Erosion in Nuclear Piping Systems

2010 ◽  
Vol 132 (2) ◽  
Author(s):  
Harold M. Crockett ◽  
Jeffrey S. Horowitz
Keyword(s):  
Nuclear Power ◽  
Power Plants ◽  
Nuclear Power Plants ◽  
Cavitation Erosion ◽  
Solid Particle Erosion ◽  
Particle Erosion ◽  
Droplet Impingement ◽  
Accelerated Corrosion ◽  
Piping Systems ◽  
Flow Accelerated Corrosion

Various mechanisms degrade components and power piping in nuclear power plants. The mechanism with the greatest consequence has been flow-accelerated corrosion (FAC). FAC has caused ruptures and leaks and has led to numerous piping replacements. United States utilities use a combination of EPRI guidance, software, and aggressive inspection programs to deal with FAC. However, current technology does not detail guidance for erosive forms of attack including, cavitation erosion, flashing erosion, droplet impingement, and solid particle erosion. These forms of degradation have caused shutdowns, and leaks have become a maintenance issue. This brief will present a description of erosive damage mechanisms found in nuclear power plants.

Tackling Erosion in Nuclear Piping Systems

2007 ◽  
Author(s):  
Harold M. Crockett ◽  
Jeffrey S. Horowitz
Keyword(s):  
Nuclear Power ◽  
Power Plants ◽  
Training Module ◽  
Droplet Impingement ◽  
Damage Mechanisms ◽  
Accelerated Corrosion ◽  
Computerized Training ◽  
Piping Systems ◽  
Research Plan ◽  
Flow Accelerated Corrosion

Various mechanisms degrade power piping in nuclear power plants. The most important mechanism has been flow-accelerated corrosion (FAC). FAC has caused ruptures and leaks and has led to numerous piping replacements. U.S. utilities are using a combination of EPRI software and aggressive inspection programs to deal with FAC. However, current technology does not deal with erosive forms of attack including, cavitation erosion, flashing erosion, droplet impingement, and solid particle erosion. These forms of degradation have caused shutdowns and leaks have become a maintenance issue. To deal with these problems EPRI has begun a series of projects in this area. The first of these was a comprehensive report on erosion in piping systems. This work was followed with a computerized training module designed to educate utility engineers about erosive attack. Further steps are planned to deal with these forms of degradation. The first will be a meeting with knowledgeable EPRI and utility engineers to prioritize the damage mechanisms. From this meeting a research plan will be developed. This paper will present a description of erosive damage mechanisms and describe the planned R&D to deal with these mechanisms.

Effects of Flow Accelerated Corrosion on Piping Steady-State Vibration Evaluations

2003 ◽  
Author(s):  
Brian J. Voll
Keyword(s):  
Steady State ◽  
Nuclear Power ◽  
Power Plants ◽  
Pipe Wall ◽  
Vibration Monitoring ◽  
Accelerated Corrosion ◽  
Monitoring Programs ◽  
Wall Thinning ◽  
Piping Systems ◽  
Flow Accelerated Corrosion

Piping steady-state vibration monitoring programs were implemented during preoperational testing and initial plant startup at most nuclear power plants. Evaluations of piping steady-state vibrations are also performed as piping and component failures attributable to excessive vibration are detected or other potential vibration problems are detected during plant operation. Additionally, as a result of increased flow rates in some piping systems due to extended power uprate (EPU) programs at several plants, new piping steady-state vibration monitoring programs are in various stages of implementation. As plants have aged, pipe wall thinning resulting from flow accelerated corrosion (FAC) has become a recognized industry problem and programs have been established to detect, evaluate and monitor pipe wall thinning. Typically, the piping vibration monitoring and FAC programs have existed separately without interaction. Thus, the potential impact of wall thinning due to FAC on piping vibration evaluations may not be recognized. The potential effects of wall thinning due to FAC on piping vibration evaluations are reviewed. Piping susceptible to FAC and piping susceptible to significant steady-state vibrations, based on industry experience, are identified and compared. Possible methods for establishing links between the FAC and vibration monitoring programs and for accounting for the effects of FAC on both historical and future piping vibration evaluations are discussed.

A Procedure for Determining the Safe Operation Time of Equipment and Pipelines Based on Nondestructive Testing Results

Vestnik MEI ◽  
2020 ◽  
Vol 6 (6) ◽  
pp. 11-17
Author(s):  
Dmitriy A. Kuz'min ◽  
◽  
Aleksandr Yu. Kuz'michevskiy ◽  
Artem E. Gusarov ◽  
◽  
...  
Keyword(s):  
High Pressure ◽  
Wall Thickness ◽  
Nuclear Power ◽  
Power Plants ◽  
Nuclear Power Plants ◽  
Operation Time ◽  
Safe Operation ◽  
Accelerated Corrosion ◽  
Equipment And Pipelines ◽  
Flow Accelerated Corrosion

