1 NCSX VV Assembly Joint Issue B. Nelson 17 Mar 2005

2 Presentation Outline Purpose of spacer and baseline design overview Alternate design Design comparison Discussion Recommendation

3 Purpose of spacer End flanges of field periods may distort due to port extension welding Spacer provided for fit-up of field periods at final assembly Assembly welds Spacer Spacer between field periods

4 Baseline spacer design Barn door (open) Facility interior Assembly welds Spacer Vessel Oversized spacer flanges are machined to match vessel profile for final assembly Weld Prep VACUUM SIDE Backing Gas VACUUM SIDE Clamp Mount holes Spacer Flex Seal with glass rope gasket* * Seal is welded to spacer. Each spacer has two, continuous, poloidal welds, as well as flex seal for backing gas and leak checking

5 Baseline spacer design requires precise measurement and machining End flanges of vessel field periods are measured after field periods are assembled, port extensions welded, and vessel locked in place relative to mod coils “Virtual” fitup is accomplished by knowing relationship between vessel flanges and mod coil positions. Mod coils dictate assembled position TF Coil Vacuum Vessel Modular Coil Coil Support Structure Vessel Port Extensions Vessel Support

6 Baseline spacer design requires special assembly motion At assembly, spacer must be rotated about radial axis and moved in radially to clear mod coil wings Simulation (courtesy of Tom Brown) predicts 1.5 inches of clearance

7 We are buying three VVSA kits from Major Tool consistent with the baseline spacer design Spacer Field Period Assembly Port extensions End Cap for leak check

8 Issues with baseline design Lack of confidence in ability to measure vessel field periods accurately enough to machine the spacer to fit within 1/8 inch J-groove weld is harder to weld than double bevel weld, welders prefer double bevel Major Tool thinks alternate design is cheaper for them to supply Special spacer assembly / manipulation fixture could be expensive Etc.

9 Alternate Design Spacer is fabricated as 5 or more splice plates, supplied by Major Tool At final assembly, splice plates are trimmed and fit into position from inside the vessel Welds are made with v-groove prep and backing rings / backing plates Cover gas is all supplied from front side Splice plates 6 inches 3/8 in max mismatch Splice plate VV period shell weld Backing ring / plate

10 Design Comparison 1800 hours, MTM est. Baseline DesignAlternate design Feature/requirementDescription cost impact critical path schedule impact Description cost impact critical path schedule impact 1Spacer configurationcomplete spool with machined flanges baseline 5 or more formed pieces -$250k 2field period assembly end configuration machined flanges weld backing ring around od incl in 1. 3measurement / modelinglaser scan of vessel & flanges $38k no- prior to asm. Same as baseline $38k0 4intermediate leak checkingblankoff flanges seal welded to gas seal rings same individual seals for each port or weld blankoff flanges to backing ring same 5spacer fitup and accommodation of misalignment spacer flanges machined, based on field period measurements $30k prior to assy, 4-6 wks. (MTM est.) individual pieces measured and trimmed and/or re- formed to fit, assume 10 pcs. $41k total of 30 plates; 1 day/plate 2 man crew 6weld prepmachined into spacer flanges (j-groove), part of 4 above edges ground to provide v- groove bevel $10k 7welding6 poloidal locations $20k 30 pcs. 16" perimeter each CONCERN: SHRINKAGE OF POL. WELDS. $20k assumed the same 8positioning at assembly3 special assembly fixtures synchronized with field period radial motion, $60k TB guessfitting & tacking pieces by hand $10k 3 wks could be reduced by teams

11 Design Comparison (2) Baseline DesignAlternate design Feature/requirementDescription cost impact critical path schedule impact Description cost impac t critical path schedule impact 9gas seal for weldingflex seal behind weld joint $1k stuff ceramic rope into flange gap at asm backing ring welded to field period assembly for poloidal welds $12kprior to asm cross backing bars for toroidal welds (?) $30k 30 10helium leak checkingsame as gas seal $4k after welding same as gas seal $0k no leak checking 11thermal insulationinsulation pre-applied to spacer $0k 0insulation pre-positioned prior to fitup of pieces $10k Pull draw string to position insul. 12coil protection during welding gas seals and thermal insulation (microtherm) same weld backing rings and thermal insulation (microtherm) same 13integration of radial portpart of spacer port of outboard spacer segment 14Drawing modificationsNone required0 Need to delete flanges, show segmentation, verify pieces can be inserted,etc. $50k2 mm ? 15Add rigidizing fixtures for alignment of VV (note: 4" from turrett to flange weld) same $18k same $18k

12 Design Comparison – Summary BaselineAlternate Technical Can’t measure Mod coils require 10 times VV accuracy Worst case requires trial fit-up Poloidal weld shrinkage not quantified? R&D could quantify J-groove not preferred weld joint Weld tests say either joint will work Vessel moves during fit-up operations Splice plates must be pre-formed to fit, not forced to fit in place Screw up the spacer machining? Must fix with weld repair Re-forming plates to fit requires on-site press and expertise or off-site forming R&D could quantify Schedule Potentially less time needed during final assembly More time needed for custom fit-up during final assembly (+4 weeks?) Cost Current baseline budget: $75k Estimated cost per chart: $171k Delta: add $96k Current baseline budget: $75k Est. cost with MTM rebate: $-18k Delta: save $93k Current baseline budget: $75k Est. cost w/o MTM rebate: $239k Delta: add $164k

13 Design Comparison – Recommendation Baseline design is feasible even if alternate has certain advantages Measurement issue must be solved for mod coil assembly Alternate will require design changes, may require additional R&D We do not want to slow down nor distract MTM Cost rebate from MTM for alternate design may not be realized Better is the enemy of good enough at this stage of project Therefore: Keep the baseline design

14 Major Tool estimates 1800 hours for splice plate fitup and welding 600 hours for each VVSA joint – 1800 hours to do all three “spacers”: 7-8 weeks Start with the panel that has the port hole. Work the way around, tacking in each panel. Then have three welders in – one at each joint simultaneously

15 Major Tool estimates $40-50k for splice plate R&D mockup From MTM to Mike Viola: 40-50K for a test spool piece same as before except without the flanges. He could have the material next week to provide. 34.5”-36” diameter ~24” wide will give enough material for 1 – 6” spool piece, 2 – 12” 8” end pieces, 2 – 1” backing strips