NNSA is responsible for maintaining and enhancing the safety, reliability, and performance of the United States nuclear weapons stockpile. For this reason, NNSA manages eight sites, which have the ability to design, produce, and run scientific tests and experiments on nuclear weapons in order to meet current and future national security requirements.

• Kansas City Plant
  NNSA's Kansas City Plant (KCP) is responsible for manufacturing and procuring nonnuclear components for nuclear weapons, including electronic, mechanical, and engineered material components. It supports national laboratories, universities, and U.S. industry.  The facility is managed by Honeywell Federal Manufacturing & Technologies, LLC. The KCP is located in Kansas City, Missouri.
• Lawrence Livermore National Laboratory
  NNSA's Lawrence Livermore National Laboratory (LLNL) is a design laboratory that is responsible for the safety and reliability of the nuclear explosives package in nuclear weapons. It supports surveillance, assessment, and refurbishment of the nuclear weapons stockpile. LLNL also possesses unique high-energy-density physics capabilities and scientific computing assets. The lab is managed by Lawrence Livermore National Security, LLC and is located in Livermore, California.
• Los Alamos National Laboratory
  NNSA's Los Alamos National Laboratory (LANL) is a design laboratory responsible for the safety and reliability of the nuclear explosives package in nuclear weapons. This laboratory possesses unique capabilities in neutron scattering, enhanced surveillance, radiography, and plutonium science and engineering. LANL is contractor-run by Los Alamos National Security, LLC and is located in Los Alamos, New Mexico.
• Nevada Test Site
  NNSA's Nevada Test Site (NTS) safely conducts high-hazard operations, testing, and training in support of NNSA, the U.S. Department of Defense, and other federal agencies. It provides the government with the capability to return to underground nuclear testing should the President deem it necessary. NTS is contractor-run by National Security Technologies, LLC and is located in Las Vegas, Nevada.
• Pantex Plant
  Pantex Plant, located 17 miles northeast of Amarillo, Texas, in Carson County, is charged with maintaining the safety, security and reliability of the nation’s nuclear weapons stockpile. The facility is managed and operated by B&W Pantex for NNSA. Work performed at Pantex includes support of the nuclear weapons life extension programs; nuclear weapons dismantlement; the development, testing and fabrication of high explosive components; and interim storage and surveillance of plutonium pits. 
• Sandia National Laboratories
  NNSA's Sandia National Laboratories (SNL) is responsible for the development, testing, and production of specialized nonnuclear components and quality assurance and systems engineering for all of the United States' nuclear weapons. SNL is contractor-run by Lockheed Martin Corporation. The labs are located in Albuquerque, New Mexico; Livermore, California; Kauai, Hawaii; and Tonopah, Nevada.
• Savannah River Site
  The Savannah River Site (SRS) is owned by the U.S. Department of Energy, but NNSA operates Tritium facilities on the site to supply and process tritium, a radioactive form of hydrogen gas that is a vital component of nuclear weapons. The NNSA-SRS loads tritium and non-tritium reservoirs; including reclamation of previously used tritium reservoirs, receipt, packing and shipping of reservoirs; recycling, extraction, and enrichment of tritium gas and laboratory operations.  Today, the Tritium Extraction Facility (TEF) at SRS is the only source of new tritium for the U.S. nuclear weapons stockpile.  TEF safely and efficiently extracts tritium gas from rods irradiated in a commercial reactor.  Also at SRS is NNSA's Office of Site Engineering and Construction Management, which manages the activities related to U.S. nonproliferation efforts to dispose of surplus highly enriched uranium under NNSA’s Uranium Enrichment project and dispose of surplus weapons-grade plutonium through the Mixed Oxide (MOX) Fuel Fabrication Facility, the Pit Disassembly and Conversion Facility (PDCF), and the Waste Solidification Building in F Area. SRS is currently managed and operated by Washington Savannah River Company. It is located south of Aiken, South Carolina.  
• Y-12 National Security Complex
  The Y-12 National Security Complex (Y-12) serves as the nation’s only source of enriched uranium nuclear weapons components and provides enriched uranium for the U.S. Navy.  Y-12 is a leader in materials science and precision manufacturing and serves as the main storage facility for enriched uranium.  Y-12 also supports efforts to reduce the risk of nuclear proliferation and performs complementary work for other government agencies.