The Department of Energy is seeking expressions of interest for construction services related to the Enhanced Capability Subcritical Experiment at the Nevada National Security Sites (NNSS). The project involves significant modifications to the PULSE Complex, including the construction and installation of advanced testing equipment for radiological isotopes, which is critical for the Stockpile Stewardship program aimed at ensuring the safety and reliability of the nuclear weapons stockpile without nuclear testing. Interested contractors should provide their company information, business size, and capability statements, with the potential subcontract lasting three to five years and work issued through Task Orders against a Master Agreement. For further inquiries, contact Keisha Garcia at GarciaKR@nv.doe.gov or Kimberly Kruskie at kruskikl@nv.doe.gov.