2006 Fiscal Year Final Research Report Summary
EVALUATION OF TRTIUM INVENTORY IN LOW-ACTIVATED FUSION MATERIALS BASED ON IRRADIATION EXPERIMENTS
| Project/Area Number |
16360458
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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 fusion studies
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| Research Institution | KYOTO UNIVERSITY |
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Principal Investigator |
TAKAGI Ikuji Kyoto University, Graduate School of Engineering, Associate Professor, 工学研究科, 助教授 (20206717)
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| Co-Investigator(Kenkyū-buntansha) |
MORIYAMA Hirotake Kyoto University, Graduate School of Engineering, Professor, 工学研究科, 教授 (90127150)
MORITANI Kimikazu Kyoto University, Graduate School of Engineering, Assistant Professor, 工学研究科, 助手 (50111943)
AKIYOSHI Masafumi Kyoto University, Graduate School of Engineering, Assistant Professor, 工学研究科, 助手 (70378793)
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| Project Period (FY) |
2004 – 2006
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| Keywords | TRITIUM INVENTORY / RADIATION DAMAGE / HYDROGEN TRAPPING / ION BEAM ANALYSIS / LOW ACTIVATION / VANADIUM / COPPER / DEFECT |
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| Research Abstract |
Tritium inventory in low-activated materials such as vanadium, copper, aluminum and iron has been experimentally studied using ion beam techniques. Samples were irradiated with energetic helium or hydrogen ions and simultaneously charged with deuterium atoms from plasma. Deuterium was representative of tritium. Deuterium depth profiles in the samples were observed by nuclear reaction analysis.
Irradiation to vanadium yielded much amount of traps for hydrogen isotopes and the deuterium inventory significantly increased. As the traps were annihilated around 500 K, lower than fusion operating temperatures, the traps would not affect the tritium inventory. As vanadium is exothermic for hydrogen dissociation, dissolved tritium would mainly contribute to the inventory. Vanadium alloy of V-Cr-Ti showed the same characteristics as vanadium.
Two types of the traps were produced in copper by the irradiation. One was considered to be vacancies and the other interstitial loops. Both the traps were n
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ot annihilated at 673 K, which indicated that the traps much increased the tritium inventory of copper tubes in the cooling system. As copper is endothermic for hydrogen dissociation, trapped tritium would mainly contribute to the inventory.
No traps were observed in aluminum, which was heavily irradiated by helium ions. It is expected that the tritium inventory in aluminum is very low at any operating conditions of the fusion reactor.
As for vanadium, the deuterium concentration in iron significantly increased due to the trap produced by irradiation. The trap was considered to be vacancy which was annihilated around 500 K. Iron is a candidate for low-inventory materials.
In the experiments, parameters such as the diffusion 'coefficient, the trap density, the equilibrium constant for trapping and de-trapping and trap production rate have been quantitatively determined. Knowing the reactor conditions such as the damage rate and the incident fuel particle flux, the tritium inventory can be evaluated with these parameters. Less
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Research Products
(12 results)
