The efficacy of a porous w/liquid Li hybrid system as a self-healing, adaptive plasma-material interface in future plasma-burning nuclear fusion reactors

The tungsten surface in a fusion reactor is subject to the steady-state heat flux 10−15MW , and a particle flux of 1E24 ions/m^2s . These high heat and particle fluxes can result in recrystallization, surface morphology, and W erosion, which must stay below 20ppm to prevent radiative cooling of the core. The focus of this work is to develop a material system that has the favorable bulk properties of W while reducing the impact of Plasma- Material Interactions (PMI) on tungsten by introducing an interface material that is compatible with both the impinging plasma as well as the structural W below the interface. One such system is a porous tungsten-liquid metal hybrid system, having the bulk, thermomechanical properties of a high defect sink tungsten foam, that have demonstrated such in inertial fusion while being a scaffold for a liquid metal (Li in the case of this study) with favorable PMI properties. The purpose of this study is to determine the efficacy of this hybrid material system as a plasma interface,by examining the feasibility of porous tungsten, made via a spark plasma sintering process, as a stable structure for incorporation of a liquid metal as well as a passive flow media for liquid lithium. Additionally, determination of PMI effects on this system, and a quantitative study of liquid/vapor Li interface are also examined. Liquid Li compatibility is tested two different ways: surface wetting/imbibition will be determined by static wetting angle measurements at surface temperature range from 200°C to 400°C within a vacuum environment of the Materials Characterization Test Stand (MCATS) at the University of Illinois. D inventory and depth profile in porous W substrates with 1μm Li deposited and melted is quantified with in-operando NRA during 60eV D+ plasma exposure to a fluence 2E24 ions/m^2 with the retention behaviour relative to lithium percolation quantified with in-operando He Elastic Recoil Detection. Finally, a 1-D drift diffusion model to study and quantify the extent of surface protection due to heat flux dissipation via a radiative vapor shield is under development using applications belonging to the Multiphysics Object- Oriented Simulation Environment (MOOSE) will be discussed.

Name thesis:degree_name

Ph.D.

Level thesis:degree_level

Dissertation

Discipline thesis:degree_discipline

Nuclear, Plasma, Radiolgc Engr

Grantor

University of Illinois at Urbana-Champaign

Year dc:date

2023

Author dc:creator

• Kapat, Aveek S

Contributors dc:contributor

• Allain, Jean Paul
• Curreli, Davide
• Ruzic, David
• Miljkovic, Nenad

• Porous Tungsten
• Liquid Lithium
• Plasma-facing Components
• D Retention
• Interfacial Phenomena
• Vapor Shielding

Statement dc:rights

• © 2023 Aveek S. Kapat

Language dc:language

en, eng

Handle dc:identifier

https://hdl.handle.net/2142/121294

OAI record oai:identifier

https://www.ideals.illinois.edu/oai-pmh?verb=GetRecord&metadataPrefix=etdms&identifier=oai%3Awww.ideals.illinois.edu%3A2142%2F121294