Plasma and Fusion Research

Volume 11, 2405064 (2016)

Regular Articles

Hydrogen Gas-Driven Permeation through F82H Steel Coated with Vacuum Plasma-Sprayed Tungsten
Yue XU1), Yoshi HIROOKA1,2), Takuya NAGASAKA1,2) and Juro YAGI1,2)
1)
The Graduate University for Advanced Studies, 322-6 Oroshi, Toki 509-5292, Japan
2)
National Institute for Fusion Science, 322-6 Oroshi, Toki 509-5292, Japan
(Received 30 November 2015 / Accepted 14 March 2016 / Published 17 May 2016)

Abstract

The subject of hydrogen isotopes transport through tungsten coated reduced activation ferritic steels such as F82H has attracted increasing interest in the fusion engineering research community. This paper reports on laboratory-scale studies that have been done to assess the hydrogen permeation properties of vacuum plasma-sprayed tungsten (VPS-W) coatings at the temperature range of 200 - 500 °C. W coatings with thicknesses of 46 μm and 90 μm have been investigated. It has been found that the observed permeation rates through composite VPS-W/F82H specimen are reduced to ∼7% compared to that of pure F82 H. VPS-W coating is porous and has an open system of connected pores, which density is evaluated to be ∼7%. The main effect of the W coating on hydrogen permeation is to reduce the incoming flux at the W/F82H interface owing to pore diffusion in the coating and to reduce the effective surface area for hydrogen dissolution in the substrate.

Keywords

gas-driven permeation, tungsten coating, reduced activation ferritic steel

DOI: 10.1585/pfr.11.2405064

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