The United States Air Force (USAF) has revealed that its planned upgrade of its tactical nuclear weapons fleet, which focuses on the procurement of the B-61 Mod.12 freefall tactical nuclear weapon, will see an estimated $3.6 billion being spent on the weapon over the next two decades. Crucially, according to reports, the upgrade adds a tail kit to the weapon which has a unit cost of $606,000 which is designed to improve the accuracy of the USAF and the North Atlantic Treaty Organisation’s (NATO) tactical free-fall nuclear weapons stockpile. At stroke, the B-61 Mod.12 will replace a host of disparate tactical nuclear weapons in the USAF and NATO stockpiles including the B-61 Mod.3/4/7/10 freefall nuclear bombs, with between 400 and 500 new weapons. The US government furnishes several NATO members with tactical nuclear weapons which remain in the custody of the United States but which can be released for the Alliance to use in times of war. The new weapon will also be carried by the USAF’s forthcoming Northrop Grumman B-21 Raider strategic bomber. Moreover, the weapon is expected to equip the USAF and USMC Lockheed Martin F-35A/B Lightning series of fighters.