The agency said the early completion underscores its capacity to deliver on the Trump Administration’s national security mission with urgency. The B61-13 is to be certified for delivery by U.S. strategic bomber aircraft.
Development of the bomb is part of a wider effort by NNSA and the Department of War to develop new technical solutions for defeating hard and deeply buried targets. The B61-13 is one of six ongoing warhead modernization programs being carried out by NNSA.
“The progress on the B61-13 program demonstrates the Nuclear Security Enterprise’s ability to respond to evolving geopolitical requirements with speed and precision,” said NNSA Administrator Brandon Williams. “Completing the 2026 baseline deliverables ahead of schedule is a clear indicator of discipline and operational focus. This milestone directly supports our goals to modernize our nuclear deterrent and sends a message to our adversaries that our national defense remains agile, secure, and effective.”
The B61-13 is a modern variant of the B61 nuclear bomb, described by NNSA as the longest-serving and most versatile weapon in the U.S. nuclear stockpile. NNSA completed the first B61-13 unit in May 2025, almost a year before the original target date and less than two years after the program was announced.
NNSA said the pace made the B61-13 one of the most rapidly produced nuclear weapons since the end of the Cold War. The newer variant incorporates the same modern safety, security and accuracy features as the B61-12, whose life extension program was completed in January 2025.
In a modern two-stage thermonuclear weapon, the canned subassembly includes the secondary-stage capsule and other parts sealed inside a thin metal container made of stainless steel or aluminum alloy. Together with the primary, the canned subassembly forms part of the warhead’s nuclear explosive package.
NNSA said diamond stamping means a weapon component has met all requirements of its certification process. It also means the component is approved for deployment to the U.S. nuclear stockpile as war reserve quality.
The B61-13 has a higher nuclear yield than the B61-12 and is oriented toward defeating certain harder and large-area military targets. NNSA said the capability provides additional flexibility for the President’s nuclear response options.
NNSA said all of its warhead modernization programs are ahead of schedule. The agency said it is continuing its record of 100% on-time or ahead-of-time delivery to the Department of War in this decade.
Source: U.S. Department of Energy’s National Nuclear Security Administration (press release).
