Abstract: Both gadolinia nuclear fuel rods and urania fuel rods are non-destructively tested to determine the enrichment concentration of the fuel pellets therein by serially conveying the gadolinia rods and the urania rod along separate test channels through an active scanner where they are irradiated from a common neutron souce, and the neutron-induced gamma ray emissions are counted as a measure of the enrichment concentrations at a multiplicity of points distributed along the rod length. The enrichment counts are corrected for background radiation, variations in fuel density, and, in the case of gadolinia rods, for gadolinia content by passing these rods through a magnetometer.

Abstract: Both gadolinia nuclear fuel rods and urania fuel rods are non-destructively tested to determine the enrichment concentration of the fuel pellets therein by serially conveying the gadolinia rods and the urania rod along separate test channels through an active scanner where they are irradiated from a common neutron source, and the neutron-induced gamma ray emissions are counted as a measure of the enrichment concentrations at a multiplicity of points distributed along the rod length. The enrichment counts are corrected for background radiation, variations in fuel density, and, in the case of gadolinia rods, for gadolinia content by passing these rods through a magnetometer.

Abstract: An apparatus using X-ray fluorescence for gauging the thickness of a zirconium barrier layer on the interior surface of a zirconium alloy nuclear fuel tube is disclosed. A gamma radiation source coaxially positioned in the tube emits gamma rays which excite K-alpha and K-beta Sn X-ray in the zirconium alloy substrate. Fluorescent X-rays passing back through the barrier layer are detected by an X-ray detector coaxially positioned in the tube. Attenuation of the exciting gamma rays and the fluorescent X-rays by the barrier layer is used to determine barrier layer thickness.

Abstract: An apparatus is provided for the automatic assembly of nuclear fuel rod bundles in a predetermined coordinate array. Each fuel rod is identified during its travel and positioned according to an identifying code carried on its lower end plug which designates the fuel enrichment and additive level of the rod.