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Kobayashi, Makoto*; Wang, W.*; Kurata, Rie; Matsuyama, Masao*; Hayashi, Takumi; Yamanishi, Toshihiko; Asakura, Yamato*; Oya, Yasuhisa*; Okuno, Kenji*
Fusion Science and Technology, 60(1), p.403 - 406, 2011/07
Times Cited Count：0 Percentile：0.01(Nuclear Science & Technology)The trapping and release mechanisms of hydrogen isotopes for the stainless steel (SS) oxidized at various temperatures were investigated. The oxide layer was mainly consisted of iron oxides (Fe
O
) and its decomposition temperature was almost consistent with the release temperature of deuterium, where major chemical form was a molecular deuterium (D
). The deuterium retention was increased as the oxidation temperature increased. It was considered that the thickness of oxide layer would make a large influence on the retention of hydrogen isotopes. On the other hand, the amount of released deuterium as heavy water (DO) was independent with oxidation temperature. It was considered that the formation of hydrogen isotope as water form was depended on the amount of FeO on the top most surface layer of SS.
Uchida, Shunsuke; Asakura, Yamato*; Suzuki, Hiroaki*
Nuclear Engineering and Design, 241(7), p.2398 - 2410, 2011/07
Times Cited Count：32 Percentile：90.86(Nuclear Science & Technology)In PWR, it has been assumed that Li and B ions deposited on fuel under sub-cooled boiling conditions. Accumulated B on the fuel led to AOA. The amount of B deposited on the fuel was evaluated from two directions. The first calculated the amount with the extended MED model and the other estimated it from the viewpoint of reactor reactivity. It was concluded that: (1) the calculated B deposition amount on the fuel, which was one or two orders larger than measured amounts and Ni oxides compounds, was seldom measured in the fuel deposits due to its high release rate; (2) its hideout return during the reactor shutdown period was seldom observed due to its high concentration in the primary coolant; (3) one of the most promising approaches to evaluate its accumulation on the fuel during plant operation was the MED model calculation; and (4) control of Ni concentration in the primary coolant resulted in decreased Ni oxide deposition and then mitigation of AOA occurrence.
Sugiyama, Takahiko*; Yamanishi, Toshihiko; Munakata, Kenzo*; Asakura, Yamato*; Yamamoto, Ichiro*; Glugla, M.*
no journal, ,
We report a design of the column interior which was designed to fit into the existing facility dedicated for LPCE process characterization (under the limitation of the TLK facility). The experimental conditions such as liquid and gas flow-rates, temperature have been established during preliminary investigations carried out at Nagoya University. The column to be used in the TLK facility is stainless steel tube with 55 mm internal diameter and 2 m length. The tritium separation experiments are performed at 120 kPa, 343 K. A stage-wise model was also developed to predict separative performance of the column. This model requires the channeling coefficients. The channeling coefficient which represents axial dispersion of the packed bed is evaluated against flow rates of water by impulse response. Analytical results with the present model present effects of the catalysis quantity and the gas-liquid ratio on separative performances of the column.
Kadowaki, Haruhiko; Matsuo, Hidehiko; Yamane, Naoki; Asakura, Yamato*; Matsushima, Akira
no journal, ,
no abstracts in English
