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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 30, Issue 6 - Dec 1998
Volume 30, Issue 5 - Oct 1998
Volume 30, Issue 4 - Aug 1998
Volume 30, Issue 3 - Jun 1998
Volume 30, Issue 2 - Apr 1998
Volume 30, Issue 1 - Feb 1998
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Verification and Sensitivity Analysis on the Elastic Stiffness of the Leaf Type Holddown Spring Assembly
Song, Kee-Nam ;
Nuclear Engineering and Technology, volume 30, issue 4, 1998, Pages 287~297
The elastic stiffness formula of leaf type holddown spring(HDS) assembly is verified by comparing the values of elastic stiffness with the characteristic test results of the HDS's specimens. The comparisons show that the derived elastic stiffness formula is useful in reliably estimating the elastic stiffness of leaf type HDS assembly. The elastic stiffness sensitivity of leaf type HDS assembly is analyzed using the formula and its gradient vectors obtained from the mid-point formula. As a result of sensitivity analysis, the elastic stiffness sensitivity with respect to each design variable is quantified and design variables of large sensitivity are identified. Among the design variables, leaf thickness is identified as the most sensitive design variable to the elastic stiffness of leaf type HDS assembly. In addition, the elastic stiffness sensitivity, with respect to design variable, is in power-law type correlation to the base thickness of the leaf.
A Communication Method Between Distributed Control System and Function Test Facility Using TCP/IP and Shared Memory
Kim, Jung-Soo ; Jung, Chul-Hwan ; Kim, Jung-Taek ; Lee, Dong-Young ; Ham, Chang-Sik ;
Nuclear Engineering and Technology, volume 30, issue 4, 1998, Pages 298~307
In order to design mutual communication between a distributed control system and a function test facility, we used the Inter-Process Communication(IPC) in two systems and Transmission Control Protocol/Internet Protocol(TCP/IP) protocol. The data from the function test facility are put in the shared memory using an IPC, which is then accessed by the distributed control system through an Application Program Interface(API). The server in the function test facility includes two processes(one for sending and one for receiving), which are generated by the fork function from the client signal. The client in the distributed control system includes two separate programs(one for receiving and one for sending).
INSTORE : A PC-Based Database Program for Occupational Radiation Exposure of a Nuclear Power Plant
Cho, Yeong-Ho ; Kang, Chang-Sun ; Mun, Ju-Hyung ; Kim, Hak-Su ;
Nuclear Engineering and Technology, volume 30, issue 4, 1998, Pages 308~317
Ensuring occupational radiation exposure(ORE) as low as is reasonably achievable(ALARA) has been one of very important requirements in a nuclear power plant. It is well known that about 70 percent of occupational dose has incurred from maintenance jobs in the outage period. To reduce occupational dose effectively, the high-dose jobs in the outage period should be identified with their dose reduction potentials and methods. In this study, a PC-based ORE database program, INSTORE, is developed to evaluate ORE doses in individual jobs, and the ORE data of Kori Units 3 and 4 are assembled to the database. Based on customary job classification, radiation work is classified into 26 main jobs which comprise 61 detailed jobs, and occupational doses are assessed according to each detailed job. As a result, high-dose jobs are identified with dose reduction priority in terms of collective ORE dose. It is recommended that adeqaute dose reduction methods for these jobs should be prepared to improve their working conditions and procedures.
Hydrogen Absorption Behavior of Zr-2.5Nb Pressure Tubes in Wolsong Unit 1
Choo, Kee-Nam ; Kwon, Sang-Chul ; Kim, Young-Suk ;
Nuclear Engineering and Technology, volume 30, issue 4, 1998, Pages 318~327
The deuterium uptake behavior of Zr-2.5Nb pressure tubes in Wolsong Unit 1 was analyzed in terms of longitudinal location, operation time, and coolant temperature. The results were compared with those obtained from Canadian CANDU reactors. The amount of deuterium uptake was higher at the outlet part than at the inlet part and was also higher when subjected to a longer operation time and a higher coolant temperature. The hydrogen uptake of Zr-2.5Nb in a hydrogen gas atmosphere was dependent on the microstructure of the alloy. The aged Zr-2.5Nb consisting of
-Nb phases showed higher hydrogen uptake than that consisting of
-Zr phases. The hydrogen in the alloy decreased the rate of oxidation. This could be explained in terms of the cathodic controlled reaction of Zr-2.5Nb oxidation.
