In November 2022, the Air Force updated its safety rules for airlift of nuclear weapons to allow the C-17A Globemaster III aircraft to transport the new B61-12 nuclear bomb.
The update, accompanied by training and certification of the aircraft and crews, cleared the C-17A to transport the newest U.S. nuclear weapon to bases in the United States and Europe.
The C-17As of the 62nd Airlift Wing at Joint Base Lewis-McChord serve as the Prime Nuclear Airlift Force (PNAF), the only airlift wing that is authorized to transport the Air Force’s nuclear warheads.
The updated Air Force instruction does not, as inaccurately suggested by some, confirm that shipping of the weapons began in December. But it documents some of the preparations needed to do so.
Politico reported in October last year that the U.S. had accelerated deployment of the B61-12 from Spring 2023 to December 2022. Two unnamed U.S. officials said the U.S. told NATO about the schedule in October.
But a senior Pentagon official subsequently dismissed the Politico report, saying “nothing has changed on the timeline. There is no speeding up because of any Ukraine crisis, the B61-12 is on the same schedule it’s always been on.”
Although the DOD official denied there had been a change in the schedule, he did not deny that transport would begin in December.
The B61-12 production scheduled had slipped repeatedly. Initially, the plan was to begin full-scale production in early-2019. By September 2022, the National Nuclear Security Administration (NNSA) was still awaiting approval to begin full-scale production. Finally, in October 2022, NNSA confirmed to FAS that the B61-12 was in full-scale production.
Two unarmed B61-12 trainers are loaded on a C-17A during an exercise at Joint Base Lewis-McChord AFB in April 2021. (Image: U.S. Air Force.)
The B61-12 is intended as an upgrade and eventual replacement for all current nuclear gravity bombs, including the B61-3, -4, -7, and probably eventually also the B61-11 and B83-1. To that end, it combines and improves upon various aspects of existing bombs: it uses a modified version of the B61-4 warhead with several lower- and medium-yield options (0.3-50 kilotons). It compensates for its smaller explosive yield (relative to the maximum yields of the B61-7 and -11) by including a guided tail-kit to increase accuracy, as well as a limited earth-penetration capability.
At this point in time, it is unknown if B61-12 shipments to Europe have begun. If not, it appears to be imminent. That said, deployment will probably not happen in one move but gradually spread to more and more bases depending on certification and construction at each base.
There are currently six active bases in five European countries with about 100 B61 bombs present in underground Weapons Storage and Security Systems (WS3) inside aircraft shelters. A seventh site in Germany (Ramstein Air Base) is active without weapons present and an eighth site—RAF Lakenheath—has recently been added to the list of WS3 sites being modernized. The revitalization of Lakenheath’s nuclear storage bunkers does not necessarily indicate that U.S. nuclear weapons will return to UK soil, especially since as recently as December 2021, NATO’s Secretary General stated that “we have no plans of stationing any nuclear weapons in any other countries than we already have . . . ” However, the upgrade could be intended to increase NATO’s ability to redistribute the B61 bombs in times of heightened tensions, or to potentially move them out of Turkey in the future. In addition, four other sites have inactive (possibly mothballed) vaults (see map below).
This research was carried out with generous contributions from the John D. and Catherine T. MacArthur Foundation, the New-Land Foundation, the Ploughshares Fund, the Prospect Hill Foundation, the FTX Future Fund and Longview Philanthropy, the Stewart R. Mott Foundation, the Future of Life Institute, Open Philanthropy, and individual donors.