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Sasaki, Yuji
Kagaku Kogaku, 84(9), p.425 - 427, 2020/09
The reduction of waste volume and hazardous substance though separation methods concerning atomic energy must be requested. As disposal methods or temporary measures, geological disposal, transmutation and interim storage are proposed. In order to perform effectively the disposal methods, the development of separation method of aimed elements is indispensable. Here, the new separation method of U and Pu from spent nuclear fuel and minor actinide separation and fission products from high level radioactive waste are explained.
Sasaki, Yuji; Tsubata, Yasuhiro; Shirasu, Noriko; Morita, Keisuke; Suzuki, Tomoya
Nihon Genshiryoku Gakkai Wabun Rombunshi, 14(3), p.202 - 212, 2015/09
We have been developing the new partitioning method of high-level radioactive waste by single-cycle extraction process. This process is composed of extraction of actinides (An) and fission products (FP, e.g., Pd, Ru, Mo and Tc), and mutual separation by back-extraction. The extractant employed in this process is required to extract soft, hard acid metals and oxonium anions simultaneously. The NTAamide (hexaoctyl-nitrilotriacetamide) is one of the candidate extractants. After extraction of An and FP, the mutual separation by back-extraction should be set up. Pd and Ru extracted by NTAamide can be back-extracted by complexing agents such as thiourea, systeine, diethylenetriamine, and trisaminoethylamine, and the back-extraction of Mo can be performed by methylimino-diethylacetamide (MIDEA), NTAamide(C2) and iminodimethylphosphoric acid, and Re can be done by aqueous phase with high pH.
Sasaki, Yuji; Tsubata, Yasuhiro; Shirasu, Noriko; Morita, Keisuke; Suzuki, Tomoya
Proceedings of 21st International Conference & Exhibition; Nuclear Fuel Cycle for a Low-Carbon Future (GLOBAL 2015) (USB Flash Drive), p.1653 - 1656, 2015/09
The concept for the new partitioning method of high-level radioactive waste (HLW) by single-cycle extraction process has been investigated. This process is based on extraction of actinides (An) and fission products (FP), and mutual separation by reverse extraction. Solo extractant and several stripping reagents will be utilized in this process. The extractant employed in this process is required to extract soft (platinum metals), hard acid metals(An), and oxonium anions (Mo, Tc) simultaneously. NTAamide is one of the candidate extractants. After extraction of An and FP by NTAamide(C8), the mutual separation among these metals by reverse extraction will be followed using the suitable water-miscible reagents. The extraction of An and FP, and the masking effect by some water-miscible reagents has been studied.
Yamaguchi, Tetsuji
Genshiryoku Bakkuendo Kenkyu, 6(1), p.147 - 149, 1999/12
no abstracts in English
Meguro, Yoshihiro; ; Takeishi, Hideyo; Yoshida, Zenko
Radiochimica Acta, 75(4), p.185 - 191, 1996/00
no abstracts in English
Sasaki, Yuji; Tsubata, Yasuhiro; Morita, Keisuke; Shirasu, Noriko
no journal, ,
no abstracts in English
Sasaki, Yuji; Tsubata, Yasuhiro; Morita, Keisuke; Shirasu, Noriko; Shimazaki, Shoma; Kitatsuji, Yoshihiro
no journal, ,
no abstracts in English
Sasaki, Yuji; Suzuki, Shinichi; Morita, Keisuke
no journal, ,
Many kinds of metals with high concentration exist in high level radioactive waste (HLW). Most of metals have high radioactivity and strong heat, then there should be removed from aqueous phase. Target metals in HLW are as follows, actinides, lanthanides, zirconium, molybdenum, technetium, cesium, strontium, and palladium, due to long range radioactivity, huge environmental burden, and high concentration then troublemsome metals. We try to separate these metals by solvent extraction. Actinides and lanthanides can be extracted by TODGA (tetraoctyl-diglycolamide) from nitric acid, Zr is done by malonamide (or HDEHP), Mo, Re (substitution for Tc) and Pd can be extracted by MIDOA (methylimino-dioctylacetamide), and Sr and Cs can be removed by crown ether compounds. These extractants, except for HDEHP, belong to CHON compounds, which leads less secondary waste generation.
Sasaki, Yuji; Matsumiya, Masahiko*
no journal, ,
In Japan, the decreases of radioactive waste and its toxicity in HLW are noticed. Thus we need to recover Cs and Sr of heat source and Mo and platinum group metals of limiting factor to produce solidified glass, and treat them by proper method. From these ideas, it is important to develop the four-group partitioning process that JAEA conducted energetically. We focus on the recovery of actinides and fission products by solvent extraction method, and explain the outline in this conference.
