The Water-Cooled Lithium-Lead (WCLL) is one of the four breeding blanket concepts proposed by Europe for the demonstrating fusion power reactor DEMO. In the WCLL, tritium, required for the D-T fusion reaction, is produced in the electrically conducting lead-lithium that flows inside the blanket. Its velocity field is strongly influenced by the external magnetic field used for plasma confinement due to a magnetohydrodynamic (MHD) effect, and by the temperature field. The non-isothermal condition is due to the presence of the heat flux incident on the first wall (FW), the plasma-facing area of the blanket, and the volumetric heat generation caused by the flux of energetic particles passing though the component.