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Harada, Akio; Sato, Tadashi*; Nakajima, Kunihisa; Komuro, Yuichi; Shiraishi, Hirotsugu*; Hattori, Takamitsu; Ikuta, Yuko; Yachi, Shigeyasu; Kushita, Kohei
JAERI-Review 2005-026, 55 Pages, 2005/09
JAERI-Review-2005-026.pdf:1.95MB
This report provides an example of answers to the problems of the 37th Examination for the Chief Engineer of Nuclear Fuel. This examination was done as a national qualification in March 2005. Brief explanations or references are added to some answers.
Ikezoe, Yasumasa; Suzuki, Kazuya; Nakashima, Mikio; Yokoyama, Atsushi; Shiraishi, Hirotsugu; Ono, Shinichi*
JAERI-Research 98-051, 43 Pages, 1998/09
JAERI-Research-98-051.pdf:1.63MB
no abstracts in English
Kodama, Takashi*; Nakano, Masamichi*; Matsuoka, Shingo*; Matsuura, Chihiro*; Ito, Yasuo*; Kurosu, Katsuya*; Shiraishi, Hirotsugu; Katsumura, Yosuke*
no journal, ,
It has been known that although a considerable amount of hydrogen is produced radiolytically in the high level liquid waste, only small part is emitted into the gas phase when the liquid depth is large. We report here the results of an experimental study which shows that the liquid-depth effect is caused not by the reaction between hydrogen and radicals, as has been previously suggested, but by Pd-catalyzed reaction between hydrogen and nitric acid. The method for evaluating the magnitute of the effect is also proposed.
Kodama, Takashi*; Nakano, Masanao*; Hayashi, Yoshiaki*; Matsuoka, Shingo*; Ito, Yasuo*; Matsuura, Chihiro*; Shiraishi, Hirotsugu; Katsumura, Yosuke*
no journal, ,
We have reported in the previous meeting that the accumulation of radiolytically produced hydrogen in high-level liquid waste is suppressed owing to some oxidation reaction catalyzed by Pd in the solution. In this report, we present the results of a hydrogen bubbling experiment with mock high-level liquid waste, made to clarify the species involved in the reaction. Analysis was made on nitrous acid and nitric acid in the solution, and also on nitrogen oxide in the outlet gas. It was found that although the concentration of nitrous acid present in the solution is small, nitrogen oxide, consisting mostly of NO, is detected in the gas at concentration corresponding to the decrease of nitric acid in the solution. The amount of the produced nitrogen oxide matched roughly with an estimated amount of reacted hydrogen, confirming that nitric acid is the oxidant.
Kodama, Takashi*; Nakano, Masanao*; Hayashi, Yoshiaki*; Matsuoka, Shingo*; Ito, Yasuo*; Matsuura, Chihiro*; Shiraishi, Hirotsugu; Katsumura, Yosuke*
no journal, ,
We report here an evaluation for hydrogen concentration that may be attained in the upper space of the high-level liquid waste tank when the gas sweeping function happens to be lost. The parameters are the rate of radiolytic production of hydrogen, the rate of Pd-catalyzed hydrogen consuming reaction, and the solubility of hydrogen. For the first, a literature value on nitric acid solution was used, while for the second and third, experimental estimate was made in the present study with mock high-level liquid waste. All data have been taken at ambient temperature. For simplicity, it was assumed that both the gas and the liquid are homogeneous, and that the two phases are in equilibrium regarding hydrogen concentration. These led to an estimate of 0.6% for the hydrogen concentration in the gas phase, a value smaller than the lower limit of explosion.