bluuebunny/crossref_metadata_2025 huggingface dataset:
Numerical Simulation of Thermal Striping Phenomena in T-Junction Piping System Using Large Eddy Simulation
Authors: Tanaka Masa-Aki , Ohshima Hiroyuki , Monji Hideaki
Published: July 2009

In Japan Atomic Energy Agency (JAEA), simulation code “MUGTHES (MUlti Geometry simulation code for THErmal-hydraulic and Structure heat conduction analysis in boundary fitted coordinate)” has been developed to evaluate thermal striping phenomena that are caused by turbulence mixing of fluids in different temperature. MUGTHES employs Boundary Fitted Coordinate (BFC) system to treat complex geometries in power plants. And MUGTHES can deal with three-dimensional transient thermal-hydraulic problem coupled with three-dimensional transient heat conduction in the surrounding structure in consideration of conjugated heat transfer. In this paper, numerical schemes for thermal-hydraulic simulation employed in MUGTHES are described including LES model. A simple method to limit numerical oscillation is adopted in energy equation solving process. A new iterative method to solve Poisson equation in BFC system is developed for effective transient calculations. This method is based on BiCGSTAB method and SOR technique. As the code validation of MUGTHES, a numerical simulation in a T-junction piping system with LES approach was conducted. Numerical results related to velocity and fluid temperature distributions were compared with an existing water experimental data and the applicability of numerical schemes with LES model in MUGTHES to the thermal striping phenomenon was confirmed.
A New Monte Carlo Code for Nuclear Criticality Calculations
Authors: Shen Huayun , Wang Kan
Published: July 2009

A Monte Carlo code for nuclear criticality calculation is presented. Three different estimators of keff, which is well-known, are included. Also, the technique of combining them is adopted. Besides, when the individual estimators are calculated, the code adopts multi-generations rather than successive generations. The results demonstrate that the effect of multi-generations is obvious.
Spent Nuclear Fuel Radiotoxicity Evaluation in the Context of Minor Actinides Management With ADS Systems
Authors: Vezzoni Barbara , Calgaro Barbara , Cerullo Nicola , Forasassi Giuseppe
Published: July 2009

The most effective way to reduce the time to reach a radiotoxicity reference level is, probably, the transmutation of Minor Actinides with fast fission processes. The definition of a critical approach to justify GEN.IV nuclear facilities, as minor actinides transmuters, is the main topic of this work. In this direction, firstly the evaluation of the reference level best estimation was performed, followed by the qualitative and quantitative radiotoxicity evolution in the ICRP Recommendations, their impact on P&T chosen strategy and on US and European rules in order to preliminarily analyze industrial ADS burning capability. Computational tools used are MCNPX-2.5.0 and ORIGEN-2.2 codes in synergy with the state of art of internal dosimetry in ICRP Publications, 10 CFR Part.20 and 96/29/EURATOM. One order of magnitude difference between the radiotoxicity evaluated by the 10 CFR Part.20 (1994) coefficients and the radiotoxicity evaluated by the actual European rules coefficients was identified.
Development of a Hybrid Turbulent Particle Dispersion Model and Implementation in the Gasflow Code
Authors: Xu Zhanjie , Travis John R. , Breitung Wolfgang
Published: July 2009

Dust mobilization in a vacuum vessel is one of the key issues endangering the security of the International Thermonuclear Experimental Reactor (ITER), in case of Loss of Vacuum Accidents (LOVA). The turbulent behavior of particles in turbulent flows has to be modeled for successful numerical simulations about particle mobilization. In this study a Lagrangian approach is adopted to formulate the particle transport especially for dust-dilute flows mostly encountered in the vacuum vessel of ITER. Based on the logic frame of the approach and the used Computational Fluid Dynamic (CFD) computer code in the study, a hybrid turbulent particle dispersion model is proposed. The hybrid model features both a deterministic separated flow (DSF) model and a stochastic separated flow (SSF) model, which are two popular turbulent dispersion models applied in particle simulations, and takes the advantages of the both models. The proposed model is implemented into the particle model of the CFD code successfully and the simulation results are verified against experimental data. The verifications manifest the validities of the proposed model. In this paper general information about the work of dust mobilization is introduced and the particle turbulent dispersion models are reviewed briefly at first. The hybrid model is then proposed based on the SSF model. An experiment about particle dispersions in an advective wind channel flow with decaying turbulence in the streamwise direction is reviewed in the third section. In the following section about model verification, the decaying turbulence parameters in the channel flow are verified against experimental data as the first step, the parameters about the particle dispersions in the verified flow field are then verified against the data. The work is concluded finally.
Influence of Passive Autocatalytic Recombiners on Iodine Volatility: THAI Technical Scale Experiments
Authors: Poss Gerhard , Kanzleiter Teja , Funke Friedhelm , Langrock Gert , Allelein Hans-Josef , Nowack Holger , Weber Gunter
Published: July 2009

