A turbine component has an airfoil portion with at least one central core element, a pressure side wall, and a suction side wall. The airfoil portion also has a serpentine cooling passageway in at least one of the walls. In a preferred embodiment, the airfoil portion has a serpentine cooling passageway in both of the pressure and suction side walls. A refractory metal core for forming the serpentine cooling passageway(s) is also described.