Details

Autor(en) / Beteiligte

• Emdee, E.D.
• Goldston, R.J.
• Schwartz, J.A.
• Rensink, M.E.
• Rognlien, T.D.

Titel

Study of lithium vapor flow in a detached divertor using DSMC code

Ist Teil von

• Nuclear materials and energy, 2019-05, Vol.19 (C), p.244-249

Ort / Verlag

United States: Elsevier Ltd

Erscheinungsjahr

2019

Quelle

Electronic Journals Library

Beschreibungen/Notizen

• •The lithium vapor box divertor localizes dense lithium vapor to cause stable detachment.•This localization is formed by local evaporation and nearby condensation.•Lithium vapor flow in a lithium vapor box design was simulated.•We find the lithium exits the baffles for this configuration at a rate of  ∼ 4 g/s.•This should be acceptable since ionization of  ∼  60 g/s of lithium is taking place to cause detachment.•Changes in detachment front position over 19 cm can cause a factor of 18 increase in lithium ionization rate•Unbaffled results are more modest, but nonetheless promising. A detached divertor is predicted to be necessary to handle the heat fluxes of a demonstration fusion power plant. The lithium vapor box divertor localizes dense lithium vapor to cause stable detachment. This localization is formed by local evaporation and nearby condensation. We provide a simulation of lithium vapor flow using the SPARTA Direct Simulation Monte Carlo (DSMC) code. Simulations of a baffled vapor box divertor’s lithium mass flow are within a factor of two of an ideal-gas choked nozzle flow calculation. Lithium flow and density within each chamber are given for a 200 MW power input Demo-scaled vapor-box example configuration. We find the lithium exits the baffles of this configuration at a rate of  ∼ 4 g/s. This should be acceptable since ionization of  ∼ 60 g/s of lithium is taking place to cause detachment [3]. A simple model of the Fusion National Science Facility (FNSF) divertor plasma is also explored. We compare our simulations using SPARTA to a similar UEDGE simulation, showing the lithium ionizations rates can be emulated to a reasonable degree. The addition of baffles causes a decrease in far SOL ionization by a factor of eight. Changes in detachment front position over a range of 19cm can cause more than a factor of 18 increase in ionization rate, indicating detachment location is highly stable to variations in heatflux. Unbaffled results are more modest, but nonetheless promising with a factor of six change in ionization over the same region.