• Title/Summary/Keyword: piping material

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Evaluation of Creep Behaviors of Alloy 690 Steam Generator Tubing Material (Alloy 690 증기발생기 전열관 재료의 크리프 거동 평가)

  • Kim, Jong Min;Kim, Woo Gon;Kim, Min Chul
    • Transactions of the Korean Society of Pressure Vessels and Piping
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    • v.15 no.2
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    • pp.64-70
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    • 2019
  • In recent years, attention has been paid to the integrity of steam generator (SG) tubes due to severe accident and beyond design basis accident conditions. In these transient conditions, steam generator tubes may be damaged by high temperature and pressure, which might result in a risk of fission products being released to the environment due to the failure. Alloy 690 which has increased the Cr content has been replaced for the SG tube due to its high corrosion resistance against stress corrosion cracking (SCC). However, there is lack of research on the high temperature creep rupture and life prediction model of Alloy 690. In this study, creep test was performed to estimate the high temperature creep rupture life of Alloy 690 using tube specimens. Based on manufacturer's creep data and creep test results performed in this study, creep life prediction was carried out using the Larson-Miller (LM) Parameter, Orr-Sherby-Dorn (OSD) parameter, Manson-Haford (MH) parameter, and Wilshire's approach. And a hyperbolic sine (sinh) function to determine master curves in LM, OSD and MH parameter methods was used for improving the creep life estimation of Alloy 690 material.

Eddy Current Testing of Type-439 S/S Tube of MSR in Turbine System (터빈 습분분리재열기 Type-439 스테인리스강 튜브 와전류검사)

  • Lee, Heejong;Cho, Chanhee;Jung, Jeehong;Moon, Gyoonyoung
    • Transactions of the Korean Society of Pressure Vessels and Piping
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    • v.4 no.2
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    • pp.50-56
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    • 2008
  • The tubes in heat exchanger are typically made of copper alloy, stainless steel, carbon steel, titanium alloy material. Type-439 ferritic stainless steel is ferromagnetic material, and furnish higher heat transfer rates than austenitic stainless steels and higher resistance to corrosion-induced flaws. Ferritic stainless steel can be found in low-pressure(LP) feedwater heaters and moisture separator reheaters(MSRs) in turbine system. LP feedwater heaters generally utilize thin wall Type-439 stainless steel tubing, whereas MSRs typically employ a heavier wall tubing with integral fins. Service-induced damage can occur on the O.D(outside diameter) surface of Type-439 ferritic stainless steel tubing which is employed for MSRs tubing, and the most typical damage mechanism is vibration-induced tube-to-TSP(tube support plate) wear and fatigue cracking. The wear has been reported that occurs mainly on the OD surface. Accordingly, in this study, we have evaluated the flaw sizing capability of magnetic saturation eddy current technique using magnetic saturation probe and flawed specimen.

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Evaluation of APR1400 Steam Generator Tube-to-Tubesheet Contact Area Residual Stresses

  • KIPTISIA, Wycliffe Kiprotich;NAMGUNG, Ihn
    • Transactions of the Korean Society of Pressure Vessels and Piping
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    • v.15 no.1
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    • pp.18-27
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    • 2019
  • The Advanced Power Reactor 1400 (APR1400) Steam Generator (SG) uses alloy 690 as a tube material and SA-508 Grade 3 Class 1 as a tubesheet material to form tube-to-tubesheet joint through hydraulic expansion process. In this paper, the residual stresses in the SG tube-to-tubesheet contact area was investigated by applying Model-Based System Engineering (MBSE) methodology and the V-model. The use of MBSE transform system description into diagrams which clearly describe the logical interaction between functions hence minimizes the risk of ambiguity. A theoretical and Finite Element Methodology (FEM) was used to assess and compare the residual stresses in the tube-to-tubesheet contact area. Additionally, the axial strength of the tube to tubesheet joint based on the pull-out force against the contact joint force was evaluated and recommended optimum autofrettage pressure to minimize residual stresses in the transition zone given. A single U-tube hole and tubesheet with ligament thickness was taken as a single cylinder and plane strain condition was assumed. An iterative method was used in FEM simulation to find the limit autofrettage pressure at which pull-out force and contact force are of the same magnitude. The joint contact force was estimated to be 20 times more than the pull-out force and the limit autofrettage pressure was estimated to be 141.85MPa.

Investigation on the thermal butt fusion performance of the buried high density polyethylene piping in nuclear power plant

  • Kim, Jong-Sung;Oh, Young-Jin;Choi, Sun-Woong;Jang, Changheui
    • Nuclear Engineering and Technology
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    • v.51 no.4
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    • pp.1142-1153
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    • 2019
  • This paper presents the effect of fusion procedure on the fusion performance of the thermal butt fusion in the safety class III buried HDPE piping per various tests performed, including high speed tensile impact, free bend, blunt notched tensile, notched creep, and PENT tests. The suitability of fusion joints and qualification procedures was evaluated by comparing test results from the base material and buttfusion joints. From the notched tensile test result, it was found that the fused joints have much lower toughness than the base material. It was also identified that the notched tensile test is more desirable than the high speed tensile impact and free bend tests presented in the ASME Code Case N-755-3 as a fusion qualification test method. In addition, with regard to the single low-pressure fusion joint performances, the procedure given by the ISO 21307 was determined to be better that the one specified in the Code Case N-755-3.

