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Unternehmung WENDELSTEIN 7-X Max-Planck- Institut für Plasmaphysik Torsten Bräuer1CMSC, Charlotte, July 2008 High geometric precision in the construction.

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Presentation on theme: "Unternehmung WENDELSTEIN 7-X Max-Planck- Institut für Plasmaphysik Torsten Bräuer1CMSC, Charlotte, July 2008 High geometric precision in the construction."— Presentation transcript:

1 Unternehmung WENDELSTEIN 7-X Max-Planck- Institut für Plasmaphysik Torsten Bräuer1CMSC, Charlotte, July 2008 High geometric precision in the construction of the WENDELSTEIN 7-X fusion experiment T. Bräuer Max-Planck-Institut für Plasmaphysik Unternehmung WENDELSTEIN 7-X D Greifswald, Wendelsteinstraße 1 Content:Fusion basics and assembly strategy Second order datum point system on components Survey of first magnet half module Conclusion, outlook Fusion Experiment WENDELSTEIN 7-X

2 Unternehmung WENDELSTEIN 7-X Max-Planck- Institut für Plasmaphysik Torsten Bräuer2CMSC, Charlotte, July 2008 WENDELSTEIN 7-X is a fusion experiment ! Physical Aim: Prove of the stellarator principle as a realistic concept for a future power plants but no break even, no Tritium Control of a plasma at very high temperatures of 100 Mio Kelvin Quasi stationary operation Technical aim: Construction of the device under industrial like conditions Very tight collaboration with manufacturers Creation of a very strong, very precise magnet field with a relative accuracy of 1...2·10 -4 WENDELSTEIN 7-X: fusion basics

3 Unternehmung WENDELSTEIN 7-X Max-Planck- Institut für Plasmaphysik Torsten Bräuer3CMSC, Charlotte, July 2008 Design scheme of W7-X Main dimensions of W7-X Main radius:5.5m High: 5.5m Mass:725t 50 non planar coils (NPC) (Ø 3.0 m, m = 5 t) 20 planar coils (PLC) (Ø 3.5 m, m = 2 t) Coil support structure (CSS) Plasma vessel (PV) Outer vessel (OV) WENDELSTEIN 7-X: assembly strategy Fivefold symmetry of torus Flip symmetry of a module

4 Unternehmung WENDELSTEIN 7-X Max-Planck- Institut für Plasmaphysik Torsten Bräuer4CMSC, Charlotte, July 2008 Fivefold and flip symmetry: Fivefold symmetry: 5 identical modules with 10 NPC and 4 PLC, CSS, PV Flip symmetry: 2 flip symmetric half modules per module 5 NPC und 2 PLC per half module Flip symmetric half modules of CSS Flip symmetric half modules of PV WENDELSTEIN 7-X: assembly strategy

5 Unternehmung WENDELSTEIN 7-X Max-Planck- Institut für Plasmaphysik Torsten Bräuer5CMSC, Charlotte, July 2008 Steps of half module assembly: 1.Adjustment of coils Accuracy requirements: 0.5 … 1.5 mm 2.Adjustment of coil support structure Accuracy requirements: 1.0 … 1.5 mm WENDELSTEIN 7-X: assembly strategy

6 Unternehmung WENDELSTEIN 7-X Max-Planck- Institut für Plasmaphysik Torsten Bräuer6CMSC, Charlotte, July 2008 Module and torus assembly: 3.Two half modules are jointed together 4.Module is lowered in half shell of outer vessel and adjusted to final position WENDELSTEIN 7-X: assembly strategy

7 Unternehmung WENDELSTEIN 7-X Max-Planck- Institut für Plasmaphysik Torsten Bräuer7CMSC, Charlotte, July 2008 Adjustment of components: mainly done by Laser-Tracker (LTD) 6 … 12 datum points per component Adjustment residual:0.5 … 1.5 mm Survey accuracy:0.2 … 0.3 mm Final surveys and documentation: Mainly done by photogrammetry Short survey time Flexible lines of sight and camera positions possible Survey accuracy:0.2 … 0.4 mm Access to datum points becomes more and more difficult with progress of assembly due to using fitted holes for assembly purposes and blocking of lines of sight by components and staff folders Creation of a second order datum point system with a high number of points is necessary ! WENDELSTEIN 7-X: assembly strategy

8 Unternehmung WENDELSTEIN 7-X Max-Planck- Institut für Plasmaphysik Torsten Bräuer8CMSC, Charlotte, July 2008 WENDELSTEIN 7-X: second order datum points Half module of support structure: Size [m]: 1,5 x 2,5 x 2,5; weight 5 t Creation of a second order datum point system for photogrammetry on the components Non planar coil: size [m]: 2,5 x1,5 x 3,5; weight 5.5 t Usually 12…20 original datum points per component Installation of additional 200 second order points for photogrammetry Roughly 200…300 pictures necessary Roughly 1day

