[en] This document provides the auditable safety analysis for the post-deactivation, long-term surveillance and maintenance (S ampersand amp;M) phase of the U Plant. The U Plant is an inactive, surplus facility constructed in 1944 as one of three original chemical separations plants. However, U-Plant was never used for its original purpose and was eventually transferred to S ampersand amp;M. In 1957 it was converted to the tributyl phosphate process to recover uranium from the bismuth phosphate process waste. In 1958 it was placed on standby and was used to store inoperable and contaminated equipment from other facilities.This document evaluates the ability of the U Plant to withstand the effects of natural phenomena hazard events and describes the active support systems used to maintain ventilation and/or prevent the spread of contamination. This document also evaluates S ampersand amp;M activities that are routinely required (i.e., the S ampersand amp;M of facility barriers, equipment, structures, and postings [including repair and upgrade]; measures to identify, remove, or repair damaged asbestos; measures to identify, remove, or appropriately manage existing containers of hazardous substances; the performance of spill response measures as needed; and perform nondestructive assaying, waste characterization, and sampling). This document identifies the type and nature of the hazards presented by the U Plant and the specific controls that are required to maintain these hazards at acceptable levels