LEP: Extending stockpile life

Posted: February 7, 2013 - 6:10pm | Y-12 Report | Volume 9, Issue 2 | 2013

The Life Extension Program allows safe, effective weapons to remain in the stockpile well beyond their original service life.

Nuclear weapons are intricate and, in a sense, handmade devices that cannot be stored indefinitely — and be expected to function — without ongoing care and maintenance. Weapon components periodically require evaluation and replacement.

Fifteen years ago the Life Extension Program, or LEP, funded by Defense Programs, was established to care for and prolong the safety and effectiveness of the nuclear stockpile. Today Y-12 and other sites across the Nuclear Security Enterprise collaborate in that effort.

Weapon component production, surveillance, dismantlement and storage are four distinct facets of Y-12's mission. Production includes the manufacture of new components, which oftentimes are combined with recycled components into subassemblies. This process, referred to as refurbishment, extends the lifetimes of systems in the active weapons stockpile and ensures their effectiveness.

Another aspect of this mission is surveillance testing, which determines how weapons in the active stockpile are aging. Dismantlement involves separating components of retired weapons and recovering nuclear materials from them. Storage occurs throughout all these processes (see Y-12 and the Nuclear Security Enterprise).

When a refurbishment program is launched, the goal is to extend the weapon's life by 20 to 30 years.

Routine service checks

The decision to begin an LEP is based on several factors, such as new technology needs and the conditions revealed during quality evaluations. In those evaluations, personnel conduct something similar to post-mortem investigations as they dismantle and analyze selected units from the stockpile.

“As nuclear testing is no longer an option, aging effects cannot be directly tested,” stated a product engineer. Life extension makes it possible to maintain credible nuclear deterrents at a much lower cost than the expense of producing brand-new weapons and conducting elaborate underground tests.

Tom Thrasher, LEP manager in Stockpile Programs, said, “Although the current stockpile is healthy, LEPs allow us to keep a safe and effective weapon in the stockpile well beyond its original service life.”

The refurbishment family

Many facilities in the Nuclear Security Enterprise contribute to LEP efforts. Considerable physical work on warheads and bombs is completed at Y-12 and at the Pantex Plant. Pantex manufactures high-explosive components as well as assembles and disassembles units. Y-12 manufactures, assembles and disassembles the enriched uranium and other key components of canned subassemblies.

Nuclear design laboratories Los Alamos National Laboratory and Lawrence Livermore National Laboratory and the non-nuclear design lab Sandia National Laboratories use the results of quality evaluation and surveillance activities to assess the current health of the stockpile, to design components and systems, and to certify the refurbished models when they enter the stockpile. The Savannah River Site and the Kansas City Plant provide essential and limited-life material and components for use in the production of weapons. Some of those items are shipped to Y-12 for building canned subassemblies; others go to Sandia or Pantex for constructing components or completing weapon assembly.

Examples in the stockpile

Not all weapon types require the same treatment, though. Specific solutions must be found to extend the life of a particular warhead or bomb. Information gathered during investigations can influence consideration of additional programs for life extension.

Not every weapon system built remains a part of the stockpile. Some older systems have been completely dismantled, and others have been retired and await final dismantlement. Only those systems the military identifies as necessary for the nation's strategic needs are considered for LEPs. Y-12 has successfully executed LEPs and other refurbishment activities since 1998. The first LEP, the W87, came in the 1990s with the first production unit completed in 1998. Other LEPs followed. The W76 LEP is under way, and others are planned.

Preparing for the future

Most nuclear weapons in the U.S. stockpile were manufactured 30 to 40 years ago, and no new nuclear weapons have been produced since the Cold War's end. The U.S. hasn't conducted underground nuclear tests since 1992.

Success with LEPs and the national policy to forgo designing new weapons are ample motivation for continuing LEPs for other weapon systems in the stockpile. Through recycling usable parts, components and materials to create reliable units for future use and manufacturing new components as needed, LEPs safeguard the nation's nuclear deterrent.