Application of Laser Profilometry for Fitness-for-Service Assessment on Pressure Vessel External Corrosion

2012 ◽  
Author(s):  
Grant Nelson ◽  
Ian Bradley ◽  
Martin Fingerhut ◽  
Deli Yu
Keyword(s):  
Pressure Vessel ◽  
Structural Integrity ◽  
Element Analysis ◽  
Level 3 ◽  
Ultrasonic Techniques ◽  
Laser Profilometry ◽  
External Corrosion ◽  
Inspection Data ◽  
Integrity Analysis

In order to safely extend the life of damaged in-service components, Fitness-For-Service (FFS) assessments are used to evaluate structural integrity. These FFS assessments largely depend upon the quality of the inspection data. Compared to traditional inspection methods such as pit gauge or ultrasonic techniques, laser profilometry provides faster results with higher resolution and accuracy. Improved inspection data enables more precise FFS assessments and leads to fewer unnecessary repairs and non-conservative assessments. This paper examines how laser profilometry measurements were taken of several corrosion areas on the exterior shell of a pressure vessel in order to complete a FFS assessment equivalent to an API 579 Level 2 assessment. The results of the FFS assessment show how laser profilometry data may be used in a detailed structural integrity analysis to consider a vessel safe for continued use. A discussion of how laser profilometry data could also be used for an API 579 Level 3 assessment, using finite element analysis, in areas not acceptable for Level 1, or 2 assessments is included.

Modelling the Fabrication of a Pressure Vessel Toroidal Seal

2007 ◽  
Author(s):  
N. A. Leggatt ◽  
R. Dennis ◽  
P. R. Hurrell ◽  
S. E. Gould ◽  
R. R. Kane
Keyword(s):  
Pressure Vessel ◽  
Structural Integrity ◽  
Creep Behaviour ◽  
Post Weld Heat Treatment ◽  
Element Analysis ◽  
Hardening Law ◽  
Novel Approach ◽  
History Of ◽  
Manufacturing History ◽  
Integrity Analysis

Welding remains the key process in fabricating, as well as repairing, pressure vessel systems. Unfortunately, many manufacturing and through life service problems occur in or near welded regions. The through life integrity of welded components, e.g. distortion, fatigue, fracture, metallurgy and corrosion control remains a key challenge for structural integrity. The work reported in this paper investigates the complex manufacture and assembly of a pressure vessel toroidal seal. The seal is first created by depositing a series of austenitic welds onto a ferritic pressure vessel to build up a plinth, thus forming a transition weld. The transition weld is then subject to a high temperature Post Weld Heat Treatment (PWHT) to stress relieve the welds and to temper the HAZ in the welds. An austenitic toroidal ring is positioned onto the plinths and welded in place thus forming the toroidal seal. The seal is manufactured from a 347 austenitic stainless steel comprising good ductility and corrosion resistance. The manufacture of the seal is simulated using 2D axisymmetric finite element analysis that are available to support both the design and integrity analysis of welded components. As well as the inherent residual stresses associated with welding, additional effects are important, for instance the austenitic to ferritic transition welds between the vessel body and plinths. This paper presents a novel approach to the simulation of weld metal deposition that is ideally suited to the modelling of transition welds and subsequent PWHT. The plinth welds undergo PWHT and so the creep behaviour of the welds is simulated. A series of intermittent as well as end of manufacture PWHT’s are investigated. Additionally the choice of material hardening law for the austenic weldment is studied. The full manufacturing history of the seal is taken into account within the analysis including welding, component machining and component geometry fit up.

Casing Design for an Oxygen Concentrator

1999 ◽  
Author(s):  
Stephanie H. Swindle ◽  
Beth A. Todd ◽  
James F. Cuttino
Keyword(s):  
Quality Of Life ◽  
Structural Integrity ◽  
Chronic Obstructive ◽  
Gas Mixture ◽  
Improve Quality ◽  
Chronic Obstructive Pulmonary Disorder ◽  
Element Analysis ◽  
Pulmonary Disorder ◽  
Oxygen Concentrator

Abstract Human bodies depend on a steady flow of oxygen for the heart and lungs. When a person has Chronic Obstructive Pulmonary Disorder (COPD), a device called an oxygen concentrator can be used to improve quality of life. An oxygen concentrator is an electrically powered device that takes in room air and converts it to an oxygen rich gas mixture suitable for breathing. Although a few models are battery powered, oxygen concentrators are not easily portable because they are bulky and weigh between 25–50 lbs. In this study, components were identified for re design to reduce the overall weight of the device. For instance, the concentrator casing was identified as its heaviest component. Using finite element analysis, changes in wall thickness and dimensions can be investigated to reduce weight while maintaining structural integrity. By reducing the weight of the casing, the oxygen concentrator will be easier to transport.

