A New and Controversial U.S. Nuclear Weapon Goes to Sea
The W76-2 is a small, tactical nuclear warhead designed to counter enemy tactical nuclear weapons.
The warhead is actually derived from the existing W76 warhead, each of which is large enough to flatten a city.
Arms control advocates warned that the new nuclear weapon was not needed.
Somewhere in depths of the Atlantic Ocean the USS Tennessee is carrying out a mission it’s carried out dozens of times: deter adversaries from launching a surprise attack on the U.S. But this time it's carrying a new weapon, one designed to prove that Washington can retaliate against a tactical nuclear attack by launching one of its own.
The weapon is the W76-2 nuclear warhead. Normally, ballistic missile submarines such as the USS Tennessee go to sea with 20 Trident II D-5 submarine-launched missiles, each carrying 4-5 W76 or W-88 warheads. Each W76 warhead has an explosive yield of 90 kilotons, or 90,000 tons of TNT. That’s enough to flatten a city or industrial target: by comparison, the atomic bomb dropped on Hiroshima was just 16 kilotons. Others D-5s carry the more powerful 455 kiloton W-88 warhead.
The U.S. has a fleet of 12 nuclear ballistic missile submarines like the Tennessee, with a handful at sea at all times. Their mission is to hide underwater, waiting for the signal that the U.S. has undergone nuclear attack. These submarines are designed to ride out an attack and then launch their missiles against the offender in a devastating counterattack. The idea is that no country would launch a surprise nuclear attack the U.S. unless it could assure itself that it would not suffer a retaliatory strike. Tennessee and her sister ships guarantee retaliation, thus deterring the enemy from attacking.
The W76-2 is actually a typical W76 thermonuclear warhead modified to detonate at a lower explosive yield of just 5 kilotons—or 5,000 tons of TNT. The Pentagon believes Russia is mulling a strategy in which it might launch a tactical nuclear weapon in order to end a conflict on its own terms. This “escalate to de-escalate” strategy is designed to shock adversaries such as the U.S. or NATO, forcing them to either retaliate with a tactical nuclear weapon of their own or throw in the towel.
The logic behind the W76-2 is that it will provide the U.S. with the ability to counter a low-yield nuke with one of their own—one that can’t be shot down. This will, theoretically, prevent an adversary from launching a nuke—and maybe even starting the conventional war itself—knowing ahead of time that Washington is prepared ahead of time for a nuclear tit-for-tat.
The Federation of Scientists believes that USS Tennessee went on patrol sometime in late December 2019, which means it’s still out there right now. FAS also estimates that two of the Trident II D-5 missiles have a single W76-2 tactical nuclear warhead.
Is all this necessary? Maybe not. Arms control activists campaigned hard against the W76-2, arguing that it was not a necessary weapon system, but the Trump Administration pushed ahead to rapidly develop and field it. The Federation of American Scientists has posted an in-depth discussion of the technology, strategy, and politics of the new warhead.
For now, the W76-2 will probably go to sea with all future missile submarine patrols.
Source: Federation of American Scientists
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