Passive Autocatalytic Recombiners (PARs) in PWR-Containments remove hydrogen released in case of a severe accident with core damage by catalytic oxidation with the oxygen of the containment atmosphere. The removal of hydrogen in autocatalytic recombiners (PARs) results in temperature levels at the catalytic surfaces up to 900 °C and leads to elevated temperatures up to several hundred degrees of the gas flowing over these surfaces. Under such operating conditions suspended CsI and other iodide particles transported with the convective gas flow through PARs can be converted into volatile iodine thus influencing the iodine source term. Even low conversion rates might lead to a significant influence on the concentration of gaseous iodine in the early phase of an accident where high CsI/I2 ratios of 100:1 or even higher can be expected. In the frame of the German national THAI programme two technical-scale experiments, AER-2 and AER-5, have been performed to investigate the conversion rates CsI → I2 occurring under realistic PAR operating conditions and beyond, and the influence of PARs on CsI aerosol parameters. An original SIEMENS (now AREVA NP) type PAR has been operated under realistic thermalhydraulic conditions. CsI aerosol has been generated by evaporating ultra pure CsI in an inductive furnace and monitored in the THAI vessel, following re-condensation, by low pressure impactors and filters. Experiments with hydrogen concentrations of up to 5 vol% H2 under normal conditions and of up to 10.5 vol% H2 in a steam-inerted atmosphere have been performed. An approved and qualified sampling and detection method has been applied to determine gas borne molecular iodine concentrations. CsI → I2 conversion rates of 3% have been observed as an upper limit under realistic thermalhydraulic conditions. The results are compared to CsI → I2 conversion rates achieved in the French RECI experiments. These experiments investigated the interaction of catalytic material and metal iodides (CsI, CdI) in a lab-scale setup showing conversion rates up to 60%. However, these experiments might deviate from representative thermochemical conditions. A comparison of THAI and RECI results — as far as appropriate concerning aerosol parameters and gas temperatures — shows conversion rates in comparable dimensions. In other cases they differ significantly. The potential contribution of an operating PAR (metal iodide interaction) to the iodine source term together with the restricted knowledge from both THAI and RECI tests, means that further investigations are required.
Results on Attenuation of Neutron Embrittlement Effects
Authors: Brumovsky´ Milan , Kytka Milosˇ , Server William , Soneda Naoki , Spanner Jack
Published: July 2009

A carefully designed irradiation experiment was conducted in which a 180-mm thick reactor pressure vessel (RPV) wall has been simulated using eighteen 10-mm slices of some key RPV steels and irradiated under test reactor conditions to investigate the through wall attenuation of neutron embrittlement. Results from two of the irradiated materials (a low copper content plate and a high copper content Linde 80 flux weld) were reported in 2006. Another RPV plate, the international reference steel, JRQ, was also extensively irradiated in the simulated RPV wall. Comparisons of predicted attenuation changes in toughness properties using measured Charpy V-notch results are presented for the JRQ steel and compared to the results from the low copper content plate and the high copper content Linde 80 weld metal. Also, Charpy V-notch and Master Curve fracture toughness test results are compared for the low copper plate and the high copper weld. Predictions are made of through-wall attenuation following the practice defined in ASTM E 900-02 and Regulatory Guide 1.99, Revision 2, in which the attenuation of high energy neutron fluence (E > 1 MeV) is projected based upon an approximate displacements per atom (dpa) change through the wall thickness.. The resultant degree of material damage using this dpa-based fluence change is estimated using the ASTM E 900–02 embrittlement correlation model and compared to the experimental data.
Chiller Condenser Service Water Cooling Valve Maintenance
Authors: Boughton Ken , Hansen Paul N.
Published: July 2009

This paper presents issues associated with Chilled water system operations at a Nuclear facility that experiences problems with the cooling water flow control valves during the cold season under low load conditions. The system is used to provide safety related functions of cooling rooms such as the control rooms due to radioactive and toxic gas hazards. The valves experience excessive cycling under low load conditions during the cold seasons leading to maintenance and availability problems with the system. This problem is driven by the current system design and the need to utilize a chilled water system during times when natural ambient temperature conditions are low. The Chilled water system uses refrigeration units to cool the chilled water and service water to provide the heat sink for the refrigeration condensing units. The focus of the discussion is the cooling water (service water) flow control valves, which are the major source of the maintenance problem. The paper presents the integrated behavior of the Chilled water system to properly characterize the issue and the solutions. The paper will present the system details and performance parameters necessary to evaluate the problem. The behavior of the valves will be evaluated based on the system operations. This paper evaluates the technical merits of several options to provide stable control of the flow control valves, prevent high-pressure chiller unit trips and solve flow control valve actuator excessive wear.
An Experimental Research on the Effect of the Axial Power Distribution on the Critical Power
Authors: Liu Wei , Kureta Masatoshi
Published: July 2009

