bluuebunny/crossref_metadata_2025 huggingface dataset:
Lessons Learned in Implementation of Guidelines for Quantifying Support System Initiating Event Frequencies
Authors: Weston Rupert A. , Mossa Ashley J.
Published: July 2009

The pilot implementation results for Regulatory Guide 1.200 identified four probabilistic risk assessment (PRA) technical elements that required additional guidance. One of these elements involved the use of fault tree technique to quantify the frequencies of support system initiating events (SSIEs). To address this technical element, guidelines were developed by the Electric Power Research Institute (EPRI) to provide a common industry approach for addressing the identification and quantification of SSIEs. The EPRI guidelines were issued as an interim report to allow trial use and pilot implementation by the industry prior to finalizing the guidelines. These interim guidelines provide an industry-consensus approach for addressing areas of concern in the development of support system initiating event models to ensure that the associated supporting requirements of the American Society of Mechanical Engineers (ASME) PRA Standard for internally initiated events are satisfied. A Pressurized Water Reactor Owners Group (PWROG) pilot implementation of the EPRI interim guidelines was conducted to determine whether the pilot participants have adequately addressed all areas of concern in the development of SSIE models. To determine this, a SSIE model currently used was selected by each of four the pilot participants and subject to detail review to demonstrate whether these models meet the expectations of the EPRI interim guidelines. The EPRI interim guidelines identified the areas of concern to be addressed in using fault tree technique to develop and quantify SSIE models. The guidelines addressed several areas of concern including the treatment of passive failures, the assignment of an appropriate mission time for primary and secondary failures, treatment of common cause failures (CCFs) between running and standby equipment, and consideration of all combinations of CCFs. The PWROG pilot implementation of the interim guidelines summarized the lessons learned and provided feedback to EPRI for consideration in finalizing the guidelines. In addition to the compilation of lessons learned, the PWROG implementation of the EPRI interim guidelines identified existing practices used to develop fault tree models for quantifying SSIE frequencies. Such practices did not necessarily follow a common approach and did not fully meet the expectations of the interim guidelines. Detailed reviews of the SSIE models currently in use at nuclear power plants (NPPs) for the pilot participants demonstrated that the elements of evaluation described in the interim guidelines were not addressed consistently among the PWROG pilot participants. Recommended improvements were identified and incorporated in the SSIE models to meet the expectations of the EPRI interim guidelines. The re-quantification of SSIE frequencies based on the recommended improvements, demonstrated that by not adequately addressing all elements in the evaluation, the SSIE frequency may be under-estimated.
Crosstalk and Time Response of a Plastic Scintillation Optical Fibers Array for Neutron Imaging
Authors: Wu Yue-Lei , Hu Hua-Si
Published: July 2009

The cladding material, to eliminate scattered neutrons and recoil-protons crosstalk, among the plastic scintillation optical fibers was optimized by MCNP Code and gold or tungsten metal powder (⩽50μm) was selected. A prototype of plastic scintillation optical array was built. The array was irradiated by a 60Co gamma source, and its timing response (2.74ns) was obtained in a Time of Flight (TOF) system which is sensitive to 50ps.
PIV Measurements of Jet Flow Mixing in the Vicinity of Rod Bundles Using Matched-Index of Refraction
Authors: Amini Noushin , Dominguez-Ontiveros Elvis E. , Estrada-Perez Carlos E. , Fortenberry Stephen D. , Hassan Yassin A.
Published: July 2009

In this study, the velocity field of impinging jets within a rod bundle was developed. Velocity measurements were accomplished using Particle Image Velocimetry (PIV). Additionally, Matched-Index of Refraction (MIR) techniques were implemented to allow the visualization of flow characteristics within interior areas of the rod bundle which would typically be obstructed. Such measurements are of importance and essential to the development of new models to predict the systems’ hydraulic behavior.
Component Reliability Considerations for New Designs and Extended Operation of Boiling Water Reactor (BWRs)
Authors: Kiss E.
Published: July 2009

To achieve high reliability for new designs and extended operation of Reactor Pressure Vessels and Internals it is mandatory to apply the technical knowledge gained during operation of the existing Plants to assure that sufficient “Margin” is built into the new design. This paper discusses the importance of four key structural degradation mechanisms that have been shown by operational experience to affect the reliability of the BWR. These are: 1) Stress Corrosion Cracking (IGSCC) of Stainless Steel and Nickel-based Alloys; 2) Irradiation Assisted SCC (IASCC) of Stainless Steel and Nickel-based Alloys; 3) Irradiation Embrittlement of RPV low alloy Steel; 4) Corrosion Assisted Fatigue of Carbon and Low Alloy Steel. While the focus of this paper is the BWR, the mechanisms discussed are equally applicable to the PWR, although the water chemistry effects and mitigations will be different.
Experimental and Numerical Investigation of Flashing Driven Natural Circulation System
Authors: Sajith P. P. , Vedula R. P. , Mitra Sushanta K.
Published: July 2009

