M. Sochor

Bio: M. Sochor is an academic researcher from Max Planck Society. The author has contributed to research in topics: Wendelstein 7-X & ASDEX Upgrade. The author has an hindex of 5, co-authored 12 publications receiving 89 citations.

Structural analysis of W7-X: Overview

Abstract: The Wendelstein 7-X (W7-X) modular stellarator is in the assembly phase at the Max-Planck-Institut fur Plasmaphysik (IPP) in Greifswald, Germany. The goal of the project is to demonstrate that this type of machine is a viable option for a fusion power-plant. The “pentagonal” magnet system of the machine encompasses 50 non-planar and 20 planar superconducting coils with sophisticated support structure. Structural reliability of components as well as resulting deformations and displacements during various modes of operation have to be considered not only for the magnet system but also throughout the whole cryostat whose main components are the plasma vessel, outer vessel, ports, and thermal insulation. A reliable prediction of the W7-X structural behaviour is only possible by employing complex finite element (FE) simulations with a hierarchical set of FE models. A special strategy has been developed and implemented for the task. The design is basically completed, main parameters are defined, and most of the W7-X components are manufactured. Therefore, the focus in the analysis is being shifted to the creation of parametric FE models which allow performing fast analyses of possible non-conformities, changes in the assembly procedure, and future exploration of operational limits. This paper gives an overview of the implemented analysis strategy, the applied safety margins, and focuses on the most remarkable results.

Strategy of Structural Analysis of W7-X Magnet System

Abstract: The Wendelstein 7-X (W7-X) stellarator project goal is to demonstrate that the stellarator is a viable option for a fusion power-plant. The W7-X is in advanced construction phase and has entered the assembly phase in Greifswald, Germany. The W7-X "pentagonal" basic magnet system is highly sensitive to the parameter variations; therefore the strategy of the structural analysis with the ultimate goal to create a tree of numerical models, which has to reliably predict stellarator structural behaviour, is in development and implementation phases. This paper gives an overview of the strategy and focuses on challenging boundary conditions and the most interesting results of the analyses

Structural analysis of W7-X: Main results and critical issues

Abstract: The Wendelstein 7-X (W7-X) stellarator project goal is to demonstrate that the stellarator is a viable option for a fusion power plant. W7-X is in an advanced state of construction and has entered the assembly phase at the Max-Planck-Institute fur Plasmaphysik (IPP) in Greifswald, Germany. The W7-X “pentagonal” basic magnet system is highly sensitive to parameter variations; the cryostat comprises two vessels, which are interconnected elastically by 299 ports. The strategy of the structural analysis for this complex mechanical system is being developed and implemented with the ultimate goal to create a tree of numerical models which reliably predict the stellarator structural behaviour. This paper gives an overview of the strategy, addresses the critical issues and focuses on the most interesting results of the analyses.

Main Results and Critical Issues of W7-X Structural Analysis

Abstract: The goal of the Wendelstein 7-X (W7-X) stellarator project is to demonstrate that this type of machine is a viable option for a fusion power-plant. At present the W7-X experiment is in the assembly phase at the Max-Planck-Institut for plasma physics in Greifswald, Germany. The reliable prediction of the structural behavior of the W7-X machine is only possible by employing complex finite element (FE) analyses with a hierarchical set of FE models. A special strategy has been developed for the structural analysis which is under implementation now. This paper gives an overview of the analysis strategy, the applied structural criteria and critical issues, and focuses on the most remarkable results. The main attention is paid to the components that have been changed or optimized recently.

Technical challenges in the construction of the steady-state stellarator Wendelstein 7-X

Abstract: The next step in the Wendelstein stellarator line is the large superconducting device Wendelstein 7-X, currently under construction in Greifswald, Germany. Steady-state operation is an intrinsic feature of stellarators, and one key element of the Wendelstein 7-X mission is to demonstrate steady-state operation under plasma conditions relevant for a fusion power plant. Steady-state operation of a fusion device, on the one hand, requires the implementation of special technologies, giving rise to technical challenges during the design, fabrication and assembly of such a device. On the other hand, also the physics development of steady-state operation at high plasma performance poses a challenge and careful preparation. The electron cyclotron resonance heating system, diagnostics, experiment control and data acquisition are prepared for plasma operation lasting 30 min. This requires many new technological approaches for plasma heating and diagnostics as well as new concepts for experiment control and data acquisition.

Status of Wendelstein 7-X construction

Abstract: Wendelstein 7-X (W7-X) represents the continuation of fusion experiments of the stellarator type at the Max-Planck Institute for Plasma Physics (IPP). The aim of W7-X is to demonstrate the suitability for a fusion reactor of this alternative type of magnetically confined plasma experiment. W7-X is being built at Greifswald in the northeast of Germany. The size of device (725 tons, height of 5 m, diameter 16 m) and the superconductive magnet system distinguish W7-X from earlier stellarators at IPP. The paper provides a summary of the status of the main components, the mastering of the technical challenges during component acceptance testing and during machine assembly. Latest results of the assembly work are especially highlighted. The scope of the construction of W7-X was modified and additional acceleration measures were implemented to mitigate risks and delays. Some aspects of these changes are explained in this paper.