The reliability of nuclear power plants (NPPs) has an influence on power generation safety and stability. The reliability of NPP equipment and pipelines (E&P), and the frequency of in-service inspections are directly linked with damage mechanisms and their development rates. Flow accelerated corrosion (FAC) is one of significant factors causing damages to E&P because these components experience the influence of high pressure, temperature, and high flow velocity of the inner medium. The majority of feed and steam path components made of pearlitic steels are prone to this kind of wear. The tube elements used in the coils of high pressure heaters (HPH) operating in the secondary coolant circuit of nuclear power plants equipped with a VVER-1000 reactor plant were taken as the subject of the study. The time dependences of changes in the wall thickness in HPH tube elements are studied proceeding from an analysis of statistical data of in-service nondestructive tests. A method for determining the initial state of the E&P metal wall thickness before the commencement of operation is proposed. The article presents a procedure for predicting the distribution of examined objects' wall thicknesses at different times of operation with determining the occurrence probability of damages caused by flow accelerated corrosion to calculate the time of safe operation until reaching a critical state. A function that determines the boundary of permissible values of the HPH wall thickness distributions is obtained, and it is shown that the intervals of in-service inspections can be increased from 6 years (the actual frequency of inspections) to 9 years, and the next in-service inspection is recommended to be carried out after 7.5 years of operation. A method for determining the existence of FAC-induced local thinning in the examined object has been developed. The developed approaches and obtained study results can be adapted for any pipelines prone to wall thinning to determine the frequency of in-service inspections (including an express analysis based on the results of a single nondestructive in-service test), the safe operation time, and quantitative assessment of the critical value reaching probability.

Flow Accelerated Corrosion Program in the Belgian Nuclear Power Plants

2009 ◽  
Author(s):  
Anne-Sophie Bogaert ◽  
Michel Desmet ◽  
Arnaud Gendebien
Keyword(s):  
Nuclear Power ◽  
Power Plants ◽  
Nuclear Power Plants ◽  
Ultrasonic Inspection ◽  
Accelerated Corrosion ◽  
Balance Of Plant ◽  
Nuclear Plants ◽  
Set Up ◽  
Predictive Software ◽  
Flow Accelerated Corrosion

Since the Surry-accident of 1986, Electrabel and Tractebel Engineering have performed extensive ultrasonic inspection campaigns to detect pipe wall thinning due to Flow Accelerated Corrosion (FAC) in the Balance-of-Plant systems of the seven Belgian nuclear power plants. Since 2000 EPRI’s predictive software CHECWORKS is used as a means to focus future inspections on the most susceptible components. In 2005, Tractebel Engineering participated in a benchmark set-up by the Framatome Owners Group (FROG) that compared the different FAC predictive models used by the FROG members. In 2006, Electrabel and Tractebel Engineering decided to perform an assessment of the way in which the follow-up of Flow Accelerated Corrosion (FAC) is done in the Belgian nuclear plants. This paper summarizes the Flow Accelerated Corrosion program in the Belgian nuclear plants as well as some of the main aspects of the Flow Accelerated Corrosion management, including the use of a predictive software, the method of inspections and the actions taken to keep the FAC program up to date.

Development of an On-Line Ultrasonic System to Monitor Flow-Accelerated Corrosion of Piping in Nuclear Power Plants

2004 ◽  
Vol 270-273 ◽  
pp. 2232-2238 ◽  
Author(s):  
Na Young Lee ◽  
Chi Bum Bahn ◽  
Sang Geun Lee ◽  
Ji Hyun Kim ◽  
Il Soon Hwang ◽  
...  
Keyword(s):  
Nuclear Power ◽  
Power Plants ◽  
Nuclear Power Plants ◽  
Accelerated Corrosion ◽  
On Line ◽  
Flow Accelerated Corrosion

Effect of Bending Load on the Failure Pressure of Wall-Thinned Pipe Bends

2010 ◽  
Author(s):  
Jin Weon Kim ◽  
Oon Young Jung
Keyword(s):  
Internal Pressure ◽  
Nuclear Power ◽  
Power Plants ◽  
Degradation Mechanism ◽  
Operating Conditions ◽  
Accelerated Corrosion ◽  
Failure Pressure ◽  
Bending Load ◽  
Piping Systems ◽  
Flow Accelerated Corrosion

Under normal operating conditions, piping systems in nuclear power plants (NPPs) are subject not only to internal pressure but also to bending loads induced by deadweight and thermal expansion [1]. Bending is thus considered to be an important factor in evaluating the integrity of defective piping components. Local wall-thinning due to flow-accelerated corrosion is a main degradation mechanism of carbon steel piping systems in NPPs [2], and the integrity evaluation of wall-thinned piping components has become an important issue [3]. This study investigated the effects of bending load on the failure pressure of wall-thinned pipe bends under internal pressure. Our previous study experimentally evaluated the bending load effects on the failure pressure of wall-thinned elbows under displacement controlled in-plane bending load [4], but the numbers of experimental data were insufficient to determine the effects of bending load on the failure pressure of wall-thinned pipe bends. Therefore, the present study systematically evaluates the effects of bending load on the failure pressure of wall-thinned pipe bends using parametric finite element analyses.

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