Uranium, plutonium and neptunium co-recovery with irradiated fast reactor MOX fuel by single cycle extraction process

Nakahara, Masaumi; Sano, Yuichi; Nomura, Kazunori; Washiya, Tadahiro; Komaki, Jun

Proceedings of 3rd International ATALANTE Conference (ATALANTE 2008) (CD-ROM), 5 Pages, 2008/05

Among minor actinides, Np has a possibility to be co-recovered with U and Pu by tri-n-butylphosphate (TBP) according to its extractable valences; Np(IV) and Np(VI). Therefore, the Np valence needs to be adjusted to extractable Np(VI). In this process, partitioning section purification section are deleted, and the flow sheet is designed by single cycle. This works using the dissolver solution of irradiated MOX fuel from fast reactor "JOYO" has been carried out with centrifugal contactors, whose residence time is considerably smaller than that of mixer-settler. The feed solution is adjusted to having high HNO concentration. This condition adjusts the Np valence for its extraction. As expected, about 99% of Np was recovered with U and Pu. Through this series of studies, the U, Pu and Np co-recovery process using high HNO concentration feed solution was successfully demonstrated.

Development of uranium crystallization system in "NEXT" reprocessing process

Oyama, Koichi; Nomura, Kazunori; Washiya, Tadahiro; Tayama, Toshimitsu; Yano, Kimihiko; Shibata, Atsuhiro; Komaki, Jun; Chikazawa, Takahiro*; Kikuchi, Toshiaki*

Proceedings of International Conference on Advanced Nuclear Fuel Cycles and Systems (Global 2007) (CD-ROM), p.1461 - 1466, 2007/09

Japan Atomic Energy Agency (JAEA) has been developing the crystallization process technology in cooperation with Mitsubishi Materials Corporation, Saitama University and Waseda University. We have carried out experimental studies with uranium, MOX and spent fuel dissolved solution, and flowsheet analysis was researched. Crystal refinement study has been started to get more purified crystal. In association with these studies, an innovative continuous crystallizer and its system was developed to ensure high process performance. From the design study, an annular type continuous crystallizer was selected as the most promising design, and performance was confirmed by small-scale test and engineering scale demonstration at uranium crystallization conditions. In this paper, the research and development of crystallization process are described.

Recent activities on aqueous partitioning at JAEA

Kimura, Takaumi; Komaki, Jun; Morita, Yasuji

Proceedings of 9th OECD/NEA Information Exchange Meeting on Actinide and Fission Product Partitioning and Transmutation, p.151 - 158, 2007/00

The Japan Atomic Energy Agency (JAEA) has been conducting research and development (R&D) on partitioning and transmutation (P&T) technologies using commercialized fast reactors (FR) or accelerator driven system (ADS) in the transmutation cycle. Various partitioning technologies have been investigated in the R&D activities for aqueouspartitioning of radioactive nuclides, especially actinides. This paper overviews some of the activities on the partitioning at JAEA.

The Study on the Corrosion of Pool Components by the Evaluation of Micro-elements Variation in fuel storage Water, 1983

Ochiai, Kazuya; Takeda, Korehiro; Watanabe, Kazuyoshi; Komaki, Jun*

PNC TN841 84-62, 22 Pages, 1983/09

PNC-TN841-84-62.pdf:0.38MB

As a part of the IAEA coordinated programme on BEFAST, behavior of spent fuel assemblies during extended storage, corrosion of pool components has been investigated. In this study the concentrations of micro-elements of corrosion products (Fe, Cr, Ni) in pool water have been periodically measured and the evaluation of corrosion has been made from the results of analysis. The concentration of micro-elements of corrosion products (Fe, Cr, Ni) was almost constant during this study. Corrosion rate was estimated to be only a little as compared with the pool lining in thickness of 3 mm (the side) or 4 mm (the base).

Research and development program for advanced aqueous reprocessing technologies; Results of main technologies development and future plan

Washiya, Tadahiro; Sano, Yuichi; Komaki, Jun; Funasaka, Hideyuki; Sugiyama, Toshihide

no journal, , 

no abstracts in English

Continuous multi-stage separation test of selective U extraction with mono-amide extractant of D2EHDMPA

Morita, Yasuji; Ban, Yasutoshi; Hotoku, Shinobu; Suzuki, Shinichi; Kimura, Takaumi; Komaki, Jun

no journal, , 

A N,N-dialkylamide (mono-amide) can be used as an alternative to TBP and as a selective extractant for U(VI). A multistage continuous extraction test for U(VI) selective separation from a solution containing U, Pu and simulated fission products was performed using N,N-di(2-ethylhexyl)-2,2-dimethylpropanamide (D2EHDMPA). Results showed that the extracted ratio for U(VI) and Pu(IV) was 99.6% and 0.1%, respectively, and decontamination factor for Pu in back-extracted U fraction was 990. An extraction process for U separation with D2EHDMPA can be established without using any reagent except nitric acid.