NCSX Mod Coil C1 features requiring rework at PPPL

This report focuses on the issues that could delay the start of coil winding and may require rework. Additional inspection(s) with the focus on FPA and Machine Assy should be performed. Some of these issues are NCRs for MTM. These items should be corrected by MTM prior to shipment of subsequent coils. The other items are design details that could be changed so they are not repeated in subsequent coils.

Dimensional NCR Height of “shoulder” below the winding surface (SE sh2) should be 2.69” This space is required for the winding clamp studs. On “D-Datum” side there are 2 areas that do not conform. From clamp locations the height ranges from 1.68” to 2.38”. Possible solution is to grind material away at these locations. Between clamp locations the height ranges from 1.43” to 2.25”. This condition does not exist on the “E-Datum” side.

Surface finish NCR Surface finish along the shoulder below the winding surface is supposed to be 250 rms but is actually 500 rms (or much worse). Technicians are warning that stud welding may be problematic and that these areas may have to be ground/polished. Studs can alternatively be TIG welded, but that

Poloidal Break The poloidal break appears to have been machined as a “straight” section and does not conform to the curved profile of the winding surface. At the interface between the break and the structure, there are discontinuities in the winding surface that must be smoothed out. There is risk of contaminating and compromising the break if filing or grinding are performed in-situ. This may be an MTM NCR – further measurement with Romer will be required to make final determination.

Poloidal Break The thickness of the flanges of the poloidal break is 0.850”. We believe that the design value is much greater (1.25” ??). Further investigation is required to determine whether this is a structural problem. Possible MTM NCR.

Female Wing The area of the C-coil where the wing protrudes into the adjacent coil is too high resulting in potential clearance issues during field period assy. This is remedied by grinding away ~ 1/8” thickness over a ~one square foot area of the as-cast surface. This is a design issue, not an MTM NCR

Large flange C-bore The counterbore of one of the “E-Datum” flange bolt holes is shrouded by the casting. It appears that a “standard” dielectric cup will not fit into this location. Solution is to come up with an alternative dielectric shroud, or grind away the material that projects over the hole.

Cooling line holes thru casting The holes for the cooling tubes through the casting are too small. They should be enlarged. The holes for the cooling tubes (bottom side of the casting) are located such that there are interferences with the shoulder of the and with the flange bolts/dielectric cups. These are both design issues, not MTM NCRs

Spherical seats The spherical seats (coil to coil positioning during FPA) are appear to not be machined accurately. There are ridges and other material protrusions on what should be a precision feature. Additional dimensional inspection is required to determine if they are dimensionally acceptable. We may have to grind/hone these features to a better finish. This is probably an MTM NCR.