hyung-Koo ; Sohn, Dong-Seong ;
Nuclear Engineering and Technology, volume 35, issue 1, 2003, Pages 55~63
Threshold porosity above which fission gas release channels would be formed in the rim egion of high burnup UO
fuel was estimated by the Monte Carlo method and Hoshen-Kopelman algorithm. With the assumption that both rim pore and rim grain can be represented by cube, pore distribution in the rim was simulated 3-dimensionally by the Monte Carlo method according to porosity and pore size distribution. Then, using the Hoshen-Kopelman algorithm, the fraction of open rim pores interlinked to the outer surface of a fuel pellet was derived as a function of rim porosity. The simulation showed that porosity of 24-25% is the threshold above which the number of rim pores forming release channels increases very rapidly. On the other hand, channels would not be formed if the porosity is less than about 23.5%. This is consistent with the observation that, for porosity less than 23.5%, almost no fission gas is released in the rim. However, once the rim porosity reaches beyond 25%, extensive open paths would be developed and considerable fission gas release would start in the rim.
The Explicit Treatment of Model Uncertainties in the Presence of Aleatory and Epistemic Parameter Uncertainties in Risk and Reliability Analysis
Ahn, Kwang-ll ; Yang, Joon-Eon ;
Nuclear Engineering and Technology, volume 35, issue 1, 2003, Pages 64~79
In the risk and reliability analysis of complex technological systems, the primary concern of formal uncertainty analysis is to understand why uncertainties arise, and to evaluate how they impact the results of the analysis. In recent times, many of the uncertainty analyses have focused on parameters of the risk and reliability analysis models, whose values are uncertain in an aleatory or an epistemic way. As the field of parametric uncertainty analysis matures, however, more attention is being paid to the explicit treatment of uncertainties that are addressed in the predictive model itself as well as the accuracy of the predictive model. The essential steps for evaluating impacts of these model uncertainties in the presence of parameter uncertainties are to determine rigorously various sources of uncertainties to be addressed in an underlying model itself and in turn model parameters, based on our state-of-knowledge and relevant evidence. Answering clearly the question of how to characterize and treat explicitly the forgoing different sources of uncertainty is particularly important for practical aspects such as risk and reliability optimization of systems as well as more transparent risk information and decision-making under various uncertainties. The main purpose of this paper is to provide practical guidance for quantitatively treating various model uncertainties that would often be encountered in the risk and reliability modeling process of complex technological systems.
The Step Complexity Measure - Its Meaning and Applications
Park, Jinkyun ; Wondea Jung ; Kim, Jaewhan ; Jaejoo Ha ;
Nuclear Engineering and Technology, volume 35, issue 1, 2003, Pages 80~90
According to related studies, it was revealed that the procedural deviation plays a significant role in initiating accidents or incidents. This means that, to maximize safety, it is indispensable to be able to answer the question of “why the operators deviate from procedures\ulcorner” In this study, the SC (step complexity) measure is introduced to investigate its applicability for studying the procedural deviation, since it was shown that the change of the operators' performance is strongly correlated with the change of SC scores. This means that the SC measure could play an important role for researches related to the procedural deviation, since it is strongly believed that complicated procedures would affect both the operator' performance and the possibility of the procedural deviation. Thus, to ensure this expectation, the meaning of the SC measure is investigated through brief explanations including the necessity, theoretical basis and verification activities of the SC measure. As a result, it is confirmed that the SC measure can be used to explain the change of the operators' performance due to the task complexity implied by procedures. In addition, it seems that the SC measure nay be useful for various purposes, particularly for scrutinizing the relationship between the procedural deviation and complicated procedures.