Development of a device for nondestructive inspection of gadolinia containing fuel

A device for nondestructive inspection of the content and distribution of gadolinia pellets in gadolinia-containing fuel rod has been developed. The basis of the inspection is to determine magnetic susceptibility of the pellets by a magnetic induction method. The device features the ability to correct, by the use of harmonic signals, for the effect of ferromagnetic material (iron) which is often contained in the pellets in small quantities. The experimental results show that the technique is capable of measuring gadolinia content with an accuracy of ± 0.2 w/o and detecting deviated (rogue) pellets with 1 w/o differential content at a speed of up to about 2 m/min