ELECTROLYTIC OXIDATION OF ZIRCONIUM IN NITRATE SOLUTIONS

Zirconiurn alloys used in the fabrication of nuclear fuel elements can be disintegrated and converted to insoluble oxides by electrolytic treatment in concentrated nitrate solutions. This reaction shows promise as a technique for reprocessing nuclear fuels clad with Zircaloy-2. For a particular applied voltage, nitric acid achieves the highest rate of attack, but the reaction can be carried out at rates of 2 mg/(cm/sup 2/)(min) or greater in either 7.5M sodium nitrate or 2.3M aluminum nitrate. A reaction rate of 7 mg/(cm/sup 2/) (min) can be easily attained in either 8M nitric acid or 7.5M sodium nitrate. The rate of reaction is a function of the temperature and tho applied voltage. An as-yet unsolved problem is the carry--down of uranium with the insoluble zirconium oxide product. (auth)