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Andrew Ruminski - One of the best experts on this subject based on the ideXlab platform.

  • Failure Analysis of a Low-Temperature Carbon Steel Pipe from a Nuclear Power Station Cooling Water System
    Journal of Failure Analysis and Prevention, 2015
    Co-Authors: Andrew Ruminski
    Abstract:

    This paper presents the results of a failure examination on an ASTM A106 Carbon Steel Pipe from component cooling water system at a nuclear power station. The Pipe was associated with a large motor air cooler. Through-wall cracking occurred after over three decades of total service and approximately one decade following a refurbishment. The Pipe was filled with demineralized water and operated at a temperature

  • failure analysis of a low temperature Carbon Steel Pipe from a nuclear power station cooling water system
    Journal of Failure Analysis and Prevention, 2015
    Co-Authors: Andrew Ruminski
    Abstract:

    This paper presents the results of a failure examination on an ASTM A106 Carbon Steel Pipe from component cooling water system at a nuclear power station. The Pipe was associated with a large motor air cooler. Through-wall cracking occurred after over three decades of total service and approximately one decade following a refurbishment. The Pipe was filled with demineralized water and operated at a temperature <40 °C. Sections of the failed Pipe along with a similar non-leaking section were examined with light optical microscopy, scanning electron microscopy, energy dispersive spectroscopy, mass spectrometry, a gas analyzing furnace, and a microhardness indenter to provide data about the failure mechanism and the base material. The results of the study showed that the failure was the result of outside diameter initiated, intergranular stress corrosion cracking. The failure occurred in the vicinity of a weld in the heat-affected zone (HAZ) of the Pipe. Other areas of non-through-wall cracking were also observed in the Pipes outside of the HAZ.

Joonhyun Lee - One of the best experts on this subject based on the ideXlab platform.

  • assessment of wall thinning in Carbon Steel Pipe by using laser generated guided wave
    Nuclear Engineering and Technology, 2010
    Co-Authors: Doyoun Kim, Younho Cho, Joonhyun Lee
    Abstract:

    The objective of this research is to estimate the crack location and size of a Carbon Steel Pipe by using a laser ultrasound guided wave for the wall thinning evaluation of an elbow. The wall thinning of the Carbon Steel Pipe is one of the most serious problems in nuclear power plants, especially the wall thinning of the Carbon Steel elbow caused by Flow-Accelerated Corrosion (FAC). Therefore, a non-destructive inspection method of elbow is essential for the nuclear power plants to operate safely. The specimens used in this study were Carbon Steel elbows, which represented the main elements of real nuclear power plants. The shape of the wall thinning was an oval with a width of 120mm, a length of 80mm, and a depth of 5mm. The L(0,1) and L(0,2) modes variation of the ultrasound guided wave signal is obtained from the response of the laser generation/air-coupled detection ultrasonic hybrid system represent the characteristics of the defect. The trends of these characteristics and signal processing were used to estimate the size and location of wall thinning.

  • Evaluation of Corrosion in Carbon Steel Pipes by Laser-Generated Guided Wave
    IUTAM Symposium on Recent Advances of Acoustic Waves in Solids, 2010
    Co-Authors: Youn Kim, Younho Cho, Joonhyun Lee, Jaesun Lee, Jan Drewes Achenbach
    Abstract:

    The objective of this research is to locate and evaluate wall thinning in Pipe elbow by a non-contact guided wave technique with laser source as a transmitter and air-bone transducer as a receiver, respectively. Wall thinning of Carbon Steel Pipe is one of the most serious problems in nuclear industry; especially the one in Carbon Steel Pipe elbow caused by FAC (Flow-Accelerated Corrosion). Therefore, development of a robust NDE technique for the Pipe elbows is essential for safe operation of nuclear power plants. Specimens used in this study were Carbon Steel which is widely used in real nuclear power plants. The geometry of wall thinning was given as 120mm extent, 80mm-length and 5mm-depth. The L(0,1) and L(0,2) dominant modes group shows a promising variation in the ultrasound guided wave data analysis based on the response obtained by the laser generation/air-coupled detection system. The trends of these characteristics and subsequent signal processing were used to estimate the size and location of wall thinning.

