More economical methods of manufacturing aluminum-uranium fuel elements used extensively in high thermal-neutron flux reactors might be employed if the quantity of silicon allowed in the fuels could be substantially increased. Since silicon has created problems in reprocessing this type of fuel, various core and cladding alloys were examined for the effect of the silicon content upon dissolution, extraction, and solids production during dissolution. Dissolution rates in nitric acid were related to the metallurgical compositions of the alloys which, in turn, were related to their silicon content, but the effect was not sufficient to interfere with the reprocessing of the fuels. Emulsion stabilization, a problem during liquid-liquid extraction of uranium, is caused by the silicon that dissolves from the alloy as the intermetallic phase U(Al,Si)3. Silicon present in the alloy at a silicon:uranium atom ratio <1 is in the intermetallic fuel particle, while silicon in excess of approximately one atom per atom of uranium does not enter into the intermetallic phase and is present in the alloys as segregations of elemental silicon. This elemental silicon does not dissolve and remains in the dissolver solution as undesirable solids.