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Journal Articles

Plutonium experiments of pyrochemical reprocessing

Kitawaki, Shinichi; Sakamura, Yoshiharu*

Denki Kagaku Oyobi Kogyo Butsuri Kagaku, 79(12), p.975 - 976, 2011/12

no abstracts in English

Journal Articles

Electrorefining test of U-Pu-Zr alloy fuel prepared pyrometallurgically from MOX

Kitawaki, Shinichi; Nakayoshi, Akira; Fukushima, Mineo; Sakamura, Yoshiharu*; Murakami, Tsuyoshi*; Akiyama, Naoyuki*

Proceedings of International Conference on Toward and Over the Fukushima Daiichi Accident (GLOBAL 2011) (CD-ROM), 5 Pages, 2011/09

In the FaCT project, the metal fuel cycle including metal fuel fast reactor and pyrochemical reprocessing has been being developed. JAEA and CRIEPI have continued a collaborative study on pyrochemical reprocessing. In the pyrochemical reprocessing, actinides in the spent fuels dissolve anodically in the LiCl-KCl, and U is collected selectively on a solid cathode, Pu and MA are recovered simultaneously in a liquid Cd cathode. In the previous electrorefining tests, at the anode Zr was allowed to dissolve into the electrolyte salt together with U, Pu and MA. The Zr co-dissolution may cause some problems. In this study, through the anode dissolution test of U-Pu-Zr alloy fuel, the controlling the dissolution of the Zr and the improvement of dissolution ratio of U, Pu were studied. The U-Pu alloy was prepared from MOX pellets by using the electrochemical reduction method. U-Pu-Zr ternary alloy was produced by alloying the obtained U-Pu alloy and prepared U-Zr alloy. U-Pu-Zr ternary alloy was immersed into electrolyte salt, and electrolysis test was carried out.

Journal Articles

Anodic behaviour of a metallic U-Pu-Zr alloy during electrorefining process

Murakami, Tsuyoshi*; Sakamura, Yoshiharu*; Akiyama, Naoyuki*; Kitawaki, Shinichi; Nakayoshi, Akira; Fukushima, Mineo

Journal of Nuclear Materials, 414(2), p.194 - 199, 2011/07

 Times Cited Count:13 Percentile:74.14(Materials Science, Multidisciplinary)

An electrorefining is one of the main steps of pyrochemical reprocessing of spent metallic fuels (U-Zr, U-Pu-Zr). The electrorefining is carried out dissolving a portion of Zr together with actinides to accomplish a high dissolution ratio of actinides. However, the electrorefining with Zr co-dissolution should bring some practical problems in the pyrochemical reprocessing. Therefore, electrorefining tests of non-irradiated U-Pu-Zr alloy were performed with minimizing the amount of Zr dissolved in LiCl-KCl-(U, Pu, Am)Cl$$_{3}$$ melts at 773 K. The tests were performed both by potentiostatic electrolysis at -1.0 V (Ag$$^{+}$$/Ag) that was more negative than the Zr dissolution potential and by galvanostatic electrolysis with a limited amount of Zr dissolution. The ICP-AES analysis of the anode residues confirmed that a high dissolution ratio of actinides (U; $$>$$ 99.6%, Pu; 99.9%) was successfully demonstrated at both electrolyses.

Journal Articles

Solubility of Pu and rare-earths in LiCl-Li$$_{2}$$O melt

Kato, Tetsuya*; Sakamura, Yoshiharu*; Iwai, Takashi; Arai, Yasuo

Radiochimica Acta, 97(4-5), p.183 - 186, 2009/05

 Times Cited Count:3 Percentile:26.15(Chemistry, Inorganic & Nuclear)

The solubility of Pu and rare-earths were measured in LiCl-Li$$_{2}$$O melt where the sesquioxides were precipitated. As shown in the solubility measurement of Pu(III), Nd(III) and Gd(III) at 923 K, the solubility increased proportionally with Li$$_{2}$$O concentration in the melt. It was also found that the element of larger ionic radius has higher solubility as far as the trivalent rare-earths and Pu.

