| 摘要 |
<p>1434501 Processing radio-active substances SAINT - GOBAIN TECHNIQUES NOUVELLES 15 May 1974 [18 May 1973] 21449/74 Heading G6R Irradiated solid material, e.g. spent nuclear fuel elements, is processed to remove tritium and recover uranium and plutonium by dissolving the material in nitric acid, extracting U and Pu with an organic solvent, washing the organic phase first with an aqueous solution containing tritium and nitric acid and then with a small amount of tritium-free nitric acid in order to remove tritium, and then contacting the organic solution with an aqueous phase to extract the U and Pu; the organic phase and aqueous effluents containing tritium are recycled. In the embodiment described, gas from the fuel element shearing stage and the dissolving stage is condensed and dehydrated to remove tritiated water. After recovery of U and Pu from the tributyl phosphate organic extract by contact with aqueous solutions, the organic phase is washed with sodium carbonate solution which is concentrated and combined with the aqueous phase from the first extraction. This aqueous phase is concentrated to obtain a solid residue containing the fission products. The tritiated water and nitric acid removed from the aqueous phase are rectified and recycled, part of the tritiated water being removed from the process.</p> |
