Laser measuring machine for 3D noncontact inspection of geometric parameters of grid spacers for nuclear reactors VVER-1000

Ensuring a high reliability of fuel assemblies of nuclear reactors makes strict demands on geometric parameters of grid spacers. They determine the preset position of the fuel element beam in the transversal and longitudinal directions of fuel assembly and the required tension in the cell - fuel element junction, which is highly important for excluding of fuel element corrosion and for maintenance of normal thermal regime of this assembly. A laser measuring machine (LMM) using a three-channel measuring head based on multipoint structured illumination and scanning X-Y table, for 100% noncontact 3D inspection of grid spacers geometric parameters of Russian nuclear reactor VVER-1000, has been developed and produced at TDI SIE. The LMM structure, operation and software are described and the results of its industrial testing are presented and discussed. LMM makes it possible to measure for half an hour (with errors less than 18 gm) the following grid spacer geometric parameters: diameters of its cells and of guiding channels, the distances between cells centers and shifts of cell centers relative to design drawing. In addition, LMM also measures grid spacer overall dimensions "for spanner".