定常プラズマ照射下の液体金属中での水素透過に関する研究

Hydrogen Plasma-driven Permeation (PDP) experiments through two different liquid metal membranes: lithium and GaInSn have been conducted in the temperature range from 300 to 500 ◦C. A technique employing a mesh sheet to hold a liquid metal for PDP has been utilized for the first time. It has been found that PDP is surface recombination limited for lithium and is diffusion limited for GaInSn. Hydrogen surface recombination coefficients for liquid lithium and hydrogen diffusivity in GaInSn have been obtained respectively

Hydrogen and helium recycling from a JxB-force convected liquid metal Ga67In20.5Sn12.5 under steady state plasma bombardment

A series of first-of-a-kind laboratory-scale experiments on the JxB-force convected liquid metal divertor concept have been carried out in the temperature range from room temperature to ∼200 °C, employing a eutectic alloy: Ga67In20.5Sn12.5, the melting point of which is 10.5 °C. The electrical current conducted through the alloy is set at about 70A and the magnetic field is set at about 700 G. It has reproducibly been observed that hydrogen as well as helium particle recycling is noticeably reduced under steady state plasma bombardment when the liquid is convected by the JxB force

Steady state hydrogen, deuterium, helium and argon plasma interactions with a liquid metal: Ga67In20.5Sn12.5 convected by Lorentz force

Steady state hydrogen, deuterium and helium plasma interactions with a liquid metal: Ga67In20.5Sn12.5 at termperatures between room temperature and ∼250°C have been investigated with JxB-forced convection, using a laboratory-scale facility: VEHICLE-1. Noticeably reduced recycling has been observed for all these gases, when JxB-forced convection is applied, under respevtive plasma bombardment. Preliminary fluid dynamics modeling has been done to interpret experimental observations. For hydrogenic species, a trend has been found, indicating temperature-dependent retention saturation levels. With thermal desorption spectrometry, the amount of deuterium retention after saturation at ∼250°C has been evaluated to be of the order of 1014D/cm3 whereas the retention of inert gases is found to be undetectable

A study on hydrogen isotopes transport in a liquid metal GaInSn by plasma-driven permeation method

The application of liquid metals such as gallium, tin and lithium as plasma-facing materials is a potential means to resolve the technical issues associated with power exhausting and particle handing in magnetic fusion devices. GaInSn alloy with melting point of 10.5°C, is employed as a modeling material to explore the plasma-driven permeation (PDP) method to study the hydrogen isotopes (hydrogen and deuterium) transport parameters in a liquid metal. Static liquid GaInSn membranes sitting on a mesh sheet are exposed to hydrogen/deuterium plasmas in the linear plasma device VEHICLE-1 with the temperature range of 280–496°C. Hydrogen/deuterium diffusivity are obtained by fitting the time evolutions of permeation fluxes. The dynamic hydrogen/deuterium retention in the liquid GaInSn are found to be low (∼1015D/cm3), which are consistent with the thermal desorption spectroscopy (TDS) measurement following plasma exposure. The hydrogen and deuterium transport parameters are found to be close to each other. Keywords: Liquid metal, Plasma-driven permeation, Diffusivity, Recombination coefficient, Retentio

Hydrogen Isotopes Plasma-Driven Permeation through Tungsten Coated Reduced Activation Ferritic Steel F82H

Hydrogen isotopes plasma-driven permeation (PDP) through F82H coated with two different types of tungsten coatings, i.e., sputter-deposited tungsten (SP-W) and vacuum plasma-sprayed tungsten (VPS-W) has been studied in the temperature range of 300 - 550 °C. It has been found that hydrogen isotopes PDP fluxes through VPS-W coated F82H are reduced compared to that through bare F82H. However, the PDP fluxes through SP-W coated F82H are enhanced compared to bare F82H. Reduced or enhanced PDP fluxes are related to the different microstructure of tungsten coatings and its surface recombination characteristics

Hydrogen Gas-Driven Permeation through F82H Steel Coated with Vacuum Plasma-Sprayed Tungsten

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