In this paper, an experimental research on the effect of the axial power distribution on the critical power is performed under the atmospheric pressure with using a circular tube. The circular tube is axially divided into 3 insulated levels and is heated separately by 3 DC power suppliers. Axial uniform heating condition, the upper three-layer simulation and the center three-layer simulation of the double-humped core of Innovative Water Reactor for Flexible Fuel Cycle (FLWR) are selected as the cases for the detailed evaluation. The effects of relative power ratio on the critical power, the critical quality and the critical boiling length under different heating conditions are ascertained for the detailed evaluation cases. With using the experimental data, existed correlating methods for the boiling transition are evaluated. As the result, a combination of the critical quality-boiling length (χBT – LB) method and the critical heat flux-critical quality (qBT – χBT) method is found a good correlating to the present data with a changed axial power distribution.
Surface Tension of Sodium Dispersing Nano Particles: A Basic Study on Mitigation of Sodium-Water Reaction
Authors: Nakamura Kouichi , Zhang Zhi-Gang , Sugiyama Ken-Ichiro , Yamada Masahiko
Published: July 2009

In sodium-cooled fast reactors, it is very important to evaluate sodium-water reaction from the viewpoint of safety. If once it happens in the steam generator, it is desirable its scale is small and its reaction is mild. The sodium dispersing nano particles is expected to mitigate the sodium-water reaction. Nano particles is titan particles whose diameter is tens nanometer and dispersing rate in sodium is several percent. In order to find out the effect clearly, it is essential to evaluate the reaction behavior and characteristics of physical properties closely. For this purpose, we tried to measure the surface tension of sodium dispersing nano particles as an important part of foundational physical property. We had employed the pendant drop method for the measurement, with which we can measure surface tension from the shape of pendant drop. This method is suitable for our measurement because nano sample is very limited. The measurement was done in a sealed box keeping inert gas atmosphere, which is required for sodium experiment because of an easy chemical reaction of sodium with oxygen and moisture. At first, we did a series of experiments for pure sodium. We succeeded to make pendant drops between 150°C and 350°C. For the measurement, we selected only the drops in clear mirror surface with axial symmetry. The scatter range of obtained results is slightly larger than that of a recommended equation. We estimated that it was caused due to a weak wet condition on the edge face of nozzle. Then we measured the surface tension of the sodium dispersing nano particles under the same condition. The obtained results almost show values larger than those of pure sodium. The dispersion rate of nano particles has an uncertainty in the present study. However even in giving the worst evaluation, the measured surface tensions for the sodium dispersing nano particles show larger values than those for the pure sodium.
Control Assembly Ejection Modeling for VVER-440 Reactor by PARCS-RELAP Coupled Code
Authors: Bznuni Surik , Malakyan Tsolak , Amirjanyan Armen , Poghosyan Shahen , Ghasabyan Levon
Published: July 2009

Control Assembly ejection in VVER-440 initiated by the loss of integrity of the Control Assemblies drive housing has been analyzed. This event causes a very rapid reactivity insertion to the core and cmall break LOCA which potentially could lead to rapid power increase and redistribution of heat release in the core resulting in a fuel, cladding and coolant temperature rise; primary pressure increase, radiological consequences due to loss of primary coolant and potential loss of cladding integrity and fuel disintegration (if applicable). Methodology of the analysis is based on conservative assumptions as well as on deterministic approach for selection of functioning logic of systems and equipments to maximize reactor core power and minimize power decreasing reactivity feedback. Computational analyses were performed by 3D kinetics PARCS-RELAP coupled code. VVER-440 fuel cross-section libraries, diffusion coefficients and kinetics parameters were calculated by HELIOS code. Several Control Assembly ejection modeling approaches have been used in PARCS to address Control Assembly’s fuel part movement problem in VVER-440. The most conservative one has been developed.
Development and Validation of a Porous Medium Computational Fluid Dynamics Model for a Jet
Authors: Drzewiecki Timothy J. , Mount Brian L. , Lopez de Bertodano Martin
Published: July 2009

The fast boron shutdown injection in a PHWR consists of a jet flowing through a very large moderator tank that contains an array of cylindrical coolant channels. The accurate prediction of the turbulent jet mixing is required to determine an accurate distribution of boron inside the moderator tank to model the insertion of negative reactivity into the reactor during fast shutdown. A CFD code is used to determine the distribution of boron in the moderator tank. The flow is analyzed with a porous medium model based on volume averaged momentum, turbulent kinetic energy, and turbulence dissipation equations. The additional source terms arise due to the averaging must be constituted. The constitutive relations that are implemented in the present model are: (i) the drag force on an array of cylinders for the momentum equations and (ii) the additional mixing effect of the cylinders which results in the sources of turbulent kinetic energy and turbulence dissipation transport model. The CFD analysis is performed on a porous, axis symmetric domain. The CFD results are finally compared with data for the boron concentration distribution obtained in a scaled geometrically similar experiment, demonstrating the validity of the approach.
Assessment of the Applicability of the Abrasive Water Jet Technique for Dismantling the Reactor of Fugen: Studies for Reducing the Usage of Abrasive and for Surveying the Cutting Situation Under the Water
Authors: Nakamura Yasuyuki , Morishita Yoshitugu , Maruyama Shinichiro , Tezuka Shinichi , Ogane Daisuke , Takashima Yuji
Published: July 2009

