Following last week’s reports about the US Navy having fielded a low-yield submarine-launched ballistic missile (SLBM) warhead on one of its Ohio-class ballistic missile submarines, the Pentagon has now confirmed this to be true.
John Rood, Under Secretary of Defense for Policy, said on February 4 that the navy had fielded the W76-2 low-yield SLBM, without going into details about which submarine could be underway with the warhead.
According to an article from the Federation of American Scientists (FAS), who was the first to report on the event, the submarine in question is likely the USS Tennessee (SSBN-734), which got underway from Kings Bay Submarine Base, Georgia, for an Atlantic Ocean patrol in late 2019. Tennessee is one of five ballistic-missile submarines stationed at the base and is capable of carrying up to 20 SLBMs with multiple warheads. The submarine completed a dry dock maintenance period at the base’s Trident Refit Facility (TRF) in the second half of 2019.
As stated by Rood, the US defense department identified in its 2018 Nuclear Posture Review the requirement to “modify a small number of submarine-launched ballistic missile warheads” to address the conclusion that potential adversaries, like Russia, believe that employment of low-yield nuclear weapons will give them an advantage over the United States.
“This supplemental capability strengthens deterrence and provides the United States a prompt, more survivable low-yield strategic weapon; supports our commitment to extended deterrence; and demonstrates to potential adversaries that there is no advantage to limited nuclear employment because the United States can credibly and decisively respond to any threat scenario,” Rood said.
According to FAS, the W76-2 is estimated to have an explosive yield of about five kilotons. The first W76-2 (known as First Production Unit, or FPU) was completed at Pantex in February 2019.
FAS estimates that approximately 50 W76-2 warheads were produced.
According to the US National Nuclear Security Administration, the W76-2 program is a modification of the W76-1 warhead to provide a low-yield, sea-launched ballistic missile warhead capability.