• Title/Summary/Keyword: Sharp Flaw

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Development of CANDU Pressure Tube Integrity Evaluation System : Its Application to Delayed Hydride Cracking and Blister (CANDU 압력관에 대한 건선성평가 시스템 개발-지체수소균열 및 블러스터 평가에의 적용)

  • 곽상록;이준성;김영진;박윤원
    • Journal of the Korean Society for Precision Engineering
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    • v.19 no.11
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    • pp.174-182
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    • 2002
  • The integrity evaluation of pressure tube is essential for the safety of CANDU reactor, and integrity must be assured when flaws or contacts between pressure tube and surrounding calandria tube are found. In order to complete the integrity evaluation, not only complicated and iterative calculation procedures but also a lot of data and knowledge are required. For this reason, an integrity evaluation system, which provides an efficient way of the evaluation with the help of attached databases, was developed. The developed system was built on the basis of ASME Sec.? and FFSG issued by the AECL, and applicable for the evaluation of blister, sharp flaw and blunt notch. Delayed hydride cracking and blister evaluation modules are included in the general flaw and notch evaluation module. In order to verify the developed system, several case studies have been performed and the results were compared with those from AECL. A good agreement was observed between those two results.

Development of CANDU Pressure Tube Integrity Evaluation System;Its Application to Sharp Flaw and Blunt Notch (CANDU 압력관에 대한 건전성 평가시스템 개발;예리한 결함 및 둔한 노치에의 적용)

  • Gwak, Sang-Rok;Lee, Jun-Seong;Kim, Yeong-Jin;Park, Yun-Won
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.24 no.1 s.173
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    • pp.206-214
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    • 2000
  • The pressure tube is a major component of the CANDU reactor, which supports nuclear fuel bundle and it's containment vessel. If a flaw is found during the periodic inspection from the pressure tube s. the integrity evaluation must be carried out. and the safety requirements must be satisfied for continued service. In order to complete the integrity evaluation, complicated and iterative calculation procedures are required. Besides, a lot of data and knowledge for the evaluation are required for the entire: integrity evaluation process. For this reason. an integrity evaluation system, which provides efficient of evaluation with the help of attached databases, was developed. The developed system was built on the basis of ASME Sec. XI and FFSG(Fitness For Service Guidelines for zirconium alloy pressure tubes in operating CANDU reactors) issued by the AECL, and covers the delayed hydride cracking(DHC). This system does not only provide various databases including the 3-D finite element analysis results on pressure tubes, inspection data and design specifications but also is compatible with other commercial database software. In order to verify the developed system, several case studies have been performed and the results were compared with those from AECL. A good agreement was observed between those two results.

COMPARISON OF SIGNAL PROCESSING TECHNIQUES FOR UT-NDE ON NUCLEAR POWER PLANTS

  • Lee, Young-Seock;Kim, Se-Dong
    • Proceedings of the Korean Institute of IIIuminating and Electrical Installation Engineers Conference
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    • 2004.11a
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    • pp.359-364
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    • 2004
  • This paper deals with the comparison of signal processing techniques of ultrasonic data. The goal of signal processing is the ultrasonic speckle suppression and the visibility enhancement of flaw-reflected ultrasonic echo. The performance of conventional SSP(split spectrum processing) method and the wavelet denoising method are compared and discussed for tested ultrasonic data. Tested ultrasonic data obtained from the weld area of centrifugal-casted stainless steel material and safe-ending material with holes and notch of variable depths are presented. In experimental results, the outputs of wavelet-based denoising method show the clear and sharp peaks at the positions of flaw-reflected echos comparing with those of SSP method.

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A Study on the Shipbuilding Yard Information System Based on Wireless LAN (Wireless LAN 기반의 조선소 현장 정보시스템에 관한 연구)

  • SEO K. H.;KIM H. M.;KIM S. Y.
    • Journal of Ocean Engineering and Technology
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    • v.19 no.6 s.67
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    • pp.86-91
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    • 2005
  • Regarding some of tire important works in tire shipyard, like tire production process, quality control, and material handling, there are many elements that disturb tire work-flaw. For example, there are mistakes in manufacturing, delay of production, and poor quality. These kinds of disturbances are from tire delay of communication time between tire production field and tire management. Therefore, it would be possible to strengthen tire competitiveness of shipbuilding industries by applying tire information technology based on Wireless Local Area Network (Wireless LAN), in order to establish tire multi-possession of real time production information in limited large shipbuilding yard. In this study, tire construction concept of tire information system, based on Wireless LAN, is proposed to build communication infrastructures in shipyards. The various information regarding shipbuilding inspection, process management, and material flaw are analyzed and constructed to databases in tire middle ware system, as tire platform for using Personal Display Agent (PDA). At last, tire middle ware system, which delivers tire information, is developed by tire C$\sharp$ and Microsoft.net; also, tire PDA application system is structured in WinCE O/S, and is tested and evaluated under tire server linked condition.

