A METHOD OF STRIPPING AND REPLATING NICKEL ELECTROPLATED URANIUM

摘要

The bulk of development work concerned the resolution of the nickel stripping bath. Borrowing an idea from Canadian Patent 666,198(1) (for the dissolution of aluminum coatings from uranium fuel rods), an acidic solution was developed to include both a catalytic agent (mercuric nitrate) to accelerate the removal of nickel and an inhibitor (nickelous nitrate) to retard the reaction with uranium. The final formulation of the stripping bath contains 20 g Hg(N03)3 H20 and 20 g Ni (N03)2 • 6H20 in 250 ml HN03 , 250 ml H2S04 and 500 ml H20. Utilization of this solution under prescribed conditions thoroughly strips nickel and simultaneously etches the uranium substrate, allowing immediate replating from a NiS04 bath without additional etching steps. Freshly machined uranium test coupons, 2 inches long and 1/4 inch in diameter, were used in the development of the process;no attempt was made to adapt the final process to field specimens of partially corroded fuel elements.