bluuebunny/crossref_metadata_2025 huggingface dataset:
Numerical Study of Heat Transfer Enhancement in Narrow Rectangular Channel With Rotated Elliptic Dimple With Inclined Slit
Authors: Wang Chuntao , Lu Qi , Qiu Xiang , Liu Yu , Deng Jian , Sun Jie
Published: December 2022

In order to enhance heat transfer performance of the reactor core coolant in the narrow rectangular channel of nuclear power system and ensure the safety of the reactor core without local high temperature as well as not cause excessive pressure loss, three different shapes of protruded elliptic dimple were adopted in the channel for numerical research. Firstly, the angle between long axis of the elliptic dimple and direction of the mainstream was rotated, which was defined as a rotated angle θ ranging from 0° to 90°. Secondly, streamwise (in line with the mainstream) slit was processed on the dimple. The last, inclined slit was processed on the dimple. There were five quantitative and two qualitative indicators to account for comprehensive effects of heat transfer, flow resistance and temperature distribution on the wall of the channel, namely, Nu for heat transfer capacity, f for flow resistance, performance evaluation criteria PEC for combination of heat transfer and flow resistance, Tmax and Tavg for maximum and average temperature on the outer wall respectively, velocity field near the inner wall and temperature distribution on the outer wall to show more detail information of the flow and heat transfer characteristics. The study results showed that with increase of θ, heat transfer efficiency and flow resistance all increased. Dimple with whether streamwise slit or inclined slit helped to reduce flow resistance. The dimple with streamwise slit performed best in flow resistance performance and the dimple with inclined slit performed best in heat transfer performance.
The Optimization Design of Direct Vessel Injection Diversion Structure
Authors: Hou Jianfei , Wang Qingli
Published: December 2022

A nuclear power plant adopts the way of direct vessel injection to inject safety injection water directly into the downcomer of reactor pressure vessel after accident. In order to avoid the splash phenomenon when the high speed safety injection water coming through the direct vessel injection nozzle impacts the core barrel, a diversion structure installed on the barrel is introduced into the reactor pressure vessel to guide the direction of safety injection water from horizontal to downward. As the existence of the gap between the diversion structure and direct vessel injection nozzle, a significant proportion of leakage of safety injection water occurs and it will affect the effectiveness of safety injection. After the analysis of flow field around the gap, a optimization to the diversion structure is taken out to reduce the leakage flow rate by adding different shapes and dimensions of baffles, such as semicircular baffles and inverted U-shaped baffles. Computational fluid dynamics method is adopted to simulate the flow in downcomer of reactor pressure vessel with different diversion structures and the shape of downcomer is simplified into cuboid for the convenience of simulation. Results show that all the optimization schemes can reduce the leakage flow rate in different degrees. The diversion structure with semi-circular plates and rounded transition between top plate and back plate can reduce the leakage most. Current work shows the rationality of the research direction and provides guidance for similar research in the future.
Investigation on the Simulation of Turbulent Heat Transfer of Liquid Metal Flow in a Narrow Rectangular Channel
Authors: Zhang Xue , Yu Hongxing , Deng Jian , Du Sijia , Zhang Xilin , Zou Ziqiang , Feng Wenpei , Zhang Yaoxiang
Published: December 2022

Liquid metal has the advantages of high boiling point and strong thermal conductivity and is selected as the coolant for a new generation nuclear system. In addition, the narrow rectangular channel is used in the small reactors or research reactors due to its compact structure and high heat transfer capacity. In order to accurately simulate the turbulent heat transfer of liquid metals in narrow rectangular channels, based on the relevant experimental data, this paper explored suitable numerical simulation methods. First of all, according to the research object, the appropriate experimental data was selected, and the geometric modeling, mesh division, and the mesh independence verification were carried out. It was ensured that the y+ meets the requirements of each turbulence model and wall treatment model. Several typical turbulence models and the wall treatment models were evaluated. For the low Prandtl number fluid such as liquid metal, it is necessary to select a suitable turbulent Prandtl number model in the RANS simulation. The sensitivity of the calculation results to the turbulent Prandtl number was analyzed. Finally, the existing turbulent Prandtl number models were evaluated. The suitable Prt at different Pe was given based on experimental value, so that the turbulent heat transfer of liquid metal in a narrow rectangular channel can be accurately simulated.
Study on Natural Circulation Flow Resistance Characteristics in a Rod Bundle Channel
Authors: Zhu Zhiqiang , Ren Tingting , Li Shuaijun , Tian Chunping , Yan Changqi , Wang Jianjun
Published: December 2022

