Development for ultra-trace analysis method of U and Pu in safeguards environmental samples at the clean facility

Takahashi, Masato; Magara, Masaaki  ; Sakurai, Satoshi ; Kurosawa, Setsumi; Esaka, Fumitaka  ; Taguchi, Takuji; Takai, Konomi; Fukuyama, Hiroyasu; Lee, C. G.; Yasuda, Kenichiro   ; Kono, Nobuaki; Gunji, Hideho; Inagawa, Jun; Suzuki, Daisuke   ; Gunji, Katsubumi*; Saito, Yoko; Miyamoto, Yutaka   ; Ichimura, Seiji; Watanabe, Kazuo; Usuda, Shigekazu

Based on the strengthen safeguard program of the IAEA to detect undeclared nuclear activities, the method of precise and accurate isotope ratio determination for uranium and plutonium in the environmental samples (cotton swipes) has been developed at JAERI. The samples should be treated in clean environment in order to secure the analytical reliability by eliminating external contamination from the samples containing trace amount of uranium and plutonium. Since the measurement by ICP-MS is favorable to bulk analysis from view points of analytical capacity and operation simplicity, we have studied sample preparation procedures for the trace amount of uranium and plutonium to be applied to ICP-MS. Up to the present, interfering factors involved during analytical processes and the ICP-MS measurement of uranium and plutonium were examined. As a result, uranium and plutonium isotope measurement more than 100 pg and 100 fg, respectively, became possible at JAERI clean facility. At presentation, other progress in the development will be reported.