Air-conditioning duct is difficult to predict the date to occur of corrosion such as affect the function. Therefore, the current conservation method is mostly corrective maintenance. Therefore, was used the test pieces of six types and ACM-sensor in order to solve the corrosion speed from corrosion environment and relationship of corrosion quantity of test pieces. In addition, was used the duct molded articles various in order to check the corrosion degree of when processed the duct. As a result, we we...
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Preventive maintenance plan of the air-conditioning duct using the ACM-sensor

Pipe wall thinning is an aging process that has a significant effect on the safety and safe operation of power plants and its appropriate management is an issue common to a ll electric power companies. Tohoku Electric Power Co., Inc. has been putting an emphasis on pipe wall thickness management since 2006, when a through-hole possibly due to droplet-impact erosion was found in the vent piping of high-pressure feedwater heater No.2 at Onagawa Nuclear Power Station unit 2. Following this incident, extensive...
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Overview of Pipe Wall Thickness Management at Tohoku Electric Power

Since June 2014, the Higashidori Nuclear Power Station had been taking the assessment of the on-site fault in the conformity assessment of the new regulatory standard. After that, although the assessment of the fault located directly under key facilities ended in 2018, We are taking an assessment of active fault examination considered as an epicenter at present. This document is a summary of the supplementary survey including geology survey such as reflection survey and boring exploration for active fault a...
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Supplemental investigation on faults in site of Higashidori Nuclear Power Plant Unit 1

Electromagnetic acoustic transducer (EMAT) provides non-contacting measurements and is often applied to monitoring in high temperature environment. Electromagnetic acoustic resonance method (EMAR) is transmits an ultrasonic burst wave, and the driving frequency of bust wave is swept. Then signal amplitude of each frequency is computed by the superheterodyne processing at the interval. Pulse-EMAR method is transmits an ultrasonic pulse wave propagating, but the pulse wave is not swept. Then echo waves recei...
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Influence of bottom shape in the pipe wall thinning inspection using an electromagnetic acoustic resonance method