Abstract: Tubes, especially nuclear fuel element jacket tubes, in many cases must be polished internally as well as externally. Previously there was not a satisfactory process for doing this. An electropolishing process for the inner surface of tubes for achieving uniform polishing is desirable. This is accomplished with apparatus in which a metal lance is inserted into the tube being treated. Insulating spacers at the point of the lance and rearwardly thereof from a cathode therebetween spaced uniformly from the inner surface of the tube. Electrolyte flows through such space and preferably is supplied from the interior of the lance.

Abstract: Block fuel elements are prepared according to application Ser. No. 218,244 of Jan. 17, 1972, and now abandoned, from isotropic graphite granulates and coated fuel particles solely by pressing and without any mechanical processing. The cooling channels are pressed directly along with the other parts of the fuel elements.

Abstract: Molded block fuel elements having an isotropic structure useful for gas cooled high temperature power reactors are prepared by first producing an isotropic graphite granulate of high density with a definite porosity from a molding powder and then hot pressing this isotropic granulate together with coated fuel particles at low pressure to isotropic fuel element. The molding powder for making the granulate is made from a mixture of natural graphite and binder resin, synthetic graphite and binder resin or a mixture of both types of graphite powder with binder resin.

Abstract: Molded or pressed block fuel elements of high power for gas cooled high temperatures are produced by molding in steel tools using outer dies or bars and punches arranged to be freely moveable in the axial direction and moving said moveable dies or bars and punches in the molding process.

Abstract: Prismatic graphite molded objects for high temperature fuel elements are prepared by producing the outer geometry and the holes for cooling channels and for receiving fuel and fertile materials in the formation of the carbon object.