The United States has successfully completed the production program for the new thermonuclear bomb B61-12, which is the outcome of a weapon development initiative carried out by the National Nuclear Security Administration (NNSA) since 2008.
Notably, the actual production took relatively little time, with the first bomb being manufactured in November 2021 and the last on December 18, 2024, although the NNSA has only now disclosed this information.
The overall development and production of the B61-12 cost approximately $9 billion. While the B61-12 is not fundamentally a new bomb, it utilizes a nuclear warhead from existing older bombs, specifically the B61-4, and is intended to replace several types of nuclear bombs, including the B61-3, -4, -7, and -10. The total number of B61-12 bombs produced is estimated to be around 500 units, although this figure is not officially disclosed.
The primary goal of the modernization is to significantly enhance the accuracy of deployment, with an allowable deviation of up to 30 meters from the target point. Essentially, this involves the development and production of only the tail section of the bomb. This will enable the selection of yield options ranging from 0.3, 1.5, 10, to 50 kilotons when preparing the munition for use.
It is also important to understand that the B61-12 is a free-fall bomb. This means that for its deployment, the carrier—such as the F-15, F-16, F-35, B-2, B-21, and the European Tornado—must be positioned directly above the target. There are no additional guidance kits, like those in JDAM-ER, or acceleration features, as seen in the AASM Hammer.
Therefore, there are quite reasonable assumptions that in the event of an actual nuclear war, the combat use of such free-fall bombs would be highly questionable. Nevertheless, the U.S. is already preparing for the serial production of another version of this bomb—the B61-13—which will have a yield of 360 kt. The purpose of this bomb will be to destroy highly fortified targets, such as Putin's bunker.