Evaluation of Fluoride,Cerium(Iv),and Cerium(Iv)--Fluoride Mixtures as Dissolution Promoters for Puo sub 2Scrap Recovery Processes.

摘要

Fluoride,cerium(IV),and cerium(IV)-fluoride mixtures were evaluated as promoters for nitric acid dissolution of unirradiated PuO sub 2scrap. Fluoride was most effective in promoting rapid and complete dissolution of 80to 160 g of PuO sub 2 /liter of dissolvent. Cerium(IV) was unsuitable at the high PuO sub 2 /dissolvent ratios normally used in scrap processing because high Ce(IV) concentrations or a Ce(IV) regeneration process were required. Mixing Ce(IV) and fluoride at a ratio of 4KF/Ce(IV) in 8M HNO sub 3increased the PuO sub 2dissolution rate at PuO sub 2concentrations of less than 10 g/liter,but not at the desired high PuO sub 2 /dissolvent ratios. The dissolution rate of PuO sub 2scrap in HNO sub 3 -F exp -and HNO sub 3 -Ce(IV) solutions was related inversely to the temperature of the PuO sub 2fabrication process.