A simplified lithium vapor box divertor

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

doi:10.1088/1741-4326/ab2825

Title: A simplified lithium vapor box divertor

Journal Article · Fri Jul 05 00:00:00 EDT 2019 · Nuclear Fusion

DOI:https://doi.org/10.1088/1741-4326/ab2825· OSTI ID:1558761

^[1];

^[1]; Schwartz, J. A. ^[1]; Rensink, M. ^[2]; Rognlien, T. D. ^[2]

Princeton Plasma Physics Lab. (PPPL), Princeton, NJ (United States)
Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)

A detached divertor plasma is predicted to be necessary to mitigate the heat fluxes and ion energy, and so sputtering, at the divertor plate of a fusion power plant. It has proven difficult in current experiments, however, to prevent the detachment front, once formed, from running up to the main plasma resulting in deterioration of pedestal performance. The lithium vapor box divertor localizes a dense cloud of lithium vapor away from the main plasma, in order to induce detachment at a stable, distant location. The vapor localization is created by local evaporation and nearby condensation, a configuration inaccessible for non-condensing seed impurities. This paper provides simulations of lithium vapor flow using the SPARTA direct simulation Monte Carlo (DSMC) code, in which the lithium vapor dynamics are governed by Li–Li collisions that should dominate in regions with little plasma. Inertia is included in this code, permitting the formation of shocks. The plasma model implemented in SPARTA is based on UEDGE results for the location of ionization and recombination. We find that a simplified lithium vapor box configuration, without baffles, provides robust stabilization of the detachment front and acceptable lithium vapor flow to the main chamber. Lithium is evaporated from a capillary porous surface on the private-flux side of the divertor, distant from the main plasma, and is condensed on the other side walls of the divertor chamber. The condensed lithium flows back to the evaporator through 2 cm internal diameter pipes. The capillary pressure differential at the surface of the evaporator is capable of overcoming MHD back-force in the piping, with a great deal of margin if a sandwich flow channel insert is implemented. Very little lithium should be accumulated on the first wall of the main chamber if it is maintained at 600 °C, as expected for a power-producing fusion system.

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Research Organization:: Princeton Plasma Physics Lab. (PPPL), Princeton, NJ (United States); Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)

Sponsoring Organization:: USDOE Office of Science (SC), Fusion Energy Sciences (FES)

Grant/Contract Number:: AC02-09CH11466; AC52-07NA27344

OSTI ID:: 1558761

Alternate ID(s):: OSTI ID: 1823218

Report Number(s):: LLNL-JRNL-793360; TRN: US2000242

Journal Information:: Nuclear Fusion, Vol. 59, Issue 8; ISSN 0029-5515

Publisher:: IOP ScienceCopyright Statement

Country of Publication:: United States

Language:: English

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Cited by: 4 works

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