The role of sidestream recycle in hydrogen isotope separation and column cascade design

Sidestream recycle combined with sidestream equilibration is important in hydrogen isotopic distillation processes because it offers a means to reduce the number of columns required for the extraction of pure homonuclear species. This directly implies simpler systems, reduced control problems, and reduced material inventories. Measurements were recently completed for a single distillation column using feed compositions (about 50:50 D:T) and product flows similar to those expected in an ITER-type device with recycle of an equilibrated sidestream withdrawn from the column. Dynamic studies were conducted with flowrates changing as might be expected for typical Tokamak operations. These experimental results are compared with computer simulations of the dynamic process. The impact of these sidestream recycle studies on the design of isotope separation systems is discussed, especially with respect to column design, tritium inventory, dynamic performance, stability, and system control.