Applicability of a cryogenic distillation system for D-T isotope rebalancing and protium removal in a DEMO power plant

•A bleed and recycle stream is used to calculate how much exhaust gas separation from a fusion reactor is required.•Separating all torus exhaust gases is unnecessary and energy consuming.•Cryogenic distillation (CD) is shown to be a feasible separation technology within exhaust composition bounds.•Reference and alternative scenarios show that isotope imbalance is an important parameter.•Further work is necessary in comparing CD to other isotope separation methods.