Natural circulation with flashing can be utilized in the cooling of the moderator in advanced Heavy Water Reactor. A model natural circulation loop has been designed, fabricated and characterized in order to understand the various transients and the steady state conditions that occur during the flashing driven natural circulation process. Non-dimensional numbers are identified. Numerical simulation, using RELAP 5, has been conducted to model the natural circulation loops. The single channel loop is further modified to study flashing by using two parallel risers. Stable flashing could not be attained with both the channels. However, using parallel channels in the single phase region which combine into a single channel in the zone where flashing occur produced stable flow. It is observed that a stable flashing driven two-phase flow occurs only by reducing the inlet subcooling to a very low value with respect to the riser exit pressure. The presence of inlet restriction does not help in reducing the oscillation period, but the stable flashing was observed at lower power values. The initial pressurization and subsequent depressurization to the desired working pressure of the system reduces the flow instabilities considerably. It appears that non-dimensional Zuber number, Friction number and Froude number can be used to characterize flashing driven natural circulation systems.
Experiments to Investigate Flow Regime Transition for Steam and Subcooled Water From Stratified Flow to Slug Flow in Horizontal Pipe
Authors: Kadakia Hiral J. , Williams Brian G. , Schultz Richard R.
Published: July 2009

Steam flowing over horizontally-stratified subcooled water in a circular-cross-section pipe may result in condensation-induced water hammer (CIWH). This subject has been studied by a number of researchers and representative data are given by Bjorge and Griffith 1986 who studied the conditions that lead to CIWH. Bjorge & Griffith give a good description of the phenomena including its precursors and characteristics.
Analysis of Two-Phase Flow Instability in Multichannel System
Authors: Zhao Fu-Yu , Hou Su-Xia , Tai Yun
Published: July 2009

Two-phase flow instability in parallel multichannels is an important problem that affects operation safety of all large-capacity power boilers and nuclear reactor systems. Occurrence of instabilities and their modes of oscillations can be evaluated by investigating into a characteristic equation, its roots and composing channels transfer functions. It is also shown that a governing matrix is reduced to a diagonal one by using its eigenvalues, the oscillation modes being divided into number of channels separate fundamental modes. Characteristics of each oscillation mode are given by examining corresponding characteristic equations, which are applied for the prediction of oscillation modes of systems composed of a few slightly different channels.
Legal and Regulatory Issues Raised by Future Power Plant Design and Siting Considerations
Authors: Guyon Edwin F.
Published: July 2009

It is proposed that the regulations governing currently existing, as well as anticipated improved and evolutionary reactor designs (such as Gen III and Gen III+), may be inadequate to appropriately regulate newer and fundamentally different designs (such as Gen IV, Pebble Bed, FBR, as well as small long-lifetime units (Toshiba/CRIEPI). Recent interest has been raised in underground nuclear parks, medium to small semi-portable reactors to provide the energy for advanced oil recovery programs (from oil shale and tar sands) and other uses. This paper will identify an overall framework for proposed future licensing procedures not in conflict with existing statutes and regulations. The goal is to demonstrate that the extension of current laws and regulations into such contemplated areas will do much to reduce costs, simplify procedures, and enhance operational safety and security in the areas of proliferation, containment, and waste utilization and/or disposal.
Fluid Flow Analysis in a Pebble Bed Modular Reactor Using RANS Turbulence Models
Authors: Mkhosi Margaret , Denning Richard , Fentiman Audeen
Published: July 2009

The computational fluid dynamics code FLUENT has been used to analyze turbulent fluid flow over pebbles in a pebble bed modular reactor. The objective of the analysis is to evaluate the capability of the various RANS turbulence models to predict mean velocities, turbulent kinetic energy, and turbulence intensity inside the bed. The code was run using three RANS turbulence models: standard k-ε, standard k-ω and the Reynolds stress turbulence models at turbulent Reynolds numbers, corresponding to normal operation of the reactor. For the k-ε turbulence model, the analyses were performed at a range of Reynolds numbers between 1300 and 22 000 based on the approach velocity and the sphere diameter of 6 cm. Predictions of the mean velocities, turbulent kinetic energy, and turbulence intensity for the three models are compared at the Reynolds number of 5500 for all the RANS models analyzed. A unit-cell approach is used and the fluid flow domain consists of three unit cells. The packing of the pebbles is an orthorhombic arrangement consisting of seven layers of pebbles with the mean flow parallel to the z-axis. For each Reynolds number analyzed, the velocity is observed to accelerate to twice the inlet velocity within the pebble bed. From the velocity contours, it can be seen that the flow appears to have reached an asymptotic behavior by the end of the first unit cell. The velocity vectors for the standard k-ε and the Reynolds stress model show similar patterns for the Reynolds number analyzed. For the standard k-ω, the vectors are different from the other two. Secondary flow structures are observed for the standard k-ω after the flow passes through the gap between spheres. This feature is not observable in the case of both the standard k-ε and the RSM. Analysis of the turbulent kinetic energy contours shows that there is higher turbulence kinetic energy near the inlet than inside the bed. As the Reynolds number increases, kinetic energy inside the bed increases. The turbulent kinetic energy values obtained for the standard k-ε and the RSM are similar, showing maximum turbulence kinetic energy of 7.5 m2·s−2, whereas the standard k-ω shows a maximum of about 20 m2·s−2. Another observation is that the turbulence intensity is spread throughout the flow domain for the k-ε and RSM whereas for the k-ω, the intensity is concentrated at the front of the second sphere. Preliminary analysis performed for the pressure drop using the standard k-ε model for various velocities show that the dependence of pressure on velocity varies as V1.76.
Radiation Protection Technician Two-Year Associates of Applied Science Curriculum for National Implementation
Authors: Miller William H. , Jonassen David , Marra Rose , Schmidt Matthew , Easter Matthew , Ionas Ioan Gelu , Neumeyer Gayla M. , Etter Randy , Meffert Bruce , Graham Christopher C.
Published: July 2009

