TY - JOUR
T1 - Helium gas permeability of SiC/SiC composite developed for blanket component
AU - Hino, Tomoaki
AU - Jinushi, Takahiro
AU - Hirohata, Yuko
AU - Hashiba, Masao
AU - Yamauchi, Yuji
AU - Katoh, Yutai
AU - Kohyama, Akira
PY - 2003/3
Y1 - 2003/3
N2 - To employ SiC/S/C composite us blanket components of a fusion reactor, permeation behavior of helium gas has to be investigated since the helium is used as the coolant. For this purpose, a vacuum system consisting of upstream and downstream chambers was fabricated for the measurement of permeability, and the permeability was measured for several SiC/SiC composite materials recently developed. For the pressure range from 102 to 105 Pa in the upstream chamber, the pressure rise due to the permeation of helium in the downstream chamber linearly increased with the pressure of the upstream chamber. Then, the permeability was roughly constant for the pressure range of the upstream chamber. The permeabilities of SiC/SiC composites produced by polymer impregnation and pyrolysis (PIP), hot pressing (HP) and melt-infiltration-finished PIP were 5 × 10-5, 4 × 10-6, and 9 × 10-7 m2/s, respectively. In the matrix structure of the SiC/SiC composite made by the PIP method with a high permeability, cracking in the matrix and pores of micron size were observed. Compared to these materials, SiC/SiC composites produced by liquid phase sintering using submicron or nanopowder of β-SiC and the HP method had extremely low permeabilities. The permeability of the SiC/SiC composite made by using submicron or nanopowder of β-SiC became 1.5 × 10-9 or 4 × 10-11 m2/s. Based upon the present data, the helium gas flow was analyzed for a blanket module consisting of only SiC/SiC composite. If a vacuum pump is attached to the module, the helium leak into a plasma can be ignored, compared to the heliums produced by fusion reactions. Hence, the entire module can be made by only SiC/SiC composite, from a viewpoint of helium permeation.
AB - To employ SiC/S/C composite us blanket components of a fusion reactor, permeation behavior of helium gas has to be investigated since the helium is used as the coolant. For this purpose, a vacuum system consisting of upstream and downstream chambers was fabricated for the measurement of permeability, and the permeability was measured for several SiC/SiC composite materials recently developed. For the pressure range from 102 to 105 Pa in the upstream chamber, the pressure rise due to the permeation of helium in the downstream chamber linearly increased with the pressure of the upstream chamber. Then, the permeability was roughly constant for the pressure range of the upstream chamber. The permeabilities of SiC/SiC composites produced by polymer impregnation and pyrolysis (PIP), hot pressing (HP) and melt-infiltration-finished PIP were 5 × 10-5, 4 × 10-6, and 9 × 10-7 m2/s, respectively. In the matrix structure of the SiC/SiC composite made by the PIP method with a high permeability, cracking in the matrix and pores of micron size were observed. Compared to these materials, SiC/SiC composites produced by liquid phase sintering using submicron or nanopowder of β-SiC and the HP method had extremely low permeabilities. The permeability of the SiC/SiC composite made by using submicron or nanopowder of β-SiC became 1.5 × 10-9 or 4 × 10-11 m2/s. Based upon the present data, the helium gas flow was analyzed for a blanket module consisting of only SiC/SiC composite. If a vacuum pump is attached to the module, the helium leak into a plasma can be ignored, compared to the heliums produced by fusion reactions. Hence, the entire module can be made by only SiC/SiC composite, from a viewpoint of helium permeation.
KW - Helium gas
KW - Permeability
KW - SiC/SiC composite
UR - http://www.scopus.com/inward/record.url?scp=0038713281&partnerID=8YFLogxK
U2 - 10.13182/FST03-A259
DO - 10.13182/FST03-A259
M3 - Article
AN - SCOPUS:0038713281
SN - 1536-1055
VL - 43
SP - 184
EP - 190
JO - Fusion Science and Technology
JF - Fusion Science and Technology
IS - 2
ER -