Specific Features of Wendelstein 7-X Structural Analyses

Fusion Engineering and Design

et al. 2015

Self Cite

Please cite this article in press as: P. van Eeten, et al., Features and analyses of W7-X cryostat system FE model, Fusion Eng. Des. (2015), http://dx.a b s t r a c t The Wendelstein 7-X stellarator is presently under construction at the Max-Planck-Institute for Plasma Physics in Greifswald with the goal to verify that a stellarator magnetic confinement concept is a viable option for a fusion power plant.The main components of the W7-X cryostat system are the plasma vessel (PV), outer vessel (OV), ports, thermal insulation, vessel supports and the machine base (MB). The main task of the cryostat system is to provide an insulating vacuum for the cryogenic magnet system while allowing external access to the PV through ports for diagnostic, supply and heating systems.The cryostat is subjected to different types of loads during assembly, maintenance and operation. This ranges from basic weight loads from all installed components to mechanical, vacuum and thermal loads. To predict the behavior of the cryostat in terms of deformations, stresses and support load distribution a finite element (FE) global model has been created called the Global Model of the Cryostat System (GMCS).A complete refurbishment of the GM CS has been done in the last 2 years to prepare the model for future applications. This involved a complete mesh update of the model, an improvement of many model features, an update of the applied operational loads and boundary conditions as well as the creation of automatic post processing procedures.Currently the GMCS is used to support several significant assembly and commissioning steps of W7-X that involve the cryostat system, e.g. the removal of temporary supports beneath the MB, transfer of the PV from temporary to the final supports and evacuation of the cryostat. In the upcoming months the model will be used for further support of the commissioning of W7-X which includes the first evacuation of the PV.

Section: Introductionmentioning

confidence: 99%

Features and analyses of W7-X cryostat system FE model

Eeten

Bräuer

Fusion Engineering and Design

et al. 2015

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“…In order to avoid false alarm and to guarantee smooth operation, it is necessary to implement a compensation of the effect using signals of temperature sensors located on the cryogenic structures. Moreover, it is expected that magnetic 2.5 T configurations are to be extended not only to several reference magnetic configurations fully analyzed before [4] (see Table I) but also to many other regimes proposed by physicists with the goal to scan different plasma parameters. Both of these facts are considered in the present preparation activities.…”

Section: Preparation For Next Phase Of Operation a Generalmentioning

confidence: 99%

“…In order to assess the mechanical integrity of the MS during design, assembly, commissioning, and first phase of operation, two global FE models in ANSYS and ABAQUS were intensely used and benchmarked [4]. The large amount of nonlinear components in the MS makes its behavior prediction challenging.…”

Section: Introductionmentioning

confidence: 99%

Mechanical Monitoring Issues in Preparation to Next Step of Wendelstein 7-X Operation

IEEE Trans. Plasma Sci.

Carls

Zhu

et al. 2018

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The largest modular stellarator Wendelstein 7-X (W7-X) has successfully passed the first phase of operation in Greifswald, Germany. The sophisticated W7-X superconducting magnet system (MS) with its nonlinear support system has been carefully monitored using an extensive set of mechanical and temperature sensors. This paper focuses on detailed consideration of cyclic MS behavior during operation with limiter configurations of plasma. Measurement results are carefully compared with predictions from updated numerical models and critical issues are highlighted. As a result, the structural monitoring tool is extended to follow enhanced requirements and expectations. This paper is a preparation for upcoming more demanding phases with longer plasma pulses to guarantee safe and reliable W7-X operation with different divertor and scraper element configurations. The procedure to establish required sensor configurations, and to analyze and release new plasma regimes being compatible with W7-X component design values is also described. Index TermsNumerical finite-element (FE) analysis, stellarator, structural monitoring, Wendelstein 7-X (W7-X).

“…To investigate the deformations/deflections of the cryostat, a finite element (FE) model has been set up, the "global model of the cryostat system" (GMCS) [17,18]. This model has been used to perform detailed calculations for different load cases (cryostat and PV evacuation, PV baking, normal operation with PV and OV evacuated, etc.).…”

Section: Structural Investigations Of the Cryostatmentioning

confidence: 99%

Experience with the commissioning of the superconducting stellarator Wendelstein 7-X

Bosch

Fusion Engineering and Design

Brakel

et al. 2015

The super-conducting stellarator Wendelstein 7-X is presently under construction at the Max-Planck-Institute for Plasma Physics in Greifswald, Germany. Assembly of the device is almost completed and the periphery systems and the diagnostic and heating systems are well advanced. Commissioning of the device has been prepared over the last two years and has started in April 2014. This is the first time since decades that a superconducting fusion device is commissioned in Europe.