PPPL-4892
NSTX-U Vacuum Vessel Design Modification
Authors: N.D. Atnafu, et. al.
Abstract:
The NSTX-U requirements will double the
Toroidal Field (TF), Plasma Current (Ip), Beam Injection
Power, and extend pulse length. The larger centerstack requires
re-aiming of the Multi Pulse Thomson Scattering (MPTS) lasers
and Vacuum Vessel (VV) modifications at Bay L. The second
neutral beam requirements include larger tangency radii and
thus a VV modification at Bay K and Bay J. A cap design for a
new weldment was developed to achieve these larger beam
trajectories without losing the utility of the Bay J port for
diagnostics. Analyses of loads indicated the need for
reinforcements of the vessel at the midplane. NSTX has 6 picture
frame type Resistive Wall Mode (RWM) coils around the
exterior circumference of the vacuum vessel; each coil surrounds
pairs of ports. The modifications needed for the upgrade were
intended to minimize the impact to the RWM fields at the
plasma. A Pro E global model segment was used to model the
vacuum vessel. ANSYS was used to apply loads and investigate
reinforcement configurations. A focused effort and analysis
produced a design capable of achieving the desired performance
of the upgrade while maintaining utility and continuity of RWM
coil physics pre- and post-upgrade physics performance. The
installation of the Bay J-K and Bay L Port Caps was completed
and the reinforcing weldments have been partially installed.
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Submitted to: SOFE 2013 Proeedings (June 0213) 25th Symposium on Fusion Engineering, San Francisdco, CA (June 10-14, 2013
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Download PPPL-4892 (pdf 266 Kb 4 pp)
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