Using deionized water as the working fluid, an experimental study on the resistance characteristics of single-phase and two-phase flow under natural circulation conditions is carried out in a 3 × 3 rod bundle channel. For the single-phase flow, the flow regime transition of rod bundle channel is not as obvious as that of conventional channels such as a circular tube. The flow regime transition in the channel is judged by the change trend of drag coefficient and the flow regime division is obtained. The transition Reynolds number from laminar flow to turbulent flow is approximately 800, and the correlations of the single-phase frictional resistance coefficient for different flow regimes are given. The natural circulation and forced circulation conditions have no obvious influence on the flow state transition. For the two-phase flow, under vertical conditions, a new two-phase frictional pressure drop correlation is fitted on the basis of the Chisholm correlation based on the experimental results. Moreover, the experiment for two-phase flow resistance under the inclined conditions are carried out, and the variation of the two-phase resistance with the mass quality is given, and the correlations of the two-phase friction pressure drop based on different inclination angles are proposed.
A Study on the Steady-State Flow Behavior of the Boiling-Driven Open Natural Circulation System
Authors: Hou Xiaofan , Wang Qianglong , Jiu Jinrong , Chen Hanying , Yao Shiwei
Published: December 2022

Natural circulation is widely used in the many industries owing to inherent safety. A typical case is Passive Containment Cooling System in the Chinese third-generation nuclear plant HPR1000. It uses an open natural circulation structure and contains an inner-containment heat exchanger, an outer-containment altitude water tank and connecting pipes. The altitude water tank connects with atmosphere, making its operation pressure is atmospheric pressure. For designing such an open natural circulation system, the steady-state flow behavior of of which is an important evaluate indicator, because it can directly reflect the flow capacity and heat transfer capacity of the PCS system. Considering that the long-term stable operating condition of the PCS system is the boiling-driven open natural circulation flow. Therefore, it is of significance to study the steady-state flow characteristics of the boiling-driven open natural circulation system.

In this paper, a theoretical formula to determine the steady-state flow behavior of a open boiling-driven natural circulation. Due to the lack of condensation process of two-phase circulation fluid, the integral result of steady momentum equation is not equal to zero. A special formula processing of accelerated pressure drop integral result is taken in this paper during the formula derivation process. The theoretical analysis results of which were validated by the experimental data. This paper aims at providing technical support for the design of open natural circulation systems.
Effect of Pilot Solenoid Valve Throat Diameter on Dynamic Response Time in Main Steam Valve Set
Authors: Liu Chuang , Zang Jia-lin , Jin Zhi-jiang , Qian Jin-yuan
Published: December 2022

The Main Steam Valve Set (MSVS) is set at the outlet of the steam generator in the secondary circuit of the Nuclear Power Plant, which plays a key role in overpressure protection of the steam generator. In actual working conditions, the response time of the MSVS is generally longer than the specified time due to the substandard flow coefficient of the pilot valve, which is directly connected to the upper chamber of main valve. In this paper, the flow characteristics of solenoid valve under different throat diameters and opening degrees is analyzed by. The result shows that the velocity and pressure of the flow field in the solenoid valve have an obvious change when the opening degree change from 25% to 50%. But after that, they stay unchanged approximately as the opening degree increases. Also, the outlet mass flow increases fast during the first 50% opening degree. The outlet mass flow when ds is 32 mm is higher than that when ds is 28mm. But when ds is 36 mm, the mass flow has no obvious change. Because the mass flow has a direct effect on response time, the research has a reference for the structural design of the solenoid valve in the MSVS, and ensure the safety of Nuclear Power Plants.
Sleeve Spacing Analysis on Flow Characteristics of Double-Layer Sleeve Control Valve
Authors: Nie Jia-xi , Chen Wei-ping , Hou Cong-wei , Lin Zhen-hao , Jin Zhi-jiang , Qian Jin-yuan
Published: December 2022

Sleeve control valves are one of the most main components of a nuclear piping system, and they are used for superheated steam adjustment, including the flow rate, pressure, temperature, etc. The sleeve, as its core component, plays a critical role in the regulation of flow characteristics in the valve. Therefore, it is very important to study the effect of the sleeve structure of valve core on the flow characteristics in the sleeve control valve. In this paper, the steady numerical model of double-layer sleeve control valve based on the compressible superheated steam was established with full opening, and the effects of sleeve spacing on flow characteristics of double-layer sleeve valve were analyzed based on the standard k-ε turbulence model. The flow characteristics of double-layer sleeve control valve including velocity, turbulence intensity, and Mach number was investigated with four kinds of different sleeve spacing. When the spacing of double-layer becomes larger, it will affect the flow characteristic of double-layer sleeve control valve greatly. This work has a certain reference value for the design of the thickness of the sleeve opening of the sleeve control valve.
Application of Boron Feedback From BOA CIPS/CILC Analysis on Neutronic Models
Authors: Fisher Jesse , Mangham Gary , Briggs Christopher , Wang Guoqiang , Zhang Baocheng
Published: December 2022