  • ANALYSIS OF ROUND ROBIN TEST FOR ULTRASONIC THICKNESS MEASUREMENT OF WALL THINNED Pipe IN NUCLEAR POWER PLANT
    AIP Conference Proceedings, 2008
    Co-Authors: Dae-hoon Lee, Joonhyun Lee, Seungjoon Lee, Sung-ho Lee
    Abstract:

    It is well recognized that one of the most serious problems on the maintenance of piping system in Nuclear Power Plants (NPPs) is the wall thinning of Carbon Steel Pipe components. The objective of this research is to verify confidence of wall thinning measurement system by conducting Round Robin Test (RRT). 23 specimens with different size and shape of Pipe were used according to standard practice in RRT. The gage R&R analysis was introduced for each sigma quality level, so that repeatability and reproducibility can be estimated from RRT results.

  • Study on Damage Mechanism of Pipe Using Ultrasonic Wave and Acoustic Emission Technique
    Key Engineering Materials, 2007
    Co-Authors: Jin Kyung Lee, Sang Pill Lee, Joonhyun Lee
    Abstract:

    A study on corrosion evaluation by using ultrasonic waves and acoustic emission technique is presented. The experimental equipment was established to improve the corrosion process of Carbon Steel Pipe. The Carbon Steel Pipe was under 473K temperatures and 10Mpa pressure conditions, and ultrasonic wave and acoustic emission techniques were used to inspect the degree of corrosion after a certain period of time. Ultrasonic bulk waves are limited by the poor time resolution when used in the measurement of corrosion depth in thin wall structures because the corroded surfaces cause unclear echo signal edges. Therefore, in this study, the ultrasonic guided waves were generated on the Pipe because the thickness of Pipe was thin. Various wave modes were subsequently generated on the Pipe to evaluate the implications of corrosion thinning on group velocity, transmission and reflection amplitudes. The amplitudes of the transmitted and the reflected waves are influenced by couplent material. In order to reduce the effect of coupling acoustic emission sensor was used. Acoustic emission technique has lots of parameters to evaluate the corrosion besides amplitude parameter. Among parameters energy, count, and frequency were useful parameters to measure the degree of corrosion inside the Carbon Steel Pipe under 473K temperatures.

  • Evaluation of Wall-Thinning in Pipes Using Laser-Generated Guided Waves
    Key Engineering Materials, 2006
    Co-Authors: Jong-ho Park, Joonhyun Lee, Min Rae Lee
    Abstract:

    Local wall thinning is one of the major causes for the structural fracture of Pipes of nuclear power plants. Therefore, assessment of local wall thinning due to corrosion is an important issue in nondestructive evaluation for the integrity of nuclear power plants. In this study, lasergenerated guided waves were used for Pipe inspection, where a laser beam illuminated through linear slit array was used as the transmitter and the air-coupled transducer was used as the receiver. Slits was used in order to enhance the mode-selectivity of guided waves, since the space of slits is equal to the wavelength of the generated wave. The air-coupled transducer detected the selected single mode by turning its detection angle that was calculated from the relations between the wave propagation velocity in air and the phase velocity in dispersion curves. Experimental results for a 4- mm thick Carbon Steel Pipe showed that the detection of the specific mode was useful in the distinction of the wall-thinning thickness in the Carbon Steel Pipe.

Kyong-ho Chang - One of the best experts on this subject based on the ideXlab platform.

  • Prediction of residual stresses in high strength Carbon Steel Pipe weld considering solid-state phase transformation effects
    Computers & Structures, 2010
    Co-Authors: Chin-hyung Lee, Kyong-ho Chang
    Abstract:

    In this paper, prediction of axial and hoop residual stresses produced in high strength Carbon Steel Pipe weld was made by employing a sequentially coupled 3-D thermal, metallurgical and mechanical FE model. Solid-state phase transformation during welding was incorporated into the FE model by allowing for volumetric changes and the associated changes in yield stress induced by austenitic and martensitic transformations. In the FE model, temperature-dependent thermo-physical and mechanical properties were considered, and phase transformation plasticity was also taken into account. The results showed the importance of incorporating solid-state phase transformation in the simulation of the Pipe welding.

Douglas Munson - One of the best experts on this subject based on the ideXlab platform.

