High temperature reactor spherical elements identified - by inductive receiver and bridge circuit to measure detuning and phase displacement

摘要

A method of detecting articles of electrically conducting material, pref. spherical fuel elements, moderator elements and absorber elements of a high temperature reactor, makes use of an inductive receiver through which the spherical elements each pass individually; a bridge circuit is connected to the receiver and the amplitude of the bridge detuning is evaluated, to give a signal. In addition to the evaluation of the amplitude, the phase displacement to the bridge supply voltage which occurs during the bridge detuning is utilised for detecting the individual elements. The bridge circuit is pref. operated with a carrier frequency in the range 50 kHz-1 MHz. The temp. existing at the measuring point has practically no influence upon the indicator signals obtained. Either a column of spheres or each individual sphere may be detected.