The reactor of FUGEN NPP consists of many number of double-tube arranging a pressure tube (P/T) and a calandria tube (C/T) coaxially. In the case of dismantling both a P/T and a C/T simultaneously, it is preferable to use the mechanical cutting method because it does not apply the heat to highly activated P/T and C/T, as a result, it would be suppressed to release activated particles into surrounding environment. The method is also required to use a smaller cutting device for permitting the remote control of it in a narrow space, and to have a relatively long standoff for cutting the double-tube simultaneously. The authors chose the abrasive water jet (AWJ) cutting method as one of the mechanical cutting method for dismantling the reactor. The authors have also developed the smaller AWJ cutting device and confirmed that the device is applicable to the cutting of the double-tube. On the other hand, it is an issue to reduce an amount of abrasive because it becomes the secondary radioactive waste after the cutting work. It is also difficult to survey the cutting condition by any visual methods like a TV camera in the water becoming cloudy by both used abrasive and cut metal grit. For solving these issues, the following two studies were conducted. (1) The recycle of used abrasive was examined. And it was also confirmed to be able to predict an optimal supply rate of abrasive by considering the conservation of momentum between the water jet and the abrasive. (2) It was possible to judge whether the material could be cut or not by detecting the change in the frequency characteristics of vibration or sound caused during the cutting process.
Experimental Study on the Effects of Fault Movement on the Engineered Barrier System
Authors: Naito Morimasa , Saito Yuya , Tanai Kenji , Yui Mikazu
Published: July 2009

An experimental approach is introduced for understanding how the engineered barriers of a deep geological repository system are affected by fault movement. The experiments are conducted using laboratory simulation test equipment. So far, the experiments indicate that the metal overpack is rotated within the bentonite buffer due to its plasticity, but not breached. Numerical analyses are also carried out to supplement the range of the experiments, which is limited by the capability of the test equipment.
The Conceptual Design Study of a TRISO Fueled Compact PWR Core
Authors: Hussain Anwar , Cao Xinrong , Ahmed Rizwan
Published: July 2009

A conceptual study has been carried out for the design of a compact PWR reactor core which employs TRISO fuel particles in zirconium-sheathed fuel rods. This study is focused on reactor core optimization which can be a potential source of energy for a sea going vessel. This compact design can also be used for power production, heating and desalination facilities in a remotely located research facility. This light water cooled and moderated core will be smaller in size as compared to a typical PWR of the same rating. Standard reactor neutronics simulation codes WIMS-D/4 and CITATION have been used for the parametric analysis and to optimize the core. TRISO fuel has been chosen for the current design study because of its superior reliability against the release of fission fragments and high negative temperature coefficient. The selected TRISO fuel particle has 0.40 mm fuel kernel outer diameter in overall 0.870 mm outer diameter. Beryllium has been chosen as reflecting material due to its better reflection properties. Fuel pitch and reflector thickness are optimized to 4 cm and 8 cm respectively. Considering the proliferation issues, a maximum 9% fuel enrichment has been selected with the total fuel inventory of 200kg of uranium. These constraints on fuel enrichment and inventory limit the maximum power to only 25MWth for one year full power operation. This designed PWR core would be compact in size due to the default design of the TRISO fuel; fission neutrons are moderated and reflected by graphite in the fuel itself which causes the increase in reactivity. This additional increment in reactivity would give flexibility to optimize the size of reactor core.
Theory to Practice: The Realities of New Reactor Licensing Application Docketing and Review
Authors: Mahan Randolph R. , Sutton Kathryn M. , Rosinski Douglas J.
Published: July 2009

The first Combined Construction and Operating License (“COL”) applications for new reactors have been submitted to the United States Nuclear Regulatory Commission (“NRC”), and more are expected soon. Preparation of these applications began several years ago based on new regulations in 10 C.F.R. Part 52 (“Part 52”) that are intended to ensure a predictable regulatory environment for new reactor licensing. Indeed, many analysts have opined that the financial viability of new nuclear construction depends largely on reducing economic and regulatory risk associated with the licensing process. In Part 52, the NRC created a new, three-part licensing framework for issuance of Design Certifications (“DC”), Early Site Permits (“ESP”), and Combined Construction and Operating Licenses (“COL”). Applicants are provided the flexibility to build pre-approved designs (DC), on pre-approved sites (ESP), without the need to re-visit issues already decided in earlier proceedings, thereby streamlining issuance of COLs. Thus, Part 52 holds the promise of a more efficient and predictable regulatory licensing process. The promised efficiencies of Part 52, however, are being tested as the NRC begins to review more DC, ESP, and COL applications. Putting new regulatory concepts into practice is always a challenge, and Part 52 is no exception. Thus, it is important to understand the evolving NRC expectations that are beginning to be revealed — expectations that must be understood to successfully license new reactors in the United States. This paper explores the developing implementation of Part 52, discusses how that development is being shaped by current regulatory and engineering realities, and considers the practical impact that these developments will have on engineers designing and constructing new nuclear units in the United States.
On Modeling Piping Supports in Dynamic Analysis of Nuclear-Power Piping Systems
Authors: Jansson Lennart G. , Zeng Lingfu
Published: July 2009

