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Shibata, Takanori; Koga, Shojiro*; Terasaki, Ryo*; Inoue, Takashi; Dairaku, Masayuki; Kashiwagi, Mieko; Taniguchi, Masaki; Tobari, Hiroyuki; Tsuchida, Kazuki; Umeda, Naotaka; et al.
Review of Scientific Instruments, 83(2), p.02A719_1 - 02A719_3, 2012/02
Times Cited Count：2 Percentile：12.31(Instruments & Instrumentation)In the NBI for large fusion devices, production of uniform negative ion beam is one of important issues. A physical model is proposed to understand the non-uniformity. It has been qualitatively shown that the non-uniform beam intensity is due to the following process; (1) formation of non-uniform EEDF, (2) localized production of hydrogen atoms/ions (H
/H
) due to (1), (3) non-uniform flux of H/H to the PG and (4) localized surface production of negative ions. However, in the past studies, the EEDF was assumed as two temperature Maxwellian distribution from measurements. Thus effects of high energy electrons are not taken into account precisely. In the present research, local EEDF is calculated by the 3D Monte-Carlo kinetic model which takes into account the spatial and magnetic configurations of the real negative ion source. The numerical result show that high energy component of the EEDF enhances the spatial non-uniformity in the production rate of H/H.
Homma, Shunji*; Ishii, Junichi; Kikuchi, Toshiaki*; Chikazawa, Takahiro*; Shibata, Atsuhiro; Koyama, Tomozo; Koga, Jiro*; Matsumoto, Shiro*
Journal of Nuclear Science and Technology, 45(6), p.510 - 517, 2008/06
Times Cited Count：11 Percentile：59.16(Nuclear Science & Technology)U-Pu co-crystallization reprocessing system is proposed for LWR fuels and its flowsheet study is carried out. This reprocessing system is based on the experimental evidence indicating that hexavalent plutonium is co-crystallized with uranyl nitrate. The system consists of five steps: dissolution of spent fuel, Pu oxidation, U-Pu co-crystallization, dissolution of the crystals, and U crystallization. The system does not require organic solvent, expecting the enhancement of safety and cost-effectiveness. The system requires a recycling of the mother liquor from the U-Pu co-crystallization step to recover almost entire amount of U and Pu. The appropriate recycle ratio is determined for LWR fuels, such that the satisfactory decontamination is achieved. The mother liquor from the U re-crystallization step contains U and Pu. The flowsheet study shows that the constant ratio of Pu to U in the mother liquor can be controlled even though the composition of the spent fuel is different.
Koga, Jiro*; Shinzato, Takushi*
JNC TJ8400 2000-054, 48 Pages, 2000/02
JNC-TJ8400-2000-054.pdf:1.23MB
The "STELLA" which is a tool for simulation of dynamical systems applied to the numerical simulation of the behavior of minor constituent, such as hydrazoic acid, forming and extinguishing on the operation of reprocessing process. The concentration of hydrazoic acid forming by the reaction of nitrite and hydrazine were determined by use of STELLA after the determination of concentration of main constituents by MIXSET-X. The results from simulation is shown that the STELLA is applicable to the numerical simulation of the behavior of minor constituent.
Matsumoto, Shiro*; Tajima, Yasunori*; Koga, Jiro*; Miyahara, Yukari*
PNC TJ1609 98-001, 26 Pages, 1998/02
no abstracts in English
Homma, Shunji*; Tajima, Yasunori*; Koga, Jiro*; Matsumoto, Shiro*
PNC TJ1609 97-001, 47 Pages, 1997/02
no abstracts in English
Shibata, Atsuhiro; Oyama, Koichi; Yano, Kimihiko; Nomura, Kazunori; Nakamura, Kazuhito; Koyama, Tomozo; Chikazawa, Takahiro*; Kikuchi, Toshiaki*; Ishii, Junichi; Homma, Shunji*; et al.
no journal, ,
no abstracts in English
