Safety increasing of nuclear reactors is urgent problem for atomic industry. It takes 100% noncontact dimensional inspection of nuclear reactor components. Optoelectronic methods and systems for 3D inspection of fuel assembly elements, including spacer grids and fuel elements, are presented. The universal structured light method for 3D inspection of Russian and western grid spacers using diffraction elements is developed. For fuel elements inspection one considers the shadow method which allows one to implement full inspection of articles under transported along the automatic production line. TDI SIE has developed the commercial version of systems for integral inspection of spacer grids and fuel elements. The experimental results of industrial testing are given.