Sensor Noise Caused by Vibrations of Flaw Detection Probe Generated in Helical Heating Tubes in a Fast Breeder Reactor and Its Countermeasures (1st Report, Experimental Results by Using Mock-up)

Abstract

This paper deals with sensor signal noise of eddy current testing (ECT) probe generated in helical heating tube in the fast breeder reactor MONJU. ECT probe is used for inspection of thickness of heating tube. The heating tube is composed of helical tube and straight tube because of advantage of thermal efficiency and compact size. However, the vibration of probe having no experience in usual straight heating tubes is generated. The vibration causes the noise and the decrease of sensor sensitivity of ECT probe. The experiment was performed by using a mock-up, and the noise characteristics of ECT sensor signal mounted in ECT probe were examined. The experimental result showed that the sensor signal noise in inserting ECT probe was higher than that in return process and the vibration in insert process had a certain outstanding frequency. It was effective for the countermeasure of sensor signal noise to attach the long and flexible guide probe to the top of ECT probe.