This paper summarizes the development of a multi-physics code system for evaluation of Crud Induced Power Shift (CIPS) phenomenon experienced in some Pressurized Water Reactors (PWR). CIPS is an unexpected change in reactor core axial power distribution, caused by boron compounds in crud deposited in the high-power fuel assemblies undergoing subcooled boiling. The approach includes a more robust method compared to previous attempts at coupling codes to account for boron deposition at the nodal level within the neutronic model based on the BOA generated CIPS results. This paper describes the updated linkage with a Python script wrapper around the multi-physics code system ANC9/FUELDUTYDRV/VIPRE-W/BOA. The multi-physics code system can then evaluate changes in core power distributions due to boron deposited in the crud for comparison to measured plant cycle flux trace data. The plant flux trace data provides additional wealth of information for reducing BOA conservatism in the CIPS analysis and benchmarking the multi-physics to the plant-specific source term and plant operation. The linkage of the code system along with the application results will be the base for future development to improve CIPS/Crud Induced Localized Corrosion (CILC) risk for a plant, allowing for the potential benefits of more aggressive fuel management via higher duty cores or improved fuel economics.
Rapid Leak Detection on Slurry Lines by Negative Pressure Wave Detection With Distributed Fiber Optic Sensing
Authors: Murray Alasdair , Godfrey Alastair , Minto Chris
Published: December 2022

Slurry pipelines can be used to move ore or waste material across large distances. The nature of slurry means that conventional mass-flow and statistical based leak detection systems are poorly suited to leak detection.

External Leak Detection Systems (LDS) based on Distributed Fiber Optic Sensing (DFOS) offer the potential to significantly reduce the overall amount of spilled product before a leak is detected and localized. Such a system has been installed on a slurry pipeline for the past 3 years and since installation there have been three unique leak events identified by the operator using the DFOS system. Two of these events are estimated to have involved leak flow rates of less than 50 LPM. Notably, in one of the incidents the operator indicated that there was no surface expression of the leak when they went to inspect the location. The incidents disclosed in this paper are done so anonymously.

Each of the leak events shared a common characteristic: the recurrent generation of localized NPW signals. This characteristic is suggested to result from the blocking and unblocking of the leak orifice by the solid material.
Centerline Segregation Rating and Its Implications on Mechanical Properties and Weldability of Line-Pipe Steels
Authors: Konar Bikram , Mohammadijoo Mohsen , Dunnett Kendal , Rashid Muhammad
Published: December 2022

In continuously cast line-pipe steel, solute elements segregate near the centerline of the slab. The extent of centerline segregation is compared with reference Mannesmann images either by visual or computer-aided techniques and provided a Mannesmann rating (MR). Originally MR was devised to gauge the casting performance, however, recently it is used as a reliability/performance metric for line-pipe qualification. Centerline segregation phenomenon in the slabs is expected to translate to through-thickness microstructural heterogeneity and precipitate formation in rolled products affecting mechanical properties. Furthermore, weldability of line-pipe steels is impacted by the interplay of heterogeneous centerline microstructure, precipitates, and the utilized welding process parameters and consumable package. In this study, X70 grade steel slabs rated with MR of 2 (MR2) and 3 (MR3) were rolled and submerged-arc welded to form pipes. Microstructural analysis, and mechanical property and hardness measurements as per ASTM standards were performed on these pipes. Despite some microstructural indication, no substantial difference was observed in the mechanical properties of the manufactured MR 2 and MR3 pipes.

WIC (Welding Institute of Canada) and pipe through-thickness weldability testing using cellulosic E8010 electrodes showed no substantial influence of MR on weldability or hydrogen-assisted crack formation. This study highlights MR of slabs is not a good reliability/performance metric for the pipelines, and it is rather important to understand the effects of other downstream processes to establish a quality control criteria.
Stress Analysis of Crossing Highway Pipe Sections Under Vehicle Load Based on the Experiment of Real-Size Pipes
Authors: He Guoxi , Xia Guoqiang , Liao Kexi , He Tengjiao , Tang Xin , Tian Zhiyuan
Published: December 2022

For long-distance natural gas pipes crossing highway, the changing load of vehicles is the most important and frequently acting-live load on buried pipes, which poses a serious threat to the integrity of the pipe. This study has designed and built a buried pipe stress test experimental system. The experimental system is mainly composed of a sealed pipe, an air compressor, and a stress-strain testing system. In this study, a total of 24 sets of stress test experiments are carried out. The research conclusions are as follows. The maximum stress of the pipe occurs at the 12 o’clock position of the pipe when the vehicle load is rolled at the middle. The increase in vehicle load results in an increasing pipe stress value. Both of the vehicle speed and the internal pressure play a certain role in protecting the pipe. After carrying out a real experimental case via Sinopec’s natural gas pipe crossing the highway, we have found that it can withstand the rolling load of a heavy vehicle of 78t, when the L325 steel pipe section that crossing the Grade-4 highway has a buried depth of 0.8m, a diameter of 355.6 × 5.6mm, and a internal pressure of 1.03MPa.
Development of a Pressure Equipment Integrity Management Program in a Multi-Jurisdictional Liquids Pipeline Environment
Authors: Sohail Touqeer , Bohaichuk Katarina
Published: December 2022

