1. NCSX WBS 17 Design Status Informal Update January 6, 2005 NCSX

2. January 6, 20052 WBS 17 Scope Old: –WBS 171 provides the cryostat insulation system to isolate the stellarator from thermal load and atmospheric exposure including moisture –WBS 172 provides the radially-translating base support structure to allow machine assembly and project-long gravity support / CTE compliance New: –WBS 17 was selected as the home for the VVSA spacer assembly fixtures

3. NCSX January 6, 20053 WBS 171 Approaches CDR Approach: –The CDR plan for the cryostat was an assembled frame of rigid supports which would be subsequently insulated with urethane or other foam in a manner similar to that of large, rigid LN2 vessels –Pro: Cost effective –Con: Extremely difficult to perform without a mess Huge ES&H issue (methylene di-isocyanurate emerging from firehose) Access to machine would require cutting and subsequent re-spray to restore

4. NCSX January 6, 20054 WBS 171 Approaches (cont.) Current Approach: –A system of bolt-together insulation modules (J. Rushinski) has been designed –Pro: Demountable, no cutting and subsequent spraying to restore –Each fundamental module form can be configured with a blank insert or a custom insert for port extensions, coil services, etc. –Potential for large volume production runs –Joints, midplane supports need additional design work

5. NCSX January 6, 20055 Fiberglass Construction Approx wt. 8,000 # (As Shown)

6. NCSX January 6, 20056 WBS 171, Insulation Penetrations –Use of Robert Childs’ (C-Mod) system of Inspec Solimide foam with inner and outer fiberglass/silicone vapor barriers – No re-invention here Bulk Insulation –Two part foam has been largely dismissed. NCFI, the Shuttle’s foam supplier, cites CTE concerns that are best avoided if at all possible. –Martin Marietta/New Orleans, Kennedy Space Center, and NCFI seem to be under a gag order on the topic of external tank insulation topics. The NCFI person threw a bone with his “avoid two-part” comment Anecdotes available

7. NCSX January 6, 20057 WBS 171, Insulation (continued) Bulk Insulation, continued –Dow’s Trymer 2000/4000 polyisocyanurate custom-cut board stock seems a best candidate for filling insulation modules K=.19 BTU/in*hr/ft**2 or R-6.5/in Lowest available CTE for rigid pedestrian stock Similar to C-Mod approach Small gaps in layered fill can be filled with expanding polyurethane foam with tolerable personnel protection measures

8. NCSX January 6, 20058 WBS 172 Approach Approach: The spirit of the CDR design is largely embraced Gone, however, are the tri-axial thermal breaks in each of 12 towers

9. NCSX January 6, 20059 WBS 172 Approach (continued) Each column top is provided with a Lubrite (grease impregnated bronze) skid plate familiar in oil patch industries. The skid plates (shown in brown) reside just below the tower finials that actually penetrate the cryostat. The above skid plate with appropriate steering/capturing hardware render the triax design unnecessary Concerns regarding toroidal loops will drive the presence of DC breaks in the 12 horizontal pipe sections

10. NCSX January 6, 200510 WBS 172 Approach (continued) T. Brown requests an iteration on the intersection of the tower finials with the radial tie castings Other: The 12 DC breaks for the horizontal stiffening tubes will be provided without argument. –An electro-magnetics analysis of any need for loop interruption near the floor is probably prudent. –Breaks cost $$$$. The rebar in the floor is certainly without isolation.

11. NCSX January 6, 200511 WBS 172 New Scope Recently added to WBS 17 is the mechanical manipulator plan for supporting the VVSA spacers during the final assembly motions. While this scope does not initially appear difficult, the designer will better know in one or two weeks if any significant issues exist.

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