Speaker
Jumpei Mochizuki
(Shizuoka University)
Description
Tritium permeation barrier (TPB) has been investigated for the establishment of an efficient fuel cycle and radiological safety in fusion power plants. One of critical issues for TPB is degradation caused by introduction of cracks and pores. Even if a microscopic crack is introduced, tritium permeation is drastically increased. The development of self-healing coating is one of techniques for solving this issue. In this study, the self-healing material was selected through oxidation experiments. Fabrication and deuterium permeation measurements of TPB coatings containing the self-healing material were carried out to examine their basic properties as TPBs.
SiC and Cr3C2 powders were heated at 773-973 K for 1-10 h in air followed by crystal structure analysis using X-ray diffraction. Since SiC was not oxidized at up to 973 K while Cr3C2 was oxidized at 873 K, Cr3C2 was selected as the self-healing material. Subsequently, yttria coatings with Cr3C2 nanoparticles have been fabricated by metal organic decomposition. Deuterium permeation experiments were performed at 673-973 K using a gas-driven permeation system.
Two types of coated samples were fabricated: Cr3C2 nanoparticles were added in a coating precursor in the first coating process (Sample 1), and the yttria coating without the nanoparticles was fabricated followed by the addition of nanoparticles in the second coating process (Sample 2). A decrease of deuterium permeability caused by crystallization was observed for both samples at 623-973 K. After the crystallization, Sample 1 showed two orders of magnitude lower deuterium permeation than that for uncoated substrate, indicating a lower surface coverage. On the other hand, Sample 2 showed three orders of magnitude lower deuterium permeation than that for uncoated substrate.Pretreatment of substrate is effective for the fabrication of the nanoparticle-containing coatings to ensure surface coverage.
Co-authors
Cui Hu
(Shizuoka University, 836 Ohya, Suruga-ku Shizuoka 422-8529, Japan)
Jumpei Mochizuki
(Shizuoka University, 836 Ohya, Suruga-ku Shizuoka 422-8529, Japan)
Seira Horikoshi
(Shizuoka University, 836 Ohya, Suruga-ku Shizuoka 422-8529, Japan)
Takumi Chikada
(Shizuoka University, 836 Ohya, Suruga-ku Shizuoka 422-8529, Japan)
Yasuhisa Oya
(Shizuoka University, 836 Ohya, Suruga-ku Shizuoka 422-8529, Japan)
