Far More Powerful B61-13 Guided Nuclear Bomb Variant Joins U.S. Stockpile

Yahoo

19-05-2025

The first production example of the new B61-13 nuclear bomb has been completed roughly a year ahead of schedule, according to the U.S. Department of Energy. The B61-13 is based on the preceding B61-12, but offers a higher maximum yield that U.S. officials say offers important additional capacity to hold hardened targets, such as underground command and control facilities, and ones spread across physically larger areas, at risk.
The U.S. military first announced plans to develop and field the B61-13, primarily as a replacement for the B61-7 variant, in 2023. The plan had previously been for the B61-12 to supplant the B61-7, as well as the B61-3 and B61-4 versions. The B61 is America's longest-serving family of nuclear gravity bombs, and you can read more about the existing members thereof here.
NNSA has completed the First Production Unit of the B61-13 nuclear gravity bomb @PantexPlant. This is a major accomplishment for stockpile modernization. Thanks to the entire NNSA team who worked to achieve this milestone nearly a year ahead of schedule.https://t.co/XNlOZsS1JU pic.twitter.com/Y4ETedebz6
— NNSA (@NNSANews) May 19, 2025
'[The] Pantex Plant has completed the first production unit of the B61-13 nuclear gravity bomb – designed to strengthen the flexibility and credibility of America's nuclear deterrent,' according to a social media post today from the Department of Energy, which also included a small glimpse of the weapon. 'This major milestone for America's nuclear stockpile was completed a year ahead of schedule!'
'Modernizing America's nuclear stockpile is essential to delivering President Trump's peace through strength agenda,' Secretary of Energy Chris Wright said in a statement today. 'The remarkable speed of the B61-13's production is a testament to the ingenuity of our scientists and engineers and the urgency we face to fortify deterrence in a volatile new age. It was my honor today to stamp the first completed unit at the Pantex Plant in Amarillo, Texas, where all the efforts of NNSA's labs, plants, and sites culminated in this amazing milestone. This achievement signals American strength to our adversaries and allies alike.'
B61-13 with DOE Gold Star Quality Stamp https://t.co/Q0a7CMom64
— Casillic (@Casillic) May 19, 2025
The Pantex Plant in Texas is where U.S. nuclear weapons are assembled and disassembled, and the facility also oversees testing and evaluation activities. Pantex falls under the oversight of the Department of Energy's National Nuclear Security Administration (NNSA), which manages the development of new and improved nuclear weapons and sustains America's existing nuclear stockpile.
'NNSA anticipated achieving the first production unit for the B61 Mod 13 later this month, almost a full year ahead of schedule,' Teresa Robbins, NNSA's Acting Administrator, had told members of the House Armed Services Committee on May 7. Robbins' prepared remarks for the hearing said that 'taking advantage of existing B61 production lines' had been a key factor in accelerating work on the new version.
'Decades of B61 design and qualification data gave NNSA's program managers and engineers from the national laboratories and production plants confidence that they could accept calculated risks to speed production,' per an NNSA press release today. 'By streamlining or in some cases combining 'design gates' – the rigorous reviews conducted at each step of a weapon design process – engineers were able to commence production far sooner than a standard schedule would allow. These efficiencies allowed B61-13 hardware 'test builds' to be manufactured just three months after the program received authorization and appropriation from Congress.'
From the pictures that have been released to date, looks essentially identical to the B61-12 externally. The B61-13 notably features the same tail kit assembly (TKA) containing an inertial navigation system (INS) guidance package that was introduced on the B61-12.
In addition, 'the B61-13 incorporates the same modern safety, security, and accuracy features as the B61-12,' according to today's NNSA release.
Yield is where the B61-13 is understood to differ most from the B61-12. All B61 variants are so-called 'dial-a-yield' weapons that can be set to detonate with varying degrees of explosive force. Though the exact figures are classified, the U.S. government has said the maximum yield of the B61-13 will be in line with the previous B61-7 version it is intended to replace, the highest yield setting on which is reportedly between 340 and 360 kilotons. The reported maximum yield of the B61-12 is 50 kilotons.
The B61-7 is one of the most powerful nuclear gravity bombs in the U.S. stockpile now. Despite the lower maximum yield, the U.S. military had previously argued that the new guidance capability found on the B61-12, which is also spin-stabilized using small rocket motors positioned around the rear of its body for additional accuracy, would allow it to hold hardened targets, even ones deep underground, at risk by being able to focus is explosive force on a more precise point. Even before the announcement of plans for the B61-13 two years ago, the U.S. government had already been steadily walking back expectations for the B61-12.
It's worth noting here that the B61-13 will be reserved for U.S. military use only, unlike the B61-12, which America's NATO allies could employ via the alliance's nuclear sharing agreements if authorized. Interestingly, in 2022, U.S. officials confirmed that not all aircraft set to be certified to carry the B61-12, particularly certain tactical jets in NATO service, will be able to employ the precision guidance capability, as you can read more about here.
In addition, unlike the B61-12, which U.S. F-15E Strike Eagles and F-35A Joint Strike Fighters are certified to employ, the B61-13 will be reserved for use by B-2 Spirit and forthcoming B-21 Raider stealth bombers. U.S. B-52 bombers are no longer certified to drop nuclear gravity bombs of any type, though they are still able to fire nuclear-tipped cruise missiles.
Overall, work on the B61-13 has come as China, America's chief global competitor and pacing threat, as well as Russia, have continued to expand their underground military infrastructure. In addition to new subterranean command and control facilities, the Chinese People's Liberation Army (PLA) has notably constructed vast new fields of new intercontinental ballistic missile (ICBM) silos in recent years. The PLA also has an underground submarine base and many airfields with cavernous hardened hangars.
Smaller countries like North Korea and Iran have also been increasingly pushing strategic and other military assets, particularly facilities tied to their nuclear and long-range ballistic missile programs, deeper underground just in response to potential conventional threats, primarily from the United States. This includes silo-based and other hardened ballistic missile launch infrastructure.
At the same time, the B61-13 is not expected to be able to hold absolutely all deeply buried targets at risk. There are still no known plans for a direct successor to the highly specialized B61-11 variant, which features a substantially reinforced outer shell and a rocket booster in the tail to help it penetrate down toward especially deeply buried targets. Russia's Kosvinsky Kamen, a key component of that country's nuclear command and control enterprise that is situated under a mountain, is understood to have been a key driver behind the B61-11's development in the first place.
B61-11 Nuclear Earth Panetrator pic.twitter.com/MgiUvrOFjS
— Casillic (@Casillic) December 14, 2021
A contracting notice in January did hint at the possibility that further B61 versions could be on the horizon. In the meantime, production of higher-yield B61-13s is now well underway.
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