Speaker
Leo Buhler
(Institute for Nuclear and Energy Technologies)
Description
A number of liquid metal blanket designs for applications in nuclear fusion reactors is currently under development. In the water cooled lead lithium (WCLL) blanket Eurofer97 is used as structural material and liquid PbLi as breeder, neutron multiplier, and as heat transfer medium. The released heat is removed by water at a pressure of 155 bar (pressurized water reactor conditions, 285°C - 325°C) that flows through cooling pipes immersed in the liquid-metal pool. The temperature at the Eurofer/PbLi interface has to be kept in the range between 300°C and 550°C. In order to withstand disruption-induced forces and water pressure in case of accidental conditions, the breeder zone is stiffened by internal plates that form rectangular ducts in which the liquid metal flows.
Numerical simulations have been performed to predict liquid metal flow distribution in model geometries for WCLL blankets under the influence of intense external magnetic fields. The flow may be driven by an applied pressure gradient and/or by buoyancy due to the presence of volumetric heat sources in the fluid and heat transfer at the pipes. Magnetic fields of different strengths are applied perpendicular to the main flow direction and buoyant and mixed convection are studied for various thermal conditions. In the present design of WCLL blankets with cooling pipes in vertical channels, internal layers develop along magnetic field lines tangentially to the tubes. Across these layers significant velocity gradients occur.
Co-authors
Chiara Mistrangelo
(Institute for Nuclear and Energy Technologies, Karlsruhe Institute of Technology, Eggenstein-Leopoldshafen, Germany)
Leo Buhler
(Institute for Nuclear and Energy Technologies, Karlsruhe Institute of Technology, Eggenstein-Leopoldshafen, Germany)