Piping analysis and its corresponding design evaluation according to ASME are complicated and tedious. One typical reason is the modeling of supports and their design evaluation. It is not exaggerated if one claims that this part of the work can consume about 1/3 of the total budgeted costs that are needed for a piping system analysis. The engineering practices of how a support should be modelled in a piping analysis differ between different regions in the world. The difference arises mainly from in what way the following two parts are weighted in a piping analysis: (1) the dynamic interaction effect between supports and piping, and (2) the big safety margin or, in other words, the conservatism, for a piping system which fulfills ASME’s requirements. In this paper a review of these practices will be first given and, thereafter, an analysis of piping-support interaction will be carried out, and finally our suggestions will be given. Some practical examples from recent projects in Nordic countries will be discussed.
Increased Concern for Degradation of Upper Steam Drum Internals Leading to Monitoring and Modifications Considerations
Authors: Popovich David P. , Hu M. H. , Barkich Jonathan L. , Nelson Peter R.
Published: July 2009

Pressurized water reactor plant steam generator upper internals have been monitored in accordance with accepted industry practice and on schedules based on the history of good inspection results with isolated cases of failures in a small percentage of plants worldwide. The current practice is, in general, to perform a small sample qualitative visual inspection. The causal factors for the historical events are indicators but, in general, not directly applicable to the current rationale for increased quantitative surveillance. There is an emerging trend toward increased indications of degradation with identifiable causal factors similar to but distinct from the traditional failure mechanisms. Primary and secondary moisture separation components and feedwater ring degradation is increasing as calculated by traditional models and according to qualitative and quantitative inspection results. Two established objective criteria for the performance functions for the steam drum components under consideration are: moisture carryover < 0.25% and material loss of 62.5 mils from nominal component thickness of 0.25 inches. These traditional acceptance criteria can be re-established based on an engineering evaluation of failure modes and effects. Two changes that have increased the concern for unacceptable degradation of steam drum components in recent years are 1) the chemistry improvements to reduce flow assisted corrosion (FAC) in the feed train piping with the concomitant reduction in entrained iron transport into steam generators, and 2) the increase in water-steam flow velocities that result from power uprates. The reduction of entrained particulate into the steam generators is positive with respect to fewer corrodents introduced but may have an unintended and previously under-analyzed effect of the transport of entrained particulate into the upper regions of the tube bundle and into the moisture separation components. The first indications of degraded moisture separator components have begun to emerge and warrant consideration of an increased surveillance program for selected plants. This paper discusses how recent changes in the operating parameters and secondary water chemistry control have created conditions for concern for exceeding the traditional moisture carryover criteria and erosion-corrosion of upper steam drum components, especially in light of extended life operation. Examples of recent developments in inspection results and considerations for improved materials, increased and improved surveillance techniques, and replacement strategies will be presented.
Specificity of Aircraft Crash Compared to Other Missile Impacts
Authors: Kœchlin Pierre , Potapov Serguei¨
Published: July 2009

Before modeling an aircraft crash on a shield building, it is very important to understand the physical phenomena and the structural behavior associated with this kind of impact. In the scientific literature, aircraft crash is classified as a soft impact, or as an impact of deformable missile. Nevertheless the existing classifications are not precise enough to be able to predict the structural response mode. In this paper, the author proposes a quantitative classification of soft and hard impacts, based on structural considerations, and in accordance with existing definitions and moreover with intuition. The experimental tests carried out during the last thirty years in the research field of aircraft crash are reviewed in the light of the new classification. It shows that this characterization has a real physical meaning: it gives the limit between two kinds of failure. Furthermore, since it is on one hand an a priori classification and on the other hand expressed in terms of non-dimension variables, it is very helpful to calibrate new experimental tests for aircraft crash. Finally, using this classification, the paper explains that during an aircraft crash, the perforation process of a concrete shield building is the result of structural waves (bending and shear waves). It opens the way to a prediction of aircraft crash perforation based on a criterion expressed in terms of stress resultant variables (combined bending moment, shear force and membrane force).
Heat Transfer to Supercritical Water in Vertical 7-Rod Bundle
Authors: Razumovskiy V. G. , Pis’mennyy E. N. , Koloskov A. E. , Pioro I. L.
Published: July 2009

The results of heat transfer to supercritical water flowing upward in a vertical tight 7-rod bundle consisting of tubes of 5.2-mm outside diameter and 485-mm heated length are presented. The heat-transfer data were obtained at pressures of 22.5, 24.5, and 27.5 MPa, mass flux within the range from 700 to 1500 kg/m2s, inlet temperature from 125 to 325°C, outlet temperature up to 379°C and heat flux up to 1.6 MW/m2 (heat flux rate up to 1.5 kJ/kg). Temperature regimes of the bundle cooled by supercritical water were stable and easily reproducible within the whole range of the mass and heat fluxes, even when a deteriorated heat transfer took place. The data resulted from the study could be applicable for a reference estimation of heat transfer in future designs of the fuel bundles.
Further Extension of the Unloading Compliance Method to Measure J-R Curves Based on CMOD Data
Authors: Cravero Sebastian , Ruggieri Claudio
Published: July 2009

