• Title/Summary/Keyword: Interface Piping System

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Seismic Performance Evaluation of Piping System Crossing the Isolation Interface in Seismically Isolated NPP (면진 원전 면진-비면진구간 연결 배관의 내진성능 평가)

  • Hahm, Daegi;Park, Junhee;Choi, In-Kil
    • Journal of the Earthquake Engineering Society of Korea
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    • v.18 no.3
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    • pp.141-150
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    • 2014
  • A methodology to evaluate the seismic performance of interface piping systems that cross the isolation interface in the seismically isolated nuclear power plant (NPP) was developed. The developed methodology was applied to the safety-related interface piping system to demonstrate the seismic performance of the target piping system. Not only the seismic performance for the design level earthquakes but also the performance for the beyond design level earthquakes were evaluated. Two artificial seismic ground input motions which were matched to the design response spectra and two historical earthquake ground motions were used for the seismic analysis of piping system. The preliminary performance evaluation results show that the excessive relative displacements can occur in the seismically isolated piping system. If the input ground motion contained relatively high energy in the low frequency region, we could find that the stress response of the piping system exceed the allowable stress level even though the intensity of the input ground motion is equal to the design level earthquake. The structural responses and seismic performances of piping system were varied sensitively with respect to the intensities and frequency contents of input ground motions. Therefore, for the application of isolation system to NPPs and the verification of the safety of piping system, the seismic performance of the piping system subjected to the earthquake at the target NPP site should be evaluated firstly.

Big data-based piping material analysis framework in offshore structure for contract design

  • Oh, Min-Jae;Roh, Myung-Il;Park, Sung-Woo;Chun, Do-Hyun;Myung, Sehyun
    • Ocean Systems Engineering
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    • v.9 no.1
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    • pp.79-95
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    • 2019
  • The material analysis of an offshore structure is generally conducted in the contract design phase for the price quotation of a new offshore project. This analysis is conducted manually by an engineer, which is time-consuming and can lead to inaccurate results, because the data size from previous projects is too large, and there are so many materials to consider. In this study, the piping materials in an offshore structure are analyzed for contract design using a big data framework. The big data technologies used include HDFS (Hadoop Distributed File System) for data saving, Hive and HBase for the database to handle the saved data, Spark and Kylin for data processing, and Zeppelin for user interface and visualization. The analyzed results show that the proposed big data framework can reduce the efforts put toward contract design in the estimation of the piping material cost.

Development of Nuclear Piping Integriry Expert System (II) -System Development and Case Studies- (원자력배관 건전성평가 전문가시스템 개발(II) -시스템 개발 및 사례해석-)

  • Jeon, Hyeon-Gyu;Heo, Nam-Su;Kim, Yeong-Jin;Park, Yun-Won;Choe, Yeong-Hwan
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.25 no.6
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    • pp.1015-1022
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    • 2001
  • The objective of this paper is to develop an expert system called NPIES for nuclear piping integrity. This paper describes the structure and the development strategy of the NPIES system. The NPIES system consists of 3 part; the data input part, the analysis part and the output part. The data input part consists of the material properties database module and the suer interface module. The analysis part consists of the LEFM, CDFD, J/T, limit load modules and the 12 analysis routines for different cracks and loading conditions are provided respectively. Analysis results are presented to screen, printer and text file in the output part. Several case studies on circumferentially cracked piping were performed to evaluate the accuracy and the usefulness of the code. Maximum piping loads predicted by the NPIES system agreed well with those by the 3-dimensional finite element analysis. In addition, even if the material properties were not fully given, the NPIES system provided reasonable evaluation results with the predicted material properties inferred from the material properties database module.

Effect of Nozzle on Leak-Before-Break Analysis Result of Nuclear Piping (노즐이 원자력 배관의 파단전누설 해석 결과에 미치는 영향)

  • Kim, Yeong-Jin;Heo, Nam-Su;Gwak, Dong-Ok;Yu, Yeong-Jun;Pyo, Chang-Ryul
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.24 no.11
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    • pp.2796-2803
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    • 2000
  • For traditional Leak-Before-Break(LBB) analyses, symmetric conditions were assumed for a pipe-nozzle interface to simplify the analysis in calculating J-integral. However. this assumption could result in an overly conservative design criteria for a pipe-nozzle interface, Since the pipe-nozzle interface is asymmetric due to the difference of stiffness between pipe and nozzle, it is required to develop a new methodology considering the nozzle effect. The objective of this paper is to evaluate the effect of nozzle no the development of LBB design criteria for nuclear pipings. For this purpose, extensive finite element analysis were performed to evaluate the effect of nozzle on Crack Opening Area(COA), Detectable Leakage Crack(DLC) length and J-integral values. In conclusion, it was proven that the application of LBB concept could be extended for more nuclear piping system by considering the nozzle.

