The collimating system in the accumulator ring and transfer lines of the Spallation Neutron Source (SNS) project is responsible for stopping 0.1&percent; of the 2 MW beam of 1.0 GeV protons that are in the beam halo. The collimating structures are a combination of movable beam scrapers and stationary absorbers. Specifically, pairs of charge‐exchange foils or scrapers moving in‐and‐out of the beam in the vertical and horizontal directions help guide the halo protons into respective absorbers which consist of an intricate design of a double wall beam tube, a water‐cooled particle bed and radial shielding. Off‐momentum protons, with the help of respective charge exchange foils and a dipole magnet, are directed to a momentum dump consisting of a cooled particle bed downstream of a double‐walled window separating it from the vacuum space. Addressed in this paper is the thermo‐mechanical response and survivability of key components of the collimating system (such as the collimating beam tube in the absorbers, the beam windows and the primary element of the bean scraper structure) in the event of intercept of the full beam under accident conditions. While the potential for the full beam to be intercepted by these components is remote, still special attention will be paid in assessing the amount of full beam (or number of pulses) they can tolerate. © 2003 American Institute of Physics