Laboratory testing of fracture specimens to measure resistance curves (J-Δa) have focused primarily on the unloading compliance method using a single specimen. Current estimation procedures (which form the basis of ASTM 1820 standard) employ load line displacement (LLD) records to measure fracture toughness resistance data incorporating a crack growth correction for J. An alternative method which potentially simplifies the test procedure involves the use of crack mouth opening displacement (CMOD) to determine both crack growth and J. This study provides further developments of the evaluation procedure for J in cracked bodies that experience ductile crack growth based upon the eta-method and CMOD data. The methodology broadens the applicability of current standards adopting the unloading compliance technique in laboratory measurements of fracture toughness resistance data (J resistance curves). The developed J evaluation formulation for growing cracks based on CMOD data provides a viable and yet simpler test technique to measure crack growth resistance data for ductile materials.
Study on Duration of Hydrostatic Leak Test for Gas Pipeline
Authors: Yan Feng , Zhang Yongxue , Zhang Hong , Duan Qingquan
Published: July 2009

A mathematical model about the duration of hydrostatic leak test for gas pipeline is developed for the first time in the paper. The influences of temperature variation, elastic deformation of the pipe and a certain amount of residual air filled within the pipe are synthetically considered in the model. The results indicate that the duration is longer while the amount of the residual air in the pipe or the volume of pipe is lager under the same pressure dropping. The required duration is increasing with the pressure going up. At the same time, the temperature variation greatly influences the pressure dropping of the pipeline. The conclusions are helpful for determining the reasonable duration of hydrostatic leak test for gas pipeline. Furthermore, it can also provide some references for judging leak test result while hot water pressure testing in winter.
Integrity of 3LPE Pipeline Coatings: Residual Stresses and Adhesion Degradation
Authors: Chang Benjamin T. A. , Sue Hung-Jue , Jiang Han , Browning Bobby , Wong Dennis , Pham Ha , Guo Shu , Kehr Al , Mallozzi Meghan , Snider William , Siegmund Al
Published: July 2009

Both fusion bonded epoxy (FBE) and 3-layer polyolefin (3LPO) coating systems have been widely applied in the world as new-construction external pipeline coatings. 3LPO is regarded as a more damage resistant coating system while FBE is considered to be more compatible with the CP system. In the past few years, several incidences of coating disbondment at the FBE-steel interface of 3LPO have been reported in the literature. The coating disbondment issue has raised concerns over the use of 3LPO. The US Department of Transportation (DOT) initiated a research program to address these technical concerns. Our research program is funded by this DOT initiative with a team of pipeline coating experts participating in this research project. The integrity of the 3LPO pipeline coating is impacted by the residual stresses and adhesion degradation by water penetration. This paper examines the effect of coating thickness on residual stress, degradation of adhesion due to immersion in hot water and their combined affect on disbondment. The integrity of 3LPO is good when the coating is applied properly. Under the following conditions, the 3LPO may delaminate: (1) inadequate FBE coating formulation, (2) inadequate FBE coating application procedure and surface preparation, and (3) induced stress due to high volume shrinkage of PO layer.
The Use of Lidar to Facilitate Design and Construction of Pipelines
Authors: Smith Bruce , Wong Yan , Adam Steve
Published: July 2009

Within the last decade, airborne lidar (Light Detection And Ranging) equipment has evolved to the point where it can provide accurate ground surface elevations on a dense grid (often 1m by 1m) along pipeline corridors, at a cost that is a fraction of the cost for a comparable ground based topographic survey. This paper explains how lidar is used to acquire topographic data and how the data are converted to digital terrain models referenced to geodetic benchmarks. The accuracy and density of topographic data acquired by lidar surveys can be used to greatly facilitate pipeline design and reduce pipeline construction costs. The major benefits include: 1) The density of ground surface elevations obtained using lidar are significantly better than can be obtained using photogrammetry or conventional ground based survey methods. 2) The survey data can be collected over large areas in a matter of days and with virtually no disturbance to landowners. 3) The digital terrain models derived from lidar survey data can be imported into existing drafting (CAD) software and used to efficiently generate centerline profiles, cross-sections and alignment sheets as required for pipeline design and construction. 4) Hillshade maps derived from lidar data have proven extremely useful in pipeline route studies because they allow surface features to be identified and often avoided, thereby minimizing pipeline construction and operating costs.
Pipeline Leak Detection Based on Acoustic Emission Using Empirical Mode Decomposition Method
Authors: Li Yibo , Li Junlin , Sun Liying , Jin Shijiu , Han Shenghua
Published: July 2009