9 Unternehmung WENDELSTEIN 7-X Max-Planck- Institut für Plasmaphysik Torsten Bräuer9CMSC, Charlotte, July 2008 Creation of a second order datum point system for photogrammetry on a coil sticky targets on the coil Support P1 Stand foot 2 Stand foot 1 Support M1 a. 2 Aux. point 3 Coil support 1 a. 2 Ref. points 3.5m Coil with original datum points Feature targets for using in fitted holes, i. e. original datum points Usually 12…15 original datum points per coil 200 new points per coil Comparison of photogrammetry and Laser- Tracker at 15 datum points WENDELSTEIN 7-X: second order datum points

10 Unternehmung WENDELSTEIN 7-X Max-Planck- Institut für Plasmaphysik Torsten Bräuer10CMSC, Charlotte, July 2008 Number of points: 221 Number of surveys: 6 Mean RMS: 42µm Conditions: No air condition Different operators For each survey a new set up of scale bars and coded targets Removing and replacing targets of datum holes 32%68% Accuracy analysis of second order datum points: LTD repeatability accuracy (σ): mm WENDELSTEIN 7-X: second order datum points Result: Under real conditions the second order datum points show additional but acceptable uncertainties and can be used in later surveys Number of points: 15 RMS:0.17 mm

11 Unternehmung WENDELSTEIN 7-X Max-Planck- Institut für Plasmaphysik Torsten Bräuer11CMSC, Charlotte, July 2008 WENDELSTEIN 7-X: Survey of first magnet half module Situation for survey of magnet half module: Two assembly stands next to each other Workflow in work shop is ongoing (crane, transport, …) No air condition Volume of half module 4 x 5 x 4 m³ Max. high over ground: 6m Lots of fixing structures, platforms …

12 Unternehmung WENDELSTEIN 7-X Max-Planck- Institut für Plasmaphysik Torsten Bräuer12CMSC, Charlotte, July 2008 WENDELSTEIN 7-X: Survey of first magnet half module Situation for survey of magnet half module: Access to the coils is blocked by: Machine table at bottom Support structure at inner side Fixing structures at back, left and right

13 Unternehmung WENDELSTEIN 7-X Max-Planck- Institut für Plasmaphysik Torsten Bräuer13CMSC, Charlotte, July 2008 WENDELSTEIN 7-X: Survey of first magnet half module Results of photogrammetry survey: accessibility of datum points 5 independent surveys Up to 750 pictures per survey First order datum points: Total number at all coils: 152 Accessible by photogrammetry: 53 Accessible by Laser-Tracker: 57 (only by using of T-Probe) Second order points: Total number at all coils: 1544 Accessible 780

14 Unternehmung WENDELSTEIN 7-X Max-Planck- Institut für Plasmaphysik Torsten Bräuer14CMSC, Charlotte, July 2008 AAB13AAB22AAB45AAB51AAC13AAC51AAB17 WENDELSTEIN 7-X: Survey of first magnet half module Results of photogrammetry survey: comparison of actual and nominal coil position Required adjustment tolerance: 1.5 mm Maximum deviation: 1.3 mm Est. repeatability accuracy of survey (68%): 0.25 mm Cross check with Laser- Tracker survey shows similar results (see below) Actual coil positions meet the tolerance requirements

15 Unternehmung WENDELSTEIN 7-X Max-Planck- Institut für Plasmaphysik Torsten Bräuer15CMSC, Charlotte, July 2008 Repeatability accuracy analysis: 32%68% Number of points: 1198 Mean RMS: 0.25 mm WENDELSTEIN 7-X: Survey of first magnet half module Number of surveys: 5 Duration of all 5 surveys:1d 2 operators 1 camera In all surveys the same set up of scale bares and coded targets No air condition Ongoing workflow in workshop

16 Unternehmung WENDELSTEIN 7-X Max-Planck- Institut für Plasmaphysik Torsten Bräuer16CMSC, Charlotte, July 2008 One Laser-Tracker survey (Laser-Tracker used with T-Probe) Duration:1d Maximum deviation of a coil measured by Laser-Tracker: 1.41 mm Meets the tolerance requirement Average of 5 photogrammetry surveys Transformation of photogrammetry to Laser-Tracker survey Cross check with Laser-Tracker: WENDELSTEIN 7-X: Survey of first magnet half module number of points: 29 Mean deviation: 0.22 mm RMS: 0.25 mm

17 Unternehmung WENDELSTEIN 7-X Max-Planck- Institut für Plasmaphysik Torsten Bräuer17CMSC, Charlotte, July 2008 WENDELSTEIN 7-X: Conclusion, outlook Conclusion, outlook : Coils of fist magnet half module have been assembled inside required tolerance! Assembly methods have been proofed and can be used for future modules Assembly is feasible under industrial like conditions, especially under fast rate of construction Photogrammetry has been proofed as a reliable and fast survey technique for final surveys Accessibility can be improved by a second order datum point system for photogrammetry, especially for the next assembly steps:module assembly assembly of torus Second order datum points show an acceptable increase of uncertainty New generation of cameras will be tested to reduce survey time and improve accuracy The experiment WENDELSTEIN 7-X will go into operation in 2014 !


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