The B61 gravity bomb, deployed to U.S. Air Force and North Atlantic Treaty Organization bases, has almost 50 years of service, making it the oldest and most versatile weapon in the enduring U.S. nuclear stockpile. Numerous modifications have been made to the B61 since it entered service in 1968, and four B61 variants remain in the stockpile: the B61-3, -4, -7, and -11.
For nearly a decade, the aging weapon system has been undergoing a life extension that consolidates and replaces three B61 weapon designs (the B61-3, -4, and -7) and combines them into one updated design: the B61-12. Los Alamos and Sandia National Laboratories are the design agencies for the B61-12 life extension program (LEP), with Los Alamos also being responsible for producing detonators and other classified components.
The B61-12 LEP refurbishes, reuses, or replaces all the bomb’s nuclear and nonnuclear components, extending the bomb’s service life by at least 20 years. The LEP addresses the bomb’s age-related issues and enhances its reliability, ease of field maintenance, safety, and use control. When fielded, the B61-12 will balance greater accuracy, provided by the modern tail kit, with a substantial reduction in yield, but without any overall change in military requirements or capability.
"The measure of success is not the absence of challenges. The measure of success is the resilience to overcome challenges.”
—Los Alamos Director Thom Mason during an event that recognized the B61-12 LEP
On November 23, 2021, the first production unit (FPU) of the B61-12 was delivered. In the FPU phase of the nuclear weapons life cycle, all weapons components have been produced through qualified processes; all the necessary qualification testing, engineering analysis, and physics certification activities have been completed; and the FPU has been built at the Pantex plant, near Amarillo, Texas. In other words, all the processes required to produce the weapon are qualified and exercised, and the B61-12 is on track for full-scale production in May 2022.
“It has been, and continues to be, an honor to work with such a diverse and integrated team of talented technicians, designers, scientists, engineers, physicists, and other professional staff to achieve the B61-12 FPU and meet one of our country’s most critical national security milestones,” says engineer and program manager Jessica Trujillo. “This has been a long journey with the support and collaboration of our national security enterprise partners. I am proud to say we have delivered a quality product that meets the highest standards of Los Alamos National Laboratory weaponry.”
On January 20, the B61-12 FPU was celebrated during a virtual event hosted by the Kansas City National Security Campus. More than 300 people attended from across the nuclear security enterprise and the United States Air Force, including Jill Hruby, head of the National Nuclear Security Administration (NNSA) and Los Alamos Director Thom Mason.
After thanking all those involved, Mason noted that work on the B61-12 is far from over. “FPU is a really important and tangible milestone, but we’ve now got to move on to rate production and completing the program,” he said. “I am absolutely confident that the team that got us to this point is going to see us through in support of our national deterrence mission—which one only needs glance at the newspapers to understand is critically important in today’s world.”
The B61-12 LEP and other ongoing weapons modernization programs will ensure the safety, security, and military effectiveness of the U.S. nuclear stockpile in this increasingly complicated and uncertain global environment.
“The effectiveness and credibility of our nuclear stockpile depends on our scientific engineering, technological, and production capabilities,” Hruby said. “[The B61-12 LEP] provides me, other leaders, our allies, and our adversaries confidence that we will be able to deliver on the life extension and modernization programs ahead. This achievement clearly demonstrates that NNSA can innovate, collaborate, and deliver our mission on behalf of the American people.” ★