Modeling and Level 3 Fitness-for-Service Assessment of a Cylindrical Pressure Vessel with General Metal Loss in Conjunction with the Numerical Thermal Transient Analysis (original) (raw)
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The aim of the present study was to establish integrity of pressurized vessel belonging to Shell Petroleum Development Company in Nigeria that experienced severe external corrosion. Fitness for service methodology according to API 579 using Level 1 and 2 was employed in the analysis of the ageing pressure vessel and the result of the evaluation indicated the external localized corrosion defect was within an acceptable boundary which implied the pressurized vessel was fit to continue in operation and still have 40 years remaining life based on the evaluated external corrosion defect present.
Science and Technology of Nuclear Installations, 2021
e safety-risk pressurized thermal shock (PTS) have on a reactor pressure vessel (RPV) is one of the most important studies for the lifetime ageing management of a reactor. Several studies have investigated PTS induced by postulated accidents and other anticipated transients. However, there is no study that analyzes the effect of PTS induced by one of the most frequent anticipated operational occurrences-inadvertent operation of the safety injection system. In this paper, a sequential Abaqus-FRANC3D simulation method is proposed to study the integrity status of an ageing pressurized water reactor subjected to PTS induced by inadvertent actuation of the safety injection system. A sequential thermal-mechanical coupling analysis is first performed using a three-dimensional reactor pressure vessel finite element model (3D-FEM). A linear elastic fracture mechanics submodel with a postulated semielliptical surface crack is then created from the 3D-FEM. Subsequently, the submodel is used to evaluate the stress intensity factors based on the M-integral approach coupled within the proposed simulation method. Finally, the stress intensity factors (SIFs) obtained using the proposed method are compared with the conventional extended finite element method approach, and the result shows a good agreement. e maximal thermomechanical stress concentration was observed at the inlet nozzleinner wall intersection. In addition, e ASME fracture toughness of the reactor vessel's steel compared with SIFs show that the PTS event and crack configuration analysed may not pose a risk to the integrity of the RPV. is work serves as a critical reference for the ageing management and fatigue life prediction of reactor pressure vessels.
Journal of Solid Mechanics, 2020
During the pressure vessels' operating life several flaws are likely to grow in long term operations under cyclic loading. It is therefore essential to take practical and predictive measures to prevent catastrophic events to take place. Fitness for service (FFS) is one safety procedure that is used to deal with maintenance of components in the petroleum industry. In this method, proposed in Codes of practices such as API 579 and BSI 7910, in certain cases, an overly conservative safety prediction is obtained when applied to the operation of pressure vessel containing surface fatigue crack growth. By using improved analytical techniques as well as nonlinear finite element methods critical cracks lengths may be derived more accurately thus reducing conservatism. In this paper, a specific pressure vessel analyzed for fitness for service which sees fatigue crack growth rate is assessed using analytical and numerical stress intensity factors. The estimated fatigue life is compared wi...
Failure Assessment of an In-service Pressure Vessel with Crack Flaw Using Failure Assessment Diagram
International Journal of Marine Engineering Innovation and Research, 2024
⎯ Failure assessment include fatigue assessment was performed for an in-service pressurize equipment utilized to support hydrocarbon proceesing activity as the response of crack-like flaw finding during phase array scanning inspection. The assessment required to ensure the integrity and the safety in the operation of deteriorated pressure vessel. The fitnessfor-service assessment in this study are consist of failure assessment using Failure Assessment Diagram (FAD) and the fatigue assessment based on API 579-1/ASME FFS-1. The assessment has demonstrated that the current condition of the equipment was pass the assessment requirement and still has adequate strength and the fatigue damage due to actual operation pressure is an insignificant factor affecting the life of the equipment. This study also investigates the correlation between the geometry of the flaw and the stress increase ratio that is expressed in the exponential function as σC/σR = 4.18e 0.82(LD/T^2)
Mathematics, 2022
The aim of this work is to present a new analytical model to evaluate jointly the mechanical integrity and the fitness-for-service of nuclear reactor pressure-vessels steels. This new methodology integrates a robust and regulated irradiation embrittlement prediction model such as the ASTM E-900 with the ASME Fitness-for-Service code used widely in other demanding industries, such as oil and gas, to evaluate, among others, the risk of experiencing degradation mechanisms such as the brittle fracture (generated, in this case, due to the irradiation embrittlement). This multicriteria analytical model, which is based on a new formulation of the brittle fracture criterion, allows an adequate prediction of the irradiation effect on the fracture toughness of reactor pressure-vessel steels, letting us jointly evaluate the mechanical integrity and the fitness-for-service of the vessel by using standardized limit conditions. This allows making decisions during the design, manufacturing and in-service of reactor pressure vessels. The results obtained by the application of the methodology are coherent with several historical experimental works.
DETERMINATION OF CORROSION RATE AND REMAINING LIFE OF PRESSURE VESSEL
DETERMINATION OF CORROSION RATE AND REMAINING LIFE OF PRESSURE VESSEL USING ULTRASONIC THICKNESS TESTING TECHNIQUE, 2014
Pressure vessels suffer a loss of mass and strength when corrosion occurs. Sound integrity of these vessels is a major factor in the oil and gas industry and Corrosion is one key component that affects the durability of such equipment.Ultrasonic thickness measuring instrument is used to accurately obtain the thickness measurement of these vessels to establish its corrosion rate and remaining life. These parameters are considered as part of the prediction and rejection criteria used to ascertain the life span and usage worthiness of LPG vessels. The outcome of the research work suggests that, the remaining life of LPG vessel cannot be safely and accurately be predicted with the short-term corrosion rate unless its year on year corrosion rate is uniform.
