Development of low activation MgB2 superconduting wires under the fusion neutron irradiation environment condition

2015 Fiscal Year Final Research Report

• Project/Area Number: 25420892
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Research Field: Nuclear fusion studies
• Research Institution: National Institute for Fusion Science
• Principal Investigator: HISHINUMA Yoshimitsu 核融合科学研究所, ヘリカル研究部, 准教授 (00322529)
• Co-Investigator(Kenkyū-buntansha): YAMADA Shuichi 自然科学研究機構, 核融合科学研究所ヘリカル研究部, 准教授 (50249968)
• Co-Investigator(Renkei-kenkyūsha): KIKUCHI Akihiro 国立研究開発法人物質・材料研究機構, 超伝導線材ユニット, 主席研究員 (50343877)
• Project Period (FY): 2013-04-01 – 2016-03-31
• Keywords: MgB2 / ホウ素同位体 / 臨界電流特性 / 核融合応用 / 引張変形

Outline of Final Research Achievements

MgB2 wire is one of the alternative superconducting materials of Nb-Ti wire for the low activation superconducting magnet system to an advanced fusion reactor. We succeeded to fabricate in-situ MgB2 wire using the B-11 isotope powder without nuclear transformation in order to enhance the stability against the neutron irradiation. Jc value was improved with smaller average particle size of the B-11 isotope powder, and the amorphous B-11 isotope powder sample was obtained to above 1,000A/mm2 at 4.2 K under 3 T. Jc-B performance of the amorphous B-11 isotope sample was higher than that of the crystallized B-11 isotope powder. We found that the finer particle amorphous isotope powder was preferable as the boron source material of the low activation MgB2 wires.
On the other hand, Jc property under the tensile deformation was improved until 500 MPa of tensile stress. This was caused by the internal compressive stress mitigation around the MgB2 core region due to the tensile deformation.

Free Research Field

超伝導材料工学