A turbine rotor blade is additively manufactured and includes an airfoil body with a radially extending chamber for receiving a coolant flow, a tip end at a radial outer end of the airfoil body, and a shank at a radial inner end of the airfoil body. The radially extending chamber extends at least partially into the shank to define a shank inner surface. An integral impingement cooling structure is within the radially extending chamber. The integral impingement cooling structure allows an exterior surface of a hollow body thereof to be uniformly spaced from the airfoil inner surface despite the curvature of the chamber. The turbine rotor blade has impingement cooling throughout the blade.