bluuebunny/crossref_metadata_2025 huggingface dataset:
Fuel Assembly Instrument Tube Tie-Rods
Authors: Wood John D. , Montgomery Larry
Published: July 2009

In March 2001, a 17×17 fuel assembly top nozzle separated from a fuel assembly while being handled in the spent fuel pool and suspended from the spent fuel handling tool. The failure mechanism was later determined to be Inter-granular Stress Corrosion Cracking (IGSCC) of the stainless steel sleeves that provide the connection between the top nozzle and the thimble tubes to form the fuel assembly skeleton. The IGSCC was attributed to spent fuel pool chemistry. Further investigation found that the failure occurred at the bulge joints which connect the 304 sleeves to the zirconium thimble tubes. The corrosion occurred at the peak of the bulge in a high stress region. The susceptible fuel assemblies are the ones having their sleeves fabricated out of “304” stainless steel. The sleeves were changed to “304L” stainless steel to avoid this risk with subsequent fuel. There are more than 18,000 IGSCC susceptible fuel assemblies in spent fuel storage pits at approximately 25 different plants. In order to meet handling needs for IGSCC affected fuel, Westinghouse developed a solution known as the Instrument Tube Tie-Rod (ITTR) as a solution for long term handling and storage. The ITTR is a metal tube that extends from the top nozzle adapter plate through the instrument tube to the bottom nozzle. It then acts as a means to reinforce the connection between the top nozzle and the balance of the fuel assembly. The ITTR is only applicable to 15×15 and 17×17 fuel types because the center location of the instrument tube. The ITTR has been designed to carry the weight of the fuel assembly during lifting/handling so that in the event that a top nozzle separates from the fuel assembly, the load is transferred directly from the top nozzle to the bottom nozzle. This design allows the fuel assembly to be handled with the standard spent fuel handling tool and procedures. Utilizing the instrument tube for the ITTR installation also allows fuel assembly core components, such as RCCAs, Thimble Plugs and Burnable Poison Assemblies to be stored in or removed from the fuel since the thimble tubes remain open. Westinghouse’s ITTR solution not only returns and ensures the structural integrity of an IGSCC affected fuel assembly (FA) while stored in either the spent fuel pool or in a dry cask but also allows any insert design to be stored in the fuel assembly. The following paper will highlight the considerations that Westinghouse undertook while in development of the ITTR project. These include the fundamental design considerations for the Instrument Tube Tie-Rods, analysis and installation tooling system used to install these at a reactor site.
Determining the Value of Monitoring and Diagnostics
Authors: Cook Bruce M.
Published: July 2009

Conventional wisdom says that condition monitoring and on-line diagnostics of plant equipment and instrumentation and control systems can provide economic benefits to the nuclear utility. However, placing a dollar value on these benefits is difficult for a number of reasons. Maintenance crew sizes have a practical minimum to address staffing requirements. Reducing the amount of maintenance activity does not necessarily result in man-power savings. Regulatory constraints limit the extent to which probabilistic arguments can be relied on to avoid or defer preventive maintenance of safety-related equipment. Increasing the instrumentation of equipment to support advanced diagnostics can result in prohibitive hidden costs in change paperwork not to mention the direct cost of the sensors and cables. Although the use of wireless technology can offset this somewhat, without a clear understanding of the economic value of monitoring and diagnostics the utility has problems in deciding where its upgrade dollars are best spent; and the vendor has difficulty in developing products that delight the customer. In order to fill this gap in understanding, a workshop was held between monitoring and diagnostic experts at Westinghouse and utility representatives to define the value proposition for predictive diagnostics in operating plants. The objectives of this workshop were to: 1) determine where monitoring and diagnostics can be used to the benefit of the plant, 2) identify technologies available to apply to monitoring and diagnostics, 3) enumerate the barriers to installation of advanced monitoring and diagnostics, 4) establish value added propositions for efforts by the utility, by major vendors such as Westinghouse, and by sub-vendors, and 5) prioritize product development to provide the largest immediate benefit to the utilities. This paper discusses the outcome of that workshop and the directions of future developments in the area of monitoring and diagnostics of plant equipment and Instrumentation and Control.
AP1000 Verification of Water Sources for Long-Term Recirculation Cooling Following a LOCA
Authors: Andreychek T. S. , Schulz T. L. , Densmore W. E. , Brown A. C.
Published: July 2009

