Speaker
Neway Atnafu
(Engineering)
Description
NSTX-U COILS BUS BARS DESIGN AND CONSTRUCTION**
Neway D. Atnafu, L. Dudek, A. Khodak, S. Gerhardt, S. Ramakrishnan, M. Smith, P. Titus
Princeton Plasma Physics Laboratory, Princeton, NJ 08543-0451
natnafu@pppl.gov
The construction of the NSTX upgrade project was completed in the fall of 2015. The multi-year capital project was budgeted at $94 Million. The reactor will used to run experiments under increased Toroidal Field (TF), Plasma Current (Ip), Beam Injection Power, and pulse length. The Bus Bars connect the magnetic coils to the power supply lines. The bus bars design consists of co-axial, water-cooled and air-cooled bus bar systems. The bus bars design was analyzed and satisfied the NSTX structural design criteria. FEM analysis was performed using ANSYS software to verify the performance of the bus bars under the increased current loads. The processes used for fabricating the bus bars include forming, machining, brazing, welding and water-jet cutting. Individual conductors were insulated using Kapton Tapes for electrical insulation and Fiber Glass Wetted with Epoxy Hysol to provide further electrical insulation and a protective mechanical coating. The joint surfaces were silver plated and the bolts torqued appropriately to maintain joint resistances within an acceptable range. Structural supports were provided as necessary to counter forces against the bus bars due to the magnetic fields, short circuit conditions and thermal boundary conditions. The insulated bus bars and assemblies were hi-pot tested to verify insulation; the joints were resistance checked; and the water-cooled buses were leak checked using hydrostatic pressure testing. At completion of the bus bars installation, pre-operational testing was performed to verify that the coils bus systems are capable of meeting the required current and voltage ratings.
*This work supported by the US DOE Contract No. DE-AC02-09CH11466
Co-author
Neway Atnafu
(Engineering, Princeton University Plasma Physics Lab, Princeton, United States)