Development of a Batch-mode-based Comparison System for 3D Piping CAD Models of Offshore Plants (Aveva Marine과 SmartMarine 3D간의 해양 플랜트 3D 배관 CAD 모델의 배치모드 기반 비교 시스템 개발)

  • Lee, Jaesun;Kim, Byung Chul;Cheon, Sanguk;Cho, Mincheol;Lee, Gwang;Mun, Duhwan
    • Korean Journal of Computational Design and Engineering
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    • v.21 no.1
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    • pp.78-89
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    • 2016
  • When a plant owner requests plant 3D CAD models in the format that a shipbuilding company does not use, the shipyard manually re-models plant 3D CAD models according to the owner's requirement. Therefore, it is important to develop a technology to compare the re-modeled plant 3D CAD models with original ones and to quantitatively evaluate similarity between two models. In the previous study, we developed a graphic user interface (GUI)-based comparison system where a user evaluates similarity between original and re-modeled plant 3D CAD models for piping design at the level of unit. However, an offshore plant consists of thousands of units and thus a system which compares several plant 3D CAD models at unit-level without human intervention is necessary. For this, we developed a new batch model comparison system which automatically evaluates similarity of several unit-level plant 3D CAD models using an extensible markup language (XML) file storing file location and name data about a set of plant 3D CAD models. This paper suggests system configuration of a batch-mode-based comparison system and discusses its core functions. For the verification of the developed system, comparison experiments for offshore plant 3D piping CAD models using the system were performed. From the experiments, we confirmed that similarities for several plant 3D CAD models at unit-level were evaluated without human intervention.

Closed-Form Solutions for Stress Intensity Factor and Elastic Crack Opening Displacement for Circumferential Through-Wall Cracks in the Interface between an Elbow and a Straight Pipe under Internal Pressure (내압이 작용하는 직관과 엘보우의 경계면에 존재하는 원주방향 관통균열의 응력확대계수 및 탄성 균열열림변위 예측식)

  • Jang, Youn-Young;Jeong, Jae-Uk;Huh, Nam-Su;Kim, Ki-Seok;Cho, Woo-Yeon
    • Journal of the Korean Society of Manufacturing Technology Engineers
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    • v.24 no.5
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    • pp.553-560
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    • 2015
  • Fracture mechanics analysis for cracked pipes is essential for applying the leak-before-break (LBB) concept to nuclear piping design. For LBB assessment, crack instability and leak rate should be predicted accurately for through-wall cracked pipes. In a nuclear piping system, elbows are connected with straight pipes by circumferential welding; this weld region is often considered a critical location. Hence, accurate crack assessment is necessary for cracks in the interface between elbows and straight pipes. In this study, the stress intensity factor (SIF) and elastic crack opening displacement (COD) were estimated through detailed 3D elastic finite element (FE) analyses. Based on the results, closed-form solutions of shape factors for calculating the SIFs and elastic CODs were proposed for circumferential through-wall cracks in the abovementioned interfaces under internal pressure. In addition, the effect of the elbow on shape factors was investigated by comparing the results with the existing solutions for a straight pipe.

Analytical Study on the Discharge Transients of a Steam Discharging Pipe (증기방출배관의 급격과도현상에 대한 해석적 연구)

  • 조봉현;김환열;강형석;배윤영;이계복
    • Journal of Energy Engineering
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    • v.7 no.2
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    • pp.202-208
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    • 1998
  • As in the other industrial processes, a nuclear power plant involves a steam relieving process through which condensable steam is discharged and condensed in a subcooled pool. An analysis of steam discharge transients was carried out using the method of characteristics to determine the flow characteristics and dynamic loads of piping that are used for structural design of the piping and its supports. The analysis included not only the steam flow rate but also the flow rates of the air and water which originally exist in the pipe. The analytical model was developed for a uniform pipe with friction through which the flow was discharged into a suppression pool. Including the combinations of system elements such as reservoir, valve and branching pipe lines. The piping flow characteristics and dynamic loads were calculated by varying system pressure, pipe length, and submergence depth. It was found that the dynamic load, water clearing time and water clearing velocity at the water/air interface were dependent not only on the system pressure and temperature but also on the pipe length and submergence depth.

