Abstract: The developed scanner for scanning fuel rod 235U enrichment uniformity is based on the 252Cf neutron activation method, in which the delay gamma rays emitted by fission products from 235U fission induced by moderated 252Cf neutrons are counted along the fuel rod moved successively through the irradiator containing 252Cf neutron sources and the BGO crystal detectors at a constant speed by a mechanical conveyor. The present equipment has two channels for inspecting two fuel at the same time. When a 252Cf source of 1.2 mg is used, the single offspec pellet which deviates from normal enrichment by ±10% can be detected at the scanning speed of 7 m/min with 97.74% confidence.