Demonstrated public safety and environmental responsibility is key to the reputation and success of pipeline companies. This sentiment extends not only to pipelines themselves, but to all facility equipment as well. That is why Enbridge Liquid Pipelines (Enbridge) developed a Pressure Equipment Integrity Management Program that is designed to ensure the safety, integrity, compliance, and operational reliability of all pressure vessels and boilers in Enbridge’s liquid pipeline facilities.

A unique aspect of Enbridge’s Pressure Equipment Integrity Management Program is how it must identify and comply with regulatory requirements in a multitude of both federal and provincial/state jurisdictions in Canada and the United States. Depending on the type of pressure equipment and its location, it may be federally regulated, locally regulated, or potentially both if there is no clear delineation between regulatory authorities. These different requirements can be complex and difficult to follow for personnel tasked with maintaining pressure equipment integrity across the entire pipeline system.

This paper will describe how a liquids pipeline company can structure a successful Pressure Equipment Integrity Management Program that is entrenched in the overall company Integrity Management System. The program must utilize clear, effective, and action-based processes and procedures that identify and comply with multi-jurisdictional requirements and are based on industry best practices. Stakeholder responsibilities shall be clearly outlined as well as process steps and required actions to be taken to effectively manage hazards and risks and maintain compliance.
Improved Fracture Toughness Test Method for Single Edge Notched Tension Specimens in Clamped-End Conditions
Authors: Zhu Xian-Kui
Published: December 2022

The oil and gas industry has favored to use fracture toughness measured using single edge-notched tension (SENT) specimen in the clamped-end conditions for the strain-based design or fitness for service analysis of pipelines. Different SENT fracture test methods have been developed, including DNV, CANMET and ExxonMobil procedures in terms of the J-integral or crack tip opening displacement (CTOD). These efforts led to the first SENT test standard BS 8571 published.

However, these SENT methods may determine inconsistent test results on fracture toughness for the same specimen because no consensus is reached for any of the methods, and different estimate equations are used for an experimental evaluation. This paper aims to develop an improved SENT fracture toughness test method after a comparative study on the primary SENT fracture test methods. Comparisons are performed on available solutions of the stress intensity factor K, the geometrical eta factor, the elastic compliance inverse equation, and the m factor for converting the J-integral to CTOD that all were obtained for the clamped SENT specimens. Through comparisons, this work identified a set of more accurate solutions for the K factor, the eta factor, the compliance equation, the m factor, and those used for weld testing. The difference between the J-converted CTOD and double clip gage measured CTOD is also discussed. On these bases, an improved SENT test method is proposed for determining more reliable fracture toughness or resistance curves for ductile pipeline steels.
Integrity Management Considerations for Pipes in Peat Muskeg and Organic Rich Soils
Authors: Thurairajah Aran , Saad Bassam , Williams Randy , Fernando Viji , Seid-Karbasi Mahmood
Published: December 2022

Gas and oil transmission pipes unavoidably traverse areas with potentially compressible soils such as Peat or Muskeg. These soils are prone to excessive displacements as a result of natural hazards or man-made activities such as excavation, fill placement or equipment crossings. Excessive soil disturbance in areas with potentially unstable soil could result in compromising the integrity of the pipes.

This paper discusses the challenges related to design, construction, and operation of pipes in potentially compressible soils such as peat and organic soils in British Columbia. It provides mitigation measures to manage the pipe concerns related to these soils. Among the design challenges discussed are geotechnical characterization of potentially unstable soil sites and special pipe trench design and foundation alternatives to minimize pipe settlement and localized stresses. To demonstrate the impact of adjacent soil fill or embankment loading on pipe integrity, soil deformation finite element analyses are carried out for various scenarios representing different unstable soil profiles, surface loading configurations, and offsets from the pipe alignment. The paper also provides integrity management measures for managing potential concerns for pipe operating in organic soil and peat environment.
Some Practical Benefits of Detailed Forensic Analysis
Authors: Leis Brian , Wang Yong-Yi , Eshraghi Amin , Rapp Steve , Vervake Gary
Published: December 2022

Integrity threats can be difficult to manage in cases where the condition assessment leads to sometimes uncertain results, and/or the mechanisms affecting that condition are complex, and so are sometimes poorly characterized. Clarity in such cases derives from forensic analysis, as illustrated in this paper, which presents and discusses such work to: 1) better understand the scope and nature of the threat involved, 2) quantify a case-specific speed of crack growth, 3) establish the viability of the predictive tools being used, and 4) establish whether a once active threat had been effectively dealt with by the operational and maintenance changes that were made to manage it.