scholarly journals Probabilistic Structural Integrity Analysis of Boiling Water Reactor Pressure Vessel under Low Temperature Overpressure Event

2015 ◽  
Vol 2015 ◽  
pp. 1-9
Author(s):  
Hsoung-Wei Chou ◽  
Chin-Cheng Huang
Keyword(s):  
Low Temperature ◽  
Pressure Vessel ◽  
Structural Integrity ◽  
Reactor Pressure Vessel ◽  
Boiling Water ◽  
Boiling Water Reactor ◽  
Analysis Model ◽  
Water Reactor ◽  
Integrity Analysis ◽  
Reactor Pressure

The probabilistic structural integrity of a Taiwan domestic boiling water reactor pressure vessel has been evaluated by the probabilistic fracture mechanics analysis. First, the analysis model was built for the beltline region of the reactor pressure vessel considering the plant specific data. Meanwhile, the flaw models which comprehensively simulate all kinds of preexisting flaws along the vessel wall were employed here. The low temperature overpressure transient which has been concluded to be the severest accident for a boiling water reactor pressure vessel was considered as the loading condition. It is indicated that the fracture mostly happens near the fusion-line area of axial welds but with negligible failure risk. The calculated results indicate that the domestic reactor pressure vessel has sufficient structural integrity until doubling of the present end-of-license operation.

Structural Integrity Analysis of Nuclear Power Plant Pressure Vessel Penetration Nozzle Repaired

2016 ◽  
Vol 853 ◽  
pp. 346-350
Author(s):  
Lin Wei Ma ◽  
Jia Sheng He ◽  
An Qing Shu ◽  
Xiao Tao Zheng ◽  
Yan Wang
Keyword(s):  
Power Plant ◽  
Nuclear Power Plant ◽  
Pressure Vessel ◽  
Nuclear Power ◽  
Structural Integrity ◽  
Degradation Mechanism ◽  
Design Requirement ◽  
Original Design ◽  
Asme Code ◽  
Integrity Analysis

Primary water stress corrosion cracking (PWSCC) has been observed in CRDM nozzles, BMI nozzles and other penetration nozzles. The industry has used the repair method of replacement of nozzles fabricated of Alloy 690. After the replacement of the nozzle, the structural integrity analysis of new nozzle and welds should be performed to ensure the pressure boundary compliance with the original design requirement. In this paper, the pressurizer top head instrument nozzle of PWR nuclear power plant is evaluated as a typical pressure vessel penetration nozzle. The results showed that the repaired nozzle satisfies the ASME Code design requirement and the crack growth of the postulated flaw in 40 years of the nuclear plant life is acceptable.PWSCC degradation mechanism has been observed in CRDM nozzles, BMI nozzles and other penetration nozzles [1]. In some nuclear power plants built in China earlier, such as DAYABAY nuclear power plant and QINSHAN nuclear power plant, PWSCC degradation mechanism has been found in CRDM nozzle welds which manufactured of Alloy 600 and welded of Alloy 82/182[2]. The repair of the degraded nozzles is the popular choice for the nuclear power plant owners. After the replacement of the nozzle, the structural integrity analysis of new nozzle and welds should be performed to ensure the pressure boundary compliance with the original design requirement. In this paper, the pressurizer top head nozzle of PWR nuclear power plant is evaluated as a typical pressure vessel penetration nozzle. Stress intensities were conservatively determined for pressure and applicable thermal transients and compared to the allowable values of the ASME Code, Section III. Thermal stress of the transients was obtained from 3D finite element model (FEM). Residual stress of J-groove weld was obtained from 2D FEM analysis and used for fracture mechanics analysis. All of the analysis showed that the repaired nozzle satisfies the ASME Code design requirement and the crack growth of the postulated flaw in 40 years of the nuclear plant life is acceptable.

My Pipes Are Corroding! When Should I Repair? Getting the Answers You Need for Maintaining Pipeline Integrity

2015 ◽  
Author(s):  
Michael Turnquist
Keyword(s):  
Finite Element ◽  
Life Assessment ◽  
Metal Loss ◽  
Element Analysis ◽  
Element Mesh ◽  
Level 3 ◽  
External Corrosion ◽  
Remaining Life Assessment ◽  
Ultrasonic Thickness

