Design and technological solutions for the plasma facing components of WENDELSTEIN 7-X

The stellarator device Wendelstein 7-X (W7-X) is now in the final stage of assembly. All the machine components have been built and in mid 2014 the commissioning activities should start. The first objective of W7-X is to prove the stellarator optimization principles, i.e., to reach at least the same confinement quality as a similar sized tokamak. The second objective is to demonstrate stable high-power steady-state operation. In the present paper, after a short description of the device, the ongoing activities to complete the construction will be summarized, focusing on the optimization of the layout of the torus hall and on the completion and assembly of the in-vessel components. The main lessons learned during the assembly will be presented as well as the application of the quality control, the handling of non-conformities and the design change procedures. The planning of the commissioning sequences to perform the integral tests of the major W7-X systems is discussed in order to prepare the W7-X device to start plasma operation.

Section: The W7-x Machinementioning

confidence: 99%

Wendelstein 7-X—Status of the project and commissioning planning

Gasparotto

Baylard

Bosch

et al. 2014

“…Each divertor unit has ten target modules. Each module is composed of 8-12 TEs and in total there are 890 TEs for the whole divertor system [8]. A prototype was developed for the horizontal HHF target module 09 (TM-H09), see figure 2, with twelve TEs.…”

Section: Hhf Divertor Targetsmentioning

confidence: 99%

Thermo-mechanical analysis of Wendelstein 7-X plasma facing components

Peng

Bykov

Köppen

et al. 2013

Self Cite

The stellarator experiment Wendelstein 7-X (W7-X) is designed for stationary plasma operation (30 minutes). Plasma facing components (PFCs) such as the divertor targets, baffles, heat shields and wall panels are being installed in the plasma vessel (PV) in order to protect it and other invessel components. The different PFCs will be exposed to different magnitude of heat loads in the range of 100 kW/m2 to 10 MW/m2 during plasma operation. An important issue concerning the design of these PFCs is the thermo-mechanical analysis to verify their suitability for the specified operation phases. A series of finite element (FE) simulations has been performed to achieve this goal. Previous studies focused on the test divertor unit (TDU) and high heat flux (HHF) target elements. The paper presents detailed FE thermo-mechanical analyses of a prototype HHF target module, baffles, heat shields and wall panels, as well as benchmarking against tests. Xuebing PengMr.Max Planck Institute for Plasma Physics, EURATOM Association,Greifswald, Germany 14 September 2012 Dear Dr. Ing.Olaf, Please accept the attached manuscript of the paper, named Thermo-mechanical analysis of Wendelstein 7-X plasma facing components, for SOFT-27 special issue. The paper is about the thermo-mechanical analysis of Wendelstein 7-X plasma facing components, including the high heat flux divertor targets, baffles, heat shields and wall panels, in order to verify their suitability for steady state operation.I greatly appreciate you taking time to read this letter and the paper, and am look forward to hearing from you. Best regardsSincerely yours, Xuebing Peng. Cover Letter Research Highlights Thermo-mechanical analysis of HHF divertor module TM-H09 shows that it can withstand heat loads of 10 MW/m 2 in steady state when the supports was optimized accordingly.  FE calculations indicate that the tiles of baffles and heat shields can withstand stationary heat loads of 250 kW/m 2 , but that the pulse length of plasma operation must be limited depending on the number of full load (500 kW/m 2 ) cycles.  Gap requirements for wall panels during assembly were defined based on several FE calculations. The stellarator experiment Wendelstein 7-X (W7-X) is designed for stationary plasma operation (30 minutes). Plasma facing components (PFCs) such as the divertor targets, baffles, heat shields and wall panels are being installed in the plasma vessel (PV) in order to protect it and other in-vessel components. The different PFCs will be exposed to different magnitude of heat loads in the range of 100 kW/m 2 to 10 MW/m 2 during plasma operation. An important issue concerning the design of these PFCs is the thermo-mechanical analysis to verify their suitability for the specified operation phases. A series of finite element (FE) simulations has been performed to achieve this goal. Previous studies focused on the test divertor unit (TDU) and high heat flux (HHF) target elements. The paper presents detailed FE thermo-mechanical analyses of a prototype HHF target modu...

“…Parallel to these works, the installation of the invessel components has been continued [5] and will be finished in November 2014: The plasma vessel walls are covered with normal-graphite tiles on CuCrZr-structures in the inner side and stainless steel cushions in the outer side of the plasma vessel (both components are foreseen for water-cooling, but are not cooled in the first operation phase 1.1). For this first operation phase, no divertor will be installed, but 5 graphite limiters are installed in the five modules in the bean-shape crosssection of the plasma 6].…”

Section: Introductionmentioning

confidence: 99%

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

Bosch

Bykov

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.