The results of two recent laboratory hydrotests are summarized concerning pups containing SCC colonies, as are the details of forensic analyses of the cracking exposed by that testing. The high-level goals were to: establish the form(s) of SCC active on the pipeline; quantify its average cracking speed (ACS) relative to published guidance; and determine whether the changes that had been made to manage that SCC had proven effective through evidence of dormant cracking.

Fractography and metallography done to identify traits characteristic of SCC clearly showed intergranular features and other key traits of high-pH cracking. As expected, the SCC colonies showed a wide range of crack sizes. The fractography also showed clear evidence of a prior hydrotest that along with other benchmarks over time led to a case-specific ACS, which was slower than published industry guidance. Comparison of predictions concerning failure pressure and other aspects made prior to the hydrotests established the viability of the predictive tools that had been used. Finally, indicators of dormancy such as heavily corroded intergranular features that continued down secondary cracking were used to establish that the SCC local to the dig sites considered had been mitigated.
Susceptibility of a Virtual Pipeline Network to Fatigue and Cracking Threats in Hydrogen Service
Authors: Burkinshaw Ollie , Sandana Daniel , Gallon Neil , Bhatia Arti
Published: December 2022

Over the coming decade many projects will be initiated to convert existing natural gas pipelines to hydrogen service, often with ambitious schedules. However, there is currently little experience globally in successfully converting pipelines to hydrogen service and operating them safely. In North America, the gas transmission infrastructure represents construction from the 1920s up to the present day. This infrastructure contains a wide spectrum of different pipeline materials with large variations in properties, and an array of different resident and time-dependent integrity threats.

Prior to embarking on changes to hydrogen service, it is imperative to understand and mitigate the effects associated with the change in risk profile, driven by the known effects of hydrogen gas on the toughness and fatigue resistance of steel pipelines. These effects are complicated by the significant variation and uncertainty in the extent to which different pipeline materials will be affected.

Many papers and industry projects have examined the effects of hydrogen on material properties. However, few have assessed the scale of the challenge posed to safe operation and integrity management involved with repurposing an entire infrastructure. This paper uses a novel approach to explore how the current natural gas transmission network might stand up to a hypothetical switch to 100% hydrogen.

Available data gathered through inspections of gas transmission pipelines in North America will be utilised to create a virtual pipeline network. This virtual system is built from a range of different pipeline sizes, attributes and material properties to most closely represent a ‘typical’ proportion of the gas transmission network in North America. An array of cracks and crack-like integrity threats with sizes and morphologies that reflect typical frequencies and severities observed from real projects will be introduced into this virtual network.

This virtual network is a construct that allows the impact of hydrogen conversion on integrity management to be explored in a way that is representative of what a gas transmission pipeline operator may expect to encounter across a range of assets. The impacts will be explored through different scenarios, representing different extents of reductions in toughness and increases in fatigue crack growth rates, based on available material test data. This approach will provide an indication of the number of features that may be currently stable in natural gas but that may fail in hydrogen service. This hypothetical exercise will draw insights into the practicalities of safe operation of pipelines being contemplated for hydrogen service and the scale of the task that would be necessary to navigate this transition.
Estimating Pipeline Probability of Failure Due to External Interference Damage Using Machine Learning Algorithms Trained on In-Line Inspection Data
Authors: White James , Taylor Katherine , Martin Jonny , Carrell Steven , Palmer-Jones Roland
Published: December 2022

External interference damage is one of the main causes of pipeline failure reported in publicly available industry statistics from agencies such as the Canada Energy Regulator (CER) and the United States Pipeline and Hazardous Materials Safety Administration (PHMSA). Thus, failures due to external interference are often the most significant contributors to pipeline probability of failure in risk assessments and can play a significant role in operator decisions regarding risk-control expenditures, for example when it comes to the installation of additional impact protection, pipeline diversion or pressure restrictions.

The probability of failure due to external interference damage can be estimated by combining the probability that damage occurs (i.e. that the pipeline is hit), the probability that the impact is sufficient to cause instant failure and the probability of degradation to failure, given that damage has occurred. Degradation to failure is assessed using industry standard engineering models (such as the limit state functions given in Annex O of CSA Z662-19 [1]). However, the key challenge is predicting where, when, and with what energy the external interference damage may happen.

The prediction of a “hit rate,” or impact frequency, can often be subjective or based on statistics, which may not always be applicable or accurate for use on the pipeline under assessment. Top-of-line (TOL) deformation damage (dents) reported by in-line inspection (ILI) are a clear indicator of past external interference, which could have been introduced by third parties, contractors or the operator themselves. ILI data from ROSEN’s Integrity Data Warehouse (IDW) — which at the time of writing contains results from over 18,000 inspections — has been used to train machine learning models to estimate the frequency of external interference damage (per km-year). The distribution of dent sizes combined with pipe parameters is used to estimate a distribution of dent force.