  • Basis of the Fatigue Capacities, Stress Intensification Factors, and Flexibility Factors for High Density Polyethylene Pipe in the ASME Boiler and Pressure Vessel Code, Section III, Division 1
    Volume 4: Codes Standards Licensing and Regulatory Issues; Fuel Cycle Radioactive Waste Management and Decommissioning; Computational Fluid Dynamics (, 2012
    Co-Authors: Timothy M. Adams, Douglas Munson
    Abstract:

    For corroded piping in low temperature systems, such as service water systems in nuclear power plants, replacement of Carbon Steel Pipe with high density polyethylene (HDPE) Pipe is a cost-effective solution. Polyethylene Pipe can be installed at much lower labor costs than Carbon Steel Pipe and HDPE Pipe has a much greater resistance to corrosion. HDPE Pipe has been successfully used in non-safety related systems in nuclear power facilities and is commonly used in other industries such as water mains and natural gas Pipelines. Via Code Case N-755-1, the ASME Boiler and Pressure Vessel Code (BPVC), Section III, Division 1, currently permits the use of non-metallic HDPE piping in buried safety Class 3 piping systems. This paper presents the basis for the fatigue stress values to be used for HDPE in the ASME BPVC Section III, Division 1, Class 3 Construction. This information was developed based on testing support by the Electric Power Research Institute. Stress Intensification Factors (SIF) and flexibility factors for use in the design and analysis of HDPE piping systems in nuclear safety-related applications will be provided in the Code and the basis of these stress intensification and flexibility factors is provided. This data may also be useful for applications of HDPE Pipe in commercial electric power generation facilities and chemical, process, and waste water plants via its possible use in the B31 series piping codes.Copyright © 2012 by ASME

  • Determination of Material Damping Values for High Density Polyethylene Pipe Materials
    Volume 1: Codes and Standards, 2012
    Co-Authors: Douglas Munson, Timothy M. Adams, Siegrid Hall
    Abstract:

    For corroded piping in low temperature systems, such as service water systems in nuclear power plants, replacement of Carbon Steel Pipe with High Density Polyethylene Pipe is a cost-effective solution. Polyethylene Pipe can be installed at much lower labor costs than Carbon Steel Pipe and High Density Polyethylene Pipe has a much greater resistance to corrosion. This paper presents the results of Electric Power Research Institute sponsored testing to determine material damping values for High Density Polyethylene Pipe material. This was determined by experimental methods using the log decrement approach. Cantilevered beam samples were deflected, released and the resulting free vibration response was recorded. The possible relationship of the damping value to the natural frequency and the stress level of the test samples is also studied. The results of the testing are presented along with suggested damping values to be used in the seismic analysis of High Density Polyethylene piping.Copyright © 2012 by ASME

  • Dynamic Testing of High Density Polyethylene Vent and Drain Configurations
    Volume 8: Seismic Engineering, 2012
    Co-Authors: Douglas Munson, Timothy M. Adams, Shawn Nickholds
    Abstract:

    For corroded piping in low temperature systems, such as service water systems in nuclear power plants, replacement of Carbon Steel Pipe with high density polyethylene (HDPE) Pipe is a cost-effective solution. HDPE Pipe can be installed at much lower labor costs than Carbon Steel Pipe, and HDPE Pipe has a much greater resistance to corrosion. This paper presents the results of the seismic testing of selected vent and drain configurations. This testing was conducted to provide proof of the conceptual design of HDPE vent and drain valve configurations. A total of eight representative models of HDPE vent and drain assemblies were designed. The models were subjected to seismic SQURTS spectral acceleration up to maximum shake table limits. The test configurations were then checked for leakage and operability of the valves. The results for these tests, along with the test configurations, are presented. Also presented are the acceleration data observed at various points on the test specimens.Copyright © 2012 by ASME

  • Determination of Tensile Elastic Modulus in High Density Polyethylene Piping at Seismic Strain Rates
    Volume 1: Codes and Standards, 2012
    Co-Authors: Douglas Munson, Timothy M. Adams, Shawn Nickholds
    Abstract:

    For corroded piping in low temperature systems, such as service water systems in nuclear power plants, replacement of Carbon Steel Pipe with High Density Polyethylene Pipe is a cost-effective solution. Polyethylene Pipe can be installed at much lower labor costs than Carbon Steel Pipe and High Density Polyethylene Pipe has a much greater resistance to corrosion. Data was developed by the three testing tasks for use in the seismic design of above ground High Density Polyethylene Piping systems. This paper presents the results of testing to determine the relationship between tensile elastic modulus and strain rates commensurate with seismic loading. This is accomplished by first establishing a seismic strain rate for High Density Polyethlene using detailed finite element analysis. The results of this analysis are used to establish a test matrix tensile testing. Next, tensile tests are conducted using standard ASTM D-638 Type III tensile specimens. The tensile testing is conducted at three pull speeds to establish a basic relationship between tensile elastic modulus and strain rates. This relationship is then used to calculate the modulus at the strain rates expected under seismic loading. This paper presents the results of this testing and the suggested tensile modulus for use in seismic analysis.Copyright © 2012 by ASME

Changkyong-ho - One of the best experts on this subject based on the ideXlab platform.