Attachments

Update on diagnostics integration (Brent Stratton)
Feasibility of bolted VV joint (Mike Cole)
Modular coil clamp design (Kevin Freudenberg)
Status of Type C winding form (Williamson)

Discussion

Brent Stratton provided an update on diagnostics planning and integration. He reviewed changes in the port geometry since the CDR, proposed a naming scheme for ports, and reviewed electrical feedthrough requirements for diagnostics. Stratton also reviewed requirements for the SRX array.

Mike Cole and Paul Goranson provided an assessment of the bolted vacuum vessel joint. The bottom line was that there did not appear to be enough room for a bolted joint between the vacuum vessel and plasma. A recommendation was made and accepted to adopt a welded joint concept. The welded joint concept shown was primitive. Features such as a backing plate (to prevent damage to the insulation during welding), a cover plate (to facilitate leak checking and mitigate concerns about virtual leaks in structural welds), and a groove for diamond wire cutting were absent. The R&D required to manage the risks associated with the welded joint, such as distortion due to field welding, was not identified. Mike Viola agreed to forward to ORNL some welded joint approaches recommended by the VV suppliers.

Brad Nelson presented the current modular coil clamp design. The clamp design features a slanted surface on the side of the clamp to permit sliding relative to the top surface. Larry Dudek discussed the PPPL experience with the clamps that were fabricated for the racetrack coil. When bolting the clamps together, there is no sliding because the bolts go into shear as soon as the two surfaces come in contact. Nelson indicated that it was necessary to take the original bolts after potting and replace them with bolts with an undersized shank in order to permit this motion. Nelson also stated that it was necessary to back off the bolts attaching the clamps to the structure after potting by a fraction of a turn to allow for thermal growth.

There was considerable discussion as to whether a low modulus clamp (G10 or ScotchPly) might provide a simpler, more reliable solution. There was also considerable discussion on how the thick, fiberglass VPI mold (which had not been included in the thermal models) would affect thermal perfromance.

David Williamson provided an update on modeling the Type C winding form. Completion of the prototype model is targeted for August 4.