The following may all influence the likelihood and energy of external interference damage and may be considered as predictor variables in a machine learning model:

• Local population density

• Land use

• Excavator types (typical bucket dimensions)

• Frequency of crossings (road, rail, other services)

• Pipeline burial depth

• Additional impact protection

• Pipeline markers and warning tape

• Patrol and surveillance frequency

• Operational control activities

• Pipeline material properties

This paper presents an approach to estimate the probability of failure due to external interface damage that use more accurate and justifiable impact frequency statistics, which are generated using worldwide ILI data and additional influencing factors based on pipeline exposure, resistance and mitigations.
A Risk-Based Design Approach for Uncased Pipe Under Roads and Railways
Authors: Nathoo Hafeez , Nessim Maher , Stephens Mark
Published: December 2022

A risk-based pressure design approach has been developed for uncased pipe under roads and railways. Similar to the approach currently used in Canadian Standard Association’s Standard Z662, the approach uses a set of hoop stress factors to calculate the minimum wall thickness from the pipe’s pressure, diameter, and specified minimum yield strength. The hoop stress factors were calibrated to meet specified reliability targets considering the risk factors specific to roads and railways, which include elevated probabilities of mechanical damage due to higher construction activity rates, safety impact on road users, and potential costs of traffic interruption in case of a pipeline failure. The hoop stress factors are defined as a function of the safety class, which is determined according to the approach described in a companion IPC paper.

This paper describes the development approach and provides a comparison between its results and the designs obtained from the current CSA Z662 approach. An analysis confirming adequacy of the resulting wall thicknesses to withstand normal traffic loads is also presented. The approach is being proposed as an alternative to the hoop stress factors currently used in CSA Z662.
Full-Scale Coating Abrasion Test to Supplement Laboratory Testing
Authors: Futch David B. , D'Ambrosio David
Published: December 2022

Laboratory coating qualifications often require determining the ability of the coating to resist abrasion and gouging. These tests help inform a pipeline operator on the coating’s ability in extreme conditions, often those that may be required during a horizontal directional drill (HDD) when specifying an abrasion resistant overcoat (ARO) would be considered. However, these laboratory bench-top tests subject the coating to subscale loading that typically is not of the magnitude that can be experienced during pipeline construction.

An HDD is a trenchless pipeline installation method where a pipeline is pulled through a pilot hole and is likely to increase in popularly over the coming decades as current pipeline right of ways become more congested and urban sprawl increases. As HDDs increase, their construction will be pushed to the extreme: longer distances, larger/heavier pipe, and through more challenging formations. Drilling through more challenging formations, such as granite, will subject additional abrasion and gouging to the pipe coating. Therefore, there remains a need to supplement traditional laboratory bench-top testing with a full-scale alternative that more closely represents the abrasion and gouging risk experienced during an HDD.

This paper provides an overview of common subscale abrasion testing as well as the newly developed, innovative full-scale test. This full-scale test was designed to subject a pipe sample and ARO coating to varying obstructions pneumatically engaged against the outside pipe/coating surface. Obstructions utilized during this test development included: (1) a granite block selected to represent a natural formation, (2) a round tip selected to represent wear, and (3) carbide-tipped machining inserts selected to simulate aggressive gouging. Applying larger loads pneumatically to each obstruction simulates higher loading during an HDD — either due to a longer pull, heavier pipe, or variations in drilling mud/ballast. Finally, this paper will review industry accepted HDD load calculations providing a selection chart to determine the thickness of an applied ARO sacrificial overwrap.
Effectiveness of Subsurface Drainage for Mitigation of Landslides Affecting Pipelines
Authors: Rashidi Mohammad , Ebrahimi Ali , Mosaiebian Arash
Published: December 2022

Landslides can pose a threat to the integrity of new and existing pipelines if they are not mitigated. Improving subsurface drainage of groundwater is one of the most widely used stabilization strategies for mitigating landslides affecting pipelines because subsurface drainage requires minimal design and costs and can improve the overall stability. The appropriate design and implementation of this approach could lower the groundwater table within the landslide as a primary factor triggering landslide movement by reducing the driving force and increasing the shear strength or resisting force within the landslide mass. Thus, the subsurface drains are conventionally employed in the mitigation of most landslides that may threaten pipelines either as a single strategy or in conjunction with other measures.