Journal Articles

Chlorination of UO$$_{2}$$, PuO$$_{2}$$ and rare earth oxides using ZrCl$$_{4}$$ in LiCl-KCl eutectic melt

Sakamura, Yoshiharu*; Inoue, Tadashi*; Iwai, Takashi; Moriyama, Hirotake*

Journal of Nuclear Materials, 340(1), p.39 - 51, 2005/04

 Times Cited Count:26 Percentile:84.93(Materials Science, Multidisciplinary)

A new chlorination method using ZrCl$$_{4}$$ in a molten salt has been investigated for the pyrometallurgical reprocessing of spent oxide fuels. UO$$_{2}$$, PuO$$_{2}$$ and rare earth oxides(La$$_{2}$$O$$_{3}$$, CeO$$_{2}$$, Nd$$_{2}$$O$$_{3}$$ and Y$$_{2}$$O$$_{3}$$) were allowed to react with ZrCl$$_{4}$$ in a LiCl-KCl eutectic salt at 500$$^{circ}$$C to give a metal chloride solution and a precipitate of ZrO$$_{2}$$. By keeping the system quite still, the solution settled so that the ZrO$$_{2}$$ precipitate could be separated.

Journal Articles

Distribution behavior of plutonium and americium in LiCl-KCl eutectic/liquid cadmium systems

Sakamura, Yoshiharu*; Shirai, Osamu; Iwai, Takashi; Suzuki, Yasufumi

Journal of Alloys and Compounds, 321(1), p.76 - 83, 2001/05

 Times Cited Count:53 Percentile:89.97(Chemistry, Physical)

no abstracts in English

Oral presentation

Production of U-Pu alloy and injection casting of U-Pu-Zr slug for JOYO irradiation test

Kato, Tetsuya*; Nakamura, Kinya*; Sakamura, Yoshiharu*; Iwai, Takashi; Arai, Yasuo

no journal, , 

no abstracts in English

Oral presentation

Electrolytic recovery of UO$$_{2}$$ from spent fuel with LiCl-KCl; Preliminary experiment by simulated spent fuel consisted of UO$$_{2}$$ and noble metals

Okamura, Nobuo; Koizumi, Tsutomu; Fukushima, Mineo; Kurata, Masaki; Sakamura, Yoshiharu*

no journal, , 

no abstracts in English

Oral presentation

Development of electrochemical reduction process for oxide nuclear fuel, 9; Solubility measurement of Pu$$_{2}$$O$$_{3}$$ in molten LiCl-Li$$_{2}$$O

Kato, Tetsuya*; Sakamura, Yoshiharu*; Iwai, Takashi; Arai, Yasuo

no journal, , 

In order to apply the pyrometallurgical reprocessing to spent oxide fuels, reduction techniques of oxide in molten salt have been studied. In the previous reduction experiments, a small amount of Pu has been found to move out of the reduced fuel and dissolve into molten LiCl-Li$$_{2}$$O. In this study, solubility of Pu in molten LiCl-Li$$_{2}$$O was measured to obtain quantitative data for the Pu dissolution. The Pu solubility in the molten LiCl-Li$$_{2}$$O containing Pu$$_{2}$$O$$_{3}$$ precipitates increased with increasing Li$$_{2}$$O concentration in the molten salt to be approximately 0.3wt%Pu at 8wt%Li$$_{2}$$O and 923 K.

Oral presentation

Development of metal pyro-processing, 11; Development of actinide recovery process from residue of pyro-processing

Kitawaki, Shinichi; Nakayoshi, Akira; Sakamura, Yoshiharu*; Akiyama, Naoyuki*

no journal, , 

no abstracts in English

Oral presentation

Development of metal pyro-processing, 10; Anodic behavior of U-Pu-Zr alloy fuel in electrorefining process

Sakamura, Yoshiharu*; Murakami, Tsuyoshi*; Akiyama, Naoyuki*; Kitawaki, Shinichi; Nakayoshi, Akira; Fukushima, Mineo

no journal, , 

no abstracts in English

Oral presentation

Development of anodic dissolution of spent metallic fuel electrorefining process, 1; Anodic dissolution test of U-Pu-Zr alloy fuel

