Sensor noise caused by vibrations of flaw detection probe generated in helical heating tubes in a fast breeder reactor and its countermeasures. 3rd report. Parameter study by numerical simulations

An eddy current testing (ECT) probe is used for a diagnosis of a helical heating tube installed in a fast breeder reactor, and a vibration of ECT probe makes the diagnosis difficult. In our previous report, we proposed an analytical model of the ECT probe incorporating with a frictional force and confirmed that the vibration was caused by Coulomb friction. In this paper, it is shown that numerical simulations utilizing the analytical model agree with various experimental results of the vibration of ECT probe, so that the reliability of the analytical model and the numerical simulation is increased. It follows that a preceding estimation of the vibration is available by the numerical simulation. Based on a behavior of the entire probe, which is obtained by the numerical simulation, we discuss a countermeasure to suppress the probe vibration. The validity of countermeasure is demonstrated through the numerical simulations. (author)