Aiming to counter "threats from potential adversaries" and "[respond] to the demands of a rapidly evolving security environment," the Department of Defense (DOD) reported that the United States is developing a new version of the thermonuclear gravity bomb B61. The new bomb, known as B61-13, still needs authorization and funding from Congress.
The Pentagon made the announcement public through a statement issued last Friday. If approved by Congress, the "B61-13 would be produced by the National Nuclear Security Administration (NNSA)," an agency that operates under the Department of Energy (DOE).
In statements reported by the DOD statement, John Plumb, assistant secretary of defense for space policy, said that this effort "is reflective of a changing security environment and growing threats from potential adversaries." He also added:
The United States has a responsibility to continue to assess and field the capabilities we need to credibly deter and, if necessary, respond to strategic attacks, and assure our allies.
However, this new version would not increase the United States' total nuclear arsenal, as Plumb stated, since it would only replace older models.
Regarding the specific characteristics of the B61-13, the Pentagon notes that the bomb "would be deliverable by modern aircraft, strengthening deterrence of adversaries and assurance of allies and partners by providing the President with additional options against certain harder and large-area military targets."
18 times more powerful than the bomb detonated in Nagasaki
According to the Federation of American Scientists, the B61-13 would have 360 kilotons of maximum power. That is, 50 kilotons more than its predecessor, the B61-12.
As a comparison, the nuclear bomb that detonated in Nagasaki, Japan, during World War II had 20 kilotons of power, 18 times less than the B61-13.