Sakamura, Yoshiharu*; Murakami, Tsuyoshi*; Akiyama, Naoyuki*; Iizuka, Masatoshi*; Kitawaki, Shinichi; Nakayoshi, Akira

no journal, , 

no abstracts in English

Oral presentation

Electrochemical reduction behavior of U, Zr mixed oxide

Kitawaki, Shinichi; Nakayoshi, Akira; Sakamura, Yoshiharu*; Akiyama, Naoyuki*

no journal, , 

no abstracts in English

Oral presentation

Anodic dissolution of U-Pu-Zr alloy fuel prepared pyrometallurgically from MOX

Kitawaki, Shinichi; Nakayoshi, Akira; Fukushima, Mineo; Murakami, Tsuyoshi*; Sakamura, Yoshiharu*; Akiyama, Naoyuki*

no journal, , 

no abstracts in English

Oral presentation

Electrochemical measurement of diffusion coefficient of actinides and rare earths in liquid Cd

Murakami, Tsuyoshi*; Sakamura, Yoshiharu*; Akiyama, Naoyuki*; Kitawaki, Shinichi; Nakayoshi, Akira; Koyama, Tadafumi*

no journal, , 

no abstracts in English

Oral presentation

Electrochemical reduction behavior of ZrO$$_{2}$$ and (U,Zr)O$$_{2}$$ in a LiCl molten

Nakayoshi, Akira; Kitawaki, Shinichi; Kofuji, Hirohide; Sakamura, Yoshiharu*; Akiyama, Naoyuki*

no journal, , 

no abstracts in English

Oral presentation

Reduction behaviors of zirconium oxide compounds in LiCl-Li$$_{2}$$O melt

Sakamura, Yoshiharu*; Iizuka, Masatoshi*; Koyama, Tadafumi*; Kitawaki, Shinichi; Nakayoshi, Akira; Kofuji, Hirohide

no journal, , 

An electrolytic reduction process of oxide fuels has recently been developed, however it was found that the behaviors of rare earth elements and zirconium are expected to be complicate because their oxides are stable and complex oxide compounds may form. After Fukushima- Daiichi reactor accident, studies on applicability of pyrometallurgical process to damaged fuel debris consisting of ZrO$$_{2}$$-UO$$_{2}$$ have been started. In this study, reduction behaviors of ZrO$$_{2}$$, ZrO$$_{2}$$-Li$$_{2}$$O and ZrO$$_{2}$$-UO$$_{2}$$ were investigated. It was proved that ZrO$$_{2}$$ can be reduced to metallic form in LiCl melt and that ZrO$$_{2}$$ easily reacts with dissolved Li$$_{2}$$O to give Li$$_{2}$$ZrO$$_{3}$$. After ZrO$$_{2}$$ is converted to Li$$_{2}$$ZrO$$_{3}$$, zirconium metal is hardly obtained even in a LiCl melt with low Li$$_{2}$$O concentration.

Oral presentation

Behavior of ZrO$$_{2}$$ in LiCl-Li$$_{2}$$O melt

Sakamura, Yoshiharu*; Iizuka, Masatoshi*; Kitawaki, Shinichi; Nakayoshi, Akira; Kofuji, Hirohide

no journal, , 

Zirconium dioxide formed complex oxide like Li$$_{2}$$ZrO$$_{3}$$ or Li$$_{8}$$ZrO$$_{6}$$ according to the concentration of Li$$_{2}$$O in the LiCl-Li$$_{2}$$O melt. It was clarified that ZrO$$_{2}$$ could be reduced to metal and formed lithium zirconate was difficult to be reduced by electrolytic reduction operations.

Oral presentation

Reduction behaviors of zirconium oxide compounds in LiCl-Li$$_{2}$$O

Kitawaki, Shinichi; Nakayoshi, Akira; Kofuji, Hirohide; Sakamura, Yoshiharu*; Iizuka, Masatoshi*

no journal, , 

no abstracts in English

Oral presentation

Reduction behavior of zirconium oxide in LiCl-Li$$_{2}$$O melt

Sakamura, Yoshiharu*; Iizuka, Masatoshi*; Kitawaki, Shinichi; Nakayoshi, Akira; Kofuji, Hirohide

no journal, , 

no abstracts in English

38 (Records 1-20 displayed on this page)