The AP1000 Nuclear Power Plant uses natural recirculation of coolant to cool the core following a postulated Loss Of Coolant Accident (LOCA). Recirculation screens are provided in strategic areas of the plant to remove debris that might migrate with the water in containment and adversely affect core cooling. An evaluation of the potential for debris to plug the AP1000 recirculation screens was performed consistent with the guidance identified in Regulatory Guide 1.82 Revision 3, the Pressurized Water Reactor (PWR) Industry Guidance of NEI 04-07, and the Nuclear Regulatory Commission’s Safety Evaluation on NEI 04-07. The evaluation considered various contributors to screen plugging including debris that could be produced by a LOCA, resident containment debris and post-accident chemical products that might be generated in the coolant pool that forms on the containment floor post-accident. The evaluation accounted for the AP1000 containment design, equipment locations, recirculation screen redesign and containment cleanliness program. A unique aspect of this evaluation is the use of available industry data and its application to the AP1000 design to support the evaluation. Specifically, available industry data from existing plant walkdowns was used to both characterize the fibrous and particulate debris that could comprise resident debris in containment prior to the LOCA, and estimate the amount of that debris. The evaluation also combined generic PWR Industry containment sump chemical effects information with AP1000 specific post-accident coolant chemistry and sump transient conditions to evaluate potential chemical effects. The collection of resident containment debris on the recirculation screens in the post-LOCA recirculation mode may result in a head loss across containment recirculation screens that could restrict the recirculation flow required to cool the core effectively. Using specific design features of the AP1000, the debris loading evaluated from latent containment debris and post-accident chemical effects and conservatively applying an available screen head loss correlation, the head loss across the AP1000 containment recirculation screens due to the collection of latent debris on the screen under natural circulation conditions was calculated. Calculations were also made for pressure drop across the AP1000 In-Containment Refueling Water Storage Tank (IRWST) screens resulting from latent containment debris accumulation on those screens under accident conditions. Finally, calculations were made for pressure drops at the AP1000 core resulting from debris accumulation on the bottom of the fuel. This paper will present the methods used to apply the available PWR Industry data to the AP1000 design, along with the results of the calculations performed which demonstrate the acceptability of the design of the AP1000 recirculation screens.
Simulations of Basic Gas Mixing Tests With Condensation in the PANDA Facility Using the GOTHIC Code
Authors: Andreani Michele , Paladino Domenico , George Tom
Published: July 2009

In the framework of the OECD SETH project, a number of experiments related to safety issues in the containment of a nuclear reactor have been performed in the large-scale facility PANDA. The tests have been designed to provide an adequate database for basic assessment of CFD and advanced lumped parameter (LP) codes. The test geometry consists of two interconnected vessels (compartments) with fluid injected in one vessel. The gas distribution in the injection vessel and the distribution of gases and the propagation of the stratification in the adjacent vessel are measured. Four of these tests were performed with initial and boundary conditions that resulted in substantial condensation rates. Three of these experiments featured vertical injection (with production of a plume), and in one, the transient response due to a high-momentum horizontal injection (jet) was investigated. The injected fluid was either saturated steam or a superheated mixture of steam and helium, and the fluid initially present in the vessels was pure air. These experiments have been analysed with the advanced containment code GOTHIC, and the main results are presented here. In general, the results obtained with the code and the standard mesh were in good agreement with the data. Limitations in modeling local phenomena controlled by complex flow patterns (e.g. heat transfer in the region of an impinging jet) and the need for refined meshes to reproduce certain aspects of the transients (e.g. erosion of the interface between layers of different gas composition) were also identified.
ACR-1000® Plant Layout
Authors: Pedherney Brian , Elgohary Medhat , Alizadeh Justin
Published: July 2009

Atomic Energy of Canada Limited (AECL) has established a successful, internationally recognized line of CANDU® reactors that use heavy water moderator and pressure tubes; in particular the medium-sized CANDU-6 reactor. AECL has consistently adopted an evolutionary approach to the enhancement of CANDU nuclear power plant designs over the last 30 years. This approach has been extended further in the development of the ACR-1000®. The ACR-1000 design has evolved from AECL’s in-depth knowledge of CANDU structures, systems, components and materials, as well as the experience and feedback received from builders, owners and operators of CANDU plants. While retaining the proven strengths and features of CANDU reactors, the ACR design incorporates innovations and state-of-the-art technologies where appropriate. Part of this innovation is to develop an efficient and optimized plant layout that includes diverse features and requirements from many engineering disciplines. The ACR-1000 plant layout satisfies safety requirements and regulations and includes input from construction, operations and maintenance feedback from existing stations/utilities, while maintaining the process functional configuration for the overall layout of the plant, building and systems. This paper discusses a number of key aspects in developing the ACR-1000 plant layout design using representative sketches and 3D CADDS illustrations.
Competitiveness of Small-Medium, New Generation Reactors: A Comparative Study on Capital and O&M Costs
Authors: Carelli Mario D. , Mycoff Clark W. , Garrone Paola , Locatelli Giorgio , Mancini Mauro , Ricotti Marco E. , Trianni Andrea , Trucco Paolo
Published: July 2009