Development of Integrity Evaluation System for CANDU Pressure Tube (CANDU 압력관에 대한 건전성 평가 시스템 개발)

  • Kwak, Sang-Log;Lee, Joon-Seong;Kim, Young-Jin;Park, Youn-Won
    • Proceedings of the KSME Conference
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    • 2000.11a
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    • pp.843-848
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    • 2000
  • The pressure tube is a major component of the CANDU reactor, which supports nuclear fuel bundle and it's containment vessel. If a flaw is found during the periodic inspection from the pressure tubes, the integrity evaluation must be carried out, and the safety requirements must be satisfied for continued service. In order to complete the integrity evaluation, complicated and iterative calculation procedures are required. Besides, a lot of data and knowledge for the evaluation are required for the entire integrity evaluation process. For this reason, an integrity evaluation system, which provides efficient way of evaluation with the help of attached databases, was developed. The developed system was built on the basis of ASME Sec. XI and FFSG(Fitness For Service Guidelines for zirconium alloy pressure tubes in operating CANDU reactors) issued by the AECL, and covers the delayed hydride cracking(DHC). Various analysis methods are provided for the integrity evaluation of pressure tube. In order to verify the developed system, several case studies have been performed and the results were compared with those from AECL. A good agreement was observed between those two results.

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Experimental Determination of Stress Intensity Factors by Displacement Freezing Method (變位 凍結法에 의한 應力擴大係數의 實驗的 決定法)

  • 최선호;권재도;서인보
    • Transactions of the Korean Society of Mechanical Engineers
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    • v.7 no.4
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    • pp.434-440
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    • 1983
  • For the determination of stress intensity factors, three methods have been used conventionally; the photoelastic method, the compliance method and the electrical resistance method. These methods, however, have common short coming upon experimental performance; the difficulty of cutting out sharp crack tips and arbitray crack forms similar to the practical one on the specimen. to eliminate this flaw, one of the author previously presented new methods, that is, for the determination of $K_{III}$ mode, the membrane analogy was applied and the slab analogy was used for the determination of $K_{I}$ and $K_{II}$ . The validity of this method was proved through the performance of a series of experiments of which theoretical solution are known.n.n.

Integrity Evaluation System of CANDU Reactor Pressure Tube

  • Kim, Young-Jin;Kwak, Sang-Log;Lee, Joon-Seong;Park, Youn-Won
    • Journal of Mechanical Science and Technology
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    • v.17 no.7
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    • pp.947-957
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    • 2003
  • The pressure tube is a major component of the CANDU reactor, which supports nuclear fuel bundle. In order to complete the integrity evaluation of pressure tube, expert knowledge, iterative calculation procedures and a lot of input data are required. More over, results of integrity assessment may be different according to the evaluation method. For this reason, an integrity evaluation system, which provides efficient way of evaluation with the help of attached database, was developed. The present system was built on the basis of 3D FEM results, ASME Sec. XI, and Fitness For Service Guidelines for CANDU pressure tubes issued by the AECL (Atomic Energy Canada Limited). The present system also covers the delayed hydride cracking and the blister evaluation, which are the characteristics of pressure tube integrity evaluation. In order to verify the present system, several case studies have been performed and the results were compared with those from AECL. A good agreement was observed between those two results.

Integrity Assessment of Sharp Flaw in CANDU Pressure Tube Using Probabilistic Fracture Mechanics (확률론적 파괴역학을 도입한 CANDU 압력관의 예리한 결함에 대한 건전성평가)

  • Lee, Jun-Seong;Gwak, Sang-Rok;Kim, Yeong-Jin;Park, Yun-Won
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.26 no.4
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    • pp.653-659
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    • 2002
  • This paper describes a probabilistic fracture mechanics(PFM) analysis based on Monte Carlo(MC) simulation. In the analysis of CANDU pressure tube, the depth and aspect ratio of an initial semi-elliptical surface crack, a fracture toughness value and delayed hydride cracking(DHC) velocity are assumed to be probabilistic variables. As an example, some failure probabilities of piping and CANDU pressure tube are calculated using MC method with the stratified sampling MC technique, taking analysis conditions of normal operations. In the stratified MC simulation, a sampling space of probabilistic variables is divided into a number of small cells. For the verification of analysis results, a comparison study of the PFM analysis using other commercial code is carried out and a good agreement was observed between those results.