The U.S. Department of Labor awarded a $2.3 million grant to the University of Missouri-Columbia (MU) in 2006 in response to the need for well-trained Radiation Protection Technicians (RPTs). The RPT curriculum initiative resulted from significant collaborations facilitated by MU with community colleges, nuclear power plants, professional organizations, and other nuclear industry stakeholders. The objective of the DOL project is to help increase the pool of well-qualified RPTs to enter the nuclear workforce. Our work is designed to address the nuclear industry’s well-documented, increasingly significant need for RPTs. In response to this need, MU and AmerenUE’s Callaway Nuclear Power Plant first partnered with Linn State Technical College’s Advanced Technology Center (LSTC/ATC) to initiate a two-year RPT degree program. The success of this program (enrollments have been increasing over the past four years to a Fall 2007 enrollment of 23) enabled the successful proposal to the DOL to expand this program nationwide. DOL participants include the following partners: Linn State Technical College with AmerenUE – Callaway; Central Virginia Community College with AREVA; Estrella Mountain Community College with Arizona Public Service – Palo Verde; MiraCosta Community College with Southern California Edison – San Onofre; and Hill College with Texas Utilities – Comanche Peak. The new DOL grant has allowed redevelopment of the LSTC/ATC curriculum using a web-based, scenario driven format, benchmarked against industry training standards. This curriculum will be disseminated to all partners. Integral in this curriculum is a paid, three to four month internship at a nuclear facility. Two of the six new RPT courses have been developed as of the end of 2007. Four of five partner schools are accepting students into this new program starting in the winter 2008 term. We expect that these institutions will graduate 100 new RPTs per year to help alleviate the personnel shortage in this critical area of need.
New Codification Approach for the Design of NPP Containments With Metallic Liner
Authors: Be´cue Philippe , Me´zie`re Yves , Sperandio Morello , Sidaner Jean Franc¸ois
Published: July 2009

We address in this paper the case of a new generation PWR NPPs, which containment is equipped with a metallic liner on the inner face, in order to minimise leakage. A net of angles that, in addition to studs, constitute the anchoring system to the concrete, strengthens this metallic liner, also used as concrete shuttering during the construction phase. The thickness of the plate, the size and distribution of the anchors and the mechanical characteristics of the steel are the main parameters of the liner design. The accidental and in service loadings on the liner which are mainly due to the concrete pre-stressing and shrinkage and to the temperature inside the containment, can lead to local blistering. This phenomenon was observed on 900 MW PWR currently in operation in France. Difficulties related to the application of the available codification while using modern numerical methods are in a large extent due to the small strain allowable for the liner plate, considering the above loadings in addition with initial imperfections or failure of one or several studs. In order to cope with this problem, while respecting the safety requirements, a new codification approach has been developped.
Development on Dynamic Pressure Monitoring Method and Sensor for Long Pipeline Leak Detection
Authors: Chen Shili , Sun Yan , Wang Likun , Chen Pengchao , Tan Dongjie
Published: July 2009

A dynamic pressure sensor, which can be used to sample the long oil and gas pipeline leakage signal, is developed. Performances of the sensor are improved by using circuit simulation tools. Application experiments of the designed sensor show that the dynamic pressure signal is better suited for pipeline leak detection of pipeline internal pressure rapid changes occasions, and the using of the designed sensor can improve positioning accuracy.
Study on Oil and Gas Pipeline Leakage Real-Time Inspection System Based on Distributed Optical Fiber
Authors: Feng Hao , Jin Shijiu , Zhou Yan , Zeng Zhoumo , Chen Pengchao
Published: July 2009

