Fuel elements for nuclear reactors and method for testing the circulation of fuel elements in a core of a nuclear reactor

摘要

A method of testing the circulation of a bulk charge of fuel elements in the core of a pebble bed type of nuclear reactor comprises increasing the electrical conductivity of a number of fuel elements and then injecting the marked elements into a bulk charge of other unmarked elements having a lower electrical conductivity at predetermined positions in the core of a nuclear reactor and a measured times. The marked fuel elements are subsequently detected electromagnetically as they are carried in the bulk charge of unmarked elements through an electromagnetic field generated by a detection and measurement station. The elements are marked by including a material having a greater electrical conductivity than the remainder of the element and this material may be coated on the surface of the elements or incorporated in the body of the elements.