What's the modernised atomic bomb developed by US?

The United States has released the first production prototype of its upgraded B61 atomic bomb, which will encourage the country's defence industry to create an estimated 480 of the weapons and also integrate four existing variants of the bomb. 

The US Department of Energy's National Nuclear Safety Administration (NNSA) recently said the product—the B61-12 bomb—was produced on November 23. The upgraded version will replace three of the four existing modifications of the B61 ammunition, which entered service in 1968: the B61-3, B61-4 and B61-7.

According to the NNSA, as a result of the modernisation, the duration of the bomb's operational life will increase "by at least 20 years”."NNSA expects full-scale [batch] production of [B61-12] to begin in May 2022, with completion of all [these] necessary [nuclear warheads] in FY2026," the statement said.

The B61-12 bomb will differ from its predecessor, in particular, by the absence of a parachute and the presence of a new tail section with an inertial guidance system, which increases the accuracy of the application. According to Jill Hruby, the head of the NSNS, as a result of the modernisation, the power of the bomb in TNT equivalent will also decrease. 

However, Hruby added, there will be "no changes in the military characteristics" of the ammunition and also increases its safety and reliability.

NATO's most significant nuclear modernisation

According to the information she presented, the B61-12 bomb is intended for both currently available and future platforms, that is, delivery vehicles. As a result of the modernisation, all nuclear and non-nuclear components of the bomb were updated or replaced, the NNSA explained.

The first test of the B61-12, not accompanied by the detonation of an atomic charge, took place in the United States on July 1, 2015. Hans Christensen, director of information projects related to the nuclear sphere at the Federation of American Scientists, had told TASS about the US developing the first guided atomic bomb. A Senior Fellow at the Stockholm International Peace Research Institute (SIPRI), Christensen had termed the B61-12 bomb—which can be delivered by a fifth-generation American F-35 fighter-bomber—as "NATO's most significant nuclear modernisation since the 1980s". 

Recently, there has been a trend towards developing ammunition with a low-power warhead (less than 50 kilotons) and a relatively low emission of radiation. According to experts, the new B61-12 aerial bomb can significantly lower the threshold for the use of nuclear weapons and, instead of a military-political deterrent, become a potential weapon off the battlefield. In Russia, typically nuclear weapons are also moving into the high-precision class, and their power has been significantly reduced compared to the warheads of the 1960s-1970s.

The US’s bombing of Nagasaki, Japan, in the final stages of World War II in 1945 was the second and last time a nuclear weapon was deployed in combat.