A distributed optical fiber system used to detect pipeline leakage and lawless excavation is put forward in this paper. This system is based on Mach-Zehnder optical fiber interferometer theory, which uses three monomode fibers in one optical fiber cable to compose two Mach-Zehnder interferometers. Vibrations from leakage point and lawless excavation along the pipeline can be acquired by the optical fibers, so the vibrations occurred on the pipeline can be detected in real time. In this paper, the principle and the system construction are introduced, and the way of the fiber cable to influence the sensitivity is studied. And also, the polarization on the optical path is studied in this paper, and a new technology to eliminate “Polarization Debilitating” is put forward. With principle analysis and experimental results, it is demonstrated that the detection system’s measuring sensitivity and location accuracy for detecting leakage and lawless excavation are greatly improved when adopting this technology, and furthermore the cost is very low.
Research of Leak Detection and Location Method for Heat Oil Pipelines
Authors: Zhang Laibin , Chen Zhigang , Liang Wei , Wang Mingda
Published: July 2009

It is an effective method to detect leak using negative pressure wave (NPW). When heat oil pipelines in low transfer throughput and complex operational changes, usually noise will be very strong and feature signal of leak is difficult to extract. In order to improve quality of parameter information collected, a novel method based on Independent Component Analysis (ICA) is proposed to separate and filter weak aim signal from noise. In this paper signal processing principle based ICA is introduced and experiments are illustrated. The experimental results show that signal-to-noise ratio (SNR) of processed pressure signals is raised effectively and feature signal become easy to extract. At the same time, in heat oil pipelines pressure wave velocity is affected by oil and axial temperature drop. Location usually has obvious error. To solve this problem axial temperature drop is analyzed and velocity of NPW was revised. By means of Newton-Cotes integration method location formula is modified. The real experimental results show that the improved located formula made location accuracy from 2.5% to 1.0%.
Remote-Field Eddy Current Inspection Tool for Small-Diameter Unpiggable Pipelines
Authors: Burkhardt Gary L. , Goyen Todd H. , Parvin Albert J. , Peterson Ronald H. , Tennis Richard F.
Published: July 2009

Inspection of natural gas pipelines is necessary to ensure their integrity. Considerable pipeline mileage exists where the lines, particularly those in the smaller-diameter range, have internal restrictions and/or low pressure/flow rates. Conventional magnetic flux leakage (MFL) inspection pigs cannot be used because the product flow and pressure is not sufficient to propel the pig, and the large MFL magnets cannot readily move through restricted areas. To overcome these problems, an untethered, self-powered tool was developed that can adjust to inspect different pipe sizes and can retract to pass through obstructions such as elbows and tees. Southwest Research Institute developed a remote-field eddy current (RFEC) inspection system for detecting and characterizing pipe wall loss, and this system was integrated with Explorer II, a robotic transport device developed by Carnegie Mellon. The resulting tool has the capability to inspect 6- to 8-inch-diameter pipelines containing tight bends and tees, and can be launched, operated, and retrieved with the pipeline in service. This paper describes the RFEC inspection technology, the RFEC system modules developed for Explorer II, and preliminary test results.
Optimization of Short-Term Peak Shaving Scenarios for a Gas Pipeline Network
Authors: Zuo Lili , Wu Changchun , Fan Li , Wang Meng
Published: July 2009

PetroChina owns and operates the largest gas pipeline network in China of more than 10000 km in length, which includes the famous West-East gas pipeline, the first Shannxi-Beijing gas pipeline and the second Shannxi-Beijing gas pipeline etc. As an outstanding feature of the network, its two circuits of pipelines increases the flexibility of gas transmission and the guarantee of gas supply through the network. On the other hand, these two circuits complicate the topological structure, so that it is a challenge to work out an optimal operation scenario for the network. A steady and transient simulation model of the network has been built based on the gas pipeline network simulation software TGNET, and has been tuned by the historical operation data. By means of the model, several winter operation scenarios in 2007 have been simulated. The steady simulations of the network were carried out for the two planed daily flow-rates of West-East gas pipeline respectively, 41 MMSCMD and 45 MMSCMD. Given the steady operation scenarios determined by the steady simulations as the initial conditions, 4 typical short-term peak shaving scenarios in winter high load week have been analyzed, evaluated and optimized with transient simulations. The main difference of those peak shaving scenarios is the flow-rates of West-East gas pipeline and the regulating mode of underground gas storage named Dagang connected to Shanxi-Beijing gas pipeline system. The technologically and economically optimal peak shaving scenario and the optimal control pressure of end stations have been obtained. The research results shows that the actual control pressure of end stations are higher than the optimization results, indicating that the network has the potential of saving energy and reducing spending. These results not only guarantee the safety of gas supply but also reduce the spending of the gas pipeline network, offering an important value of direction for actual operation.
Numerical Simulation of Dynamic Ductile Fracture Propagation Using Cohesive Zone Modeling
Authors: Shim Do-Jun , Wilkowski Gery , Rudland David , Rothwell Brian , Merritt James
Published: July 2009