Corrosion in pipeline is a significant problem in the oil industry and there is also much interest in reducing leak due to corrosion. Correlation techniques are widely used in leak detection, and these have been extremely effective when attempting to locate leaks in metal pipes. Acoustic emission is a new non-destructive pipeline inspection technology which can be used to monitor crucial part of pipelines and detect pipe corrosion or leak in real time. However, AE signals causing by corrosion and leak are liable to noise interference on field. Aiming at solving the noise interference problems and increase the detection sensitivity and location accuracy of the leak, advanced signal analysis method based on Empirical Mode Decomposition were researched. Empirical Mode Decomposition is a great breakthrough in non-stable signal analysis and it decomposes the signals into a sum of finite intrinsic mode functions (IMF), which have real physical meaning. In the experiment, the leak signals from a 30 m pipeline were decomposed into 9 intrinsic mode functions by EMD, among which some IMF components containing typical AE characteristic can be selected to reconstruct the signal, and thus intrinsic characteristic of leak signal could be extracted and noise interference would be eliminated. Location accuracy of the leaking hole calculated with the reconstructed signals based on EMD algorithm was increased 64%.
Non-Contacting Bi-Axial Strain Measurement Method on Steel Pipeline
Authors: Westwood Stephen , Martens Michael , Kania Richard , Topp David , Kare´ Raymond , Chebaro Mohamed R.
Published: July 2009

The StressProbe is a non-contacting electromagnetic tool that responds to material strain in ferromagnetic materials. Previous studies have concentrated on uni-axial strain measurements; in this study, we extend the scope of work by measuring bi-axial strains on a pipe specimen subject to internal pressure and to a displacement-controlled, axial tensile/compressive load. Specified pressure and load combinations were obtained, and measurements from the StressProbe were compared to those from tri-axial strain gauges installed on the pipe specimen. In this paper, we present the theory behind this measurement method and the results from this study. Also discussed are measurement applications both inside and outside the pipe specimen.
Modeling Multi-Product Pipeline Hydraulics With a Spreadsheet
Authors: Horner Jim W.
Published: July 2009

Steady state computations have traditionally been used for liquid pipeline hydraulic design. The hydraulic behavior of multiproduct pipelines is more complex than single-product lines because the throughput varies with time as the different batches move through the system. Designing a multiproduct pipeline involves hydraulic simulation to ensure that the system can meet a specified time-average throughput for the design batch line-up. To calculate the time-averaged throughput, the hydraulic simulation determines the total time it takes to ship the complete design batch cycle and the methodology must account for the time-varying throughput of the pipeline. Two basic methods available to accomplish this are: the fully-transient method, and the simpler succession-of-steady-state method. A fully-transient model would rigorously solve the time-dependent equations of energy, mass and momentum conservation to determine operating capacity. A succession-of-steady-state (SSS) model is one where batches are moved through the system in small volume increments, and the steady-state capacity is calculated at each step. Fully-transient type software models are powerful, but expensive, complex and usually require lengthy simulation run times. An SSS spreadsheet model would not be used to evaluate transient phenomena, but is adequate for determination of nominal pipeline capacities. This paper discusses the development of a trans-thermal, SSS spreadsheet based model that was created as a design tool to determine pipeline capacity and evaluate the impact of design alternatives or changes.
Implementation of a Pipeline Integrity Management System at TIGF (France): The Added Value of the Pipeline Threats and Mitigations Module
Authors: Kutrowski Karine , Bos Rob , Piccardino Jean-Re´gis , Pajot Marie
Published: July 2009

On January 4th 2007 TIGF published the following invitation for tenders: “Development and Provision of a Pipeline Integrity Management System”. The project was awarded to Bureau Veritas (BV), who proposed to meet the requirements of TIGF with the Threats and Mitigations module of the PiMSlider® suite extended with some customized components. The key features of the PiMSlider® suite are: • More than only IT: a real integrity philosophy, • A simple intuitive tool to store, display and update pipeline data, • Intelligent search utilities to locate specific information about the pipeline and its surrounding, • A scalable application, with a potentially unlimited number of users, • Supervision (during and after implementation) by experienced people from the oil and gas industry. This paper first introduces TIGF and the consortium BV – ATP. It explains in a few words the PIMS philosophy captured in the PiMSlider® suite and focuses on the added value of the pipeline Threats and Mitigations module. Using this module allows the integrity analyst to: • Prioritize pipeline segments for integrity surveillance purposes, • Determine most effective corrective actions, • Assess the benefits of corrective actions by means of what-if scenarios, • Produce a qualitative threats assessment for further use in the integrity management plan, • Optimize integrity aspects from a design, maintenance and operational point of view, • Investigate the influence of different design criteria for pipeline segments. To conclude, TIGF presents the benefits of the tool for their Integrity Management department and for planning inspection and for better knowledge of their gas transmission grid.
Field Studies on the Prediction Method of Induced AC Level on Buried Pipelines Using Magnetic Field Sensors
Authors: Hosokawa Yuji , Koga Ryuji , Ametani Akihiro
Published: July 2009

