Cylinder Pipe Research Articles

REAL-TIME CORROSION CONTROL SYSTEM FOR CATHODIC PROTECTION OF BURIED PIPES FOR NUCLEAR POWER PLANT

Since the operation period of nuclear power plants has increased, the degradation of buried pipes gradually increases and recently it seems to be one of the emerging issues. Maintenance on buried pipes needs high quality of management system because outer surface of buried pipe contacts the various soils but inner surface reacts with various electrolytes of fluid. In the USA, USNRC and EPRI have tried to manage the degradation of buried pipes. However, there is little knowledge about the inspection procedure, test and manage program in the domestic nuclear power plants. This paper focuses on the development and build-up of real-time monitoring and control system of buried pipes. Pipes to be tested are tape-coated carbon steel pipe for primary component cooling water system, asphalt-coated cast iron pipe for fire protection system, and pre-stressed concrete cylinder pipe for sea water cooling system. A control system for cathodic protection was installed on each test pipe which has been monitored and controlled. For the calculation of protection range and optimization, computer simulation was performed using COMSOL Multiphysics (Altsoft co.).

Cracking of Upper Pipe of Hydraulic Prop Made of 32HA Steel: Case Study

AbstractThis article describes the cracking of a hydraulic cylinder pipe made of 32HA steel with an Ar-shielded gas tungsten arc–welded (GTAW) protective housing. Grade 32HA is a Polish grade of steel that contains approximately 0.32% carbon and is designed for use on pipes and tubes for hydraulic cylinders. A fragment of the cylinder pipe and a welded joint of the protective housing were subjected to light microscopy (LM)-based macro- and microscopic metallographic examination. Tests of mechanical properties and impact energy, measurements of hardness, and analyses of chemical composition were also carried out. It was determined that the primary reason for cracking was the overloading of the pipe with the pressure of the working liquid inside the cylinder during operation. It was also ascertained that the welding of the protective housing created a heat-affected zone in the steel; this HAZ was of a very hard and brittle martensitic structure consisting of a structural notch that increased the steel’s sus...

Analysis of prestressed concrete cylinder pipes with fiber reinforced polymer

Prestressed concrete cylinder pipe is widely used for water distribution but structural failures have happened due to deterioration and a significant amount of money has been spent every year for repair and replacement. As the robot technique with fiber reinforced polymer to rehabilitate is being developed, a need for a new analysis method that can tell how many layers are required for a certain deterioration level has arisen. Currently, no analytical tool is available for this purpose. In this study, an analysis procedure is proposed to predict the pressure and the radial displacement relation and the bursting capacity of prestressed concrete cylinder pipes under internal loading. The finite element method is used to validate the proposed method. It is found that the debond of prestressing wire, the number of the reinforcing layers, and the layer attachment angle are important factors to pipe capacity.

Characterization of Prestressed Concrete Cylinder Pipe by Resonance Acoustic Spectroscopy

AbstractPrestressed concrete cylinder pipe (PCCP) is a composite pipe structure commonly used for high-pressure water transmission. If these pipes deteriorate, they can cause a water main break, which can cause extensive property damage and compromise the potable water system. Accordingly, there has been considerable interest in developing reliable nondestructive evaluation (NDE) techniques capable of identifying damaged pipes prior to rupture. In the current study, a series of finite-element and experimental studies are undertaken to establish the groundwork for an acoustic resonance–based NDE method capable of characterizing the earliest stage of deterioration in PCCP associated with damage to its outermost layer.

Deflection of buried prestressed concrete cylinder pipe with soil-pipe interaction

The deflection of the buried pipe is a function of the load on the pipe, and also the load on the pipe is a function of the deflection. It is a typical soil-pipe interaction. The vertical deflection of buried pipe with the soil properties has been relatively well studied, however, there is no proper and practical guideline on the horizontal deflection of buried pipe considering the soil-pipe interaction. In practice, the horizontal deflection is considered as the same as the vertical deflection and it provides unnecessary conservative design. In this study, the deflection of buried prestressed concrete cylinder pipe is measured using a selected soil model. A finite element model is built to reflect the soil properties, as well as the backfill and in-situ condition. An equation for horizontal deflection of buried pipe considering soil-pipe interaction is proposed.

