We are developing remote filed eddy current testing (RFECT) method using pancake coils for evaluating local wall thinn ing of large diameter pipes. This paper shows a study to improve the detectability and sizing capability of this RFECT method. The study was performed by numerical calculations and laboratory experiments. The results show that introduci ng differential pick-up coils makes detection signals more stable and improves the detectability of our RFECT method....
英字タイトル:
Improvement of remote field eddy current testing using pancake coils

This paper shows phase characteristics of crack indications obtained with a multi-coil ECT probe, and proposes a method to reduce noise and extract crack indications from the detection signals of this multi-coil ECT p robe based on these phase characteristics. Because this multi-coil ECT probe performs two kinds of scanning patterns: U-scan and T-scan, and obtains two sets of signal distributions for one scanning area simultaneousl y, the proposed method uses a two-stage process that includes so-called a m...
英字タイトル:
Extraction of crack indications from ECT signals by using signal phase characteristics

In the process of achieving cold shutdown following the shutdown of Hamaoka Nuclear Power Station Unit 5 on May 14, 2011, the readings of conductivity meters monitoring the purity of the water in the main condensers began to rise, and the conductivity of the water in the reactor also began to rise. After cold shutdown, investigation identified that a high volume of sea water had flowed into the reactor facility due to damage to the main condenser tubes. Evaluations focusing on corrosion of materials have b...
英字タイトル:
Effect of sea water intrusion from main condenser, damaged by breakon reactor core internals, Hamaoka Unit 5

The Nuclear and Industrial Safety Agency (N I SA) has begun the review of online main tenance in nuclear power plants in its advisory committee. The experts in the committ ee study the necessary actions in the regulation and safe and secure measure to impl ement the online maintenance. This paper explains the current progress of the review....
英字タイトル:
The review of online maintenance in nuclear power plants

The new nuclear inspection system established by the Nuclear and Industrial Safety Agency (NISA) came into force in January 2009. The NISA focused on the maintenan ce program to set up the new system. The new inspection system require the report of the maintenance plan to the NISA, safety verification of the plan by the NISA, collection of deterioration data of facilities, reflection of the data on self check, and online monitor of concerned equipment. Utilities have reported approxima tely 30 of their mai...
英字タイトル:
The outline of the new nuclear inspection system and its current exercise