Most nuclear weapons in the U.S. stockpile were produced anywhere from 30 to 40 years ago, and no new nuclear weapons have been produced since the end of the Cold War.  The United States has not conducted an underground nuclear test since 1992.  Therefore, NNSA must use science-based research and development to extend the lifetime of the current weapons in the stockpile.  By extending the “life,” or time that a weapon can safely and reliably remain in the stockpile without having to be replaced or removed, of a current weapon, NNSA is able to maintain a credible nuclear deterrent without producing new weapons or conducting new underground nuclear tests.

At the time of their original production, the nuclear weapons were not designed or intended to last indefinitely.  Over time the components of nuclear warheads deteriorate, even when kept in storage, making maintenance difficult and time consuming for NNSA’s scientists, engineers and technicians.

Not all weapons and types are the same.  NNSA must develop individual life extension programs, sometimes referred to as LEPs, for each weapon type and develop specific solutions to extend the lifetime of each particular warhead or bomb.  This includes identifying and correcting potential technical issues with each weapon, and then refurbishing and replacing certain components as necessary.  Life extension efforts are intended to extend the lifetime of a warhead or warhead component for an additional 20 to 30 years.

Each facility in NNSA’s nuclear weapons complex contributes to the life extension process.  The majority of the physical work on the warhead and bombs is carried out at the Pantex Plant and Y-12 National Security Complex.  The Pantex Plant does assembly and disassembly of the warheads and bombs while the Y-12 National Security Complex manufactures, assembles, and disassembles certain key components.  The Kansas City Plant’s main mission is to manufacture and procure non-nuclear key components.  The design laboratories – Los Alamos, Lawrence Livermore and Sandia National Laboratories – assess the health of the current stockpile, design the components and systems for the life extension program warheads and bombs, and certify the life extended models when they enter the stockpile.  The Nevada Test Site provides facilities and expertise for experiments used to assess the health of the current stockpile systems and to evaluate proposed component designs for life extension programs.  The Savannah River Site provides tritium gas, an essential and limited life material used in modern warheads.

B61 Life Extension Program
The B61 life extension program will extend the life of the B61 Mods 7 and 11 for an additional 20 years by refurbishing the canned subassembly and replacing the associated seals, foam supports, cables and connectors, washers, o-rings, and limited life components. In June 2006, NNSA completed a six-year effort to deliver the first refurbished B61 nuclear bomb to the stockpile.

W76 Life Extension Program
The W76 life extension program will extend the life of the W76 warhead, used in the Navy’s Trident Strategic Weapons System, for an additional 30 years by refurbishing the nuclear explosive package, the arming, firing, and fusing system, the gas transfer system, and associated cables, elastomers, valves, pads, cushions, foam supports, telemetries, and other miscellaneous parts.