26 September 2001

Presentations

Minutes

The weekly project meeting was held on September 26.  Wayne Reiersen opened the meeting with a discussion of near term plans.  The first priority is developing a buildable, consistent stellarator core design.  The second priority is developing an updated set of work plans and budget allocations to carry the project through the CDR.  As a first step, Reiersen will contact WBS managers about proposing scopes of work and resource allocations through the CDR.  Feedback is requested by October 5.

Tom Brown presented recent progress on the vacuum vessel design.  He constructed a vessel using 15° segments and was able to provide a thickness up to 0.40".  (The nominal thickness is 0.375".)  The new vessel incorporates space for an inboard RF launcher.  The outboard geometry was revised to accommodate tangential NBI.  Brad Nelson observed that with the first wall being pulled back to the vacuum vessel in the region of the NBI port, more space would need to be provided.  This has the ripple effect of requiring that the modular coil closest to the NB port would also have to be moved further away.  Brown reported that Mike Cole was working on a vessel (using Brown's as a starting point) based on 7.5° segments.

Brown noted that interferences exist in the region of the 15°-30° cross-sections.  The minimum clearance is 0.65", leaving insufficient space for insulation and clamps, etc.  Brad Nelson agreed to define the minimum separation required between the winding pack and the outer surface of the vacuum vessel.

Brown's geometry was based on a geometry file that is supposed to represent the coils at operating temperature (85K).  In fact, the geometry represent the coils at room temperature.  ORNL will scale the geometry of the coils to room temperature prior building the Pro/E model.  (Nelson indicated that the correction factor would be 1.003 which would be order 4mm at the major radius.)

David Williamson provided a comparison of the 0918 and 0920 modular coil designs.  The 0918 design was aimed at minimizing the engineering difficulty while keeping the errors on the order of 0.6% average, 3% max.  The 0918 design does not appear to be buildable.  There is overlap of adjacent windings and interference between the modular coils and vacuum vessel.

The 0920 design was aimed at further relieving the engineering difficulty while allowing the errors to creep up a bit.  Williamson reported that the 0920 design did in fact relieve some of the engineering difficulty.  The overlap between modular coils M2 and M3 appears to have disappeared.  The coils are also much smoother outboard.  However, the interferences between M1 and M2 and between the modular coils and vacuum vessel are still present.  Williamson indicated that he will pursue:

Dennis Strickler reported that the errors in the 0920 design crept up to 1% average, 6% max which is roughly twice the error in the 0918 design.  He has passed these coil sets to PPPL for assessment of physics properties.  Strickler suggested that the design that is more favorable from an engineering standpoint, 0920, might be a good starting point for coupled CoilOpt-StellOpt studies.  Strickler also reported on recent enhancements to the CoilOpt code.

Brad Nelson reported that New England Wire has made 300' of conductor for us.  The nylon serve appears to be fraying.  Nelson indicated that this should not be a problem for us.  Following the meeting, Nelson provided data files defining the present first wall geometry.

Please forward any comments or corrections to reiersen@pppl.gov

(last edited on 09/27/2001 10:29 AM )