• Transactions of the Korean Society for Noise and Vibration Engineering
• /
• v.20 no.9
• /
• pp.828-833
• /
• 2010

Steam leakage is one of the major issues for the structural fracture of pipes of nuclear power plants. Therefore a method to inspect a large area of piping systems quickly and accurately is needed. In this paper, we proposed the method for the detecting steam leakage by using image signal processing. Our basic idea come from heat shimmer which shine with a soft light that looks as if it shakes slightly. To test the performance of this technique, experiments have been performed for simple heat source and steam generator. Results show that the proposed technique is quite powerful in the steam leak detection.

• Proceedings of the Korea Society for Energy Engineering kosee Conference
• /
• 1994.05a
• /
• pp.138-143
• /
• 1994

A simplified steam generator model has been developed for the simulation of the operational transients of CANDU nuclear power plant. For the analysis of the secondary side, a control volume approach is used and the flow conservation equations are applied for each control volume. The typical steam generator control logic such as the level control and the pressure control are incorporated into the steam generator model with appropriate interface conditions. The steam line including ASDV, CSDV, and governor valve also has been modeled. Test results for typical operational transient case show reasonable transient behavior of steam generator in a real time basis, which is promising for a CANDU engineering simulator.

• Nuclear Engineering and Technology
• /
• v.29 no.1
• /
• pp.85-91
• /
• 1997

Cross-flow existing in a shell-and-tube steam generator can cause a tube to vibrate. There are four regions subjected to cross-flow in Yonggwang units 3 and 4 (YGN 3 and 4) steam generators, which are of the same design as the steam generators for Palo Verde nuclear power plant Palo Verde units 1 and 2 steam generators have experienced localized oar at the comers of the cold side recirculating fluid inlet regions. A number of design modifications were made to preclude tube failure in specific regions of YGN 3 and 4 steam generators. Therefore, flow induced vibration experiments were done to determine the vibration magnitude of tubes in the economizer tube free lane region. The objective of this experiment is to demonstrate that the tube displacement is less than 0.01 inch rms at 100% of full power flow and to quantify the remaining design margin at 120ft and 140% of full power flow.

• Journal of computational fluids engineering
• /
• v.20 no.3
• /
• pp.87-93
• /
• 2015

In this study, a numerical analysis was performed to simulate the thermal-hydraulic response of the secondary side of a steam generator(SG) model equipped with an orifice-type SG outlet flow restrictor to a main steam line break(MSLB) at a pressurized water reactor(PWR) plant. The SG analysis model includes the SG upper steam space and the part of the main steam pipe between the SG outlet and the broken pipe end. By comparing the numerical calculation results for the present SG model to those obtained for a simple SG model having no flow restrictor, the effects of the flow restrictor on the thermal-hydraulic response of SG to the MSLB were investigated.

• Plant Journal
• /
• v.4 no.3
• /
• pp.60-65
• /
• 2008

Power plant industry has been developed at high-capacity, high-technology, and innovation. Steam turbine became the most useful equipment that dominate more than 50% of all the world electricity production. And developed new materials of the turbine blade and extended length of the turbine last blade brought reform in steam turbine performance upgrade. In this paper, when do partial load driving in high-capacity steam turbine, optimum driving method found whether there is something. In operating steam turbine, there is a lot of loss from secondary wake and throttle of the 1st stage nozzle by the biggest leading factor that load fluctuation affects in high-pressure steam turbine performance. Effect of internal efficiency by 1 stage nozzle is the biggest here, but here fluid flow and flow analysis were not yet examined closely definitely. So, Analyzed design data and acceptance performance test result to applying subcritical pressure drum type 560 MW, supercritical-pressure once through type 500 MW, and 800 MW steam turbines actually. In conclusion, at partial load driving, partial arc admission(PAA) is more efficient than full arc admission(FAA) efficiency. This is judged by because increase being proportional with gross energy of stream that is pressure - available energy if pressure of stream that is flowed in to the turbine increases, available energy becomes maximum and turbine efficiency improves. Therefore, turbine performance is that preview that first stage performance fell if decline is serious in partial load because first stage performance changes according to load.

