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Nagai, Takayuki; Kobayashi, Hidekazu; Sasage, Kenichi; Ayame, Yasuo; Okamoto, Yoshihiro; Shiwaku, Hideaki; Yamanaka, Keisuke*; Ota, Toshiaki*
JAEA-Research 2017-005, 54 Pages, 2017/06
JAEA-Research-2017-005.pdf:16.17MB
Addition of radioactive waste to a borosilicate frit affects the local structures of boron (B) and waste elements in a waste glass. Synchrotron XAFS measurement was applied to investigate the local structural changes by using simulated waste borosilicate glass samples. Following results were obtained by the B K-edge XAFS analysis. It was confirmed that B K-edge XAFS analysis enables us to discriminate sp
type boron (BO
) from sp
type boron (BO
). Addition of waste elements to a glass frit increases the percentage of BO and decreases that of BO. By decreasing the SiO
/AlO ratio or increasing the (SiO+BO)/AlO ratio in the glass composition, the BO percentage increases and the BO percentage decreases. Addition of PO
decreases the BO percentage and increases the BO percentage. Following results were obtained from XAFS measurement of the waste elements. Cerium (Ce) valence is more reduced with the increase of the BO content. Addition of PO has a tendency to reduce the Ce valence and to enhance deposition of Zr oxide. Deposition of ruthenium compounds separated from glass phase can not be improved by changing the BO content. This study was performed as a part of the project, "Improvement of vitrification process of high-level radioactive liquid wastes" on the foundation business of the Agency for Natural Resources and Energy.
Nagai, Takayuki; Kobayashi, Hidekazu; Sasage, Kenichi; Ayame, Yasuo; Okamoto, Yoshihiro; Shiwaku, Hideaki; Matsuura, Haruaki*; Uchiyama, Takafumi*; Okada, Yukiko*; Nezu, Atsushi*; et al.
JAEA-Research 2016-015, 52 Pages, 2016/11
JAEA-Research-2016-015.pdf:37.48MB
The local structure of waste elements in simulated waste glasses including V was estimated by using synchrotron XAFS measurement in this study. The results are as follows. (1) V has a high possibility which exists in the glass phase in the case of frit, and V can regard both samples as stable 4 coordination structure. (2) Zn, Ce, Nd, Zr, and Mo exist in the glass phase, and the difference is admitted by the percentage of Ce(III) and Ce(IV) by the composition. (3) Ru is separated from the glass phase as RuO crystalline, both of metal and oxide exist in Rh, and Pd is separated out as metal. (4) It was confirmed that the regularity of the local structure of Zr and Mo in the molten glasses retreats as a result of the XAFS measurement at high temperature. (5) The XAFS measurement of molten glasses were performed at 1200
C, so it would be possible to acquire excellent data by improving the shapes of the sample cell.
Ouchi, Jin; Ayame, Yasuo; Terada, Akihiko; Masaki, Toshio; Kobayashi, Hiroaki; Igarashi, Hiroshi
PNC TN8410 94-219, 473 Pages, 1994/06
None
Igarashi, Hiroshi; Ayame, Yasuo; Ouchi, Jin
Proceedings of 1993 International High-Level Radioactive Waste Management Conference, ,
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Amamoto, Ippei; Kobayashi, Hidekazu; Ayame, Yasuo; Utsumi, Kazuo*; Takeshita, Kenji*; Onoe, Jun*; Nagayama, Sachiko*; Hasegawa, Yoshio*
no journal, ,
no abstracts in English
Kawai, Kota*; Nakano, Yoshio*; Takeshita, Kenji*; Nagai, Takayuki; Kobayashi, Hidekazu; Amamoto, Ippei; Ayame, Yasuo
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Sasage, Kenichi; Kobayashi, Hidekazu; Ayame, Yasuo; Fujiwara, Koji; Shiotsuki, Masao; Miura, Nobuyuki
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Amamoto, Ippei; Kobayashi, Hidekazu; Ayame, Yasuo; Hasegawa, Yoshio*; Utsumi, Kazuo*; Takeshita, Kenji*; Inaba, Yusuke*; Onoe, Jun*; Koshizaka, Akiko*; Kaneta, Yui*
no journal, ,
no abstracts in English
Ayame, Yasuo; Iwabuchi, Hiroki; Omori, Eiichi; Miura, Nobuyuki
no journal, ,
Tokai Reprocessing Plant (TRP) is preparing for decommissioning and dismantling, and it takes decades for completion. As about 360 m of HLLW in TRP has risk of evaporation and hydrogen explosion, it must be controlled safely by keeping forced cooling and hydrogen exhausting. So, it was decided to vitrify in Tokai Vitrification Facility (TVF) by 2028 to reduce the risk. TVF was constructed in 1992 and vitrified 306 canisters until now. Full remote maintenance system is adopted for vitrification melter and HLLW tank in the cell. As noble metals in HLLW accumulate at bottom of melter, the melter must be emptied periodically and the noble metals must be removed with mechanical device. For the success of the vitrification, it is necessary to maintain the equipment by organized maintenance plan considering its aging, to expand the capacity to store canisters and to replace the melter within its design life. In this meeting, vitrification plan at Tokai site will be introduced.
