Study on stability of CsSr solvent impregnated resin against irradiation

線照射に対するCsSr含浸吸着剤の安定性に関する研究

星 陽崇; 菊池 孝浩; 森田 泰治  ; 木村 貴海 

Hoshi, Harutaka; Kikuchi, Takahiro; Morita, Yasuji; Kimura, Takaumi

高レベル廃液から発熱性のCs及びSrを選択的に分離するプロセスの研究開発を行っている。本研究ではCs又はSrに対して高い選択性を有する含浸吸着剤を調製し、線照射に対する耐久性を評価した。含浸吸着剤は硝酸溶液に浸漬させた状態で線を照射し、Cs又はSrの飽和吸着容量の変化を調べた。照射後の吸着剤はろ過後、乾燥させ、Cs又はSrを含む硝酸溶液と接触させて、飽和吸着容量を測定した。高濃度(4M)の硝酸溶液中で照射した吸着剤では照射による明確な吸着容量の低下が認められたが、低濃度(4M)の硝酸溶液中で照射した場合は、照射による吸着容量の低下はごくわずかであることが判明した。本試験から得られた知見を今後の実分離プロセスの概念設計に資する。

Minimization of radioactive waste from reprocessing process of spent nuclear fuel is strongly desired. We develop an advanced technology for separation of heat generating elements (Cs and Sr) from high level waste to optimize radioactive waste by its characteristics. Some novel solvent impregnated resins (SIRs) were prepared and these SIRs indicated promising ability to separate Cs and Sr from other typical fission products dissolved in nitric acid solution. These adsorbents contacting with nitric acid solution were exposed to ray in a vial. After the irradiation, adsorbents were filtrated through a membrane filter. The adsorption capacity was examined by using irradiated adsorbents after drying. It is concluded that both SIRs maintained their high selectivity for Cs and Sr, respectively, after irradiation. Decreasing ratio of adsorption capacity by irradiation can be estimated from these results. It contributes significantly for conceptual design of separation plant.