This paper presents the development of a dynamic ductile crack growth model to simulate an axially running crack in a pipe by finite element analyses. The model was developed using the finite element (FE) program ABAQUS/Explicit. To simulate the ductile crack propagation, a cohesive zone model was employed. Moreover, the interaction between the gas decompression and the structural deformation was simulated by using an approximate three-dimensional pressure decay relationship from experimental results. The dynamic ductile crack growth model was employed to simulate 152.4 mm (6-inch) diameter pipe tests, where the measured fracture speed was used to calibrate the cohesive model parameters. From the simulation, the CTOA values were calculated during the dynamic ductile crack propagation. In order to validate the calculated CTOA value, drop-weight tear test (DWTT) experiments were conducted for the pipe material, where the CTOA was measured with high-speed video during the impact test. The calculated and measured CTOA values showed reasonable agreement. Finally, the developed model was employed to investigate the effect of pipe diameter on fracture speed for small-diameter pipes.
Preliminary Failure Assessment for Spiral Welded Defects of Pipeline
Authors: Feng Qingshan , Lin Yi-Han , Wang Fuxiang , Li Bin
Published: July 2009

The spiral welded defect of steel oil transmission pipeline is one of the main causes resulting in pipeline leakage accident. Hence the failure assessment for known-size spiral welded defects is an important step to ensure the safety of defected pipeline. Lack of suitable criterion for assessing the spiral welded manufacture defects of pipeline network in China, is a difficult technology problem to be solved desirably. This paper first summarized the basic idea of preliminary failure assessment (Grade 1A of code BS 7910:2005) with some insight of our own understanding, and then applied the preliminary failure assessment to the spiral welded defects of oil pipeline, with the use of ultrasonic inspection data of Daqing-Tieling old pipeline from LingYuan to XinMiao, Northeastern China. The calculation of both fracture and plastic collapse failure for spiral welded defects indicates some detected flaws of pipeline are not safe as the internal pressure is greater than 4.5 MPa. A leakage accident of spiral welded pipeline in Western China is also assessed through fractography analyses and failure calculations. This paper concludes that the preliminary failure assessment provides useful outcome for reference in making decision of inspection, integrity assessment and repair of spiral welded pipeline, and hence is a step of fundamental importance and practical significance before more accurate data becomes available for higher grade assessment.
Fracture Propagation and Arrest in High-Pressure Gas Transmission Pipeline by Ultra High Strength Line Pipes
Authors: Makino Hiroyuki , Takeuchi Izumi , Higuchi Ryouta
Published: July 2009

The fracture arrest of high pressure gas pipelines is one of the keen subjects for application of high strength line pipes. To examine the arrestability of high strength line pipes against crack propagation, several full scale fracture propagation tests have been conducted. The fracture propagation tests of X100 or X120 under high pressure revealed that the existing models of arrest energy prediction failed to predict the arrest energies. By careful investigations of the test results, it is found that the failure in prediction is mainly due to the uncertainty of crack velocity curve prediction. On the other hand, accuracy of predicted gas decompression curve is relatively high even in the case of high pressure condition. Experimentally, the arrest energies have been determined by full-scale fracture propagation tests with increasing toughness arrangement. Different from actual pipeline, extremely low toughness pipe has been employed in crack initiation pipe with intention of getting steady state propagation. However, arrestability of pipe might be underestimated in the increasing toughness arrangement test as the initial crack velocity increases. Together with recalibrated crack velocity curve, Sumitomo model (HLP method with Sumitomo’s crack velocity curve) predicts that even toughness arrangement, which is the case of real pipelines, could arrest the propagating shear fracture in high pressure gas pipelines by X100.
Development of High Strength Heavy Wall Seamless Pipes of X80–X100 Grade for Ultra-Deep Water Application
Authors: Kondo Kunio , Arai Yuji , Hirata Hiroyuki , Hamada Masahiko , Hitoshio Keisuke , Hisamune Nobuyuki , Murase Tsuneo
Published: July 2009

This paper describes the development of high strength heavy wall seamless pipes of X80 to X100 grade for ultra-deep water application. Steel pipes with higher strength generally tend to have low fracture toughness either in pipe body or in weld joint and low weldability. Therefore, improvement of fracture toughness and weldability are particularly important with respect to development of higher strength seamless pipes. Metallurgical research in laboratory test was carried out and the effect of microstructure of quenched and tempered steel on strength and toughness was particularly investigated. As a result uniform lower bainite phase containing no or minimized coarse martensite-austenite (M-A) constituent at a quenched condition is suitable microstructure to perform high strength and high fracture toughness after tempering. The steel having such microstructure showed excellent performance even in the high strength grade of X100. Lowering a transformation temperature from austenite phase to bainite phase during quenching process is effective to obtain suitable microstructure by adding and controlling alloy elements such as Mn, Cr, Mo. In order to suppress an increase in carbon equivalent as Pcm value by addition of alloy element, lowering content of carbon is necessary. As a consequence of the low Pcm value mitigation of hardening in coarse grain heat affected zone (HAZ) and good toughness were confirmed by welding tests. A trial production of the developed steel based on a new metallurgical design mentioned above was conducted by applying inline heat treatment process in medium-size seamless mill. In conjunction with tremendously rapid cooling system of inline heat treatment facility the seamless pipes of the trial production achieve grades X80 of 40 mm wall thickness and X80 to X100 grades of 20 mm WT by changing tempering temperature. A good combination of high strength and good fracture toughness was confirmed.
Prediction of the Failure Pressure of Corroded Pipelines Subjected to a Longitudinal Compressive Force Superimposed to the Pressure Loading
Authors: Benjamin Adilson C.
Published: July 2009