Smaller size reactors are going to be an important component of the worldwide nuclear renaissance. An inappropriate application of the economy of scale would label the small-medium size reactors as not economically competitive with larger plants because of capital costs ($/kWe) and O&M costs ($/kWh) that would appear to be significantly higher. However, the economy of scale applies only if the considered designs are similar, which is not the case here, since the small size allows original design solutions not accessible to large size reactors. In the paper the historical trend of capital costs vs. plant size is estimated from literature, and a reference exponent factor for the economy of scale for the light water reactor is derived. Then the paper identifies and briefly discusses the various factors which, beside size, contribute in differentiating the capital cost of smaller reactors with respect to large reactors. In this reference frame the evaluation for of the following factors is provided: · design characteristics · modular build · multiple units · accelerated learning in construction · operation, and shorter construction time. The IRIS reactor is used as the example of small modular reactor (SMR), but the analysis and conclusions are applicable to the whole spectrum of small nuclear plants. The results show that when all these factors are accounted for in a set of realistic and comparable configurations, and with the same power installed in the site, the capital costs of small and large plants installations are practically equivalent. Considering the O&M cost the paper shows how the plant size is not the only and fundamental cost driver. In fact there is a range of other factors (e.g. location, regulatory issues, capacity factor, plant obsolescence and number of reactors on a site) able to influence the annual O&M cost for a specific plant. The paper provides a preliminary evaluation of these factors by historical analysis of reactors built in the United States, concluding, also in this case, that when all the factors are considered the difference between the average cost ($/KWh) of Large Size vs. SMR is about 20% less than would be expected.
ACR-1000® Constructability and Modularization
Authors: Byrne J. , Elgohary M. , Canas B. , Shemavonian D. , Ricciuti R. , Hiebert L.
Published: July 2009

Many industries are using skids, modules and prefabrications to enhance construction productivity, reduce schedules and thus reduce costs. The leaders in this regard are offshore oil and gas, chemical and refinery, ship building, etc. Atomic Energy of Canada Ltd. (AECL®) has had considerable success at the Qinshan Nuclear Power project in China with the use of modularization, which proved extremely effective in paralleling of activities and shortening the schedule. Extensive use has been made of skids and modules in Japan and this also has proven effective in shortening schedules in the construction of nuclear power plants. Secondary benefits of modularization and prefabrication include decreased site congestion and logistical issues, increased worker safety, and better quality control of fabrication. Modules and prefabrication allow work to be shifted to areas where skilled trades are more readily available from a site where skilled trades are very limited. One of the objectives for the ACR-1000® (Advanced CANDU Reactor®) project is to produce a design to allow for a very secure construction schedule. The construction method and strategy, consisting of extensive use of prefabrication and modularization, has been defined very early in the ACR-1000 conceptual phase of the layout and design process. This is addressed through a constructability programme that integrates the civil design with site erection and module installation. This paper presents the ACR-1000 construction strategy and methods and show examples of how the integrated civil design approach with modularization and prefabrication are utilized to shorten the construction schedule and reduce the project risk.
Simulation of the Operation in Passive Mode of Reactor Cavity Cooling System of High-Temperature Gas-Cooled Reactor
Authors: Matev Alex
Published: July 2009

The Reactor Cavity Cooling System (RCCS) of a High-Temperature Gas-Cooled Reactor (HTGR) may be required to operate in a “passive” mode when heat is removed from the reactor cavity by letting RCCS water inventory to boil off to atmosphere. Overheating of the reactor cavity concrete walls may lead to a failure of the reactor vessel support structures and its shift off the design position. Dislocation of the massive reactor vessel may cause multiple ruptures of pipes, connected to both the upper and lower vessel heads. Such breaks of the reactor pressure boundary will enable air ingress into the core, fuel oxidation and overheating, and possible release of fission products into the environment. The computer code TINTE [3] was used to simulate a “Depressurized Loss Of Flow Circulation (DLOFC) Without Reactor Scram” accident and determine from its results the magnitude, axial distribution, and time dependence of the heat flux on the RCCS cooling panels. The computer code RELAP [4] was used to model the operation in “passive” mode of one RCCS train, consisting of a tank and four standpipes. This paper describes the application of both RELAP and TINTE for the simulation of RCCS operation in passive mode. The main conclusion from this analysis is that the proposed way of using both codes is suitable to perform scoping studies and design evaluation of RCCS of a pebble-bed HTGR.
Steady Thermal Hydraulics Analysis for a Graphite-Moderated Channel Type Molten Salt Reactor
Authors: Zhang Dalin , Qiu Suizheng
Published: July 2009

