This study investigated the rotation of tubes in opposite directions to enrich heavy water in a transverse-flow concentric-tube thermal diffusion column inserted as a spacer in the annular region with a wire spiral, having a diameter equal to the annular spacing. Equations for the optimal speed of tube rotation to achieve a maximum separation and maximum output were derived. Instead of using a stationary column without a wire spiral.. considerable improvement in performance can be obtained if a rotated wired column is employed, operating at the optimal speed of tube rotation to create a desirable cascading effect.