Development of a screening method for fine uranium particles in safeguards environmental samples by fission-track technique

Lee, C. G.; Suzuki, Daisuke   ; Inagawa, Jun; Esaka, Fumitaka  ; Magara, Masaaki  ; Sakurai, Satoshi ; Shinohara, Nobuo ; Usuda, Shigekazu

A screening method for uranium particles according to their enrichment has been developed by using the characteristics of fission tracks. The etching rate of fission tracks by the uranium particles increases with the U enrichment of uranium particle. This result strongly suggests that the enrichment-based screening of the uranium particles is possible by controlling the etching time. In order to verify the effectiveness of the developed screening method, a mixed sample containing uranium particles with different enrichment was used. A two-step filtration system that can collect particles with desired diameters was used for the collection of uranium particles in order to avoid the influence of the differences in the diameters on the etching behavior of fission tracks. It was shown that the enrichment-based screening of the uranium particles is possible by comparing the fission track morphology and particle size in addition to controlling etching time.