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Takeuchi, Masayuki; Aihara, Haruka; Nakahara, Masaumi; Tanaka, Kotaro*
Procedia Chemistry, 21, p.182 - 189, 2016/12
Times Cited Count：2 Percentile：81.17(Chemistry, Inorganic & Nuclear)A simulation technology with electrolyte thermodynamic model has been developed to evaluate the precipitation behavior in reprocessing solution based on nitric acid solution. The simulation results were compared with the experiment data from non-radioactive simulated HLLW with ten elements and Pu-Zr-Mo solution, and the reliability of the thermodynamic model was verified. Most of the precipitation species was zirconium molybdate hydrate from the both data. It is demonstrated that the chemical species and amount of the precipitation calculated by thermodynamic model reflected well that of experiments. This study has shown the thermodynamic simulation model is one of the useful tools to estimate the behavior of precipitation from the reprocessing solution.
cell including dissolver off-gas treatmentMineo, Hideaki; Kihara, Takehiro; *; Kimura, Shigeru; *; ; Uchiyama, Gunzo; Hotoku, Shinobu; Watanabe, Makio; ; et al.
JAERI-Conf 99-004, p.498 - 507, 1999/03
no abstracts in English
Aihara, Haruka; Kitawaki, Shinichi; Takeuchi, Masayuki; Syed Masud, R.*; Mimura, Hitoshi*
no journal, ,
no abstracts in English
-containing iron phosphate glassFujisawa, Masaharu*; Takebe, Hiromichi*; Kobayashi, Hidekazu; Amamoto, Ippei
no journal, ,
High level radioactive waste contains a relatively large amount of MoO. Mo is known to be a difficult element to incorporate in nuclear waste glass such as borosilicate glasses. On the other hand, phosphate glasses is able to contain MoO over a wide and continuous compositional range. In this study, the effect of MoO addition on properties of iron phosphate glass is studied. The glass transition temperature was evaluated. The immersion tests were performed according to MCC-2 test method due to evaluate the water durability. The additional effects of MoO are discussed in terms of glass structure.
Abe, Risako*; Hirasawa, Izumi*; Miyazaki, Yasunori; Takeuchi, Masayuki
no journal, ,
no abstracts in English
Shimohashi, Kengo*; Hirasawa, Izumi*; Miyazaki, Yasunori; Takeuchi, Masayuki
no journal, ,
no abstracts in English
Sue, Kasumi*; Hirasawa, Izumi*; Miyazaki, Yasunori; Takeuchi, Masayuki
no journal, ,
no abstracts in English
Sue, Kasumi*; Hirasawa, Izumi*; Miyazaki, Yasunori; Takeuchi, Masayuki
no journal, ,
no abstracts in English
Kamoi, Kensuke*; Hirasawa, Izumi*; Miyazaki, Yasunori; Takeuchi, Masayuki
no journal, ,
In spent nuclear fuel reprocessing, one of the unsettled issues is an undissolved fuel component that generates various kinds of sludge. A typical example is Zirconium Molybdate Dihydrate (ZMH). Because of its poor water solubility and strong adsorbability at high reaction temperature, ZMH is easily encrusted to the wall of reprocessing equipment, which leads to critical problems such as pipe blockage and degradated heat transfer performance. Therefore, a practical method is required to suppress the encrustation of ZMH. In this study, the crystal state of ZMH was elucidated to find out a dominant factor that promoted accumulation and resulting encrustation on the surface. The ZMH crystal changed from elliptic to cubic as the reaction progressed while the crystal habit unaffected the crystal state. The following three steps were taken place in the ZMH encrustation process. (1) Small particles which are precursors of ZMH and which the ratio of Zr:Mo is 1:1, encrustate to the pipe, (2) Small particles are connected to form a layered amorphous, and (3) ZMH single crystals and aggregates encrustate on the layered amorphous.
Sue, Kasumi*; Hirasawa, Izumi*; Miyazaki, Yasunori; Takeuchi, Masayuki
no journal, ,
no abstracts in English
Sue, Kasumi*; Hirasawa, Izumi*; Miyazaki, Yasunori; Takeuchi, Masayuki
no journal, ,
no abstracts in English
Nagai, Takayuki; Katsuoka, Nanako; Okamoto, Yoshihiro; Akiyama, Daisuke*; Kirishima, Akira*
no journal, ,
Zirconium molybdate, sodium nitrate, strontium nitrate, and barium nitrate were added to the glass raw material and heated. After heating, the sample was analyzed by using XAFS measurement to investigate the formation mechanism of molybdates, which is the main component of the yellow phase in the vitrification process.
Okamoto, Yoshihiro; Nagai, Takayuki; Katsuoka, Nanako; Akiyama, Daisuke*; Kirishima, Akira*
no journal, ,
XAFS analysis of heat-treated samples under various conditions using zirconium molybdate as starting material was performed to compare the formation of calcium molybdate. It was found that zirconium molybdate decomposes by heat treatment at 1073K to form zirconium oxide, but the zirconium immediately dissolves into the glass. On the other hand, after decomposition, the molybdenum continued to maintain the form of molybdate ions, eventually becoming calcium molybdate. However, it was found that calcium molybdate was formed at a lower temperature in the latter case when sodium was present in the raw glass from the beginning or when it was supplied as sodium nitrate without being included in the raw glass.