The Molten Salt Reactor (MSR) is one of the six GENIV systems capable of breading and burning. In this paper, a graphite-moderated channel type MSR was selected for conceptual research. For this MSR, a ternary system of 0.15LiF-0.58NaF-0.27BeF2 was proposed as the reactor fuel solvent, coolant and also moderator simultaneously with ca.1 mol% UF4 dissolving in it, which circulates through the whole primary loop accompanying fission reaction only in the core. 169 hexagonal graphite elements, each with a central fuel channel, are arranged in the core symmetrically by 30° angles. The theoretical models of the thermal hydraulics under steady condition are conducted in one-twelfth of the core and calculated by the numerical method. The DRAGON code is adopted to calculate the axial and radial power factors. The flow and heat transfer models in the fuel salt and graphite are founded basing on the fundamental mass, momentum and energy equations. The calculated results show the detailed mass flow distribution in the core; and the temperature of the fuel salt, inner and outer wall in the calculated elements along the axial direction are also obtained.
Development of ABWR Feedwater Pump and Controller Model
Authors: Huang Hui-Wen , Shih Chunkuan , Hung Hung-Chih , Chen Shu-Chuan , Wang Li-Hsin , Liao Ben-Ching
Published: July 2009

This work developed a stand-alone ABWR (Advanced Boiled Water Reactor) feedwater pump and controller model which was incorporated with a simplified reactor vessel and steam line model. The purpose of this work is to improve the existing model in PCTran-ABWR, a nuclear power plant (NPP) simulation code. INER has been using this computer code as an NPP simulation model for Software Safety Analysis (SSA) and software Fault Injection (FI) of digital instrumentation and control (I&C) research for years. The feedwater pump model includes three turbine-driven feed water pumps and one motor-driven feed water pump. The feedwater controller includes a one-element / three-element water level controller and a specific feedwater speed controller for each feedwater pump. The feed water turbines are driven by the steam from main steam line. As a result, the reactor dome pressure can affect the driving force of the three turbine-driven feed water pumps. It means if the dome pressure becomes low enough, the turbine-driven feed water pumps cannot function normally. The reactor dome pressure transient also affects the pressure difference of feedwater pump discharge pressure and the reactor dome pressure, which can actually affect the feedwater flow rate and reactor water level. The time-lag of feedwater control valve is also considered in this model. Hence, the slower response of turbine-driven feed water pump than that of motor-driven feed water pump can be observed. A number of test cases namely step change of dome pressure, load rejection, and four tests of feedwater pumps transfer were performed in this work to demonstrate the feasibility of dynamic response of this model. Therefore, this model will be implemented into the existing PCTran-ABWR plant simulation code to improve the response of feedwater pump and controller model. This stand-alone model can also be a feedwater control strategy tool to observe the possible responses of various feedwater control architectures.
Realistically Improved Finite Element Analysis of Spring Supports in a Nuclear Fuel Spacer Grid
Authors: Kim Jae-Yong , Yoon Kyung-Ho , Kim Hyung-Kyu
Published: July 2009

The most important function of grid springs in a spacer grid is to position the fuel rods appropriately using a friction force and to prohibit the fuel rods from dropping during a normal reactor operation. While the fuel burn-up increases, spring force of grid springs decreases because the spring stiffness of grid springs is degraded by a high temperature and an irradiation effect in a reactor core. Therefore this phenomenon has to be reflected when the initial spring force of a grid spring is being designed. Usually, characterization tests of grid springs are conducted to verify designed grid springs have suitable spring forces. (Kim, 2007) FE model using a contact definition and rigid beam elements for a welding bead for predicting the spring stiffness without any spring test was established and verified in a previous research. In those days, two assumptions were used and the analysis for an unloading process was not included in spite of its importance for a spring design. In this paper, the fact that the assumptions have no effect on the analysis results is proven and a realistically improved FE analysis method using coupling constraints for a welding bead is suggested for investigating the spring’s characteristics under an in-grid boundary condition.
French Codes Used for EPR and Comparison With ASME Practices
Authors: Faidy Claude
Published: July 2009

On December 2005, the French regulator issued a new regulation for French nuclear power plants, in particular for pressure equipment (PE). This regulation need first to agree with non-nuclear PE regulation and add to that some specific requirements, in particular radiation protection requirements. Different advantages are in these proposal, it’s more qualitative risk oriented and it’s an important link with non-nuclear industry. Only few components are nuclear specific. But, the general philosophy of the existing Codes (RCC-M, KTA or ASME) have to be improved. For foreign Codes, it’s plan to define the differences in the user specifications. In parallel to that, a new safety classification has been developed by French utility. The consequences is the need to cross all these specifications to define a minimum quality level for each components or systems. In the same time a new concept has been developed to replace the well known “Leak Before Break methodology” by the “Break Exclusion” methodology. This paper will summarize the key aspects of these different topics and regularly compare with ASME practices.
Influence of Pipeline Misalignment on the Local Buckling Response
Authors: Al-Showaiter Aiman , Taheri Farid , Kenny Shawn
Published: July 2009

