A research program to control tritium in supercritical CO2 (SC-CO2) gas-cooled reactors is presented. This type of reactor is attractive because it offers higher thermal efficiency and lower reactivity with the primary coolant. This program consists of two activities; development of tritium permeation barriers in the heat exchanger tubes and development of tritium removal method from the SC-CO2. For permeation reduction, a glassy coating was developed as the tritium permeation barrier for the SC-CO2 system. Experimental results showed the physical and chemical integrity of the coating for 100 hours soaking in the SCCO2. Significant permeation reduction of 1/20 to 1/60 are obtained. But, further permeation reduction is desired through a new coating technique development, since the permeation reduction at lower temperatures is small.