| 摘要 |
<p>Uranium and zirconium are separated from spent nuclear fuel elements containing them by inserting the element within a fluidised bed of inert granular solids, introducing anhydrous hydrogen chloride to convert the zirconium to <PICT:0925178/III/1> zirconium tetrachloride and recovering the latter, and thereafter introducing gaseous fluorine which reacts with the uranium and fission products to form a gaseous uranium hexafluoride-containing effluent gas which is fractionated to recover the uranium hexafluoride. The hydrochlorination of the zirconium may be carried out 350-450 DEG C. whilst the fluorination is suitably effected at 350-475 DEG C. As shown in Fig. 1 a jacketed reactor 10 is provided with a foraminous support 26 for supporting the zirconium clad uranium rod 22. The reactor is initially heated to 350-450 DEG C. by introducing liquid sodium into the jacket 16 whilst fluidising with a helium or argon stream; thereafter hydrogen chloride is introduced through line 28 whilst coolant is introduced through the jacket to control the exothermic reaction. Zirconium tetrachloride product is withdrawn via a filter 30 to line 32. Heated sodium is then passed through jacket 16 to raise the temperature to 400 DEG C. whereupon gaseous fluorine in a concentration of 5-100% of the gaseous phase is introduced through line 34; the uranium hexafluoride, plutonium hexafluoride and other volatile fission product fluorides are withdrawn through a line 36 to a distillation zone where uranium hexafluoride is recovered.</p> |