The Development of Prestressed Concrete Cylinder Pipe in China

Prestressed Concrete Cylinder Pipe (PCCP) consists of a steel cylinder lined with concrete, then helically wrapped with a wire and coated with a dense mortar. PCCP has excellent structural properties, so it is widely used in various water-transportation projects around world. This paper presents a review of development of PCCP in China, which was summarized as three stages: the period of exploratory development, the period of cooperativedevelopment, and the period of independent development. The development process of design and production technique, the application in China, the construction and development prospect of PCCP were made a detailed discussion in each stage.

A comparative study of corrosion resistance of different coatings for mortar–embedded steel plates

In view of corrosion problem encountered in mortar–embedded steel plates used in joints of precast concrete cylinder pipes, an experimental study was undertaken at the initiative of the manufacture of the pipes to evaluate the relative performance of three chosen types of commercial coatings namely, red oxide, zinc primer, and epoxy coatings for protection of mortar–embedded steel plates against chloride-induced corrosion. Three different types of experiments were planned for this comparative performance evaluation: natural corrosion, accelerated corrosion and chloride exposure test. Test specimens were prepared using cement–sand mortar with cement–sand ratio of 0.5 (ASTM type I cement) and water–cement ratio of 0.5, using an embedded steel plate at the mid-depth. For natural corrosion, specimens admixed with 12% NaCl solution were placed in humidity and temperature controlled chamber to promote corrosion in hot–humid environment. In accelerated corrosion test, the weight loss and corrosion current densities were measured. Chloride penetration and corrosion initiation time were measured in specimens subjected to ponding with 10% NaCl solution. The results of all three tests convincingly showed that epoxy-coating, out of the three tested, performed as the best corrosion protection coating for mortar–embedded steel plates against chloride-induced corrosion.

Closure to “Pipe Efficiency Analysis at a Water Utility” by Amarjit Singh and Stacy Adachi

Closure to “Pipe Efficiency Analysis at a Water Utility” by Amarjit Singh and Stacy Adachi

Discussion of “Pipe Efficiency Analysis at a Water Utility” by Amarjit Singh and Stacy Adachi

The driving message behind the authors’ paper is that concrete cylinder pipe (CC is the abbreviation they used) is not as efficient, i.e., cost-effective, as the primary alternate water-pipe materials [cast iron, (CI), ductile iron, (DI), or PVC] used by the Honolulu Board of Water Supply (BWS). The discussers feel that the authors’ paper contains errors that affect the conclusions. The authors’ paper reports significantly variant material performance than experienced in the rest of the United States.

원자력발전소 적용 고밀도 폴리에틸렌 배관의 맞대기 융착절차 및 검증절차 분석

In nuclear power plants, lined carbon steel pipes or PCCPs (pre-stressed concrete cylinder pipes) have been widely used for sea water transport systems. However, de-bonding of linings and oxidation of PCCP could make problems in aged NPPs (nuclear power plants). Recently at several NPPs in the United States, the PCCPs or lined carbon steel pipes of the sea water or raw water system have been replaced with HDPE (high density polyethylene) pipes, which have outstanding resistance to oxidation and seismic loading. ASME B&PV Code committee developed Code Case N-755, which describes rules for the construction of buried Safety Class 3 polyethylene pressure piping systems. Although US NRC permitted HDPE materials for Class 3 buried piping, their permission was limited to only 10-year operation because of several concerns including the quality of fusion zone of HDPE. In this study, various requirements for fusion qualification test of HDPE and some regulatory issues raised during HDPE application review in foreign NPPs are introduced.