A Case Study on Construction Cost Comparison for On-Site Construction and Off-Site Construction of Plant Project (플랜트 건설의 현장시공 및 모듈시공에 대한 공사비 비교 사례연구 - Pipe Rack을 대상으로 공사비 산정 -)

  • Kang, Hyun Wook
    • Korean Journal of Construction Engineering and Management
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    • v.24 no.4
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    • pp.25-34
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    • 2023
  • The purpose of this study is to calculate and compare construction costs for On-Site Construction and Off-Site Construction in Plant Project. For this purpose, the target for calculating the construction cost was limited to the Pipe Rack(Steel Structure and Piping). The results derived according to the purpose of the study are as follows. 1)The direct construction cost for On-Site Pipe Rack construction was KRW 56 billion, with Steel Structure KRW 25.1 billion and Piping KRW 30.8 billion won. 2)Comparing the rate of change between On-Site Construction and Off-Site Construction, material costs increased by 1.9% and expenses by 192.1%, but labor costs decreased by -9.1%, resulting in a total direct construction cost increase of 8.4%. These results can be used as reference data to check the current status of the increase or decrease in construction costs when constructing Pipe Racks as Off-Site Construction.

A Simple Finite Element Modeling Method for Leak-Before-Break Crack Analysis of Pipe with Overlay Dissimilar Metal Weldments (이종금속 오버레이 용접 배관의 파단전누설균열 해석을 위한 단순 유한요소 모델링 방법)

  • Kim, Maan Won;Park, Young Sup
    • Transactions of the Korean Society of Pressure Vessels and Piping
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    • v.9 no.1
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    • pp.70-76
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    • 2013
  • Several finite element models for the leak-before-break (LBB) assessment of overlay dissimilar metal weldment were constructed and analyzed to develop a simple finite element modeling method. The J-integral, crack opening displacement (COD) and J-integral distribution along the crack front in thickness direction due to the applied moment were obtained from the analysis results of the constructed finite element models, and studied compared to the previous literatures. It is concluded that the modeling with base material only is simple and produces a slightly conservative results compared to the complex modeling composed with weld metal and base metal in the calculation of J-integrals and COD values which are used for the calculation of fracture toughness and postulated leakage crack length respectively.

A Study on the Crack Depth Sizing Using ECT Technique for Martensitic Stainless Steel (ECT를 이용한 마르텐사이트 재질의 균열결함 깊이측정 연구)

  • Kim, Wang-Bae;Cheon, Keun-Young
    • Transactions of the Korean Society of Pressure Vessels and Piping
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    • v.5 no.2
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    • pp.7-12
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    • 2009
  • The flaws detected by the non-destructive surface test methods shall be sized by means of the volumetric test such as an UT(ultrasonic test) or an ECT(eddy current test) for the purpose of analyzing and repairing them. It is generally known that the ECT is a comparatively effective technique for the small size cracks which are located shallowly from the surface. On this study, the ECT technique was tried to size the depth of the crack-like EDM notches, and it is identified that the ECT is an appropriate depth sizing technique for the shallow cracks less than 3mm in the Martensitic CA6NM material.

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Evaluation of Material Properties due to Thermal Embrittlement in CF8M Cast Austenitic Stainless Steel (CF8M 주조 오스테나이트 스테인리스강의 열취화에 따른 재료물성치 평가)

  • Kim, C.;Park, H.B.;Jin, T.E.;Jeong, I.S.;Seok, C.S.;Park, J.S.
    • Proceedings of the KSME Conference
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    • 2003.04a
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    • pp.131-136
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    • 2003
  • CF8M cast austenitic stainless steel is used for several components such as primary coolant piping, elbow, pump casing, and valve bodies in light water reactors. These components are subject to thermal aging at the reactor operating temperature. Thermal aging results in spinodal decomposition of the delta-ferrite leading to increased strength and decreased toughness. In this study, three kinds of the aged CF8M specimen were prepared using an artificially simulated aging method. The objective of this study is to summarize the method of estimating ferrite contents, Charpy impact energy and J-R curve, and to evaluate the thermal embrittlement of the CF8M cast austenitic stainless steel piping used in the domestic nuclear power plants.

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Effect of Finite Element Model on the Integrity Evaluation of Nuclear Piping (유한요소 해석모델이 원자력 배관의 건전성 평가에 미치는 영향)

  • Huh, Nam-Su;Kim, Young-Jin;Pyo, Chang-Ryul;Yu, Young-Jin
    • Journal of the Korean Society of Safety
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    • v.15 no.2
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    • pp.51-58
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    • 2000
  • Recently, the J/T analysis based on elastic-plastic finite element analysis is popularly used in the nuclear industry to assess the integrity of a cracked pipe. The objective of this paper is to evaluate the effect of stress-strain curve for weld metal, variation of crack incremental length(${\delta}a$), and crack face pressure on the J/T analysis result. For this purpose, a parametric analysis was performed and the results calculated from finite element analysis were compared with those from the piping experimental data(stainless steel weldment pipe with circumferential through-wall crack). The numerical result using base metal material property is in agreement with the experimental one and the maximum load is decreased as the ${\delta}a$ for J/T analysis is increased.

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High-Temperature Structural Analysis on the Small-Scale PHE Prototype using Weld Properties (용접물성치를 고려한 소형 공정열교환기 시제품의 고온구조해석)

  • Song, Kee-Nam;Hong, Sung-Deok;Park, Hong-Yoon
    • Transactions of the Korean Society of Pressure Vessels and Piping
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    • v.8 no.2
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    • pp.1-6
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    • 2012
  • A PHE (Process Heat Exchanger) in a nuclear hydrogen system is a key component required to transfer heat energy of $950^{\circ}C$ generated in a VHTR (Very High Temperature gas cooled Reactor) to the chemical reaction that yields a large quantity of hydrogen. A small-scale PHE prototype made of Hastelloy-X is being tested in a small-scale gas loop at Korea Atomic Energy Research Institute. Previous research on the high-temperature structural analysis of the small-scale PHE prototype had been performed only using parent material properties. In this study, high-temperature structural analysis using weld properties in weld zone was performed and the analysis results compared with the previous research.