We examine the requirements of the vacuum system for the LLNL/LBL recirculating induction linac concept. We reexamine processes, including beam stripping, background gas ionization, intra-beam charge exchange and desorption of gas molecules from the wall due to the incident ionized gas molecules and stripped ions, in the context of the proposed recirculator. We discuss implications for the vacuum system layout and estimate the cost of such a system. 18 refs., 2 figs., 1 tab