Pipeline transportation systems are generally constructed by connecting individual linepipe segments through joint-to-joint end girth welds. The mechanical behavior of shell structures, such as a pipeline, can be sensitive to initial imperfections in geometry, material properties and loading. These initial imperfections can affect the pipeline load-deformation response and reduce the limit moment and strain capacity. Initial geometric imperfections may result from fabrication processes, as related to variations in the pipeline diameter and wall thickness. These geometric imperfections may have circumferential and longitudinal variation. During the construction process, the initial geometric imperfections may be the result of end misalignment due to longitudinal pipeline offset and ovality. This study examines the influence of initial geometric imperfections associated with joint-to-joint misalignment that may be present due to the girth welding process when connecting pipeline segments. A parametric analysis was conducted using finite element methods to assess the effects of diameter-to-wall thickness ratio, internal pressure, axial force, misalignment amplitude, and misalignment orientation, on the local buckling response of pipelines. Through this parametric analysis, the moment-curvature response, variation in section geometry with increasing curvature, limit moment and strain capacity were all examined. Comparison of the results with those obtained from the engineering codes and recommended practice is also presented. This study concludes that offset misalignment orientation, with respect to the bending axis, and the increasing misalignment imperfection amplitude both affect the pipeline peak moment and global strain capacity at the limit moment.
Required Linepipe Properties for High Strain Applications and Possible Resolution by Pipe Manufacturing Technology
Authors: Asahi Hitoshi , Tsuru Eiji
Published: July 2009

Application of strain based design to pipelines in arctic or seismic areas has recently been recognized as important. So far, there has been much study performed on tensile strain limit and compressive strain limit. However, the relationship between bending buckling (compressive strain limit) and tensile strain limit has not been discussed. A model using actual stress strain curves suggests that the tensile strain limit increases as Y/T rises under uniaxial tensile stress because a pipe manufacturer usually raises TS instead of lowering YS to achieve low Y/T. Under bending of a pipe with a high D/t, an increase in compressive strain on intrados of a bent pipe at the maximum bending moment (ε-cp*) improves the tensile strain limit because the tensile strain limit is controlled by the onset of buckling or ε-cp* which is increased by lowering Y/T. On the other hand, under bending of a pipe with a low D/t, the tensile strain limit may not be influenced by improvement of buckling behavior because tensile strain on the extrados is already larger than the tensile limit at ε-cp*. Finally, we argue that the balance of major linepipe properties is important. Efforts other than the strict demands for pipe properties are also very important and inevitable to improve the strain capacity of a pipeline.
Prediction of Gas Transport Through Ground and Atmosphere to Determine the Ability of Airborne Leak Detection Methods to Detect Pin-Hole Leaks From Buried Gas Pipelines
Authors: Botros K. K. , Ennis C. J. , Zhou J. , Watson B.
Published: July 2009

New technologies for airborne detection of gas pipeline leaks have been introduced to the pipeline industry and have undergone several field-testing attempts. These technologies are based on an airborne detection device mounted on a small aircraft flying along the right of way (ROW) of the pipeline. It is proposed that during initial commissioning of the pipeline, leak testing is performed by first pressurizing the pipeline section with natural gas, and then launching an airborne leak detection aircraft to fly along the ROW in multiple passes. A delay between the completion of the pipe section pressurization and the launching of the leak detection aircraft is required in order to establish a discernable concentration of methane in the atmosphere. This ‘wait time’ includes the time required for the leak to penetrate upwards through the backfill to the ground surface and to subsequently diffuse into the atmosphere. Accuracy and reliability of these technologies clearly depend on the leak rate (i.e. leak hole size and line pressure), the depth and properties of the backfill, atmospheric conditions, prevailing wind speed and direction, and the properties of air including diffusion parameters of natural gas into air. Additionally, the accuracy of these airborne methods also depends on the altitude at which the aircraft is flying along the pipeline ROW and the degree of offset of the flight path from the centerline of the ROW. The present paper outlines the fundamental governing equations and solution techniques to predict the temporal-spatial-dependent diffusion of gas leakage from a pinhole into the ground. The mechanism of the gas transport through the ground, whether it is advective or diffusive, is dependent on the Pe´clet number, which is predominantly driven by the leak rate. Likewise, the fundamental governing equations along with solution techniques to predict the diffusion of the breakthrough flux of gas at the ground level into the atmosphere are formulated. Results of the time for the gas to break through at ground level, the concentration and gas flux at ground level, and the vertical and lateral concentration profiles of the gas in the atmosphere are all presented to facilitate assessment of the sensitivity of the airborne leak detection methods to the different ground and atmospheric parameters for a given leak rate at a given source depth.
An Analytical Interaction Rule for Corrosion Flaws
Authors: Cunha Se´rgio B.
Published: July 2009

