Speaker
Frederik Arbeiter
(Institute for Neutron Physics and Reactor Technology)
Description
Helium is considered as coolant in the plasma facing first wall of several blanket concepts for DEMO fusion reactors, due to the favorable properties of chemical inertness, no activation, comparatively low effort to remove tritium, no chemical corrosion and a flexible temperature range. Design analyses for the ITER Test Blanket Modules done by several design teams have shown ability to use helium cooled first walls with heat flux densities of 0.5MW/m². Investigations on the heat loads coming from the plasma are ongoing for current EU DEMO concepts. Typical steady state loads are predicted around 0.3MW/m², but peak values could reach and excess 1MW/m² near the lower and upper X-points, depending on the chosen first wall shape, magnetic configuration and assumptions on power fall off lengths in the scrape off layer of the plasma. Even higher short-term transient loads can be expected.
Several modifications to the helium cooled first wall channel shape were investigated in terms of heat transfer and pressure drop by computational fluid dynamics and experiments. The results indicate an excellent performance of transversal ribs (wall mounted or detached) and other mixing devices in the first wall cooling channels, enabling augmented heat flux capabilities with tolerable pumping power increases. Additional to decreasing the structural material peak temperature, a fine tuned application of heat transfer enhanced surfaces can also reduce the temperature spread within the component and thus reduce the thermo-mechanical stresses. The applicability of the investigated channel surfaces is closely linked to the manufacturing strategy of the first wall. Several manufacturing methods are explored, enabling the application of the suggested heat transfer enhanced first wall channels.
Co-authors
Axel Von der Weth
(Institute for Neutron Physics and Reactor Technology, Karlsruhe Institute of Technology, Eggenstein-Leopoldshafen, Germany)
Bradut-Eugen Ghidersa
(Institute for Neutron Physics and Reactor Technology, Karlsruhe Institute of Technology, Eggenstein-Leopoldshafen, Germany)
Christine Klein
(Institute for Neutron Physics and Reactor Technology, Karlsruhe Institute of Technology, Eggenstein-Leopoldshafen, Germany)
Florian Schwab
(Institute for Neutron Physics and Reactor Technology, Karlsruhe Institute of Technology, Eggenstein-Leopoldshafen, Germany)
Frederik Arbeiter
(Institute for Neutron Physics and Reactor Technology, Karlsruhe Institute of Technology, Eggenstein-Leopoldshafen, Germany)
Georg Schlindwein
(Institute for Neutron Physics and Reactor Technology, Karlsruhe Institute of Technology, Eggenstein-Leopoldshafen, Germany)
Heiko Neuberger
(Institute for Neutron Physics and Reactor Technology, Karlsruhe Institute of Technology, Eggenstein-Leopoldshafen, Germany)
Sebastian Ruck
(Institute for Neutron Physics and Reactor Technology, Karlsruhe Institute of Technology, Eggenstein-Leopoldshafen, Germany)
Yuming Chen
(Institute for Neutron Physics and Reactor Technology, Karlsruhe Institute of Technology, Eggenstein-Leopoldshafen, Germany)
