2001 Fiscal Year Final Research Report Summary
Trapping Phenomena of Tritium at Formation of Re-deposition Layer of Diverter Graphite
| Project/Area Number |
11480114
|
|---|
| Research Category |
Grant-in-Aid for Scientific Research (B)
|
| Allocation Type | Single-year Grants |
|---|
| Section | 一般 |
|---|
| Research Field |
Nuclear fusion studies
|
|---|
| Research Institution | KYUSHU UNIVERSITY |
|---|
Principal Investigator |
NISHIKAWA Masabumi Kyushu University, Department of New Energy, Professor, 総合理工学研究院, 教授 (90026229)
|
|---|
| Project Period (FY) |
1999 – 2001
|
| Keywords | tritium / graphite / diverter / re-deposition layer / plasma parameters / etching |
|---|
| Research Abstract |
Using the RF deuterium plasma reactor made by this Grant-in-Aid, the amount of graphite re-deposited at the various position in the reactor, the amount of deuterium trapped to the re-deposited graphite and various plasma parameters were quantified in this study. The following results have been observed.
1. More amount of graphite deposits on the substrate placed at the position far from the electrode.
2. More amount of deuterium is recovered from the re-deposited layer of graphite formed on the substrate placed on the position far from the electrode.
3. The electron temperature measured with a Langmuir probe is around 3 eV, and the bias voltage is around 10 eV.
4. Above observations imply that etching of re-deposited graphite occur when the substrate is placed on the electrode because of the bias voltage.
5. It is also observed that the D/C ratio obtained in this study, about 0.03, is far smaller from the value when D is trapped by C-H bonding. The observation in this study implies that tritium may not be trapped by the C-H bonding if the plasma temperature is low as used in this study.
|