Corrosion is a degradation mechanism that is very common in pipelines and frequently the corrosion flaws develop close one to another. Since a defect causes a perturbation in its neighboring stress field, it is a common procedure to treat close by flaws as a single one, a cluster whose dimensions envelop the whole group of defects, and some criterion must be employed to determine if two flaws are close enough to justify its clustering. The defect interaction rules available at present have practical or experimental foundations and, sometimes, one is substantially different from another. The objective of this article is to present an interaction rule based on analytical solutions for stress and strain around a volumetric flaw in a pressurized thin wall cylinder. The two possible straining modes are identified and how strain and stress propagates from a flaw into the undamaged region of the pipe is solved in the linear elastic domain. Based in this solution, a defect interaction rule is developed. This analytical interaction rule is compared to selected interaction rules commonly employed by the industry nowadays.
New Heavy Crude Oil Flow Improver Increases Production: Application Scenarios
Authors: Dreher W. Reid , Johnston Ray , Lauzon Peter , Pierce Joey
Published: July 2009

As worldwide heavy crude oil production increases, pipelines are faced with challenges to transport these higher viscosity fluids. Historically, heavy crude oil has been a challenge for existing commercially available DRAs. As crude oil gravities fall below ∼23 °API, existing DRAs become ineffective. ConocoPhillips Specialty Products Inc. (CSPI) developed a new class of DRAs to address this need. CSPI’s new heavy crude oil DRA technology, ExtremePower™ Flow Improvers, is proven to increase deliveries of produced heavy crude oil to market. In this paper we will discuss the mechanism of drag reduction, how a heavy crude oil DRA works, and two scenarios in which value is created by utilizing the product.
Using Testing Methods to Evaluate Pipeline Mechanical Integrity
Authors: Alexander Chris
Published: July 2009

Evaluating the mechanical integrity of pipelines involves a variety of tools and skill sets. Over the past several years there has been an increased interest in assessing the performance of vintage pipeline systems and specifically evaluating the effects of existing defects on future performance. Examples of defects include girth and seam welds, corrosion, dents, and wrinkle bends. While lessons learned from prior experience and analysis are critical, the role of testing in the evaluation process is receiving focused attention. This paper includes detailed discussions on how testing has been used over the past decade to help pipeline companies assess the integrity of their pipeline systems. Specific emphasis is placed on helping the reader better understand what testing techniques are most appropriate and determining how to interpret and correlate the results into useful information for operating safe pipelines. Case studies are presented that include studies on seam welds subject to cyclic pressures, wrinkle bends, girth welds, and corrosion in dents. A well-designed test program can be used to validate numerical modeling efforts and provide engineers with insights regarding in situ behavior of pipeline systems.
Concrete Containment Wall vs. Earthen Containment Dikes
Authors: Abukhodair Bassam M. , Litman Joe , Bergman Jay
Published: July 2009

The most common form of secondary containment for petroleum tanks is an earthen dike structure. Precast, pre-stressed concrete wall structures, however, can offer effective secondary containment, especially for sites that encroach on existing infrastructure, property limits, or environmentally sensitive areas. A secondary containment system constructed with concrete walls occupies a much smaller footprint than an earthen dike structure. This reduction in footprint can be critical, particularly in today’s expanding market which is placing increasing pressure on available site properties including, in many cases, the need to acquire permits for the development of environmentally sensitive areas. The new Tank #79 and Tank #80 projects at the Enbridge Griffith Terminal utilized an 880 lineal foot precast, pre-stressed concrete containment wall system. The existing site soils were sandy and unsuitable for containment berm construction. Therefore, earthen dike structure construction would have required imported clay material. However, the primary motivation for using the structural wall system at the Griffith Terminal was to reduce wetland impacts on the adjacent protected Hoosier Prairie Wetland. The concrete containment wall system saved approximately one half acre of wetland which significantly reduced wetland mitigation costs and also fulfilled the wetland permitting requirement to reduce (minimize) wetland disturbance. Finding a vendor with past experience in the fabrication of precast, pre-stressed concrete panels suitable for secondary containment was a challenge due to their limited prior use in similar containment wall systems. For the design, detailing and fabrication of this system Enbridge worked closely with precast concrete fabricators to define a typical pre-cast panel which was economical, could be easily installed, was structurally suitable for containment design forces and which would prove durable in a cold-weather environment. Additional considerations included proper sealing of adjacent wall panel joints, selecting and detailing a suitable impermeable liner to bridge the wall to the tank lot clay layer, and design and installation of supporting concrete caissons and steel piles for wall panel vertical and lateral support. The Tank #79 and #80 projects at the Griffith Terminal have benefited from the decision to depart from the traditional earthen berm and construct a structural containment wall system. These benefits included reduced wetland and overall project footprint impacts, accelerated project environmental permitting and an accelerated project construction schedule.
Development of Spatial-Temporal Pipeline Integrity and Risk Management System Based on 4 Dimensional GIS (4D-GIS)
Authors: Iwamura Kazuaki , Mochizuki Akira , Kakumoto Yoshiki , Toyama Eiji , Takahashi Shoei
Published: July 2009