There is a risk of alternating current (AC) corrosion on pipelines that are buried in proximity to overhead AC power transmission lines due to induced AC caused by magnetic fields around the power transmission lines. Grounding of the line pipes is generally applied for the mitigation of induced AC. In the present paper, studies were conducted to predict the induced AC level through the measurement of magnetic flux density using magnetic field sensors. The relationship between magnetic flux density and induced AC level was then obtained through theoretical studies. In addition, as a result of field tests conducted on an existing pipeline buried in proximity to power transmission lines, induced AC level could be predicted through the measurement of magnetic flux density using magnetic field sensors above the pipeline route. Magnetic flux density can be measured regardless of the number and location of power transmission lines as well as other metallic structures, and therefore it is expected that the AC prediction method using magnetic field sensors can be applied on the pipelines buried in proximity to multiple power transmission lines and/or to other metallic structures with complicated configuration.
Production of X80 (Grade 550) Linepipe by Electric Resistance Welding
Authors: Kostic M. , Klein R. , Lawrence T. , Lund M. , Collins L. E.
Published: July 2009

The Electric Resistance Welding (ERW) process is a highly efficient means of producing linepipe. Historically, this process has been applied to grades X70 (Grade 483) and less. However, recent upgrades to IPSCO’s 24 Inch ERW pipe mill have facilitated the production of X80 (Grade 550) material. This paper briefly describes the development trials and mill upgrades and highlights the properties achieved during the commercial production of 10 km of 24″ outside diameter × 0.250″ wall thickness X80 material with particular emphasis on the weld properties.
Effects of Ti, C and N on Weld HAZ Toughness of High Strength Line Pipe
Authors: Penniston Christopher , Collins Laurie , Hamad Fathi
Published: July 2009

As pipeline construction projects seek to implement more efficient welding techniques in order to reduce construction costs, it is important to understand the factors that affect the tolerance of the steel to welding processes. This is particularly true in the case of welding high strength steels (X70 and greater) in which increased alloy content will promote the formation of low temperature phases with limited ductility in the heat affected zone (HAZ). In the present study, the effects of titanium (0.008 to 0.015 wt%), nitrogen (60 to 100 ppm) and carbon (0.035 versus 0.060 wt%) have been examined through welds produced by a robotic gas metal arc welder.
Some Remarks on the Strain Based Assessment of Pipeline Dents
Authors: Noronha Dauro Braga , Martins Ricardo Rodrigues , Jacob Breno Pinheiro , de Souza Eduardo
Published: July 2009

In order to use the method to estimate strain in dents proposed in Appendix R of ASME B31.8 – Gas Transmission and Distribution Piping Systems – 2003 Edition, in a previous paper the authors used fourth-order B-spline curves to approximate the dent profile in both longitudinal and circumferential directions. This approach proved to be effective to estimate bending strains when the coordinates of the deepest point of the dent are known. This paper studies the impact of the distance between the closest ILI tool sensor and the dent apex on the measured dent depth and on the circumferential bending strain. The results obtained were tested against a set of nonlinear finite element analyses of dented pipelines carried out at PETROBRAS R&D Center. It was concluded that the number of sensors of the ILI tool, and consequently the maximum possible angular distance of the closest sensor in relation to the deepest point of the dent, plays a decisive role on the exactness of the results achieved. It is also mentioned that the equations to estimate the total strain in the inner and outer surface of the pipe wall presented in Appendix R contains a conceptual error and therefore shall be revised. Furthermore, longitudinal membrane strains obtained using the formula proposed in Appendix R were compared to finite element results. The comparison showed that directions on how to measure the dent length should be incorporated into the ASME B31.8 Code.
Statistical Modeling of Pitting Corrosion in Buried Pipelines Taking Into Account Soil Properties
Authors: Vela´zquez J. C. , Caleyo F. , Valor A. , Hallen J. M. , Espina-Herna´ndez J. H. , Lo´pez-Montenegro A.
Published: July 2009

Small leaks caused by external pitting corrosion are the leading cause of failure in oil and gas pipelines in many regions of Mexico. Because of this, the need for realistic and reliable pitting corrosion growth models that are capable of accounting for the chemical and physical properties of soils and pipeline coatings is especially great. In this work, maximum pit depths and soil and coating data that were gathered at excavation sites across southern Mexico are used to investigate the impact of soil and pipe characteristics on pitting corrosion in buried pipelines. Soil field-measurements included resistivity, pH, pipe-to-soil potential, humidity, chloride, bicarbonate and sulphate levels, redox potential, soil texture and coating type. Together with the local physical chemistry of the soil and the coating characteristics, the maximum pit depth and pipeline’s age were recorded at more than 250 dig sites. The time dependence of the maximum pit depth was modeled as ymax = β(t−t0)α, with β and α being positive constants, t being the pipe’s age and t0 the pit initiation time. A multivariate regression analysis was conducted with ymax as the dependent variable, while the pipeline’ age and the soil and pipe properties were used as the independent variables. The optimal dependence of β and α on these variables was found and predictive models were proposed to describe the time dependence of the average maximum pit depth and growth rate on soil and pipe properties. Besides the creation of a generic model fitted to all the gathered data, a model was proposed for each one of the three soil types identified in this study: clay, clay-loam and sandy-clay-loam. It is shown that the application of the proposed model allows for prediction of corrosion pit growth more accurately than previous models and that this improvement positively impacts on integrity management plans that address the threat posed by external pitting corrosion.