| 摘要 |
<p>Partly used nuclear fuel containing uranium or plutonium carbide is decontaminated from fission products by treatment with anhydrous or aqueous hydrofluoric acid to form UF4 and/or PuF4, or PuF3. The hydrofluoric acid may be in gaseous or liquid form and reaction may take place at a temperature up to 700 DEG C.; for example, the used fuel is diluted with alumina and treated as a fluidized bed with hydrogen fluoride vapour mixed with nitrogen, argon, or hydrogen. For complete decontamination, the product may be converted to the hexafluorides by the action of fluorine at 400 DEG C., and the hexafluorides purified by distillation. Alternatively the lower fluorides may be (a) reduced with calcium or magnesium metal in the presence of carbon or graphite to re-form the carbides; or (b) converted to oxides with steam at high temperature.</p> |