This paper presents how effective subsurface drainage systems are for improving slope stabilization in various site conditions. Included in the discussion is the predesign investigation considerations. The results of a series of two-dimensional limit equilibrium and seepage analyses are presented to evaluate the effectiveness of subsurface drainage systems. Site conditions explored in this paper include the location of the right-of-way compared to the boundary of landslide, geometry of landslide, and groundwater level. A model that uses genetic expression programming as a computational intelligence technique is introduced that predicts the effectiveness of subsurface drainage systems.
Geospatial Database Development: Supporting Geohazard Risk Assessments Through Real-Time Data and Geospatial Analytics
Authors: Johnson Clayton , Schmidt Stephen , Taylor Justin , deLaChapelle John
Published: December 2022

TC Energy owns and operates over 32,000 miles of natural gas pipelines within 38 states in the United States, a sizable portion of which crosses through terrain highly susceptible to geologic hazards. To better support geohazard risk management, TC Energy has implemented a customized web-based geohazard platform (GeoForce) to identify, inventory, and track geohazards across their U.S. pipeline system. The platform was built within the Environmental Systems Research Institute (ESRI) ArcGIS Enterprise environment and leverages a diverse amount of ESRI product offerings. The platform is hosted on ArcGIS Portal and includes multiple custom apps and dashboards which allow users to efficiently view, summarize, add, and update geohazard data. Another key component of the system is a connection to ArcGIS GeoEvent Server. GeoEvent Server allows for the delivery of near real-time geohazard threat notifications through emails and dashboards (i.e., seismic events, flooding, precipitation). The notifications also provide detailed information for the sections of the system affected by the event, and in the case of a seismic event, a suggested course of action in alignment with TC Energy procedures. ArcGIS Image Server was leveraged to host over 4 terabytes of LiDAR imagery which can be used in concert with the other geohazard datasets present in the database. Custom geospatial scripts were also developed to create a near real-time link between the GeoForce master database and TC Energy’s master data mart, asset information, regulatory, and other organizational data. These scripts flag and report where spatial and/or attribute data have changed or may no longer be valid and therefore require follow-up action to support risk management (e.g., when pipelines are abandoned, HCAs are updated, or pipe properties are updated). The scripts also store the centerline attribute changes in a table for further review to identify potential trends. The GeoForce database is also built as a launching platform for proactive analytics, and eventually predictive analytics for critical precipitation thresholds for landslide risk management, landslide susceptibility mapping, system-wide risk scoring, seismic events and ILI bending strain coincident with geohazards. Details related to the threat alerts that are issued by the geospatial system are stored and visualized in a PowerBI integration. With the incorporation of ArcGIS Notebook Server, algorithms will be developed that will review the historical threat repository that is being generated and issue threat alerts based on probability of a hazardous event occurring in proximity of the pipeline system.
Morphological Change Detection at Pipeline Crossings Using Remote Sensing: A Proof-of-Concept Study
Authors: Schueder Rudy , Engelbrecht Jeanine
Published: December 2022

A proof-of-concept research and development study was undertaken to determine to what degree changes in river morphology could be detected from satellite imagery in support of pipeline geohazard monitoring programs. Algorithms for the detection of the wetted extent and river centerline were developed in the Python programming language and applied to synthetic aperture radar and multispectral imaging data. Additional algorithms were developed to highlight meaningful changes in wetted extent and river centerline occurring between subsequent data acquisitions. The results showed that it was possible to detect morphological change using satellite imagery, but that the process was effective for rivers with a higher signal to noise ratio represented by the ratio of river width to image pixel size. For smaller rivers (20–50 m), the change in the centerline location was a more useful metric of morphological change. The change detection algorithms were successful at highlighting possibly important changes between subsequent data acquisitions but were limited by the relatively short catalogue of available images to compare changes against. Future work involves the improvement and deployment of the algorithms in operational software systems to support pipeline geohazard management programs.
Integrity Assessment of Linepipes for Transporting High Pressure Hydrogen Based on ASME B31.12
Authors: Ishikawa Nobuyuki , Sakimoto Takahiro , Shimamura Junji , Wang Jiawei , Wang Yong-Yi
Published: December 2022

Current hydrogen pipeline code ASME B31.12 requires that pipe materials shall be qualified for adequate resistance to fracture in hydrogen gas based on Article KD-10 of ASME BPVC, Sec. VIII, Division 3. In order to assess the integrity of a hypothetical hydrogen pipeline, fracture toughness and fatigue crack growth tests under gaseous hydrogen at up to 21MPa were first conducted using a recent Grade X65 linepipe with fine grained bainitic microstructure. Fatigue crack growth in the pressurized linepipe with semi-elliptical surface flaw was calculated by the procedures described in the Article KD-10 using the da/dN data obtained from the X65 linepipe and the fatigue crack growth equation specified in ASME B31.12. Pressure cycles were applied to the pipe with a surface flaw to investigate the effects of pressure range and design factor. The critical crack size was analyzed using the failure assessment diagram (FAD) concept which is also specified in Article KD-10. Significant fatigue crack growth was not observed under the lower design factor such as fD = 0.5 with small pressure range, while fatigue crack growth was drastically accelerated under the higher design factor and large pressure fluctuation. Integrity assessment by FAD analysis for longitudinal semi-elliptical crack and girth weld flaw clarified how the toughness value affects the critical condition.
Enhancing Results of Ultra-High-Resolution Axial Magnetic Flux Leakage (MFL-A Ultra) Inspection Data Utilizing Finite-Element Modeling (FEM) Simulations
Authors: Schneider Edgar , Spille Johannes , Fleming Jeff , Saad Ziad , Siggers Kevin
Published: December 2022

