Array ECT probe called Intelligent ECT probe (I-Probe) has a capability to inspect tubes of Steam Generator (SG) more productively and more accurately than conventional probes. It has been applied as full length inspection in Japan since 2003 and there is much field experience to date. On the other hand, a phenomenon in SG secondary side is known that scale deposits on the clog holes of quatrefoil type tube support plate(TSP). Water level oscillation of secondary side caused by excessive blockage of sc...
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Development of Monitoring Method for SG Secondary Side Tube Support Plate Using Array Probe

Abstract In the nuclear power plants, the reservation of safety and before-it-happens prevention of a trouble are important themes. Moreover, in connection with the life extension of a plant, life-expectancy diagnosis has also been an important subject. Although it is technology required in order that a non-destructive test may secure the safety of a power generation plant, Ultrasonic Testing (UT) is applied. However, generally the welding of stainl ess steel piping used widely in the PWR type nuclear powe...
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Ultrasonic Testing Technique for Stainless Steel Pipe

In Japan, the preventive maintenance task of the 600 series nickel basis alloy weld of the reactor vessel (RV) and the steam generator (S/G) safe end weld are pushed forward sequentially, and a defect sizing using the ultrasonic testing (UT) from the inside of the safe end is carried out when the defect was dete cted by surface inspection prior to the work. Some defects are recognized on the S/G safe end and the R/V safe end in Japan, and these defects have occurred in the axial direction of the safe end w...
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Development of Advanced Defect Sizing Technique Using Ultrasonic Testing for Nozzle Welding

Recently, preventive maintenance tasks for welding of safe-end nozzles of reactor vessels and steam generators of PWRs in Japan had been carried out sequentially. Before the maintenance tasks, inspection services were carried out and several crack indications were found by eddy current testing (ECT). These indications were found in the welding which made b y 600 series nickel base alloy and evaluated as stress corrosion cracks which were oriented to the axial direction of the nozzle. Then investigations to...
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Development of the advanced phased array UT technique for accurate sizing of cracks in the nozzlewelding

In order to solve the problems of the thickness measurement, we have developed a thin-film UT sensor having excellent high-temperature durability and conformability in thin film form. In this paper, it was confirmed that the accuracy of thickness measurement for both complex geometries and plates at high-temperature was equivalent to the accuracy of conventional thickness measurement methods. It was also confirmed that the durability at high temperature and for temperature change in the actual equipmen...
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technology using high-temperature thin-film UT sensor

Periodical measurement of pipe wall thickness for power plant is performed with manual UT during outage. Furthermore, periodical water level measurement is performed during plant operation by using UT sensor because there is a possibility that the gas-void in the piping may adversely affects the components. There is necessary to carry out the monitoring during plant operation in order to realize the improvement of those managements. However, the continuous monitoring during plant operation is difficult...
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Continuous monitoring system using high-temperature thin-film UT sensor

As for periodical measurement of pipe wall thinning, several concerns are indicated, such as unstability of measurement position and contact condition, additional work for removal of insulating material and preparing scaffold, unstability on complex geometry and difficulty of continuous monitoring under plant operation. In order to solve these concerns, we developed thin-film UT sensor which has high-temperature durability and flexibility. Furthermore, we preliminary developed prototype linear phased-a...
英字タイトル:
Monitoring of pipe wall thinning using high-temperature thin-film UT sensor