U.S. Completes $9B Upgrade for B61-12 Nuclear Warheads

The National Nuclear Security Administration (NNSA) has completed the $9-billion B61-12 warhead upgrade for deployment on F-35A, B-2, and F-15E aircraft.

Known as “gravity bombs,” the B61 series has been in service for over 50 years, making it the oldest nuclear weapon in the U.S. arsenal.

The B61-12 life-extension program consolidates and upgrades older B61 variants—specifically the B61-3, -4, -7, and -10—into a modernized version designed to extend their operational life by at least 20 years. The upgrade enhances the weapon’s safety, security, and reliability while retaining its role as a key element of U.S. and NATO nuclear deterrence.

The upgraded warhead weighs approximately 825 pounds (374 kilograms) and incorporates technologies such as an inertial navigation system for increased accuracy. Its four maneuverable tail fins enhance stand-off capability, allowing for precise delivery from a distance. These improvements do not add new capabilities but modernize the existing arsenal within international non-proliferation commitments.

Initially approved for production in 2021, the B61-12 upgrade program culminated with the delivery of the final production unit on December 18, 2024, roughly three years after full-scale production began.

The B61-12 program began design and development over 17 years ago as part of a broader effort to sustain and modernize the U.S. nuclear triad. The program was executed by the NNSA, a semi-autonomous agency within the Department of Energy, in coordination with the Department of Defense, which oversees the delivery systems for nuclear weapons.

The upgraded warhead can now be deployed across multiple platforms, including the F-35A Joint Strike Fighter, F-15E, B-2 Spirit bomber, F-16, and German and Italian Tornado jets.

In 2020, the F-15E became the first aircraft certified to carry the B61-12. By March 2024, the F-35A was also certified, making it the first fifth-generation fighter authorized to deploy the bomb. The NNSA’s October 2024 report highlighted ongoing efforts to certify additional platforms, including the B-21 Raider stealth bomber.

With the completion of the B61-12 program, the NNSA is now shifting focus to the production of the B61-13, a higher-yield variant designed to address evolving strategic threats. Announced in October 2023, the B61-13 will feature a yield of up to 360 kilotons, a significant increase from the 50-kiloton yield of the B61-12. The first production unit for the B61-13 is slated for fiscal year 2026.