Magnetohydrodynamic flow in the European HCLL blanket concept

Magnetohydrodynamic flows in a helium cooled lead lithium blanket for a future power reactor is analyzed by combined asymptotic- numeric computations. The flow is considered in real 3D geometries given by the design. The global geometry is decomposed into main geometric elements. Of special concern are the connections between the circular access tubes with the breeder boxes through poloidal manifolds. The flow then enters the breeder box through narrow distributing gaps. Another important geometric element is the region near the first wall, where the fluid has to pass another narrow gap. For applications to a power reactor, pressure drops of the order of Δp*=0.27 MPa have been estimated for an applied magnetic field of B=5 T. It turns out that the major fraction of this pressure drop arises in the poloidal manifold. For that reason further improvements in the design should focus on this particular detail. (orig.)