Electric flow coupling in the HCLL blanket concept

A modular helium cooled lead lithium (HCLL) blanket concept, in which helium is used to cool the breeder zone through cooling plates immersed in the liquid metal as well as the whole structure (first wall and stiffening plates), has been selected as part of the test blanket module (TBM) program of the European Union. In this blanket concept there are issues related to the magnetohydrodynamic (MHD) interaction of the moving liquid metal with the magnetic field that have to be addressed in order to assess the feasibility of this blanket design. Since the walls and the cooling plates are electrically conducting, an exchange of electric currents may occur that leads to an electric coupling of the flow in adjacent fluid domains.Fully developed MHD flows have been investigated numerically in four breeder units containing cooling plates. Results obtained for a pure toroidal magnetic field and for fields having a certain inclination with respect to the toroidal direction are summarized in this paper focusing on current and velocity distribution.