Several methods for the assessment of corroded pipelines subjected to internal pressure loading are currently available, for example, the ASME B31G method, the RSTRENG 0.85dL method, the DNV RP-F101 method for single defects (Part B) and the RPA method. These methods do not take into account the effect of a longitudinal compressive force on the corroded pipeline failure pressure. When the corroded pipeline is subjected to a longitudinal compressive force superimposed to the pressure loading its failure pressure may be reduced. For a buried pipeline the most common source of a longitudinal compressive force is a temperature loading. A ground movement may also produce a longitudinal compressive force in the pipeline. In this paper a new method, named RPA-PLLC, is developed. This method is a modified version of the RPA method and can take into account the effect of a longitudinal compressive force on the corroded pipeline failure pressure.
Pigging Technique Research of Submarine Gas Line in the Bo-Xi Oil Field
Authors: Cheng Xiaojiao , Yu Da
Published: July 2009

In order to deal with the single seal of ball valves and the deformation of the plugged gas pipeline at low flow rate, a foam pig was successfully modified and used in the plugged submarine gas line of the Bo-Xi Oil Field.
Research Into Problems of Plugged Submarine Gas Line in the Bo-Xi Oil Field
Authors: Yu Da , Cheng Xiaojiao
Published: July 2009

Trough research on plugging problems of the submarine gas line in the Bo-Xi oil field, the cause of plugging, composition of plug stuff were found out, and a method to predict the position of hydrate plug is proposed. The accumulated liquid volume and the transmission efficiency of the pipeline were calculated. It is suggested that a special pig was developed to sweep off the accumulated liquid in the gas pipeline and to prevent formation of hydrate plug.
Performance of Corrosion Inhibitors at High CO2 Pressures
Authors: Sintoorahat Patchareeporn , Wairatpanich Aree , Chimam Suchada , Mongkholkhajornsilp Dayin , Kang Cheolho
Published: July 2009

The objective of this study was to evaluate the performance of two corrosion inhibitors (CI-A and CI-B) under conditions similar to the second PTT’s offshore pipeline. The experiments were carried out in flow-loop system, 36 m long, 10.16 cm diameter at 10.5 and 14 bar of carbon dioxide pressure, a temperature at 50°C. The performances of corrosion inhibitors were examined under conditions of superficial liquid velocity of 0.03 m/s and gas velocities of 6, 8 and 10 m/s in 0 and 3 degree inclinations using the ER probe and X65 weight-loss coupons for corrosion rate measurement at the top and bottom of pipe. According to flow characteristics, it was found that the smooth and wavy stratified flow occurred in 0 degree. For 3 degree inclination, wavy stratified flow with big waves was dominantly presented for all conditions. Corrosion inhibitor B showed a better performance than inhibitor A in all cases. For inhibitor B, the target corrosion rates of less than 0.1 mm/yr were achieved in all conditions with 50 ppm of inhibitor concentration whereas the amount of 75 ppm inhibitor concentration was required for CI-A. The color, turbidity, and emulsion tendency with corrosion inhibitors will be also discussed in this paper.
Leak Detection Method Based on Support Vector Machine
Authors: Fan XiaoJing , Zhang LaiBin , Liang Wei , Wang ZhaoHui
Published: July 2009

Assumptive and uncertain factors, few leak samples, complex non-linear pipeline systems are the problems often involved in the process of pipeline leak detection. Furthermore, the pressure wave changes of leakage are similar to these of valve regulation and pump closure. Thus it is difficult to establish a reliable model and to distinguish the leak signal pattern from others in pipeline leak detection. The veracity of leak detection system is limited. This paper presents a novel technique based on the statistical learning theory, support vector machine (SVM) for pipeline leak detection. Support Vector Machine (SVM) is learning system that uses a hypothesis space of linear functions in a high dimensional feature space, trained with a learning algorithm from optimization theory that implements a learning bias derived from statistical learning theory. SVM is based on the principle of structure risk minimization as opposed to the principle of empirical risk minimization in conventional techniques. Thus, SVM has good performance for classification over small sample set. In this paper, an overview of the limitations of traditional statistics and the advantage of statistical learning theory will be introduced. In this paper, an SVM classifier is used to classify the signal pattern with few samples. Firstly, the algorithm of the SVM classifier and steps of using the model to identify leakage signals are studied. Secondly, the classification results of the experiment show that SVM classifier has high recognition accuracy. In addition, SVM is compared with neural network method. Then the paper concludes that in terms of classification ability and generalization performance, SVM has clearly advantages than neural network method over small sample set, so SVM is more applicable to pipeline leak detection.
A Fundamental Understanding of Erosion-Corrosion of Hydrotransport Pipes in Oil Sands Slurry
Authors: Tang X. , Xu L. Y. , Cheng Y. Frank
Published: July 2009

