The HITEX (High Temperature Isotopic Exchange) process has been proposed as a simple, reliable process to detritiate impurities in the International Thermonuclear Experimental Reactor (ITER) exhaust flow. Experimental testing of the HITEX process has demonstrated decontamination factors of up to ∼106 for a tritiated-methane impurity stream. Initial results investigating the effect of the hydrogen swamping ratio, gas recirculation rate, gas composition and initial tritium level on the system performance are reported.