A new type pipeline integrity and risk management system based on 4D-GIS (4Dimensional Geographic Information System) is proposed in this paper. 4D-GIS is a unique GIS platform which can manage 3D plus time change data and processes spatial-temporal pipeline integrity data effectively. The utilization purposes of the developed system are: 1) To understand the current/future physical status of pipeline, 2) To detect anomalies of pipelines and to propose solutions for replacing or repair, 3) To transport natural gas safely and stably. For 1), the methods for spatial-temporal data integration and data input are proposed. The developed system integrates a variety of pipeline integrity data sets such as pipeline maps, construction specification, documents, corrosion data, and cathodic protection voltage data. For 2), two new type diagnosis functions, which process integrated data, are proposed. One is the pipe safety diagnosis based on corrosion spreading prediction. The other one is insulation health diagnosis. For 3), stress distribution on corrosion and HCA (High Consequence Areas) is calculated. Thus, the system can be utilized for the decision making for pipeline-specific- problem solving by both pipeline operators and field pipeline managers. The processing results for realized functions are shown. Furthermore, the architecture of pipeline integrity and risk management system is described.
Multi-Objective Decision-Making on Peak Shaving of West-East Gas Pipeline
Authors: Zuo Lili , Wu Changchun , Zheng Hongwei , Zhang Fukun
Published: July 2009

This paper addresses the peak shaving of West-East Gas Pipeline. For a gas pipeline system, the decision-making on the peak shaving scenarios usually involves a delicate balance between low operation cost and high gas supply reliability. In order to select an acceptable peak shaving scenario from these two angles for West-East Gas Pipeline, the idea of multi-objective decision-making has been introduced. Based on design flow-rate, eight typical peak shaving scenarios have been evaluated, analyzed and optimized with the help of TGNET. During the simulation, in order to make the peak shaving process more approach to the actual operation of the pipeline system, 51 days of forecasted data are used to establish the system starting state for the study period. On the other hand, in order to reduce the effect of different peak shaving process to the subsequent operation, the study period is extended by 7 days to fully account for operating costs and conditions subsequent to the study period, which make different peak shaving scenarios comparable. According to multi-objective optimization criteria including operation cost, gas supply reliability and operation stability, different pareto peak shaving scenarios have been obtained. These scenarios show that from the object of minimizing operation cost, inlet pressure of Shanghai terminal should approach to contractual pressure, from the object of gas supply reliability and operation stability, inlet pressure of Shanghai terminal should maintain a higher value. Operators can adopt different peak shaving scenarios according to different optimization object. Furthermore, with mathematical statistics knowledge, control value of inlet pressure of Shanghai terminal is recommended. When the change of withdrawal flow-rate from underground gas storage is more frequent, the fluctuation of inlet flow-rate is smaller. When withdrawal flow-rate from underground natural gas storage increases, it will not only increase the inventory of whole pipeline and end segment, but also decrease the inlet flow-rate.
Development of Global Contract for In-Line Inspection
Authors: Gower Stephen R. , Moore Jude
Published: July 2009

In-Line inspection has increasingly been used across the oil and gas industry over the past 30 years as a key part of pipeline integrity programmes. Whilst the industry has started to develop standards through the ILI Association and the Pipeline Operators Forum the way in which the industry selects tools and contractors has not developed to the same extent. A significant amount of time is spent managing the procurement process rather than focusing on the selection of the right tools and ensuring they perform to expectations. The challenge is further exacerbated when operations are dispersed globally and involve many different operating relationships. BP has been a user of ILI technology since its introduction in the late 1970s and it has consistently grown in importance to BP in managing the integrity of an aging pipeline asset base. In 2006/2007 BP’s Exploration and Production Technology Group (EPTG) in conjunction with the Procurement and Supply Chain Management group (PSCM) carried out a review of its procurement arrangements across the globe for pipeline ILI to ascertain best practice and capture key lessons. It also gathered experience from other strategic long term supply chain initiatives around the BP Group to help inform and develop the ILI strategy. Early discussions held with ILI Suppliers confirmed that, whilst regional frameworks have been in place in some countries, extending this to a global operation would be breaking new ground in engaging ILI services and would be of benefit to both ends of the supply chain. The process not only needed to follow rigorous supply chain procedures that would meet EU Procurement Directives and BP Group requirements, it also had to meet the specific requirements of many Countries around the world. It was recognised that flexibility would be required to accommodate the introduction of new tools, developing technology and accommodate new areas of operation. BP also wanted to stimulate continuous improvement in ILI tool performance and application of innovative improved technology. More significantly a key objective of the Global Contract was to drive inspection quality and consistency, whilst maintaining a competitive but equitable pricing strategy. Successful implementation was not just about delivering a contract scope of work; it required the development of relationships and a common understanding so that when problems arise they can be resolved quickly and efficiently. This required a significant amount of work engaging both the ILI Contractors and Operating Units across the world in the process. Work on developing the Global ILI Contract was successfully concluded with contract awards in late 2007. The paper explores some of the challenges, lessons learnt and benefits of developing a Global Contract for ILI.
Modelling of Dent and Gouges, and the Effect on the Failure Probability of Pipelines
Authors: Seevam Patricia , Lyons Chris , Hopkins Phil , Toft Malcolm
Published: July 2009