Erosion-corrosion (E-C) of X-65 pipe steel was investigated in a simulated oil sand slurry through an impingement jet system. Measurements of weight-loss and potentiodynamic polarization curves combined with optical microscopy observation were performed to determine the synergism of corrosion and erosion in E-C of steel. It was found that passivity of the steel developed in static oil-water emulsion cannot be maintained in the flowing fluid due to the enhanced activity of the steel upon impingement of the emulsion/slurry. The effect of slurry impact angle on E-C of steel is complex, depending on the magnitude and synergism of shear stress and normal stress exerting on the electrode surface. There is a synergism of corrosion and erosion in E-C of steel. The contributions of corrosion and erosion to E-C rate of the steel in oil sand slurry rank approximately 30% and 70%, respectively. Erosion dominates the E-C of X-65 steel in oil sand slurry.
A New Pipeline Repair System and Its Application in China
Authors: Liu Guo , Wang Xiuyun , Lu Minxu
Published: July 2009

For the past decade composite materials has been widely accepted as a repair method for damaged gas and liquid transmission pipelines. Composite wrap can serve as an alternative to the traditional pipeline repair practices such as pipeline replacement or the installation of full-encirclement steel split sleeves. A carbon-fiber/epoxy composite wrap system has been developed to rehabilitate and restore original operational strength to corroded and eroded pipelines and piping systems. This system is a permanent, cost-effective pipeline repair technology, suitable for non-leaking defects such as pits, dents, gouges, and external corrosion. This composite wrap system has been widely used in China for rehabilitations of numerous gas and petroleum pipelines.
Recent Developments of Oil and Gas Transmission Pipeline Steels: Microstructure, Mechanical Properties and Sour Gas Resistance
Authors: Pourkia Navid , Abedini Morteza
Published: July 2009

In modern oil and gas transmission pipeline steels technology, a suitable microstructure is an important factor for improvement of strength, toughness and sour gas resistance. Therefore, thermo-mechanically controlled rolling processes have been developed and their microstructures have been changed from ferrite-pearlite to acicular ferrite. Moreover in the recent years extensive attempts have been made to improve pipeline steels properties, which include: i) Ultra fine-grained steels, which are produced by optimized usage of dynamic recrystallization and strain-induced transformation with about 1μm equiaxed ferrite grain size. ii) Ultra low carbon steels with less than 0.025 wt% carbon and significant amount of Mo and Nb microalloying elements. iii) Ultra fine acicular ferrite steels, which are produced by application of more accurate controlled thermo mechanical processes and accelerated cooling. iv) Ultra high strength X100 and X120 grade steels, which are produced by thermo-mechanically controlled processes and heavy accelerated cooling. The former is without special technological changes and mainly consist of low carbon upper bainitic microstructure while the latter needs more technological developments with very little amount of boron and mainly consists of lower bainitic microstructure. This paper gives an overview of these new pipeline steels in viewpoint of microstructure, mechanical properties and sour gas resistance. The studies show that ultra fine acicular ferrite is the best alternative microstructure for nowadays ordinary pipeline steels, but because of numerous advantages of ultra high strength pipelines steels which finally reduce the cost of pipeline projects, the trend of the investigations is focused on further development of these steels. Moreover, acicular ferrite microstructure which is generally accepted by pipeline engineers and it is just in doubt because of its differences with acicular ferrite microstructure of weld metal and numerous offered definitions, is completely described.
Cut Point Optimization of Diesel Oil: Gasoline Interfaces
Authors: Gavi´n Sergio D.
Published: July 2009

This paper presents the technical solution developed by Repsol YPF in one of its pipeline systems to reduce contaminated product generation as a result of the interfaces that are generated between diesel oil and gasolines during transport.
Comparative Analyses on Calculation of Contaminated Volume of Multi-Product Pipeline Caused by Stoppage
Authors: Gong Jing , Zheng Chengzhen , Qin Qin
Published: July 2009

Due to the failure and maintenance of the equipments, stoppage of the multi-product pipeline is inevitable and it increases the contaminated volume. However, studies on the mechanism of contaminated products generation and its increasing trend are still not satisfactory due to the uncertainty of the main factors that influence the increasing of the contaminated volume. These made the calculation of the contaminated volume caused by stoppage become the technological problem in the batch transportation of multi-product pipeline. It has been a subject that deserves continuing study. In order to calculate the quantity of contaminated volume of multi-product pipeline caused by stoppage accurately, an analytical model is developed in detail theoretically. To avoid the complexity in solving the equation, the model is further simplified. The simulation results are compared with the operational data of Lan-Cheng-Yu multi-product pipeline (LCYPP) and the deviation in calculation was within 0.2. After that, the reasons for the deviation are analyzed qualitatively. The results prove the feasibility and effectiveness of the model. It also provides a good scheme for calculating and analyzing contaminated volume of multi-product pipeline caused by stoppage and establishes the theoretical foundation for the operation and management of multi-product pipeline.
Ignition Probability for High Pressure Gas Transmission Pipelines
Authors: Acton Michael R. , Baldwin Philip J.
Published: July 2009

