This paper shows a methodology to obtain metallic uranium through a magnesiothermy\nprocess. Chile has two experimental reactors operated by the\nâ??Chilean Nuclear Energy Commissionâ? (CCHEN). One is 5 MW and the\nother is 10 MW. In order to fulfill international agreements about nuclear\nenergy for testing purposes of these reactors, CChEN purchased 19.9%\nenriched uranium hexafluoride, also known as the limit of Low Enriched\nUranium (LEU). Due to the capacity of these reactors, they need high-density\nuranium compounds for their fuel, in order to work with LEU. For this reason,\nthe uranium needs a previous conversion into metallic uranium. The\nconversion laboratory carried out experiences for reduction of UF4 with Mg.\nThe main purpose of this study was to analyze the operating conditions under\nwhich the reduction reaction takes place, the designed method and the equipment\nand materials used. The raw material used was dehydrated UF4, prepared\nby electrolytic reduction and commercial purity Magnesium. The\nreaction took place in a cylindrical reactor made of low alloy steel, with a\nconic section in the lower part. The internal zone was coated with a 2.5 cm\nthick layer of CaF2. The process started by applying external heating, according\nto a heating program, developed specially for this purpose. The reduction\nreaction took place starting at 650DegreeC. The result was a cylinder of\nuranium metal and MgF2 slag. The crossed cut uranium cylinder showed a\nsmooth and homogeneous surface without inclusions of slag, pores or blisters.\nThe yield of the reaction was of the order of 75% with respect to the expected\ntheoretical value. The uranium cone obtained fulfilled the required\nconditions for source material for nuclear fuel fabrication, with a uranium\ncontent of 97.5%.
Loading....