The standard evaluation methods for MFL-A inspections are based on simple calibration approaches that lead to stable results as long as the corrosion tends to be isolated and shallow. This paper presents a method suitable for complex and deep corrosion that utilizes FEM simulations on ultra-high resolution MFL-A data.

It follows two main aspects: The first aspect is to learn from dig verifications by using laser scans of corrosion anomalies as a finite-element model to simulate the corresponding magnetic flux to confirm the magnetic flux measurement of the ILI tool. This way the simulation model is validated.

The other aspect is to apply the achieved insights as a new depth sizing concept: the complete corrosion geometry as indicated by the ILI measurement is put into the validated FEM model to simulate the magnetic flux that should correspond to the one measured by the ILI tool.

In this new sizing method the influence of complex corrosion is considered, as all surrounding features are part of the model. Several models are calculated in order to minimize the impact of ambiguity of depth results. This increases the accuracy and, ultimately, stabilize pipeline operators’ integrity assessments.

In the big picture, novel approaches to MFL-A data interpretation, such as FEM, empower operators to make more informed decisions specific to their asset integrity management programs while reducing the costs, uncertainty and conservatism associated with these decisions.
Development of a Near-Neutral pH Stress Corrosion Cracking Growth Model for Pipelines Using Machine Learning Algorithms
Authors: Sun Haotian , Zhou Wenxing , Kang Jidong
Published: December 2022

Near-neutral pH stress corrosion cracking (NNpHSCC) is one of the leading causes of failure for buried pipelines. Characterizing the NNpHSCC growth rate accurately remains a challenging task for the pipeline industry. In this study, an NNpHSCC growth model for buried pipelines is developed based on experimental data obtained from full-scale tests conducted at the CanmetMATERIALS of Natural Resources Canada of pipe specimens that are in contact with near-neutral pH environment and subjected to cyclic internal pressures. Four machine learning algorithms, namely the random forest (RF), extremely randomized trees (ET), gradient boosting (GB) and extreme gradient boosting (XGB), are employed to estimate the crack growth rates da/dN from input variables characterizing the pipe geometry, internal pressure and environmental condition. The machine learning models are trained through hyperparameter tuning and k-fold cross validation to improve the model robustness. Model performances are validated and compared using an independent test dataset. This study provides an initial step in using machine learning tools to develop robust NNpHSCC growth models suitable for practical applications.
Considering Roadway Traffic in Quantitative Risk Assessment for Natural Gas Pipelines
Authors: Lu Dongliang , Siraj Tammeen , Warhurst Karen , Dimitriadis Konstantinos , Towers Matt
Published: December 2022

Natural gas transmission pipeline systems can extend thousands of kilometers and traverse both populated and less populated areas. Traditionally, risk assessment of natural gas pipelines performed by TC Energy mostly focuses on evaluating the impact of pipeline failures to occupants of nearby structures. However, it is recognized that natural gas pipelines at road crossings or otherwise running in proximity to roads may also pose risks to motorists or other roadway users. Incidents of pipeline failures damaging road infrastructure, resulting in casualties, have been seen in the past.

This paper reports work undertaken to investigate the risk assessment of natural gas transmission pipelines considering the consequence of pipeline failures to roadway users in addition to occupants of nearby structures. Differences between how pipeline failure consequences should be evaluated for motorists travelling at a high speed in vehicles versus occupants of non-moving structures were investigated. Relevant factors that are unique to consequence assessment for roads, such as vehicle speed and relative position between roads and pipelines, were identified, and the way in which these unique factors can be incorporated in risk assessment was studied.

Based on the results from the study, TC Energy updated its System Wide Risk Assessment program to include consequence of pipeline failures associated with roads and roadway users. Data from a total of over 180,000 km of roadway segments across North America that are located in proximity to TC Energy’s over 90,000 km of natural gas transmission pipelines were analyzed. The societal risk with and without roads were evaluated and compared. The impact of considering roadway traffic in the risk assessment in different areas was assessed and the importance of proper consideration of roadway users in quantitative pipeline risk assessment was demonstrated. The methodology developed in the study is useful in advancing the overall accuracy of risk assessment for the pipeline industry, and particularly for pipeline operators in the US, provides a quantitative assessment tool to evaluate the risks associated with roadway driven Moderate Consequence Areas (MCA) and prioritize the integrity work accordingly.