Complexation of actinides with borate and polyborates

アクチノイドとホウ酸塩及びポリホウ酸塩の錯体形成

Meier, R.; 北垣 徹  ; 香西 直文   ; Fellhauer, D.*; 小林 大志*; 大貫 敏彦

Meier, R.; Kitagaki, Toru; Kozai, Naofumi; Fellhauer, D.*; Kobayashi, Taishi*; Onuki, Toshihiko

The distribution of actinides in the Fukushima Daiichi Nuclear Power Plant (1F) is of major interest, concerning the safety during decommissioning. And if fluctuations in the neutron flux would arise during retrieval of the fuel, the immediate addition of neutron absorbers such as boric acid can become necessary. Therefore, the influence of boric compounds on actinides is an essential topic to be scrutinised in depth. In the present study the complexation of actinides with borate is experimentally investigated in aqueous solutions relevant for 1F. The main focus is on the complexation of U(VI) in the weakly acidic to alkaline pH range at room temperature under oxic conditions. The concentration of (poly)borate is systematically varied to obtain information about the complexation behaviour with U(VI) under different boundary conditions. For the analysis of the samples, ICP-MS/OES and XRD are applied. In the long term, NMR and TRLFS are also available for the evaluation of the complexes.