Patent Number: 040070859
Section: claims

1. An elongated insert for a nuclear reactor fuel element whereby the fuel element may be individually identified, the elongated insert bearing a first array of markings at positions spaced along the length of said insert to produce a series of signals on presentation of the elongated insert to a detector responsive to each marking, each marking of said first array being located at a position spaced lengthwise of said insert from other markings of said first array, and a second array of markings at positions spaced along the length of said insert to vary the series of signals produced by the first array of markings on presentation to the detector, the marking of said second array being located at only some of the positions of said first array of markings. 2. An insert as claimed in claim 1 in the form of a metal bar wherein all the markings are holes extending through the bar and the further markings are at right angles to the array at spaced positions. 3. An insert as claimed in claim 1 in the form of a metal bar wherein all the markings are grooves and the further markings are provided by deepened grooves. 4. A nuclear reactor fuel element comprising a nuclear fuel material within a protective sheath and including within the sheath an elongated insert for identifying said fuel element, wherein the insert bears a first array of markings at positions spaced along the length of said insert to produce a series of signals on presentation of the elongated insert to a detector responsive to each marking, each marking of said first array being located at a position spaced lengthwise of said insert from other markings of said first array, and a second array of markings at positions spaced along the length of said insert to vary the series of signals produced by the first array of markings on presentation to the detector, the marking of said second array being located at only some of the positions of said first array of markings.