Recent Developments of the in-divertor Optical Box of the ITER Erosion Deposition Monitor

Abstract

The primary purpose of the ITER Erosion Deposition Monitor (EDM) is to track the erosion and deposition conditions of the Divertor Vertical Targets, as well as to monitor any changes in topology and surface damage resulting from plasma-wall interactions at these targets. The optical box of this diagnostic system, which is mounted on one of the Divertor Cassettes beneath the Divertor Dome, serves to provide a rigid support and protective shielding for the optical components housed inside. The EDM is an optical diagnostic system, whose accuracy depends on the integrity of the mechanical parts. The most critical in-vessel parts of this diagnostic system can be found on one of the Divertor Cassettes of the ITER machines, exposed to high heat and electromagnetic (EM) loads. The design challenges involve finding a solution for the proper heat transfer between the different components and besides, it is creating a solid design that can withstand the loads the optical box is exposed to. To achieve the required design level, the optical box and its components went through several design changes and simulation stages. This paper focuses on the challenges of the mechanical development of the parts that can be found on the Divertor Cassette. These components are the structural elements of the optical box and the support brackets of the mirrors inside the box. The paper presents the results of the analyses and the mechanical solutions of the structure of the box and the mirror supports which could withstand the high heat load and mechanical stresses coming from the EM loads.