Pipe wall thickness measurements by ultrasonic (UT) sensors can be difficult as the roughness of the inner surface develops by certain corrosion mechanisms. In this study, the applicability of flexible UT sensors with single and dual element transducer were evaluated using carbon steel plates with localized sand erosion that simulates pipe walls with rough inner surface. While the thickness measurement by single transducer sensors with B-B method failed after certain amount of erosion, the newly develop...
英字タイトル:
Evaluation of online thickness monitoring system for wall thinning by erosion.

Pulsed Eddy Current Testing (Pulsed ECT) has a potential to reduce costs and time for pipe wall thickness measurement because it can be applied from outside of heat insulation material. Artificial defects on pipe specimen and actual piping at a power plant were inspected by Pulsed ECT. Detected positions of artificial defects were coincided well with the actual positions. It was possible to map the wall thickness of the actual power plant piping without removing wire mesh on the surface and to identify rema...
英字タイトル:
Wall thickness measurement of thinning pipe by Pulsed Eddy Current Testing device through heat insulation

Pipe wall thickness in power plant have been measured during the periodic inspection to evaluate soundness and safety by Ultrasonic Testing (UT). But it takes a long time and man power to complete measurement and evaluation. In this study, “Flex Dry UTM” is developed as a new kind of UT system for making it possible to monitor pipe wall thickness continuously. It is attached directly to pipe under the lagging material without using coupling medium. The maximum temperature it can be applied is developed to b...
英字タイトル:
Development of heat resistant ultrasonic probe for continuous wall thickness measurement and remote measuring equipment

In power plant, most of the pipe is examined for confirming the thickness of the pipe wall during the period of inspection in the suspension of the plant. As pipe thinning phenomenon can progress mostly in the running of the plant, the measuring for the thickness value in running time is needed for confirmation of health and safety evaluation precisely. In this study, “Flex Dry UTM” was developed as a new type of UT system for making it possible to monitor pipe wall thickness continuously. Its measuring per...
英字タイトル:
The evaluation of validity of accuracy in measuring thickness by ultrasonic probe for continuous measurement of pipe thickess

Online pipe thickness monitoring sensors, EMAT, Thin-film UT sensor and FLEXDRY UTM were installed to Unit4 spent fuel pool cooling system of Fukushima No.1 Power Plant. Pipe wall thinning data and ultrasonic waveform were recorded in a control PC near the pipe. EMAT can be controlled by remote PC in a office far from No4 Unit through local area network. The measured pipe wall thickness value by FLEXDRY UTM are parallel with results of conventional UM sensor well. Starting of online monitoring of Thin-...
英字タイトル:
Verification of online thickness monitoring system for radioactive pipes