University of Illinois Urbana-Champaign

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

Kapat, Aveek S

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

Description

Title
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
Author(s)
Kapat, Aveek S
Issue Date
2023-05-16
Director of Research (if dissertation) or Advisor (if thesis)
Allain, Jean Paul
Doctoral Committee Chair(s)
Curreli, Davide
Committee Member(s)
  • Ruzic, David
  • Miljkovic, Nenad
Department of Study
Nuclear, Plasma, & Rad Engr
Discipline
Nuclear, Plasma, Radiolgc Engr
Degree Granting Institution
University of Illinois at Urbana-Champaign
Degree Name
Ph.D.
Degree Level
Dissertation
Keyword(s)
Porous tungsten, liquid lithium, Plasma-Facing Components, D retention, Interfacial phenomena, vapor shielding
Abstract
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.
Graduation Semester
2023-08
Type of Resource
Thesis
Copyright and License Information
© 2023 Aveek S. Kapat

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