This case study exhibits how groundbreaking inspection methodologies combined with innovative computational analysis practices demonstrate the value of conducting fitness-for-service (FFS) assessments on sectional piping. In this instance, a fitness-for-service assessment was performed on two sections of piping experiencing external corrosion at the pipe-to-elbow seam welds. A full external scan and spot ultrasonic thickness (UT) readings were used to create the corroded geometry and verify accurate measurement of the remaining thicknesses in various corroded locations. This allowed for the actual corroded profiles to be accurately modeled using finite element analysis (FEA). Complications were present when modeling the observed metal loss. Through the use of innovative finite element mesh generation practices, the actual measured corroded geometry was modeled without the need for over-conservative geometric simplification. A Level 3 FFS assessment was then performed in addition to a remaining life assessment based on observed corrosion rates. The result of this analysis was that the piping could remain in service for at least two additional years before needing repair.

scholarly journals Plate Pack Structural Integrity Analysis for Plate and Shell Heat Exchangers at High Temperatures and Pressures

2020 ◽  
Vol 12 (2) ◽  
pp. 168781401990124
Author(s):  
Noh Hyun-Seok ◽  
Cho Jong-Rae ◽  
Song Seung-Hun
Keyword(s):  
Heat Transfer ◽  
Heat Exchangers ◽  
Structural Integrity ◽  
Element Analysis ◽  
High Temperature And Pressure ◽  
Plate And Shell ◽  
Section Viii ◽  
Temperature And Pressure ◽  
Integrity Analysis ◽  
Division 2

Heat exchangers capable of withstanding high temperature and pressure are required to achieve increased thermal efficiency and compactness. A welded plate and shell heat exchanger, developed for applications involving pressures up to 150 bar and temperatures up to 600 °C, has exhibited advantages that allow a more wide use of heat exchangers. However, few studies have tested the structural integrity of the plate pack of this design. In this paper, the structural integrity of the heat transfer pack was tested using finite element analysis. Elastic and elastic-plastic models were applied for one set of heat transfer plates, while layers of two and four plates were used to verify the effect of the boundary conditions. The plate results were evaluated according to the ASME Boiler and Pressure Vessel Code, Section VIII Division 2. Finally, the function of the end plate in the plate packs was numerically studied.

Structural Integrity Analysis of GLCC© Separator Inlet

2016 ◽  
Author(s):  
Srinivas Swaroop Kolla ◽  
Ram S. Mohan ◽  
Ovadia Shoham
Keyword(s):  
Structural Integrity ◽  
Low Cost ◽  
Attractive Alternative ◽  
Inlet Section ◽  
Element Analysis ◽  
Wide Range ◽  
Section Design ◽  
Fea Simulation ◽  
Integrity Analysis ◽  
Proper Operation

The gas-liquid cylindrical cyclone (GLCC©) is a simple, compact and low-cost separator, which provides an economically attractive alternative to conventional gravity based separators over a wide range of applications. As shown in Figure 1, over the past 20 years more than 6,000 GLCC’s have been installed around the world by the Petroleum and related industries. However, to-date no systematic study has been carried out on its structural integrity. The GLCC inlet section design is a key parameter, which is crucial for its performance and proper operation. This paper presents Finite Element Analysis (FEA) simulation results aimed at investigating the effect of various parameters on the inlet section structural integrity. Finally, recommendations on design modifications are presented, directed at strengthening the inlet section.

scholarly journals A Finite Element Analysis for Improvement of Shaping Process of Complex-Shaped Large-Size Silicon Carbide Mirrors

Materials ◽  
2021 ◽  
Vol 14 (15) ◽  
pp. 4136
Author(s):  
Ling Qiao ◽  
Jingchuan Zhu ◽  
Yingnan Wan ◽  
Congcong Cui ◽  
Ge Zhang
Keyword(s):  
Silicon Carbide ◽  
Finite Element ◽  
Structural Integrity ◽  
Casting Process ◽  
Green Body ◽  
Technological Parameters ◽  
Element Analysis ◽  
Gel Casting ◽  
Generation Mechanisms

In the gel-casting process, the proper selection of technological parameters is crucial for the final quality of a green body. In this work, the finite element method is used to investigate the mold characteristics in the gel-casting process, and the typical flow behaviors under different conditions are presented. Based on the distribution characteristics of temperature, pressure and flow field of gel polymer, the simulated results provide some possible reasons for the generation mechanisms of defects. Then, a series of simulations were performed to investigate the effect of process parameters on the molding quality of green gel-cast bodies. The results show that the decreasing loading speed can effectively reduce the number of defects and improve the molding quality. In addition, this paper presents a new technique by applying the exhaust hole to decrease the number of defects and, hence, improve structural integrity. The influence of the loading speed on the mold characteristics is well understood for the gating system with an exhaust hole, which suggests to us appropriate parameters for optimizing the molding design. This work provides a theoretical basis to explicate the generating mechanism of defects involved in the gel-casting process and acquires an optimized technique to produce a silicon carbide green body.

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