Application of the Electrical Potential Drop Technique to the Pipe Wall Thinning Monitoring in Thermal Power Plants

2008 ◽  
Author(s):  
Shin Yoshino ◽  
Seiichi Hamada ◽  
Manabu Hayakawa
Keyword(s):  
Power Plants ◽  
Pipe Wall ◽  
Thermal Power ◽  
Electrical Potential ◽  
Potential Drop ◽  
Thermal Power Plants ◽  
Technical Requirements ◽  
Wall Thinning ◽  
On Line ◽  
Drop Technique

The electrical potential drop technique is one of the promising methods for monitoring the pipe wall thinning. In order to verify this method, preliminary thickness measurements were conducted for uniform and local thinning created on plate specimens. The result showed the electrical potential drop technique had a good performance equal to the ultrasonic testing method. The success in the preliminary tests allowed this technique to be applied to some pipes in thermal power plants in order to monitor the wall thinning and this on-line monitoring has continued for two to three years. It was confirmed that this technique was valid in terms of a long-term durability. Following these results, technical requirements on the potential drop technique were proposed to the JSME (the Japan Society of Mechanical Engineers) Rules on Pipe Wall Thinning Management for Thermal Power Generation Facilities (JSME S TB1-2006) and stipulated in those rules. In this paper, these rules are simply introduced and the on-line monitoring of the pipe wall thinning by means of the electrical potential drop technique is discussed through the results in the plate-specimen-tests and the real-pipe-tests in operating thermal power plants.

Accuracy Comparison of the Electrical Potential Drop Technique and Ultrasonic Testing for the Pipe Wall Thinning in the Thermal Power Plant

2010 ◽  
Author(s):  
Shin Yoshino ◽  
Seiichi Hamada ◽  
Yoshi Kaieda
Keyword(s):  
Ultrasonic Testing ◽  
Power Plants ◽  
Pipe Wall ◽  
Thermal Power ◽  
Electrical Potential ◽  
Potential Drop ◽  
Severe Condition ◽  
The Real ◽  
Wall Thinning ◽  
Drop Technique

The electrical potential drop technique is one of the promising methods for monitoring the pipe wall thinning. In the previous paper [1], it was reported that this technique had a good performance equal to the ultrasonic testing in the preliminary test and that it had a long-term durability under a severe condition on the real pipes in operating thermal power plants. This time one of these pipes was replaced because its thickness approached the threshold. The removed pipe was cut in many pieces and its thickness was measured with calipers at several locations corresponding to where the electrical potential drop technique was applied. This result was compared with the thickness resulted from this technique and the conventional ultrasonic testing that were conducted just before the pipe removal. This comparison led to the conclusion that the accuracy in the electrical potential drop technique was almost equivalent to that in the ultrasonic testing even in the real pipe under a severe condition. In this paper, the accuracy in the electrical potential drop technique is mainly discussed.

Outline of the JSME Rules on Pipe Wall Thinning Management for Thermal Power Generation Facilities

2007 ◽  
Author(s):  
Isoharu Nishiguchi ◽  
Seiichi Hamada
Keyword(s):  
Power Generation ◽  
Power Plants ◽  
Pipe Wall ◽  
Thermal Power ◽  
Potential Drop ◽  
Thickness Measurement ◽  
Technical Standards ◽  
Technical Requirements ◽  
Wall Thinning ◽  
Thermal Power Generation

In response to the pipe wall thinning damage experienced in power plants in 2004, the Japan Society of Mechanical Engineers (JSME) has started activities to develop technical standards on the pipe wall thinning management. The first edition of the JSME rules on pipe wall thinning management for thermal power generation facilities (JSME S TB1-2006 [1]) was issued in March 2006, and its latest edition will be issued in 2007, which describes the technical requirements to meet the JSME performance-based rules for pipe wall thinning management (JSME S CA-1 2005 [2]). Based on 24,774 inspection data obtained at the thermal power plants in Japan, the latest JSME rules will show the specific attention to the need for inspection of piping systems that are susceptible to the wall thinning damage. The JSME rules describe the selection of thickness measurement locations such as downstream of piping configurations that produce turbulence, downstream of orifices, downstream of control valves, and they describe the periodic inspections including the first inspection to be scheduled taking the wall thinning rate data at the equivalent locations into consideration. The JSME rules stipulate some available inspection methods such as ultrasonic scanning, radiographic profile, eddy current and potential drop technique. This paper presents outline of the JSME rules including basic philosophy, technical requirements on the inspection and testing practices and the relation with the regulations in Japan.

A New Method of On-Line ELD for Thermal Power Plants

1988 ◽  
Vol 21 (11) ◽  
pp. 395-401
Author(s):  
Y. Tamura ◽  
Y. Fukuyama ◽  
S. Yazawa ◽  
J. Hosaka ◽  
N. Joho ◽  
...  
Keyword(s):  
Power Plants ◽  
Thermal Power ◽  
New Method ◽  
Thermal Power Plants ◽  
On Line

A NEW METHOD OF ON-LINE ELD FOR THERMAL POWER PLANTS

1989 ◽  
pp. 395-401
Author(s):  
Y. Tamura ◽  
Y. Fukuyama ◽  
S Yazawa ◽  
J. Hosaka ◽  
N. Joho ◽  
...  
Keyword(s):  
Power Plants ◽  
Thermal Power ◽  
New Method ◽  
Thermal Power Plants ◽  
On Line

Application of Potential Drop Technique to the Inspection of Welded Boiler Pressure Parts

2004 ◽  
Author(s):  
Seiichi Hamada ◽  
Yasuki Ogawa ◽  
Hideo Iida ◽  
Tomoki Kuroiwa ◽  
Masahiko Kuroki ◽  
...  
Keyword(s):  
Direct Current ◽  
Electrical Potential ◽  
Creep Damage ◽  
Potential Drop ◽  
Burst Test ◽  
Technical Requirements ◽  
Pulsed Direct Current ◽  
Drop Technique ◽  
Direct Current Potential Drop ◽  
Current Potential

In this paper, a practical method using the electrical potential drop technique was discussed to evaluate the creep damage accumulated in the welded power piping such as main steam pipe and hot reheat pipe. Round robin experimental measurements conducted by the authors et al. as academic activities in the Japanese Society for Non-destructive Inspection showed that the potential drop technique is effective for the application to the inspection of welded boiler pressure parts. The authors have conducted additional experimental and numerical studies for verification focusing on the application of the pulsed direct current potential drop technique. The authors have proposed technical requirements on the potential drop technique for the application to the inspection of welded power piping to be implemented in JSME Codes for Thermal Power Generation Facilities (2003 Edition) as a non-mandatory appendix JA. And the practical on-line measurement in the high temperature and high pressure burst test using the repair-welded power piping has been conducted. In this burst test, Tokyo Electric Power Company has tried to monitor the creep damage accumulated in the seam-welded area using the commercialized tool based on pulsed direct current potential drop technique.

A New Algorithm of On-line Eld for Thermal Power Plants

1986 ◽  
Vol 19 (16) ◽  
pp. 81-89
Author(s):  
Yasuo Tamura ◽  
Shizuo Hagiwara
Keyword(s):  
Power Plants ◽  
Thermal Power ◽  
Thermal Power Plants ◽  
On Line
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