Remaining life analysis for a pressure vessel subjected to cyclic loads based on fracture mechanics
International Journal of Fatigue, 1995
Fracture mechanics has evolved into an engineering tool able to solve problems related to the safety of structures containing defects. In practice, however, a wide choice of parallel methods as well as unsolved discrepancies in the theory requires engineering judgement and pragmatism. In this paper a practical case study is presented, concerning a maintenance strategy assessment performed on a welded pressure vessel. The pressure vessel is analysed in terms of leak-before-break arguments, proof test logic, fatigue initiation life, defect initiation and unstable growth critical sizes, fatigue crack propagation that leads to fracture or leakage, as well as probabilistic methods based on defect size distributions and NDE detection probabilities. The paper deals with some background to the theories employed, the different steps of the assessment methodology, as well as with the interpretation of the result to design a practical and safe maintenance strategy.
INVESTIGATION ON FAILURE BEHAVIOR OF UNFLAWED STEEL CYLINDRICAL PRESSURE VESSELS USING FEA
Multidiscipline Modeling in Mat. and Str., 2009
Finite element analysis (FEA) has been carried out utilizing the ANSYS software package to assess the failure of thick and thin-walled steel cylindrical pressure vessels. A simple experimental stress analysis (ESA) procedure is described to evaluate the stress components on inner and outer surfaces of the vessels under internal pressure from the measured surface strains. The procedure is validated considering the strain values of FEA for the applied pressure as measured quantities and obtained the corresponding stress components considering the stress-strain data of the material from ESA and compared with those of FEA results. Failure pressure estimates from FEA (based on the global plastic deformation) were found to be in good agreement with test results of thin as well as thick-walled cylindrical vessels made of ductile steel materials.
Continuum Mechanics and Thermodynamics, 2018
Structural integrity calculations play a crucial role in designing large-scale pressure vessels. Used in the electric power generation industry, these kinds of vessels undergo extensive safety analyses and certification procedures before deemed feasible for future long-term operation. The calculations are nowadays directed and supported by international standards and guides based on state-of-the-art results of applied research and technical development. However, their ability to predict a vessel's behavior under accidental circumstances after long-term operation is largely limited by the strong dependence of the analysis methodology on empirical models that are correlated to the behavior of structural materials and their changes during material aging. Recently a new scientific engineering paradigm, structural integrity has been developing that is essentially a synergistic collaboration between a number of scientific and engineering disciplines, modeling, experiments and numerics. Although the application of the structural integrity paradigm highly contributed to improving the accuracy of safety evaluations of large-scale pressure vessels, the predictive power of the analysis methodology has not yet improved significantly. This is due to the fact that already existing structural integrity calculation methodologies are based on the widespread and commonly accepted 'traditional' engineering thermal stress approach, which is essentially based on the weakly coupled model of thermomechanics and fracture mechanics. Recently, a research has been initiated in MTA EK with the aim to review and evaluate current methodologies and models applied in structural integrity calculations, including their scope of validity. The research intends to come to a better understanding of the physical problems that are inherently present in the pool of structural integrity problems of reactor pressure vessels, and to ultimately find a theoretical framework that could serve as a well-grounded theoretical foundation for a new modeling framework of structural integrity. This paper presents the first findings of the research project. Keywords Structural integrity • Pressurized thermal shock • Large-scale pressure vessels • Safety calculations • Thermomechanics • Modern thermodynamics Abbreviations ASME The American Society of Mechanical Engineers BFT curve Border fracture toughness curve CABINET Constraint and biaxial loading effects and their interaction considering thermal transients (WPS) CFD Computational fluid dynamics Communicated by Attila R. Imre.
Pressure vessels design methods using the codes, fracture mechanics and multia.PDF
This paper gives a highlight about pressure vessel (PV) methods of design to initiate new engineers and new researchers to understand the basics and to have a summary about the knowhow of PV design. This understanding will contribute to enhance their knowledge in the selection of the appropriate method. There are several types of tanks distinguished by the operating pressure, temperature and the safety system to predict. The selection of one or the other of these tanks depends on environmental regulations, the geographic location and the used materials. The design theory of PVs is very detailed in various codes and standards API, such as ASME, CODAP ... as well as the standards of material selection such as EN 10025 or EN 10028. While designing a PV, we must design the fatigue of its material through the different methods and theories, we can find in the literature, and specific codes. In this work, a focus on the fatigue lifetime calculation through fracture mechanics theory and the different methods found in the ASME VIII DIV 2, the API 579-1 and EN 13445-3, Annex B, will be detailed by giving a comparison between these methods. In many articles in the literature the uniaxial fatigue has been very detailed. Meanwhile, the multiaxial effect has not been considered as it must be. In this paper we will lead a discussion about the biaxial fatigue due to cyclic pressure in thick-walled PV. Besides, an overview of multiaxial fatigue in PVs is detailed.