One of the main causes of the failure, and resulting casualties, in onshore and offshore transmission pipelines is external interference (also known as ‘mechanical damage’, or ‘third party damage’). External interference can result in a dent, a gouge, or a combination of the two. The combination of dents and gouges is a severe pipeline defect. It creates an unstable stress state at the defect root where work hardening and micro-cracking may be present. This can lead to a variety of immediate and delayed failures in pipelines. The available assessment models for a dent containing a gouge contain significant variability which leads to both conservative predictions of failure pressure and wide scatter when compared to test data. Additionally, these models are used extensively in pipeline risk analysis, and the differing models can cause wide variation in pipeline failure frequency predictions. This paper is a critical evaluation of existing dent/gouge models, using the full scale test database from the ‘Pipeline Defect Assessment Manual’ (PDAM). It compares two published methodologies for assessing dents containing gouges to determine the most robust model. The paper then uses probabilistic methods to determine the effect of these models on the probability of pipeline failure in a range of pipeline geometries. The paper ends with a gap analysis on dent and gouge models, and identifies requirements for targeting further research in this area, and also makes recommendations for ‘PDAM’.
Integration of Radio Frequency Identification and GIS for Asset Management
Authors: Hlady Joseph , Mondal Somen
Published: July 2009

The use of Radio Frequency Identification (RFID) has grown substantially in the past few years. Driven mostly by the retail supply chain management industry and by inventory control (loss prevention), RFID technology is finding more acceptance in the security and personal tracking sectors beyond simple pass cards. This growth has of course resulted in greater acceptance of RFID technology and more standardization of process and systems as well as decreased per unit costs. The oil and gas industry is being exposed to the potential use of RFID technology, mostly through the safety and equipment inspection portion of construction management. However, the application of RFID technology is expected to expand to the material tracking and asset management realms in the near future. Integrating the information provided by RFIDs with EPCM project and owner/operator Geographic Information Systems (GIS) is a logical next step towards maximizing the value of RFID technology. By linking assets tracked in the field during movement, lay-down and construction to a GIS, projects will have accurate, real-time data on the location of materials as well as be able to query about those assets after commissioning. This same capability is being modified for post-commission use of RFID with facility GISs. This paper outlines how existing GISs used during the EPCM phases and those employed after commissioning can display, utilize and analyze information provided by RFID technology.
Parametric and Non-Parametric Survival Models for “Time to Failure” of Water Pipelines: Case Study
Authors: Asnaashari Ahmad , Shahrour Isam , Gharabaghi Bahram , McBean Edward
Published: July 2009

An application of survival analysis on Iranian water pipelines failure dataset is employed to shed additional light on the pipeline failure process as well as to extract useful information that can be helpful in future asset management planning. Survival analysis characterizes the distribution of the survival time for different groups of pipes, to compare this survival time among different type of materials. A parametric model is developed to simulate time to failure in the pipe network. The model was calibrated on the historical failure data collected over the period 1995 – 2001, and then it was tested using data since 2002. Using both parametric and non-parametric survival models makes it possible to establish a priority list for future water pipelines rehabilitation undertakings in accordance with their material type. Accordingly, it is recommended that implementation of pipeline rehabilitation projects proceeds firstly on metallic water mains, then on plastic water mains, and finally on cement water pipelines.
The Use of Reinforced Thermoplastic Pipe in CO2 Flood Enhanced Oil Recovery
Authors: Weller Blaine , Parvez Anwar , Conley Jeff , Slingerland Eric
Published: July 2009

Reinforced Thermoplastic Pipe (RTP) is a new technology that is reducing the cost of constructing oil and gas gathering pipelines while improving reliability. The following material will be described: RTP construction, materials, performance, compatibility, joining systems, installation methodologies, and carbon dioxide (CO2) specific test results. RTP combines high performing materials such as bimodal high density polyethylene with high strength reinforcing fibers in a unique construction to create a spoolable high pressure pipeline system. This construction is well suited to upstream flow line and gathering applications as well as distribution applications. The primary benefit of RTP is realized by the installation methodologies available which contribute overall project savings of up to 30–50% for typical oil and gas applications. Additional installation benefits include reduced right of way requirements, reduced safety hazards, and reduced environmental impact. For applications which corrode steel, the additional corrosion resistance benefits of RTP are extremely compelling. The cost of constructing pipelines has been steadily increasing in past years due to many factors including the rising cost of steel and limited availability of skilled labor. There continues to be a desire to tie in new gas wells faster due to limited construction timeframes. Pipeline corrosion is a major problem for the industry. RTP provides solutions to all of these challenges.