NSTX-U construction related analysis issues

The National Spherical Torus Experiment Upgrade (NSTX-U) is currently under construction at Princeton Plasma Physics Laboratory (PPPL) It is scheduled to start operations early in 2015. Upgrade designs were analyzed and qualified prior to the beginning of construction, but many issues arose during manufacture and assembly that required adjustments in design and analysis of components. Some designs relied on testing that occurred after final design when the actual material and processes were selected by vendors or in-house shops. Design of some components, like the bus bars, was deferred until field run interferences could be identified. Some components used materials that did not meet original specifications. New materials or processes had to be found and components sometimes needed requalification. PPPL responsible or "Cognizant Engineers" (COG's) and analysts worked closely to work out resolution of issues and perform redesign and reanalysis. Revisions to calculations were prepared and filed. Some significant items addressed during the construction period (or Title III in DOE parlance) are selected for more detailed discussion.