DIFFER
DIFFER EVENT

Plasma-facing components for the NSTX-U Recovery Project and Applications of Liquid Technologies to Conventional Energy Sources

NOTE: different day and time: Tuesday 10h00  The National Spherical Torus Experiment – Upgrade (NSTX-U), will be one of the highest power-density magnetic fusion experiments when operating at full parameters.  Following a failure in a poloidal field coil, the NSTX-U entered the Recovery Project which is redesigning several key components in order to increase operational reliability.  Among these are the plasma-facing components for both high-heat flux and low-heat flux regions of the machine.  Building on previous design experience with castellated tiles, the new high-heat flux components will be composed of isotropic graphite with surface castellations and novel fixturing mechanisms that eliminate front-access holes.  These features, alongside the elimination of leading edges through surface features (e.g. tile ramping), are increasing the operational space available to future experiments while avoiding carbon ablation phenomena associated with high-temperatures.  These improvements are expected to support upgrades to the NSTX-U that could include high-Z, metallic PFCs as well as possible liquid metal PFCs.

The use of liquid plasma-facing components is not limited to fusion energy applications alone.  The need for multiple approaches to supplying global primary energy needs suggests attention to many fuel sources, including conventional, fossil energy resources combined with carbon-capture and sequestration technologies.  Direct Power Extraction via magnetohydrodynamic (MHD) power generation is a method of converting the enthalpy in high-temperature, partially-ionized gases (e.g. combustion by-products) directly into electrical energy with no moving parts via expansion of the gas through a high-magnetic field.  Previous research into this technology in the United States identified key technological hurdles including the lifetime of the plasma-facing components.  Molten salts in a porous substrate have been identified as a potentially attractive liquid for use and simple energy-absorption estimates indicate it could outperform leading alternate materials such as Pt-capped Cu or W electrodes.  A novel combined-cycle utilizing high-field MHD and other advancements in gas-turbine technology indicate a 100 MWnet, CCS-enabled power plant at 50% cycle efficiency can be obtained.

Date
-
Location
seminar room
Speaker
Michael Jaworski
Affiliation
Princeton Plasma Physics Laboratory (PPPL)

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