Fuel location, homogeneity and amount in flat and tubular configurations

The fuel elements for the materials testing reactor BR2 can be assembled either with plates obtained by the picture-frame process, or with tubes obtained by co-extrusion. In the course of the fabrication and before reactor loading the fuel disposition, the homogeneity and the absolute amount have to be checked or measured.
The fuel disposition should be known for positioning of the core in plates and tubes and as a first quality evaluation of the product with regard to the geometrical specifications. Radiography at about 80-90keV, autoradiography and gammagraphy with a thulium-170 source have been done. By radiographing the fuel tubes a lead mandrel with the X-ray film fixed to it was placed inside the tube and subsequent X-ray shots at different angles were taken. A radioactive source scanning the fuel along its centre line in combination with a film around the tube showed records with a high resolution.