NCSX VVSA / MCWF FDR A Systems Engineering Perspective Wayne Reiersen Bob Simmons NCSX VVSA / MCWF FDR May 19-20, 2004 PPPL

19-20 May 2004NCSX VVSA / MCWF FDRReiersen 2 Systems Engineering “…the discipline of managing the development of complex systems” Translate physics requirements into engineering language Allocate performance Requirements to subsystems General Requirements Document (GRD) Subsystem Development Spec (SRD) Physics Requirements Document (PRD) Develop Pre-conceptual Design PVR Define characteristics of each part or assembly required for subsystem to work as designed Component Product Spec Fabricate part or assembly PDR FDR Develop Conceptual Design Develop Preliminary Design Develop Final Design We know what we have to do We know how we are going to do it We know it will work We are ready to build it Component MIT/QA Plan Define how required characteristics will be verified. Integrate in mfg process. CDR

19-20 May 2004NCSX VVSA / MCWF FDRReiersen 3 The Vacuum Vessel Sub-assembly (VVSA) and Modular Coil Winding Forms (MCWF) are the subjects of this FDR The VVSA is the long lead time procurement for constructing the VV The VVSA includes the field period assemblies, port extensions (to the first flange), spacers, and end pieces The Vacuum Vessel (WBS 12) also includes… NB transition port Removable port extensions Heating and cooling distribution Thermal insulation Local I&C A comprehensive FDR will be held for the other subsystem elements in Feb ‘05

19-20 May 2004NCSX VVSA / MCWF FDRReiersen 4 The Vacuum Vessel Sub-assembly (VVSA) and Modular Coil Winding Forms (MCWF) are the subjects of this FDR MCWFs are the long lead time procurement for constructing the modular coils The MCWFs include 18 winding forms (6 of each type) complete with a poloidal break The Modular Coils (WBS 14) also include the winding assemblies and local I&C A comprehensive FDR will be held for the other subsystem elements in September ’04 (Type C)

19-20 May 2004NCSX VVSA / MCWF FDRReiersen 5 SOWs, product specs, MIT/QA plans, mfg procedures, and travelers have been developed and refined during prototype fabrication Supplier QA Program Documentation Product Manufacturing, Inspection, Test, and Quality Assurance (MIT/QA) Plan Defines all steps in mfg process Defines all QC inspections and tests Identifies supporting procedures Identifies traveler to be used Statement of Work (SOW) Defines work requirements Defines QA program requirements Identifies deliverables Product Specification Defines product Identifies applicable models and drawings Defines technical requirements Defines how required characteristics will be verified Subject to NCSX approval Derived from SRD and subsystem design constraints Mfg procedures Travelers Subject to revision control Only minor modifications needed for the production articles Already reviewed

19-20 May 2004NCSX VVSA / MCWF FDRReiersen 6 VVSA and MCWF models and drawings have been completed The models are part of an integrated model of stellarator core Essential for establishing envelopes and avoiding interferences Facilitates interface definition with other stellarator core components The drawings are used to communicate information (e.g. tolerances and surface finishes) that cannot be readily incorporated into a model

19-20 May 2004NCSX VVSA / MCWF FDRReiersen 7 VVSA and MCWF drawings are in final review Work in progress Complete final design (model development) Generate drawings from models for procurement package Perform final checking  Checker  Weld engineer  Design integration  Cog engineer Perform final checking of clearances Approve drawings for fabrication Conduct VVSA / MCWF FDR Resolve issues Release final procurement package Review of models and drawings by suppliers Hardcopies of models and drawings provided to the Review Committee for their consideration Work in progress

19-20 May 2004NCSX VVSA / MCWF FDRReiersen 8 Final clearance checking of assy fit-ups is underway Many interference checks necessary Assembly fit-ups require following complex 3D trajectories  MC-to-MC to form 3-coil modules  Sliding a 3-coil module over VV and into mating 3-coil module  Sliding a 3-coil TF assembly over the 3- coil module  Concurrent positioning of completed field period assemblies and spacers (6 pieces) Interference with horizontal port Interference with vertical port These interferences were uncovered during interference checking and have been resolved

19-20 May 2004NCSX VVSA / MCWF FDRReiersen 9 Final clearance checking for the port extensions is also underway Clearance checking between long port extensions and modular coil assemblies is also complex  Multiple temperature conditions (MC RT/77K, VV RT/350C)  1 atm pressure loads and appendage loads cause deflections in the shell and port extensions – these are included in the tolerance budget  Clearances to TF/PF coils will also be checked Interference checks are important all along the way, but especially after all changes have been made

19-20 May 2004NCSX VVSA / MCWF FDRReiersen 10 VVSA design satisfies design criteria VV configuration is unique Highly shaped shell Numerous long, spindly ports High temperature (350C) bakeout Numerous loads analyzed Gravity 1 atm pressure Bakeout Disruptions (midplane and off-midplane) Design changes were incorporated as a result of analysis to make the design more robust Appendage weights will be administratively controlled Seismic and unbalanced loads are currently being analyzed Independent calculations provide confidence in these conclusions Design basis analyses are being formally documented and checked

19-20 May 2004NCSX VVSA / MCWF FDRReiersen 11 MCWF design also satisfies design criteria Several different and independent modeling approaches used Global linear models (Myatt and Fan) Local non-linear models (Freudenberg) Bounding values used for winding stiffness - MCWF stresses are within static allowables over the expected range of stiffness No potential changes in the winding design are expected to impact the MCWFs Winding pack envelope fixed Permanent clamps are spaced every 6” Fatigue properties will be established Custom alloys developed by suppliers Test coupons to be cut from prototype casting risers and tested Displacements under load preserve stellarator symmetry and appear to be acceptable (Strickler and Brooks) Design basis analyses are being formally documented and checked

19-20 May 2004NCSX VVSA / MCWF FDRReiersen 12 Mfg development and prototype fabrication efforts are drawing to a successful conclusion Roles and responsibilities within teams and with NCSX established Reporting framework established Weekly reports Earned value reports Periodic teleconferences and site visits 2-way transfer of CAD data is routine Quality requirements are understood and captured in MIT/QA Plans Prototype fabrication efforts have … Proven the manufacturability of the VVSA and MCWF designs Provided an objective measure to differentiate between potential suppliers Having two potential suppliers for each production contract has… Maintained downward pressure on costs Provided the project with options to mitigate schedule risks Prototyped how we are going to manage these contracts

19-20 May 2004NCSX VVSA / MCWF FDRReiersen 13 Design verification is a key element in our SE program Independent modeling approaches used throughout design development All design basis analyses will be formally checked Our suppliers have been involved in verifying the manufacturability of the VVSA and MCWF designs Fabrication of prototypes Review of models and drawings Advance flow solidification modeling and machining reviews of Types A and B Many topical peer reviews were conducted in the 2-month period preceding this FDR to uncover potential problems The NCSX Project is looking forward to the Review Committee’s expert input in the form of recommendations and responses to the charge questions