The Department of Energy proposes to modify Building 9731 located at the Y-12 National Security Complex (Y-12) back to its original use as a training facility. Building 9731 was the first production building completed at the Y-12 site, and the first building to house the special equipment used for the electromagnetic separation process that enriched uranium used in the first atomic bomb. Implementation of the undertaking will reduce risk to workers and the public from potential exposure to hazardous material, allow for outdated systems to be replaced (i.e. fire protection), and would extend the life of the facility. The project includes providing the building with adequate and consolidated space to house its personnel with office, break rooms, and accessible restrooms. It would also expand the current tour route to accommodate more Manhattan Project National Historical Park visitors.