Research Methodology of Cross-Flow Cylinder Pipe Hydrodynamical

Experimental setup (hydrodynamic pipe) for the study of turbulent flows has been upgraded. Test experiments with a cross-flow around a cylinder have been carried out. Using the method of flow visualization PIV (Particle Image Velocimetry) the velocity fields around the cylinder for precavitational and cavitation regimes (Re = 2,8 · 105 ) have been obtained

Retrofit Design of Damaged Prestressed Concrete Cylinder Pipes

Prestressed concrete cylindrical pipe (PCCP) has been widely used for the distribution of water in communal, industrial, and agricultural systems for a long time. However, as it deteriorates, structural failures have been experienced. Replacing the entire existing PCCP with partial damages is not an economical method. Currently, as a cost effective repairing method, a new approach using fiber reinforced polymer (FRP) has been applied. A new design procedure of this method was proposed considering various kinds of loading condition. However, it is not easy to apply this method for design purpose due to its complex procedures. The objective of this study is to provide a new design criteria and process for PCCP rehabilitation with FRP. Through this method, the appropriate quantities of FRP layers will be decided after examining of limit states of deteriorated PCCP. For this purpose, two deterioration conditions are assumed; fully deteriorated and partially deteriorated. Different limit states for each case are applied to decide the quantities of attached FRP. The concept of “margin of safety” is used to judge whether the design results are within the optimal ranges to satisfy all limit states.

Sonic/Ultrasonic Testing Provides Reliable Condition Assessment

Nondestructive sonic/ultrasonic testing has been used to evaluate concrete properties for more than 60 years and to assess the structural condition of prestressed concrete cylinder pipe cores and coatings for more than 20 years.

Bathtub curves and pipe prioritization based on failure rate

PurposeThe purpose of this paper is to analyze conditional failure rates, and prioritize water pipelines for replacement based on their expected failure rate where pipes are grouped based on age and pipe type. Thus, predictions can be made on the expected number of breaks in future years.Design/methodology/approachThe time to failure of a pipe can be characterized by the stochastic properties of the population as a whole, from which the likelihood of component failure is derived. When the corresponding failure rate is plotted against time, a bathtub‐shaped curve results. The bathtub curve assists in determining maintenance schedules depending on the age of the pipe. Failure rates help determine whether the rates are more than an acceptable best practice threshold to signal replacement.FindingsDuctile iron pipes had the highest failure rates, followed by asbestos cement pipes; PVC and concrete cylinder pipes had the lowest failure rates, but because concrete cylinder pipes are very time‐consuming to repair and very expensive to install, only PVC pipes are recommended on the basis of this study. Cast iron pipes fit the bathtub shape; ductile iron and asbestos concrete were somewhat bathtub shaped, though the early phase period was not apparent; the bathtub curve for concrete cylinder was fully inverted; while PVC pipes showed zero probability of failure during the middle period. The shapes of bathtub curves drawn on conditional failure rates were similar to those for the failure rates. The bathtub curves indicate that the general failure performance of pipe materials is somewhat contrary to general principles in manufacturing.Practical implicationsAnalysis of failure serves a practical purpose for water utilities to allocate funds for pipe maintenance and prepare a schedule for pipe replacement, so as to provide the best quality services and safe drinking water to users of the utility.Social implicationsThe proper prioritization of water supply pipes for repair and replacement is of great social importance to the public at large, which expends considerable funds to maintain their drinking water supply.Originality/valueThe study of bathtub curves has not been seen before in the analysis of water supply pipes. A unique discovery is that the traditional shape of the bathtub curve is not always applicable for water supply pipes.

PCCP risk management—State of the art and strategy optimization

During the past 70 years, prestressed‐concrete cylinder pipe (PCCP) has been used to construct approximately 19,000 mi of US water transmission mains. Numerous unanticipated performance shortfalls, caused largely by the actions of one manufacturer during the 1970s, resulted in concerns among utilities related to the use of PCCP that continue to this day. An emerging PCCP risk management strategy is to use the combination of electromagnetic inspection to gauge the current extent of deterioration, finite‐element‐based structural analysis to gauge the significance of deterioration relative to risk of failure, and acoustic monitoring to gauge the rate of deterioration. This article examines the state of the art as it relates to PCCP risk assessment and provides constructive input related to the limitations associated with the various technologies currently being used. Additionally, suggestions for improvements and ways to get the most out of a risk assessment are given.

