process for the production of single crystals of nuclear fuel with metallic component, in particular of ceramic nuclear fuel, and arrangement for the implementation of the procedure

摘要

PICT:1036512/C1/1 Single crystals of ceramic nuclear fuel material, e.g. UC, are produced by electro-thermally sublimating the material under sub - atmospheric pressure in a chamber of which the walls are at least in part formed by a body of the material, the vaporizing energy being supplied inductively at high frequency and with field concentration to the walls of said body, and condensing the vapours on portions of the chamber wall which are at a lower temperature. Fig. 1 shows an apparatus suitable for producing said crystals, and comprises an evacuated vessel 1, surrounded by an induction winding 2; element 3 is a field concentrator, namely a double cylindrical element of copper with a radial slot 3a (Fig. 2, not shown), mounted between the winding 2 and the body of UC 5 which is contained in a carrier vessel 4 of BeO. The inner surface of the field concentrator 3c is the same length as the cavity 5d in the UC body but the caps 5b are outside its sphere of action therefore the surfaces 5c are able to act as surfaces on which the UC vapour produced in the cavity can condense to form crystals. Fig. 3 (not shown) illustrates a modified form of the field concentrator, and the chamber has a cap fitted with a pin which projects into the cavity and on which the desired crystals form.