Turbulent Flow in an Axially Finned Rod Bundle with Spacer Grids
Chung, H.J. ; Cho, S. ; Chun, S.Y. ; Yang, S.K. ; Chung, M.K. ;
Nuclear Engineering and Technology, volume 30, issue 4, 1998, Pages 328~341
This paper presents in detail the hydraulic characteristic measurements using LDV(Laser Doppler Velocimetry) in subchannels of a HANARO, KAERI research reactor, fuel bundle. The fuel bundle consists of 18 axially finned rods with 3 spacer grids and has a cylindrical configuration. Axial velocity and turbulent intensity were measured. The effects of the spacer grids on the turbulent flow were investigated using the experimental results. Pressure drops for each component of the fuel bundle were measured, and the friction factors of the fuel bundle and the loss coefficients for the spacer grids were estimated from the measured pressure drops. The turbulent thermal mixing phenomena were discussed.
Nuclear Design Feasibility of the Soluble Boron Free PWR Core
Kim, Jong-Chae ; Kim, Myung-Hyun ; Lee, Un-Chul ; Kim, Young-Jin ;
Nuclear Engineering and Technology, volume 30, issue 4, 1998, Pages 342~352
A nuclear design feasibility of soluble boron free(SBF core for the medium-sized(600MWe) PWR was investigated. The result conformed that soluble boron free operation could be performed by using current PWR proven technologies. Westinghouse advanced reactor, AP-600 was chosen as a design prototype. Design modification was applied for the assembly design with burnable poison and control rod absorber material. In order to control excess reactivity, large amount of gadolinia integral burnable poison rods were used and B4C was used as a control rod absorber material. For control of bottom shift axial power shape due to high temperature feedback in SBF core, axial zoning of burnable poison was applied to the fuel assemblies design. The combination of enrichment and rod number zoning for burnable poison could make an excess reactivity swing flat within around 1% and these also led effective control on axial power offset and peak pin power, The safety assessment of the designed core was peformed by the calculation of MTC, FTC and shutdown margin. MTC in designed SBF core was greater around 6 times than one of Ulchin unit 3&4. Utilization of enriched BIO(up to 50w1o) in B4C shutdown control rods provided enough shutdown margin as well as subcriticality at cold refueling condition.
Robust Design of Reactor Power Control System with Genetic Algorithm-Applied Weighting Functions
Lee, Yoon-Joon ; Cho, Kyung-Ho ; Kim, Sin ;
Nuclear Engineering and Technology, volume 30, issue 4, 1998, Pages 353~363
algorithms of the mixed weight sensitivity is used for the robust design of the reactor power control system. The mixed weight sensitivity method requires the selection of the proper weighting functions for the loop shaping in frequency domain. The complexity of the system equation and the non-convexity of the problem make it very difficult to determine the weighting functions. The genetic algorithm which is improved and hybridized with the simulated annealing is applied to determine the weighting functions. This approach permits an automatic calculation and the resultant system shows good robustness and performance.
Statistical Evaluation of Fracture Characteristics of RPV Steels in the Ductile-Brittle Transition Temperature Region
Kang, Sung-Sik ; Chi, Se-Hwan ; Hong, Jun-Hwa ;
Nuclear Engineering and Technology, volume 30, issue 4, 1998, Pages 364~376
The statistical analysis method was applied to the evaluation of fracture toughness in the ductile-brittle transition temperature region. Because cleavage fracture in steel is of a statistical nature, fracture toughness data or values show a similar statistical trend. Using the three-parameter Weibull distribution, a fracture toughness vs. temperature curve (K-curve) was directly generated from a set of fracture toughness data at a selected temperature. Charpy V-notch impact energy was also used to obtain the K-curve by a
-CVN (Charpy V-notch energy) correlation. Furthermore, this method was applied to evaluate the neutron irradiation embrittlement of reactor pressure vessel (RPV) steel. Most of the fracture toughness data were within the 95% confidence limits. The prediction of a transition temperature shift by statistical analysis was compared with that from the experimental data.
Detectability and Sizing Ability of Rotating Pancake Coil Technique for Cracks in Steam Generator Tubes
Y. M. Cheong ; K. W. Kang ; Lee, Y. S. ; T. E. Chung ;
Nuclear Engineering and Technology, volume 30, issue 4, 1998, Pages 377~385
Many nuclear power plants have experienced unscheduled shutdown due to the leakage of steam generator tubes. The leakages are normally due to the crack, possibly stress corrosion cracking (SCC) near the tube expansion at the top of tubesheet or at the tangential point of the row-1 U-bend region. The conventional eddy current technique, which makes use of a differential bobbin coil, has been found to be inadequate for the early detection of SCC. During the in-service inspection, therefore, it is a general practice that the rotating pancake coil (RPC) is used for detecting the cracks. Even in using RPC, however, it is difficult to determine the depth of the cracks quantitatively. This paper attempts to determine the detectability and sizing ability of RPC technique for axial or circumferential cracks at the tube expansion region. The simulated cracks with various dimensions were fabricated by electro-discharge machining (EDM) method. Experimental results are discussed with theoretical calculations.