A Fiber Bragg Grating Pressure Sensor and Its Application to Pipeline Leakage Detection

The fiber Bragg grating (FBG) technology has been rapidly applied in the sensing technology field. In this paper, an FBG pressure sensor is designed and implemented to detect the leakage of prestressed concrete cylinder pipe (PCCP). The pressure sensor is mainly based on a Bourdon tube with two FBGs bonded on its outside and inside surfaces, respectively. The measurement principle and simulation analysis results are described. The wavelength shift difference of the two FBGs is utilized as a pressure sensing signal, the sensitivity is enhanced, and the temperature cross-sensitivity is compensated. Experimental results indicate that the measurement sensitivity is 1.414 pm/kPa in a range from 0 to 1 MPa, and the correlative coefficient reaches 99.949%. This kind of pressure sensor is effective to quasi-distributed measure and online monitor pressure of gas or liquid in industry and manufacture fields.

Prediction of PCCP Failure Based on Hydrophne Detecting

Abstract Prestressed Concrete Cylinder Pipe (PCCP) is a widely used water pipe all over the world. A major cause of PCCP failure is the internal wire break, which will emit acoustic signal. In this paper, a hydrophone-based PCCP real-time monitoring and failure-prediction system was proposed. By applying wavelet energy normalization analysis to signal feature extraction and Support Vector Machine (SVM) to signal recognition, a high prediction accuracy of 98.33% was achieved. The result showed that the hydrophone-based PCCP failure prediction system is much more effective and economic in real application compared with electromagnetic method and acoustic fiber optical.

Failure Analysis, Condition Assessment Technologies, and Performance Prediction of Prestressed-Concrete Cylinder Pipe: State-of-the-Art Literature Review

AbstractPrestressed concrete cylinder pipe (PCCP) is a large-diameter and high-strength pipe used in water or wastewater transmission mains. It has been widely used in North America because of its good performance, large capacity, and cost-effective price. However, some PCCPs fail after a certain time of service because of deterioration. PCCP failures can be very significant considering the pipe size and high internal pressure. To mitigate the serious results of PCCP failures, many condition assessment technologies have been developed to inspect the pipe condition, and many models have been developed to predict the performance of the pipe. These technologies and performance prediction methods have been used as reference for decision-making in PCCP pipeline management. However, because of their limitations, there is still a strong need to improve them for better application in the future. This paper, by using three databases, presents a state-of-the-art literature review of the most commonly used condition...

Gas pockets in a wastewater rising main: a case study

This paper presents a case study of an existing wastewater rising main (WWRM) in which an extreme transient event produced by simultaneous power failure of the pumps caused the rupture of a 1.2 m (48 in) prestressed concrete cylinder pipe (PCCP), causing an important leakage of sewage. The event and the methodology followed in order to validate the diagnostics of the failure are described. The detail study included in situ observation of the system, experimental investigation in a setup, hydraulic analysis, as well as details of the structural strength of the WWRM. After the extensive investigation and several simulations of fluid transients for different scenarios and flow conditions, it was found that stationary small gas pockets accumulated at high points of the WWRM were identified as the principal contributory factor of the failure. This case study serves as clear warning of the consequences of operating a WWRM with gas pockets at its high points.

Acoustics of fish shelters: Frequency response and gain properties

Many teleosts emit sounds from cavities beneath stones and other types of submerged objects, yet the acoustical properties of fish shelters are virtually unexplored. This study examines the gain properties of shelters commonly used by Mediterranean gobies as hiding places and/or nest sites in the field (flat stones, shells belonging to five bivalve species), or within aquarium tanks (tunnel-shaped plastic covers, concrete blocks, concrete cylinder pipe, halves of terracotta flower pots). All shelters were acoustically stimulated using a small underwater buzzer, placed inside or around the shelter to mimic a fish calling from the nest site, and different types of driving stimuli (white noise, pure tones, and artificial pulse trains). Results showed the presence of significant amplitude gain (3-18 dB) at frequencies in the range 100-150 Hz in all types of natural shelters but one (Mytilus), terracotta flower pots, and concrete blocks. Gain was higher for stones and artificial shelters than for shells. Gain peak amplitude increased with the weight of stones and shells. Conclusions were verified by performing analogous acoustical tests on flat stones in the stream. Results draw attention to the use of suitable shelters for proper recording of sounds produced by fishes kept within laboratory aquaria.