A wall structure capable of withstanding high thermal load, including a wall structure with an inner wall, an outer wall positioned about the inner wall, and distancing elements located between the inner and outer walls. The distancing elements are joined to at least one of the inner and outer walls by means of laser welding and thereby establishing a plurality of cooling ducts between the inner and outer walls and a weld joint formed by the laser welding and having a cross-section taken through the wall structure that is substantially T-shaped and which displays a rounded shape towards an inside one of the plurality of cooling ducts.