| 摘要 |
<p>PROBLEM TO BE SOLVED: To establish a method for selectively stripping and separating only neptunium from an organic solvent containing plutonium and uranium. SOLUTION: In a dissolution process 1, used atomic fuel is dissolved by nitrate aqueous solution. In a co-decontamination process 2 after that, the nitrate aqueous solution is irradiated with ultraviolet rays, Np is oxidized, the valence is adjusted to VI value and U, Pu and Np are extracted by a tributyl phosphate (TBP) solvent. Then, in an Np separation process 3, the TBP solvent and the nitrate aqueous solution are mixed, only Np is reduced by irradiating the liquid mixture with the ultraviolet rays, the valence is adjusted to V value, it is made organic solvent non-extractable, and only Np is extracted to the nitrate aqueous solution and separated. By separating the remaining U and Pu in a distribution process 4, the respective ones of U, Pu and Np are separated and refined at high purity.</p> |