Miura, Akihiko; Kobayashi, Hidekazu; Ayame, Yasuo; Shiotsuki, Masao; Weisenburger, S.*; Roth, G.*
no journal, ,
no abstracts in English
Kobayashi, Hidekazu; Yokozawa, Takuma; Yamashita, Teruo; Nagai, Takayuki; Amamoto, Ippei; Ayame, Yasuo
no journal, ,
no abstracts in English
Nagai, Takayuki; Nishizawa, Daiji*; Watanabe, So; Okamoto, Yoshihiro; Seki, Katsumi*; Homma, Masanobu*; Ayame, Yasuo
no journal, ,
no abstracts in English
Amamoto, Ippei; Kobayashi, Hidekazu; Ayame, Yasuo; Utsumi, Kazuo*; Takeshita, Kenji*; Onoe, Jun*; Nagayama, Sachiko*; Hasegawa, Yoshio*
no journal, ,
no abstracts in English
Asahi, Yoshimitsu; Nakajima, Masayoshi; Ayame, Yasuo
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Asahi, Yoshimitsu; Nakajima, Masayoshi; Ayame, Yasuo
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Yamashita, Teruo; Matsumura, Tadayuki; Oyama, Koichi; Harashima, Takero; Ayame, Yasuo; Kodaka, Akira
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Amamoto, Ippei; Kobayashi, Hidekazu; Ayame, Yasuo; Onishi, Takashi; Inaba, Yusuke*; Utsumi, Kazuo*; Takeshita, Kenji*; Onoe, Jun*; Koshizaka, Akiko*; Hasegawa, Yoshio*
no journal, ,
The development on synthesis of sorbent was carried out to separate the platinum group species such as Ru, Rh and Pd in high-level radioactive liquid waste. After sorption test using developed sorbents, the spherical porous silica impregnated aluminium ferrocyanide was effective to sorb the species of Ru and Pd in the nitric solution. This sorption effect remained stable when tested on actual high-level radioactive liquid waste. It was found that more treated waste could be loaded into the borosilicate glass than untreated waste.
Okamoto, Yoshihiro; Nagai, Takayuki; Kobayashi, Hidekazu; Shiwaku, Hideaki; Ayame, Yasuo
no journal, ,
The synchrotron radiation based XAFS technique, in which atomic element selectivity and adaptation to a diluted component can be achieved, has been used widely for research work on the nuclear waste vitrification technology. We have used the XAFS technique for many kinds of simulated glass samples. The use of XAFS technique is very effective since many kinds of elements are contained in the nuclear waste glass. In addition, imaging XAFS technique was introduced, since some elements such as platinum group metals in the glass are not distributed uniformly. In this presentation, we summarize some results obtained from the XAFS and imaging XAFS analyses we have performed for advancement of the vitrification technology.
Kobayashi, Hidekazu; Ayame, Yasuo; Ishidera, Takamitsu; Utsumi, Kazuo*; Takeshita, Kenji*; Onoe, Jun*; Nagayama, Sachiko*; Hasegawa, Yoshio*; Amamoto, Ippei
no journal, ,
no abstracts in English
Harashima, Takero; Yamashita, Teruo; Matsumura, Tadayuki; Oyama, Koichi; Ayame, Yasuo; Kodaka, Akira
no journal, ,
no abstracts in English