• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2007.06a
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• pp.179-183
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• 2007

This paper is to implement a low power frequency Shift Keying(FSK) receiver using Xilinx System Generator. The receiver incorporates a 16 point Fast Fourier Transform(FFT) for symbol detection. The design units of the receiver are digital designs for better efficiency and reliability. The receiver functions on one bit data processing and supports data rates 10kbps. In addition CORDIC algorithm is used for avoiding complex multiplications while computing FFT, multiplication of twiddle factor is substituted by rotators. The design and simulation of the receiver is carried out in Simulink, then the simulink model is translated to a hardware model to implement FPGA using Xilinx System Generator and to verify performance.

• Nuclear Engineering and Technology
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• v.48 no.4
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• pp.870-880
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• 2016

A steam generator tube rupture (SGTR) event with a stuck-open safety relief valve constitutes one of the most serious accident sequences in pressurized water reactors (PWRs) because it may create an open path for radioactive aerosol release into the environment. The release may be mitigated by the deposition of fission product particles on a steam generator's (SG's) dry tubes and structures or by scrubbing in the secondary coolant. However, the absence of empirical data, the complexity of the geometry, and the controlling processes have, until recently, made any quantification of retention difficult to justify. As a result, past risk assessment studies typically took little or no credit for aerosol retention in SGTR sequences. To provide these missing data, the Paul Scherrer Institute (PSI) initiated the Aerosol Trapping In Steam GeneraTor (ARTIST) Project, which aimed to thoroughly investigate various aspects of aerosol removal in the secondary side of a breached steam generator. Between 2003 and 2011, the PSI has led the ARTIST Project, which involved intense collaboration between nearly 20 international partners. This summary paper presents key findings of experimental and analytical work conducted at the PSI within the ARTIST program.

• Nuclear Engineering and Technology
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• v.35 no.3
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• pp.179-190
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• 2003

The multiple steam generator tube rupture (SGTR) event scenario with available safety systems was experimentally and analytically evaluated. The experiment was conducted on the large scaled test facility to simulate the multiple SGTR event and investigate the effectiveness of operator actions. As a result, it indicated that the opening of pressurizer power operated relief valve was significantly effective in quickly terminating the primary-to-secondary break flow even for the 6.5 tubes rupture. In the analysis, the recent version of RELAP5 code was assessed with the test data. It indicated that the calculations agreed well with the measured data and that the plant responses such as the water level and relief valve cycling in the damaged steam generator were reasonably predicted. Finally, sensitivity study on the number of ruptured tubes up to 10 tubes was performed to investigate the coolant release into atmosphere. It indicated that the integrated steam mass released was not significantly varied with the number of ruptured tubes although the damaged steam generator was overfilled for more than 3 tubes rupture. These findings are expected to provide useful information in understanding and evaluating the plant ability to mitigate the consequence of multiple SGTR event.

• Journal of Electrical Engineering and Technology
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• v.6 no.3
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• pp.375-383
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• 2011

This paper describes a real-time hardware simulator for a grid-tied Permanent Magnet Synchronous Generator (PMSG) wind power system, which consists of an anemometer, a data logger, a motor-generator set with vector drive, and a back-to-back power converter with a digital signal processor (DSP) controller. The anemometer measures real wind speed, and the data is sent to the data logger to calculate the turbine torque. The calculated torque is sent to the vector drive for the induction motor after it is scaled down to the rated simulator power. The motor generates the mechanical power for the PMSG, and the generated electrical power is connected to the grid through a back-to-back converter. The generator-side converter in a back-to-back converter operates in current control mode to track the maximum power point at the given wind speed. The grid-side converter operates to control the direct current link voltage and to correct the power factor. The developed simulator can be used to analyze various mechanical and electrical characteristics of a grid-tied PMSG wind power system. It can also be utilized to educate students or engineers on the operation of grid-tied PMSG wind power system.