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Pipe Atuo-Routing with Design Knowledge-base (선박용 배관의 Auto-Routing을 위한 설계 전문가 시스템)

  • 강상섭;명세현;한순흥
    • Korean Journal of Computational Design and Engineering
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    • v.2 no.1
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    • pp.1-10
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    • 1997
  • Finding the optimum route of ship's pipes is complicated and time-consuming process. Experience of designers is the main tool in this process. To reduce design man-hours and human errors a design expert system shell and a geometric modeler is used to automate the design process. In this paper, a framework of the intelligent CAD system for pipe auto-routing is suggested, which consists of general-purpose expert system shell and a geometric modeler. The design expert system and the geometric modeling kernel have been integrated. The CADDS5 of Computervision is used as the overall CAD environment. The Nexpert Object of Neuron Data is used as the expert system shell. The CADDS5 ISSM is used as the interface that creates and modifies geometric models of pipes. Existing algorithms for the routing problem have been analyzed. Most of them are to solve the 2-D circuit routing problems. Ship piping system, specially within the engine room, is a complicated, large scale 3-D routing problem. Methods of expert system have been used to find the route of ship pipes on the main deck.

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Failure Criteria of a 6-Inch Carbon Steel Pipe Elbow According to Deformation Angle Measurement Positions (변형각의 측정 위치에 따른 6인치 탄소강관엘보의 파괴 기준)

  • Yun, Da Woon;Jeon, Bub Gyu;Chang, Sung Jin;Park, Dong Uk;Kim, Sung Wan
    • Journal of the Earthquake Engineering Society of Korea
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    • v.26 no.1
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    • pp.13-22
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    • 2022
  • This study proposes a low-cycle fatigue life derived from measurement points on pipe elbows, which are components that are vulnerable to seismic load in the interface piping systems of nuclear power plants that use seismic isolation systems. In order to quantitatively define limit states regarding leakage, i.e., actual failure caused by low-cycle fatigue, in-plane cyclic loading tests were performed using a sine wave of constant amplitude. The test specimens consisted of SCH40 6-inch carbon steel pipe elbows and straight pipes, and an image processing method was used to measure the nonlinear behavior of the test specimens. The leakage lines caused by low-cycle fatigue and the low-cycle fatigue curves were compared and analyzed using the relationship between the relative deformation angles, which were measured based on each of the measurement points on the straight pipe, and the moment, which was measured at the center of the pipe elbow. Damage indices based on the combination of ductility and dissipation energy at each measurement point were used to quantitatively express the time at which leakage occurs due to through-wall cracking in the pipe elbow.

Software Package for Pipe Hydraulics Calculation for Single and Two Phase Flow (배관 유동의 주요 변수계산을 위한 소프트웨어 시스템의 개발)

  • Chang, Jaehun;Lee, Gunhee;Jung, Minyoung;Baek, Heumkyung;Lee, Changha;Oh, Min
    • Korean Chemical Engineering Research
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    • v.57 no.5
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    • pp.628-636
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    • 2019
  • In various industrial processes, piping serves as a link between unit processes and is an essential installation for internal flow. Therefore, the optimum design of the piping system is very important in terms of safety and cost, which requires the estimation of the pressure drop, flow rate, pipe size, etc. in the piping system. In this study, we developed a software that determines pressure drop, flow rate, and pipe size when any two of these design variables are known. We categorized the flows into single phase, homogeneous two phase, and separated two phase flows, and applied suitable calculation models accordingly. We also constructed a system library for the calculation of the pipe material, relative roughness, fluid property, and friction coefficients to minimize user input. We further created a costing library according to the piping material for the calculation of the investment cost of the pipe per unit length. We implemented all these functions in an integrated environment using a graphical user interface for user convenience, and C # programming language. Finally, we verified the accuracy of the software using literature data and examples from an industrial process with obtained deviations of 1% and 8.8% for the single phase and two-phase models.