Search

A series of experiments on deuterium plasma interaction with a liquid metal GaInSn alloy have been carried out to investigate the Lorentz-force (J × B-force) convection effects on particle recycling behavior over liquid metals under plasma bombardment. It has been found that deuterium recycling from the liquid is reduced, when forced convection is applied to the liquid. And deuterium recycling is reduced more as the current increases. A finite element analysis method has been applied to simulate the motion of the liquid and the deuterium transport process in the liquid. As a result, the deuterium transport in the liquid is accelerated by the convection.

The application of liquid metals as plasma-facing materials (PFMs) is a potential means to resolve the technical issues associated with power exhausting and particle handing in magnetic fusion devices. Natural convection is a phenomenon commonly present in liquids. To investigate the natural convection effects on deuterium transport behavior in liquid metals, a series of experiments on deuterium Plasma-Driven Permeation (PDP) through a liquid metal GaInSn alloy have been carried out. It has been found that deuterium permeation through the liquid is enhanced by one order of magnitude with natural convection. The motion of the liquid and the deuterium transport process in the liquid have been simulated by a finite element analysis method.

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: Ga 67 In 20.5 Sn 12.5 , 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.

A new laboratory-scale linear plasma device, PSIEC (Plasma-Surface Interaction system under Extreme Conditions), has been designed and constructed at Hefei University of Technology, China, to study plasma-material interactions for fusion reactor application. The PSIEC facility can generate continuous plasmas of hydrogen, deuterium, helium, argon and nitrogen. The electron density of these plasmas ranges from the order of magnitude of 1017 to 1018 /m3 and the electron temperature ranges from 1 to 40 eV. The incident ion energy is adjusted by applying a negative bias up to 110 V to the target. The plasma bombarding flux is varied from the order of magnitude of 1021 to 1022 ions/m2/s. Using the PSIEC facility, first plasma exposure experiments have been conducted on bulk tungsten and coatings. The different microstructure of tungsten have been found to lead to different damage effects under helium plasma exposure. Preliminary results allow us to expect nanocrystalline tungsten to be a promising candidate for plasma-facing material, of which the high concentration of intrinsic defects such as grain boundaries and interfaces offers the possibility of improving their irradiation resistance.