| Project/Area Number |
13680586
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| Research Category |
Grant-in-Aid for Scientific Research (C)
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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 | Fukui University |
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Principal Investigator |
NIKI Hideaki Fukui University, Faculty of Engineering, Associate Professor, 工学部, 助教授 (00135758)
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| Project Period (FY) |
2001 – 2002
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| Project Status |
Completed (Fiscal Year 2002)
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| Budget Amount *help |
¥1,000,000 (Direct Cost: ¥1,000,000)
Fiscal Year 2002: ¥1,000,000 (Direct Cost: ¥1,000,000)
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| Keywords | Laser / Isotope Separation / Selectivity / Gadolinium / Magnetic Field / レーザー同位体分離 / 偏光 / 選択則 |
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| Research Abstract |
Gadolinium (Gd) is an important element as a burnable poison in nuclear power plant due to its high neutron absorption cross section. Gd has seven isotopic components. Especially, ^<157>Gd has a distinct large cross section. The burn rate of the nuclear fuel can be enhanced by enriched ^<157>Gd. It is difficult to excite one isotope using a narrow band laser because Gd has very small isotope shifts. Separation method, however, using polarized lasers based on polarization selection rules is suitable for this element. In this method the isotopic selectivity could possibly degraded by an external magnetic field generated by a magnet contained in the electron gun as a metal evaporation source. For designing a large-scale separation facility it is important to investigate the atomic excitation behavior when an external magnetic field is applied in the laser-atom interaction region.
Obtained results in this study are summarized below.
1. Highly selective ionization of odd isotopes (^<155>Gd, ^<157>Gd) was achieved in the small-scale experiment using three linearly polarized lasers.
2. Selectivity loss was observed when an external magnetic field was applied in the laser-atom interaction region.
3. From the measurement of isotope selectivity as a function of a magnetic field strength, the angle between the laser polarization and the magnetic field, it was found that the experimental results well agreed with the results of the calculation code we developed.
4. Both the experiment and the numerical analysis showed that a magnetic field of 20mT could completely degrade the selectivity when the laser pulse widths were 5ns. This suggests that the selectivity could not be expected at all for a magnetic field of 2mT when the 50ns laser pulses are irradiated.
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