A vacuum of the order of 10−9 Torr is required in the chamber of a proposed 180-ft-diam, 3-BeV, electron-positron storage ring in order to permit beam lifetimes of many hours and to reduce background interaction rates. This pressure must be maintained in the presence of 500 kW of synchrotron radiation with a critical wavelength of 3.2 Å. The rate of radiation-induced gas evolution is investigated. The process is believed to take place via a two-step mechanism—photoelectric emission followed by electron desorption. Experimental results of various investigators are described. A combination ion-getter and titanium sublimation pumping system with total pumping speed of one half million liters per second is proposed to deal wish the problem.