A method for the production of graphite press powders and graphite press masses for the production of graphite the form bodies

摘要

1478037 Graphite compositions HOBEG HOCHTEMPERATURREAKTOR - BRENNELEMENT GmbH 21 Aug 1974 [26 Sept 1973] 36752/74 Heading C1A [Also in Divisions C3 and G6] Graphite pressing compositions containing a phenolic resin as binder are prepared by adding the starting components of a phenolic resin to a graphite powder and forming the phenolic resin by heating the mixture to a temperature at which the starting components condense to form the resin, and then optionally drying and finally grinding. The pressing composition optionally in admixture with nuclear fuel particles having a gas-tight and radiation stable coating of, for example, pyrolytic carbon or silicon carbide, fertile material particles or absorber particles for high temperature nuclear reactors can be carbonized and then heattreated. In Examples 1 and 2, graphite pressing compositions are prepared either (1) by adding a solution of phenol, formalin and water to a mixture of natural graphite powder and graphitized petroleum coke powder and heating in the presence of HCl; or (2) by heating a mixture of natural graphite, electro-graphite, phenol and hexamthylenetetramine. The resulting products are dried and ground to a particle size of 0À3 mm. Spherical nuclear fuel elements are then produced by encasing fuel particles with the pressing compositions thus obtained and pressing the thus encased particles and more pressing composition into a mould and then carbonizing followed by heat-treating at 1900‹C. in vacuo. In Example 3 the pressing composition form Example 2 and (U, Th)O 2 particles, coated with 3 pyrolitic layers with different carbon densities, are mixed together and formed into cylindrical fuel inserts, which are then carbonized and then heat-treated.