[en] A radiation field appears in the SNS accelerator tunnel due to secondary particles created from the interaction of the proton beam halo with components along the proton beam line. During operations, the proton beam losses and secondary particles activate the structural materials and tunnel walls causing a residual radiation field of decay gammas after beam termination. Detailed dose rate analyses have been performed along the entire SNS accelerator line using MCNPX Monte Carlo code for the cases of operation, and after shutdown. A set of complex geometry models has been developed for the almost 900-meter-long accelerator structure, and the losses along the proton beam line have been characterized with wide use of MCNPX geometry and general source cards capabilities. Dose rates due to residual radiation from the activated components were calculated in three steps using the Activation Analyses System in order to obtain residual gamma sources from activated components. (authors)