2004 Fiscal Year Final Research Report Summary
Evaluation Methodology for Accelerated Irradiation Effects Based on Mechanistic Approach and Its Application to Practical Materials
| Project/Area Number |
15360500
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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 | The University of Tokyo |
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Principal Investigator |
SEKIMURA Naoto The University of Tokyo, School of Engineering, Professor, 大学院・工学系研究科, 教授 (10183055)
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| Co-Investigator(Kenkyū-buntansha) |
ABE Hiroaki The University of Tokyo, Research Center for Nuclear Science and Technolog, Associate Professor, 原子力研究総合センター, 助教授 (40343925)
IWAI Takeo The University of Tokyo, Research Center for Nuclear Science and Technolog, Research Associate, 原子力研究総合センター, 助手 (30272529)
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| Project Period (FY) |
2003 – 2004
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| Keywords | Dose Rate / Accelerated Irradiation Effect / Austenitic Steel / Neutron Irradiation / Ion Irradiation / Dislocation Loop |
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| Research Abstract |
The dependence of void swelling on material and environmental variables is a concern for both fission and fusion reactors, with strong recent interest on the effects of dpa rate. A comprehensive experimental investigation of microstructural evolution has been conducted on Fe-15Cr-16Ni irradiated with 4.0 MeV nickel ions in the High Fluence Irradiation Facility of the University of Tokyo. Irradiations proceeded to dose levels ranging from 〜0.2 to 〜26 dpa at temperatures of 300, 400, 500 and 600 ℃ at displacement rates of 1 x 10^<-4>, 4 x 10^<-4> and 1 x 10^<-3> dpa/sec. This experiment is one of two companion experiments directed toward the study of the dependence of void swelling on displacement rate. The other already-published neutron irradiation experiment proceeded at seven different but substantially lower dpa rates in FFTF-MOTA at 〜400℃. In both experiments the swelling was found at every irradiation condition studied to monotonically increase with decreases in dpa rate.
The micro
… More
structural evolution under ion irradiation was found to be very sensitive to the displacement rate at all temperatures examined. The earliest and most sensitive component of microstructure to both temperature and especially displacement rate was found to be the Frank loops. The second most sensitive component was found to be the void microstructure, which co-evolves with the loop and dislocation microstructure. At the higher dpa rates employed in the ion irradiation series it was possible to nucleate voids but they never grew quickly in the loop-dominated dislocation structure, while at the lower neutron-induced dpa rates the loops quickly unfaulted to form a network and voids then accelerate in growth rate. The significance of these results is that the flux effect appears to be completely independent of irradiation temperature, in disagreement with most theoretical models which predict a shift in the swelling peak with increasing dpa rate, but with a reversal in the sign of the flux effect on the high side of the swelling peak. Another consequence of these results is that ion irradiation of simple model alloys will usually produce less swelling than neutron irradiation, primarily due to the higher dpa rates usually employed compared to that of neutron irradiations. Less
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Research Products
(34 results)
