A study about behavior of He bubbles on metal surface using high thermal pulse

2021 Fiscal Year Final Research Report

• Project/Area Number: 19K14690
• Research Category: Grant-in-Aid for Early-Career Scientists
• Allocation Type: Multi-year Fund
• Review Section: Basic Section 14020:Nuclear fusion-related
• Research Institution: National Institute for Fusion Science
• Principal Investigator: Hamaji Yukinori 核融合科学研究所, ヘリカル研究部, 助教 (60761070)
• Project Period (FY): 2019-04-01 – 2022-03-31
• Keywords: タングステン / プラズマー材料相互作用 / 熱パルス / 微細組織観察 / He誘起微細構造

Outline of Final Research Achievements

It is known that He forms a nanoscale bubble-like structure in tungsten. In order to investigate the time scale of moves of the structure in the material, we performed thermal pulse experiments creating a high temperature state for a short period of time. In this budget period, a specimen irradiation system with controllable temperature was designed and built for the linear plasma device TPD-II to enable temperature-controlled plasma irradiation. In addition, a two-color pyrometer with high-speed measurement capability was also designed and established to enable temperature measurement during thermal pulses. Observations of He bubbles by a scanning electron microscope provided information of the motion of He bubbles during thermal pulses.

Free Research Field

プラズマー材料相互作用

Academic Significance and Societal Importance of the Research Achievements

タングステン中のヘリウムバブルの運動がmsで起きることは、核融合炉のプラズマに対向する炉壁において予測される現象である。その理解のために短時間の熱パルスによる手法が有効であることが示された。また、材料中に気体粒子によるバブル構造が生じることは鋼材中の水素などでも見られており、熱パルスによるバブルの運動速度を得るこの手法は核融合分野外への応用も期待できる。