Structural Analysis of Divertor and Baffel of Steady State Tokamak (SST-1) for Electromagnetic Load and Thermal Loads Using Ansys Software

Abstract

With the advancement of developing technology for achieving fusion energy as the viable global energy source, the events of launching projects to develop advanced fusion devices are on their way in almost all countries. Tokamak is a Russian acronym for toroidally confined magnetic device for producing and confining plasma. Recent tokamaks are built with an aim to confine plasma for a long pulse duration of about 1000 seconds or more. Such an experimental plasma fusion device to operate at steady state called Steady State Superconducting Tokamak-1 (SST-1) is being developed at the Institute for Plasma Research, India. The machine will be operating with hydrogen plasma for a steady state operation of 1000 seconds pulse with the help of superconducting electromagnets and related technologies. From the history of existing tokamaks, it is obvious that the electromagnetic loadings due to plasma instabilities are highly detrimental in nature. These electromagnetic loads are the design drivers for all the subsystems components and supporting structures of all subsystems of the tokamak. Up to recent days, all the above mentioned designs have been achieved with dedicated software codes that are developed at the user ends. The codes are having a limitation of carrying out the simulation in actual model or in three dimensions. In addition, the codes are inbuilt with more approximations both in geometries as well as the type of loadings. Hence a software program with more promising results is sought by the fusion community. ANSYS is the software that has been keenly programmed with many a sort of problems in electromagnetic for which ANSYS has provided more accurate and better solution for the actual geometry in existence.

As a part of dissertation work, a detailed study on the Structural analysis for thermal and electromagnetic loads at transient conditions for divertor and baffles is needs to carry out. The eddy currents are produced on the stabilizer cage surrounding the plasma in SST-1 due to the change in position of plasma due to instabilities. The resulting electromagnetic forces on components due to the induced currents have to be analyzed for the components. The divertor and baffle plates are designed indigenously and final design has been completed and the component is under fabrication. The actual geometry of stabilizers has been modified with bolt holes and other requirements in the tokamak. The vacuum vessel of sst-1 machine will be baked to a temperature of 200 0 C and component will be at 350 0 C. There will be induced thermal loads on the components due to differential thermal expansion during the baking process & the induced stresses have to be analyzed.

The project work has to evaluate the exact currents that will be induced on the components with the actual modeling of geometry and with a mapped meshing. The works also involves the theoretical back for the complete mechanism to compare the analysis results.