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  • In-Service Inspection Service for Steam Generator Tubes
    Steam Generator is one of main components of Nuclear Power Plant. Steam Generator is a kind of Heat Exchanger. Heat is transferred from water heated from Reactor flowing the inside of Steam Generator tubes into water flowing in the outside of the tubes. And then water flowing in the outside of the tubes is finally transformed into steam. The generated steam provides the driving power of Turbine-Generator generating electricity.
    Steam Generator tubes are gradually weakened because of wearing, erosion, corrosion, stress, etc. So the integrity of tubes shall be verified using eddy current examination.

    Steam Generator Tube In-service Inspection is the legal inspection by Korea Atomic Act. According to the regulatory guide 2008-23 of the Ministry of Education, Science, and Technology, eddy current examination against Steam Generator tubes shall be performed to verify the integrity of the tubes, and to take the necessary follow-up actions, and to provide the bases for the establishment of the next inspection plan by analysing the flaw trend from the results of eddy current examination.
    ISI Service for Pipes, Components and Structures
    This Service is to verify the integrity of pipes, components and structures classified as safety class facilities using nondestructive examination (UT, MT, PT, VT) in accordance with the applicable Codes and Standards, and to take the necessary follow-up actions, and to provide the bases for the establishment of the next inspection plan by analysing the flaw trend from the results of eddy current examination.

    Nondestructive Examination Methods for this ISI Inspection Services are as follows; 1. Ultrasonic Examination : at the welding area of pipes and pressure vessels, etc. 2. Magnetic Particle Examination : at the welding area of pipes and support structures, etc. 3. Liquid Penetrant Examination : at the welding area of pipes and support structures, etc. 4. Visual Examination : at the welding area of pipes and support structures, containment vessels, etc.
    ISI Service for Reactor Vessel
    This inspection is legal inspection by Korea Atomic Act, and is to verify the integrity of Reactor vessel. The results of this inspection provide the data for the necessary follow-up actions and the bases for the establishment of the next inspection plan are provided.
    Visual Inspection Service for the Penetration Pipe of upper and lower Reactor Head.
    The safety of Reactor can be secured by verifying the integrity of the related parts using visual inspection against the penetration pipe of the upper and lower Reactor head and base material.
    Eddy current examination Service for the control rods of Westing House Type NPP.
    Reactor RCCA(Rod Cluster Control Assembly) functions the reactivity control and shutdown of Reactor. RCCA is composed with tubes put internally the absorbing material made of Ag-In-Cd alloy and capped with end-plug at the both edge, and isolated from coolant.

    Wear can be caused at the outside of tubes by the contact with guide things because of the vibration of coolant flow in the Reactor before the starting of Reactor operation.
    And Control Rod End Plugs inserted into Nuclear Fuel Assembly during operation can be shortened the lifetime due to flaw, such as crack by neutron effect.
    So the integrity of RCCA is analysed periodically by performing ECT to improve the reliability of RCCA operation.
    Eddy Current Examination Service for the Condenser Tubes.
    Eddy Current Examination Service for the Condenser Tubes is performed to maintain the integrity of power plant and to improve the rate of operation by preventing the problem of Condenser tube leakage.
    NonDestructive Testing
    Nondestructive testing asks "Is there something wrong with this material?" Various performance and proof tests, in contrast, ask "Does this component work?" This is the reason that it is not considered nondestructive testing when an inspector checks a circuit by running electric current through it. Hydrostatic pressure testing is usually proof testing and intrinsically not nondestructive testing. Acoustic emission testing used to monitor changes in a pressure vessel's integrity during hydrostatic testing is nondestructive testing.
    Another gray area that invites various interpretations in defining nondestructive testing is that of future usefulness. Some material investigations involve taking a sample of the inspected part for testing that is inherently destructive. A noncritical part of a pressure vessel may be scraped or shaved to get a sample for electron microscopy, for example. Although future usefulness of the vessel is not impaired by the loss of material, the procedure is inherently destructive and the shaving itself - in one sense the true "test object" - has been removed from service permanently.
    The idea of future usefulness is relevant to the quality control practice of sampling. Sampling (that is, the use of less than 100 percent inspection to draw inferences about the unsampled lots) is nondestructive testing if the tested sample is returned to service. If the steel is tested to verify the alloy in some bolts that can then be returned to service, then the test is nondestructive. In contrast, even if spectroscopy used in the chemical testing of many fluids is inherently nondestructive, the process is destructive if the test samples are discarded after testing.
    Hardness testing by indentation provides an interesting test case for the definition of nondestructive testing. Hardness testing machines look somewhat like drill presses. The applied force is controlled as the bit is lowered to make a small dent in the surface of the test piece. Then the diameter or depth of the dent is measured. The force applied is correlated with the dent size to provide a measurement of surface hardness. The future usefulness of the test piece is not impaired, except in rare cases when a high degree of surface quality is important. However, because the piece's contour is altered, the test is rarely considered nondestructive. A nondestructive alternative to this hardness test could be the use of electromagnetic nondestructive testing.
    Uitrasonic Testing
    Ultrasonic testing is a method that detects internal and surface flaws. It can detect inclusions in steel such as silicate and sulfide. It can find cracks which can occur in production and in service by fatigue. It can discover other flaws such as pipe, shrink and porosity which are common in casting applications. In addition to these flaw detection capabilities, ultrasonic testing can also measure physical parameters such as density, thickness and elastic modules.
    Magnetic particle Testing
    Magnetic particle testing is applied to alloys. It is most commonly used for inspecting extrusions, castings and forgings, heat treatment, machining and polishing. It is the method that decides defects visually by shapess which magnetic particles are attracted and formed when applying magnetic particle to test object,

    magnetizing by Ac or Dc.
    Liquid Penetrant Testing
    Liquid penetrant testing is a method used to detect surface flaws on large surface areas. It is very time consuming, economical and can be applied to a large number of components and materials. It can also be used to reveal surface connected flaws.
    Eddy Current Testing
    Eddy current testing is especially designed to test nonmagnetic Tube, which provides useful information to decide the time of estimating remnant life, deterioration, repairing, replacement and so on by detecting defects such as corrosion, erosion, dent, pin hole, material changing which happen to internal and external side of tube for Condenser, Heat Exchanger.
    Leak Test
    Leak testing is a method reveals the defects by the flow of gas or liquid in or out of the test specimen. The presence of leaks can be presented by water or gas seepage, or by change in pressure. It is used for inspecting vessels, storage tanks and pipeline.