engleski

Denitration of simulated radioactive liquid waste

Radioactive liquid wastes containing large amounts of nitric acid (approx. 4–7 M) generated in the nuclear fuel cycle are very undesirable by-products. Denitration of highly acidic radioactive liquid wastes with organic reducing agents has sev - eral advantages, such as a significant pH increase, possibility of separation of radioisotopes which can be utilized in other technologies, reduction of volatility of radioisotopes and fixation of certain mono- and divalent radioisotopes with zeolite. In the present work some aspects of denitration of simulated radioactive liquid wastes at laboratory level were investigated. Denitration of HNO 3 with formic acid was investigated for different [HCOOH]/[HNO 3 ] ratios. The changes in the induction time, pH increase and volume reduction were determined. It was shown that by the denitration of simulated radioactive liquid waste high pH values could be achieved which in real systems would create more possibilities in radioactive waste manage- ment. Analysis of solid phases formed after the oxidation of excess HCOOH with H 2 O 2 showed the presence of amorphous fraction as well as goethite and hematite phases, which could remove different radioactive cations from the liquid phase. The immobilization of simulated solid radioactive waste with borosilicate glass matrix was also shown.

Radioactive liquid waste ; Denitration ; Formic acid ; Borosilicate glass

nije evidentirano