• Nuclear Engineering and Technology
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• v.50 no.1
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• pp.88-96
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• 2018

Concerns over reliability assessments of the main components in nuclear power plants (NPPs) related to aging and continuous operation have increased. The conventional reliability assessment for main components uses experimental correlations under general conditions. Most NPPs have been operating in Korea for a long time, and it is predictable that NPPs operating for the same number of years would show varying extent of aging and degradation. The conventional reliability assessment does not adequately reflect the characteristics of an individual plant. Therefore, the reliability of individual components and an individual plant was estimated according to operating data and conditions. It is essential to reflect aging as a characteristic of individual NPPs, and this is performed through prognostics. To handle this difficulty, in this paper, the general path model/Bayes, a data-based prognostic method, was used to update the reliability estimated from the generic database. As a case study, the authors consider the aging for steam generator tubes in NPPs and demonstrate the suggested methodology with data obtained from the probabilistic algorithm for the steam generator tube assessment program.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2005.05a
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• pp.241-245
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• 2005

This study introduces the wind turbine (W/T) noise evaluation procedure required in the international standard (IEC 61400-11) and monitoring system for the evaluation. Noise emission characteristics of a 750kW W/T generator is investigated. Test and evaluation are performed on J48 W/T model which is under operation in Daekwanryung Wind Test Site. With the noise signal, meteorological data and W/T operational data are monitored in real time by the integrated monitoring system using LabVIEW. From the measured noise data, acoustic power level and tonality of the W/T are estimated under the wind speeds required by the international standard.

• Journal of KSNVE
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• v.10 no.4
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• pp.623-628
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• 2000

This paper presents the automatic plumbness measuring system form improving the accuracy and working time for plumbness measuring of semi-umbrella type hydraulic turbine generator. It is general practice that rotating shaft should run within acceptable vibration limit. In order to obtain more accurate measuring data for single stage shaft on the semi-umbrella type, plumbness approach must be established carefully and accurately. Generally, present plumbness procedure is required several calculation algorithm, laser sensor and data acquisition devices. As a result of application to actual new system it is confirmed that working time could be saved over 80% and accurate measurement data could be acquired.

• 한국초전도학회:학술대회논문집
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• v.10
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• pp.216-220
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• 2000

AC Superconducting Generators (ACSG) are featured by 3D magnetic flux distribution, which decreases in the direction of axis. For this reason, when ACSG is optimal designed, 3D magnetic field analysis is required. This paper proposes 2D Finite Element Analysis (FEA) results normalized by 3D FEA according to the position of armature coil and the ratio of field coil width to axial length in order to reduce the analysis time. By using the proposed data, the reasonable 3D FEA results of ACSG can be only predicted by 2D FEA results. The validity of the 3D FEA results is verified by comparison with the experimental results of 30kVA superconducting synchronous generator.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.4 no.2
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• pp.493-503
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• 2000

There are two types of generators in the MHD generation : linear type Faraday and disk type hall generator. In this paper, it is experimented disk type hall generator. Disk type generator is driven by shock tube that compresses working gas isentropically in a very short time. As a working gas, helium gas seeded with cesium is used. it is difficult to confirm the whole condition thorough oかy experiment because the things happened in MHD generator is very complex. Furthermore we can't how exactly what happen at the inside of generator's channel because the time of generation is very short and working gas flows out very high speed. Expecially it is almost impossible to measure the things occurred in the boundary layer using MHD generation experimental equipment driven shock uk. With above reasons, to know certainly how the several values happened inside disk MHD generator charge, some graphs were drawn linearly through calculation using measured experimental data. For the more, other calculated results which can't be obtained by only experiment are considered in this paper. And these calculated results are compared to experiment data how exactly done the calculation.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.31 no.10
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• pp.1046-1052
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• 2007

Elastic-plastic structural analysis for regenerative cooling chamber of gas generator was performed. Uniaxial tension test was conducted for STS316L at room and high temperature conditions to get the material data necessary for the structural analysis of the chamber which was operated under thermal load and high internal pressure. Physical properties including thermal conductivity, specific heat and thermal expansion were also measured. The structural analysis for four different types of regenerative cooling chamber of gas generator revealed that increased cooling performance decreased the thermal load and strain of the cooling channel structure. The results propose that in order for the regenerative cooling gas generator chamber to have high structural stability with endurance to high mechanical and thermal loads, it is important for the chamber to be designed to have high cooling performance.