Engineering Meeting Summary

18 December 2002 

The December NCSX Engineering meeting was held on 18 December. Hutch Neilson reviewed recent developments, including the outcome of the NCSX and QPS PAC meetings last week and the arrival of the new modular coil design.  Hutch indicated that the NCSX PDR would be moved to the week of June 23.

Wayne Reiersen elaborated on the PDR, asserting that it would accomplish two objectives - demonstrate that the project has developed to a sufficient level of maturity to establish the performance baseline AND that the VV (WBS 12) and modular coils (WBS 14) are ready to proceed with Final Design.  The PDR will be moved to the week of June 23.  Work plans should be rescheduled accordingly and coordinated with QPS work plans.

Tom Brown presented a much improved central solenoid configuration.  Discussion centered around [1] whether the bucking cylinder was steel or glass-epoxy [2] whether the bucking cylinder was (a) axially continuous - 1 piece or (b) axially discontinuous - 4 pieces keyed for torsional continuity or [3] whether the bucking cylinder was separate from the CS coils.  Brown will coordinate design studies and analyses required to come to closure on this issue.  Reiersen will assess the adequacy of the flexibility provided by this coil configuration. Target date for coming to closure is mid-January.

Brad Nelson discussed radial build requirements between the modular coils and plasma.  The minimum space provided is exceeded by the worst case build requirements.  Options for reducing the build requirements include: [1] orienting the modular coils to be normal to the vacuum vessel (saves 1" over the worst case) [2] radially translating the vacuum vessel inward after the modular coils have been slid over it (saves 1" if the pre-translated position does not create an interference outboard with the NB) and [3] reduce the envelope available behind the first wall from 4.5cm to whatever amount is required to provide an adequate SOL (2-4cm).  Art Brooks will use Nelson's guidance in generating a vacuum vessel shape and a trajectory for the modular coils during field period assembly.  Target date for defining the vacuum vessel shape is late January.

Jim Chrzanowski presented concerns about the electrical insulation, which were echoed by Raki Ramakrishnan.  Chrzanowski believes that such thin turn and ground insulation really elevates the risk of an electrical failure in the modular coils.  An alternate (thicker) insulation scheme was proposed.  Chrzanowski also advocated using copper foil rather than copper mesh to preclude the fibers in the mesh compromising the insulation.  Fan will evaluate the cooldown time with the thicker insulation.  Williamson will define the winding pack geometry for the M50 coils to determine if the reduced linear current density metric in the optimizer really does lower the copper current density in the coils.  Target date for completing these activities is mid-January.