| Project/Area Number |
16360470
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| Research Category |
Grant-in-Aid for Scientific Research (B)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
Nuclear engineering
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| Research Institution | Tokyo Institute of Technology |
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Principal Investigator |
SUZUKI Masaaki Tokyo Institute of Technology, Graduate School of Science and Engineering, Professor, 大学院・理工学研究科, 教授 (70114874)
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| Co-Investigator(Kenkyū-buntansha) |
MORI Shinsuke Tokyo Institute of Technology, Graduate School of Science and Engineering, Associate Professor, 大学院・理工学研究科, 助手 (80345389)
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| Project Period (FY) |
2004 – 2006
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| Project Status |
Completed (Fiscal Year 2006)
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| Budget Amount *help |
¥14,300,000 (Direct Cost: ¥14,300,000)
Fiscal Year 2006: ¥3,000,000 (Direct Cost: ¥3,000,000)
Fiscal Year 2005: ¥4,500,000 (Direct Cost: ¥4,500,000)
Fiscal Year 2004: ¥6,800,000 (Direct Cost: ¥6,800,000)
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| Keywords | Isotope separation / Carbon isotopes / Plasma chemistry / Glow discharge / Carbon monoxide plasma |
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| Research Abstract |
The application of the carbon isotope separation method using plasma chemical reactions in carbon monoxide plasma for the recovery of 14C from the nuclear facilities was investigated. The experimental results obtained using ^<13>CO/^<12>CO system show that the isotope separation factor increases with a decrease of discharge current, and the current waveforms are in the self-generated oscillation mode in the low discharge current region. The isotope separation factor also increases with a decrease of discharge frequency or the ballast resistance. In our previous study, maximum separation factor for 13C in wall carbon deposit of 2.31 and for 180 in CO2 0f 1.37 are obtained using natural isotopic composition CO plasma. In this study, we have performed the experimental study using isotopically enriched CO as reactant gas and also performed the numerical simulation of kinetic model for this isotope separation phenomenon. The experimental results show that 13C separation factor decreases mon
… More
otonously from 1.66 to O.65 with increasing 13C isotopic compositions from 1.1 to 87.5%. However, the calculated results predict that separation factor for 13C increases with increasing 13C isotopic contents. The application of the carbon isotope separation method for the recovery of 14C from the graphite moderator of a dismantled Japanese gas-cooled reactor, Tokai Power Station, was evaluated numerically. The 14C separation factor of 4.6 in one unit stage was estimated through the numerical simulation of a kinetic model in CO plasma. The calculated results show that the 14C concentration in the cascade tail flow can be reduced to the environmental standard recommended by the International Commission on Radiological Protection(3 Bq/cm3) and to the natural abundance level(1.3 x 10-4 Bq/cm3) in 3 and 16 stages in the stripping section, respectively, and the amount of 14C-enriched CO flow can be reduced to 1/103 and 1/106 of the feed CO amount in 9 and 19 stages in the enriching section, respectively. In the case of 3-stage processing in the stripping section and 9-stage processing in the enriching section, it is estimated that the total energy consumption by the plasma generator would be about 15 kW and the maximum inner diameter of the plasma reactor in the cascade would have to be about 60 cm. Less
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