METHOD FOR EDDY-CURRENT TEST OF GADOLINIUM CONTENT IN EACH PELLET OF URANIUM-GADOLINIUM FUEL COLUMN IN A FUEL ELEMENT AND DEVICE FOR CARRYING OUT SAID METHOD

摘要

The invention relates to a nondistuctive eddy-current test of materials and products. The inventive method and device are based on comparison of test results on the same cross section of a fuel element by means of two measuring systems. Said systems comprise transmission transducers through which a tested fuel element is displaced, and compensation converters provided with reference samples inserted therein. In the first system, the test is carried out when an external constant magnetic field formed by constant magnets is superimposed. In the second system, the test is carried out outside of magnetic field. The thus obtained results are used for computing the gadolinium content in each pellet taking into account the interference produces by ferromagnetic inclusions and the deviation of the conductivity and geometrical dimensions of the tested fuel element claddings from the reference sample claddings, and also the axial offset of the tested fuel element with respect to the axes of the transducers. The inventive method and device ensure a more accurate gadolinium determination in the presence of the ferromagnetic inclusions in the pallets.