The Physics Basis for an Advanced Physics and Advanced Technology Tokamak Power Plant Configuration, ARIES-ACT1
Authors: C.E. Kessel, F.M. Poli, K. Ghantous, N.N. Gorelenkov, M.E. Rensink,T.D. Rognlien, P.B. Snyder, H. St. John, A.D. Turnbull
Abstract:
It is useful to characterize tokamak power-plant studies in terms of two general parameters indicating the separate levels of confidence in the plasma physics operating regime and in the technology performance of system components. The advanced physics
and advanced technology tokamak configuration was last examined in 1999, and referred
to as ARIES-AT. The preceding study ARIES-RS examined in 1996 also addressed
an advanced physics option, with less advanced technology. This corner of parameter
space is revisited in light of progress in physics understanding since that time. Future
studies will address the conservative corner and the other corners that mix advanced and
conservative aspects. The plasma shape is chosen to be strong, preserving the up-down
symmetric double-null, which allows higher beta limits in the presence of a stabilizing
shell, and plasma rotation, feedback or kinetic stabilization effects. The plasma
elongation is 2.2 and triangularity is 0.625. The triangularity is lower than ARIES-AT in
order to accommodate neutron shielding on the inboard side and divertor slot design
within manifolding and other neutron shielding constraints. The aspect ratio is assumed
to be 4.0, based on previous analysis showing this to be a weakly influential parameter
between 3.0 and 5.0. The major radius of the plasma has increased to bring the peak
outboard divertor heat flux to < 15 MW/m2. In addition, the wall-plug efficiency for all
heating and current drive systems has been reduced from 0.7 to 0.4, and other
recirculating electrical requirements have been increased, which contributes to a larger
major radius as well. Time-dependent free-boundary transport simulations and high
fidelity heating and current drive analysis are used to confirm the plasma configurations
identified with the systems code, and are found to be ideal MHD stable. The pedestal is
included consistently by utilizing peeling-ballooning theory to constrain this pressure.
The free-boundary simulations have clarified the volt-second requirements needed to
assist rampup to steady state, and have shown it is possible to grow a plasma inside the
relative tight fitting plasma chamber. Increased attention has been paid to the scrape-off
layer and divertor plasma solutions, as well as examining the heat loading associated with
steady, transient and off-normal environments. Fast particle stability is examined to
determine if instabilities lead to particle losses or redistribution. Discussions of topics
including operation at the Greenwald limit, ELM avoidance and mitigation, and tritium
burnup are given.
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Submitted to: Fusion, Science & Technology (October 2013)
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Download PPPL-4952 (pdf 4.4 MB 57 pp)
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