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.

Extraction and flow sheet studies for U and Pu separation by N,N-di(2-ethyl)hexylbutanamide

Ban, Yasutoshi; Hagiya, Hiromichi; Sato, Makoto; Asakura, Toshihide; Morita, Yasuji

Proceedings of 3rd International ATALANTE Conference (ATALANTE 2008) (CD-ROM), 4 Pages, 2008/05

Since N,N-dialkylamide (monoamide) compounds extract tetravalent and hexavalent actinides, they have been proposed as alternative extractants to TBP. In the present work, numerical calculations for estimating separation performance of N,N-di(2-ethyl)hexyl-butanamide (D2EHBA) for U(VI) and Pu(IV) were carried out. A flow sheet was obtained which separate more than 99.9% of Pu(IV) from U(VI) by adjusting nitric acid concentration. Extraction properties of D2EHBA for macro concentrations of U (0.63-1.22 mol/dm(M)) and Pu (6.3 mM) were studied in a batch manner. D2EHBA diluted to 1.5 M by n-dodecane extracted up to 0.8 M of U(VI) without forming precipitation and third phase. Distribution ratios of Pu(IV) were relatively high compared with the ones obtained at tracer concentrations of Pu(IV).

MA/Ln separation with new ligand, hydrophobic derivatives of TPEN

Matsumura, Tatsuro; Takeshita, Kenji*; Mori, Atsunori*

Proceedings of 3rd International ATALANTE Conference (ATALANTE 2008) (CD-ROM), 4 Pages, 2008/05

We are developing a new MA/Ln separation process with derivatives of TPEN (N,N,N',N'-tetrakis(2-pyridylmethyl)ethylenediamine) for P&T technology. TPEN is a hexadentate ligand, which has good selectivity of Am(III) from Ln(III). However, there is a serious problem for the practical application. This is to the dissolution of a slight amount of TPEN (about 10 mol/l) to water. High enrichment of Am(III) will be restricted by the dissolution of TPEN to water. In this study, the hydrophobicity of TPEN is improved by introducing alkyl groups and the selectivity of Am(III) and Eu(III) is examined. We succeeded to synthesize a new hydrophobic derivative of TPEN, TBPEN (N,N,N',N'-tetrakis((5-butoxypyridin-2-yl)-methyl)ethylenediamine. It showed good selectivity and the maximum separation factor, SF, was 91 at pH 3.0. A hydrophobic derivative of TPEN that has potential of application to the MA/Ln separation process was synthesized successfully.

Uranium recovery in LWR reprocessing and plutonium/residual uranium conditioning in FBR reprocessing for the transition from LWR to FBR

Fukasawa, Tetsuo*; Yamashita, Junichi*; Hoshino, Kuniyoshi*; Sasahira, Akira*; Inoue, Tadashi*; Minato, Kazuo; Sato, Seichi*

Proceedings of 3rd International ATALANTE Conference (ATALANTE 2008) (CD-ROM), 7 Pages, 2008/05

In order to flexibly manage the transition period from LWR to FBR, the authors investigated the transition scenario and proposed the Flexible Fuel Cycle Initiative (FFCI). In FFCI, LWR spent fuel reprocessing only carries out the removal of about 90% uranium that will be purified and utilized in LWR after re-enrichment. The residual material (40% U, 15% Pu and 45% other nuclides) is transferred to temporary storage and/or FBR spent fuel reprocessing to recover Pu/U followed by FBR fresh fuel fabrication depending on the FBR introduction status. The FFCI has some merits compared with ordinary system that consists of full reprocessing facilities for both LWR and FBR spent fuels, that is smaller LWR reprocessing facility, spent LWR fuel reduction, storage and supply of high proliferation resistant and high Pu density material that can flexibly respond to FBR introduction rate changes. The Pu balance was calculated under several cases, which revealed that the FFCI could supply enough Pu to FBR in any cases.

Extraction chromatography for Am and Cm recovery in engineering scale

Koma, Yoshikazu; Watanabe, So; Sano, Yuichi; Asakura, Toshihide; Morita, Yasuji

Proceedings of 3rd International ATALANTE Conference (ATALANTE 2008) (CD-ROM), 8 Pages, 2008/05

Sequential process test for metal pyro-processing using U, Pu, and Am

Kurata, Masaki*; Yahagi, Noboru*; Kitawaki, Shinichi; Nakayoshi, Akira; Fukushima, Mineo

no journal, , 

CRIEPI and JAEA are continuing a collaboration study for metal pyro-processing, in which sequential process tests have been performed under practical conditions using 1kg of molten salt baths. Recent results on two kinds of sequential process test are reported. The former is the electro-chemical reduction test of MOX pellet in order to form U-Pu alloy ingots. The latter is the electrolysis test using a combination of U-Pu alloy anode and solid or liquid cadmium cathode to recover U-product or U-Pu-Am alloy product, respectively. Variation in electrode potentials, current efficiency, molten salt composition, Pu- or Am-impurity in the U-product, U/Pu or Am/Pu separation factor in the U-Pu alloy product, and etc. were measured. These tests reproduced practical operating conditions at a scale of 1/1000 that of the actual process.

JAEA key facilities for global advanced fuel cycle R&D

Nomura, Shigeo; Yamamoto, Ryuichi

no journal, , 

The current LWR cycle composed of PUREX reprocessing and MOX fuel fabrication technologies becomes a matured industrial level. However, advanced fuel cycle will be realized with the mid and long term R&D, focusing the transition period which handles at least three types of spent fuel; LWR-UOX, LWR-MOX, and FBR-MOX to produce mainly advanced reactor fuels for FBR. R&D scheme becomes more complicated, because of such kinds of spent fuels and products, succession of the current industrial technologies, and future social and technological needs. Under these conditions, two types of R&D; evolutionary and revolutionary ones are proposed. The modification and partial replacement of the current technologies can be realized through the evolutionary type R&D. The introduction of new concept and the drastic change of main process are categorized for the revolutionary R&D. Progress of such R&D is implemented by the four stages as a classic linear model. The linear model should be modified and skipped sometime by finding out how to apply the simulation model and the conventional outcomes developed in the past. The engineering demonstration should be implemented especially for the verification of design, performance, and operation including off-normal conditions. Most of JAEA facilities cover the evolutionary type R&D from basic to engineering stage. To implement the revolutionary type R&D, however, these should prepare more flexible testing parameters, new machines and process equipments, depending upon the each progress of candidate technologies.