The source rates and steady-state concentrations have been measured for oxygen, hydrogen, and tritium impurities in the Experimental Breeder Reactor II (EBR-II) sodium systems. An analytical approach is used to determine the effectiveness of the cold traps for removing oxygen, hydrogen, and tritium. The cold trap effectiveness data accumulated to date for removal of oxygen, hydrogen, and tritium indicate that EBR-II cold traps are highly effective in controlling these impurities to very low concentrations in the sodium systems.