The measurements of the zirconium tubes parameters in the RBMK reactors

Abstract

The dimensions of the zirconium tubes - diameters and wall thickness are the most important parameters for safe operation of the RBMK type reactors. In this paper the zirconium tube diameter and wall thickness measurement errors where analyzed. There was shown that the dynamic errors occur when the approach with rotating probes are used and the measurement head are positioned not precisely in the center of the tube. The dynamic errors can be reduced using multi-channel measurement system. The evaluation of maximal and minimal values of these parameter in cross section of the tube were performed using approximation of the measurement data. The developed equipment was approved in the Ignalina NPP. About 150 channels where measured during maintenance periods in the 1996. The total time necessary to perform measurements on one channel is about 2min and with preparing works takes about 10min.