• Korean Chemical Engineering Research
• /
• v.46 no.1
• /
• pp.147-155
• /
• 2008

The economics of most chemical plants are heavily dependent upon the management of the utilities used in the plants. The utilities are supplied by the centralized utility system of the plant. Among the various utilities the steam is by far the most important energy source and the management of the electricity and the process water are greatly affected by the steam. Therefore it is necessary to educate students and new employees the basic concepts about the effective distribution of the utilities and the fundamental strategies to apply the concepts in actual plant operations. The OOUS (Optimal Operation of Utility System) is an GUI educational system designed to educate the effective generation of the steam and the optimal steam distribution schemes within short period. The OOUS deals with various utility equipments and processes and shows how to save operation costs by displaying the optimal operation conditions based on the process models and the operational knowledgebase.

• Journal of Korean Elementary Science Education
• /
• v.40 no.4
• /
• pp.433-442
• /
• 2021

The purpose of this study is to develop an artificial-intelligence STEAM program for real-time interactive online class for elementary science and to analyze its effect on science academic achievement and creative problem-solving ability. The applied unit was 'Life of plant', a 4th grade science subject with high difficulty in teaching and learning mainly by memorization. The theme of the program is 'Creating a doctor of plant artificial intelligence chatbot'. The results of this study were as follows: The program developed in this study had a positive effect on elementary school students' science academic achievement and creative problem-solving ability. Therefore, the artificial intelligence STEAM program for elementary science interactive online class is effective in improving students' scientific academic achievement and creative problem-solving ability, and further research on artificial intelligence STEAM education theory, method, and practice is required.

• Proceedings of the KIEE Conference
• /
• 1996.07a
• /
• pp.83-85
• /
• 1996

Major cause of defects in steam generator tubes at nuclear power plant is the accumulation of magnetite and other byproducts of corrosion in the crevice gap between support plates and tubes. Since damaged tubes result in contamination of the secondary coolant by the radioactive primary coolant, they represent a safety hazard. Early detection of magnetite buildup is, therefore, imperative in order to take remedial measures such as chemical flushing. Although the eddy current testing is being used for the inspection of steam generator tubes, the interpretation of resulting signals is generally a difficult task. This paper uses the phase of sensor coil emf as the test signal to find a way of easier signal interpretation. Numerical study using FEM shows that the shape of resulting signal is good for identifying the relative position of the probe to the support plate, and for discreminating the different shapes and degrees of magnetite buildup in the crevice gap region.

• Journal of the Korean Society for Nondestructive Testing
• /
• v.28 no.3
• /
• pp.263-272
• /
• 2008

Many technical methods are used for nondestructive testing field for solid materials. Among those, ultrasonic inspection methods are widely used and one of the popular methods involves the extraction of an appropriate set of features followed by the use of a neural network for the classification of the signals in the feature space. This paper describes an approach which uses LMS method to determine the coordinates of the ultrasonic probe followed by the use of SAFT with centroid technique to estimate the location of the ultrasonic reflector. The method is employed for classifying UT-NDE signals from the steam generator tubes in a nuclear power plant. The classification results are presented for the ultrasonic signals from cracks and deposits within steam generator tubes.

• The Transactions of The Korean Institute of Electrical Engineers
• /
• v.56 no.7
• /
• pp.1224-1230
• /
• 2007

In this paper, we study the classification of defects at steam generator tube in nuclear power plant using eddy current testing (ECT). We consider 4 defect patterns of SG tube: I-In type, I-Out type, V-In type, and V-Out type. Through numerical analysis program based on finite element modeling, 400 ECT signals are generated by varying width and depth of each defect type. In order to improve the classification performance, we propose new feature extraction technique. After extracting new features from the generated ECT signals, multi-layer perceptron is used to classify the defect patterns. Through the computer simulation study, it is shown that the proposed method achieves 100% classification success rate while the previous method yields 91% success rate.