Fabrication Issues of Sandwich-Like Flow Inserts for Circular Pipes

Abstract

The dual-coolant lead lithium (DCLL) blanket in which the eutectic lead-lithium alloy is used as tritium breeder and coolant is a promising concept for applications in fusion power plants. The interaction of the moving electrically conducting liquid metal with the plasma-confining magnetic field induces electric currents and creates strong electromagnetic Lorentz forces opposing the flow. This may lead to high magnetohydrodynamic (MHD) pressure drops. Efficient cooling requires a sufficiently high flow velocity and, under these conditions, if currents find a shortcut through electrically conducting walls, the pressure drop will be very large. One way to reduce the MHD pressure drop in ducts is to decouple electrically the coolant flow from the load-carrying walls by insulating flow channel inserts (FCI). In order to demonstrate the capability of pressure drop reduction by FCIs in 3D MHD flow, a test section is currently being designed and manufactured for experiments in the MEKKA laboratory at the Karlsruhe Institute of Technology. The used FCIs are of sandwich-type with a ceramic layer protected from both sides by thin sheets of steel to prevent direct contact of the insulator with liquid metal. This technical note focuses on fabrication issues of sandwich-type flow channel inserts for circular pipes and shows methods and techniques for successful manufacturing.

Keywords:

• DCLL blanket
• MHD pressure loss
• Flow Channel Insert (FCI)

Acknowledgments

This work has been carried out within the framework of the EUROfusion Consortium and has received funding from the Euratom research and training program 2014–2018 under grant agreement No 633053. The views and opinions expressed herein do not necessarily reflect those of the European Commission.

Special thanks to all involved departments at KIT (IKET, TEC, IMVT, IAM, INR) and industrial in-kind support by Fischer Group, Achern, Germany and HGGS LaserCUT GmbH & Co. KG, Hatzenbühl, Germany for valuable discussions and technical support.