scholarly journals On-Line Monitoring of Pipe Wall Thinning by a High Temperature Ultrasonic Waveguide System at the Flow Accelerated Corrosion Proof Facility

Sensors ◽  
2019 ◽  
Vol 19 (8) ◽  
pp. 1762 ◽  
Author(s):  
Se-beom Oh ◽  
Yong-moo Cheong ◽  
Dong-jin Kim ◽  
Kyung-mo Kim

Pipe wall thinning and leakage due to flow accelerated corrosion (FAC) are important safety concerns for nuclear power plants. A shear horizontal ultrasonic pitch/catch technique was developed for the accurate monitoring of the pipe wall-thickness. A solid couplant should be used to ensure high quality ultrasonic signals for a long operation time at an elevated temperature. We developed a high temperature ultrasonic thickness monitoring method using a pair of shear horizontal transducers and waveguide strips. A computer program for on-line monitoring of the pipe thickness at high temperature was also developed. Both a conventional buffer rod pulse-echo type and a developed shear horizontal ultrasonic waveguide type for a high temperature thickness monitoring system were successfully installed to test a section of the FAC proof test facility. The overall measurement error was estimated as ±15 μm during a cycle ranging from room temperature to 150 °C. The developed waveguide system was stable for about 3300 h and sensitive to changes in the internal flow velocity. This system can be used for high temperature thickness monitoring in all industries as well as 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 ◽  
...  

Author(s):  
Brian J. Voll

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.


Vestnik MEI ◽  
2020 ◽  
Vol 6 (6) ◽  
pp. 11-17
Author(s):  
Dmitriy A. Kuz'min ◽  
◽  
Aleksandr Yu. Kuz'michevskiy ◽  
Artem E. Gusarov ◽  
◽  
...  

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.


2013 ◽  
Vol 2013.49 (0) ◽  
pp. 87-88
Author(s):  
Yoshiki SATO ◽  
Akira IWABUCHI ◽  
Michimasa UCHIDATE ◽  
Hitoshi YASHIRO ◽  
Akito OYAKAMA ◽  
...  

Author(s):  
Anne-Sophie Bogaert ◽  
Michel Desmet ◽  
Arnaud Gendebien

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.


2010 ◽  
Vol 132 (2) ◽  
Author(s):  
Harold M. Crockett ◽  
Jeffrey S. Horowitz

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.


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