Structural Analysis of the Waveguide Supports of the Ex-Vessel Plasma Position Reflectometry System in ITER

An International Thermonuclear Experimental Reactor (ITER) plasma position reflectometry (PPR) diagnostic system is designed to analyze the plasma edge electron density profile at four representative positions that are strategically distributed throughout the vacuum vessel. Every transmission line (TL) in the PPR is routed from the corresponding port-plug, through the port-cell and gallery, to the Diagnostic Area or Assembly Hall Building. Ex-vessel TLs are made up of oversized circular corrugated waveguides (WGs), which are positioned by adjustable supports. These WG supports are of utmost importance, not only to avoid inducing stresses on the TL in the assembly process, but also to ensure the performance of the PPR system. The current work is focused on the structural analyses of the WG supports when bearing the mechanical loads calculated in a previous global analysis of the entire PPR system. The finite element analysis (FEA) model of the WG support includes the bolt and nut assemblies, so that appropriate selection of their preload can be evaluated. The main objective of the analysis is to assess the structural integrity of the WG support according to the design and construction rules for mechanical components of nuclear installations (RCC-MR) code. WG support deformations are also calculated for load cases in Categories I and II, to assure that the PPR system maintains the service function with the required performance.