For most fuels transported by pipeline, whether or not ignition of an accidental release occurs is a critical factor in determining the extent of the resulting hazard. The probability of ignition is therefore a key input when undertaking pipeline risk assessments and the value chosen is a direct multiplier of the risk calculated. Typically, the ignition probability assigned is based on an analysis of historical data. However, the pipeline industry has a good safety record and major incidents are rare, sometimes resulting in widely differing values being used due to the scarcity of reliable data. For high pressure natural gas transmission pipelines, it is observed that ruptures of large diameter underground pipelines operating at high pressures can result in ignited releases even in remote areas with no obvious ignition sources present. Conversely, failures of small diameter pipelines operating at lower pressures rarely result in ignited releases, suggesting that ignition sources generated as a result of the failure event itself may be significant in causing ignition of high pressure natural gas releases from underground pipelines. The results of analysis previously reported at IPC2002 indicated a trend for the ignition probability to increase with pd2, with p the pipeline operating pressure (bar) and d the pipeline diameter (m). The relationship forms the basis of the default ignition probabilities recommended for use in the PIPESAFE package developed for risk assessment of gas transmission pipelines. Since the previous study was carried out, the number of pipeline rupture incidents in the dataset used has increased by about 20%, and following a recent review, the statistical analysis has been extended and refined. This paper reports the results of recent analysis of the most comprehensive incident dataset available to Advantica for natural gas transmission pipelines, presenting the correlation derived from a simple statistical analysis together with consideration of possible physical explanations for the trends observed based on an ongoing programme of research into the causes of ignition.
Experimental Study of Fatigue Crack Overload Retardation in X80 Grade Steel
Authors: Duan Qingquan , Zhang Hong , Yan Feng
Published: July 2009

The tests of fatigue crack overload retardation were performed to gain a some what deeper understanding of overload retardation. We present an experimental investigation of fatigue crack retardation behavior caused by intermediate single peak tensile overload under constant amplitude cyclic loading. The compact tension (CT) specimens of API grade X80 pipeline steel were used in fatigue test. The results show there was an instant crack extension during overloading for the tested overload ratios. As soon as the overload cycle was removed, instant delay in crack growth occurred. The results should be of interest for fracture mechanics prediction models on fatigue crack growth under variable amplitude loading and overloading effect for oil and gas pipelines.
Subscour Displacement in Clays From Physical Model Tests
Authors: Been Ken , Sancio Rodolfo B. , Ahrabian Djavid , van Kesteren Walther , Croasdale Ken , Palmer Andrew
Published: July 2009

A subscour soil displacement model is a key component to determine the safe burial depth of offshore pipelines in ice scoured environments. In order to calibrate numerical models and physical tests carried out in geotechnical centrifuges, 3D ice scour tests were carried out in a dredging flume at a scale approaching that of observed scour depths in the Caspian sea. Two soil failure mechanisms were observed. For steep keels, the soil is mainly pushed up into a mound in front of the keel. For shallow angle keels most of the scoured soil is forced under the keel and to the side of the indentor. Each mechanism results in a different subscour displacement pattern. Subscour displacement equations that include the effect of soil properties and keel angle are presented. While these equations are considered an improvement on existing sub-scour models, there remain limitations to their application in 3D sub-scour until further information relating scour depth and width to soil strength becomes available.
A Quasi-Distributed Optical Speckle Sensor and Its Application in Pipeline Security
Authors: Li Jun , Chen Pengchao , Cai Yongjun , Tan Dongjie , Zhou Hengzhang
Published: July 2009

A novel fiber optical speckle sensor based on multimode interference for underground pipeline intrusion detecting is investigated both theoretically and experimentally. The sensor utilizes a single mode to multimode to single mode (SMF-MMF-SMF) structure as a sensing unit, which cascade to create a quasi-distributed optical sensor. To pave it near the underground pipeline we can detect any valid intrusion caused by motion, sound or vibration acts on the fiber. Experimental test shows that the detecting distance can be about 30Km and the locating accuracy of intrusion event is ±500m. Compared with Mach-Zehnder interferometer based configuration it has a much higher sensitivity.
Pipeline Acoustic Pre-Warning System and Method of Signal Analysis
Authors: Chen Pengchao , Cai Yongjun , Tan Dongjie , Sun Yi , Ai Muyang , Lin Song
Published: July 2009

This paper describes a new acoustic pre-warning system for pipelines, aimed at preventing third party damage by monitoring the pipeline acoustic signals. Many environmental factors, such as the by-passing of vehicles and pedestrians, could introduce background noise into long distance transmission of pipeline acoustic signals. As a result, normal pipeline acoustic pre-warning system is disturbed to identify abnormal events. In this work, statistical methods were applied to signal analysis in order to extract feature parameters of different events. Then the optimal feature subset was obtained by gene arithmetic to differentiate hazardous events between normal events effectively. PetroChina has applied the new pre-warning system to their long distance transmission pipelines and the system operates well.