Study on Pipe Inside-Crack Growth Monitor by Electric Resistance Method

Abstract

It is discribed in this paper that the heigh sensitive inside crack growth monitor is studied and developed by using the electric resistance method from the outside surface of the piping. When the needle interval is equal to the pipe thickness, the monitor will have the best sensitivity. The limit of sensitivity is more less than 10 % of the pipe thickness. By using the detector with five needles, the correction for pipe temperature is carried out exactly. This method can be applied to the piping system, when it is difficult to decide whether the indication by the inservice inspection is flaw or not, or when the indication is seemed to be flaw in spite of very small indication. By applying the monitor in practice, it is expected to contribute to the increase in availability and reliability in the power reactor plant.