Controversy Over New W76-2 Low Yield Tactical Nuclear Warhead Unfounded

USS Tennessee leaving Kings Bay, Georgia. Credit Russ Underwood.

According to the Federation of American Scientists, the USS Tennessee (SSBN 734), which left port in Kings Bay, Georgia at the end of 2019, is the first submarine to go on patrol armed with the new W76-2 warhead, a low yield nuclear device of 5 to 7 kilotonnes of TNT (21 and 29 TJ).

To put that into context and frame of reference;

  • The most powerful conventional (non-nuclear) weapon in the world, which is currently the US military’s GBU-43/B, Massive Ordnance Air Blast “MOAB” with a yield: 44 tons TNT. (0.18 TJ)
  • The Hiroshima bomb, “Little Boy”, is estimated to have been between 12 and 18 kilotonnes of TNT (50 and 75 TJ) (a 20% margin of error)
  • The Nagasaki bomb, “Fat Man”, is estimated to be between 18 and 23 kilotonnes of TNT (75 and 96 TJ) (a 10% margin of error).

Low Yield Nuclear Weapon

The Pentagon reaffirmed its determination to field a new nuclear weapon designed to allow the U.S. to match Russian and Chinese tactical weapons on the battlefield.

The new W76-2 is simply a W76-1 (100 kilotonnes) thermonuclear weapon configured to only partially explode. A typical thermonuclear bomb is a two-stage design incorporating a primary nuclear device “boosted” to a much higher explosive yield by a “secondary” of fusion fuel. According to FAS; The National Nuclear Security Administration (NNSA) has said the low-yield version, the W76-2, would be configured “for primary-only detonation.” This could mean a yield of less than 10 kilotons.

However, critics of the new low yield warhead say it accelerates a drift towards thinking of nuclear weapons as a means to fight and win wars, rather than as purely a deterrent of last resort, and that the use of tactical nuclear weapons against similarly-armed opponents may carry a significant danger of escalating the conflict beyond anticipated boundaries,

According to several reports, including by the Carnegie Endowment for International Peace and Bulletin of the Atomic Scientists, as a result of the effectiveness and acceptability of USAF use of precision munitions with little collateral damage in the Kosovo conflict in what amounted to strategic destruction once only possible with nuclear weapons or massive bombing, Vladimir Putin, then-secretary of Security Council of Russia, formulated a concept (“escalate to de-escalate”) of using both tactical and strategic nuclear threats and strikes to de-escalate or cause an enemy to disengage from a conventional conflict threatening what Russia considers a strategic interest.[1][2][3] The lowered threshold for use of nuclear weapons by Russia is disputed by other experts.[4][5] That said, from a psychological and tactical perspective, the W76-2 is a nuclear weapon and would still be regarded as one in a theatre of war, particularly in terms of both political and radiological consequences of its usage.

Arms Control

However, in the meantime, NATO continues to move forwards with a plan to upgrade its tactical nuclear weapons with precision guidance that would make them equivalent to strategic weapons in effect against hardened targets, and to carry them on stealth / UAV aircraft that are much more survivable against current air defences.[6]


  1. Detonation simulator by Alex Wellerstein, assistant Professor at Stevens Institute of Technology.


  1. “Why Russia calls a limited nuclear strike “de-escalation””. 13 March 2013.
  2. ^“The Role of Nuclear Weapons in the U.S.-Russian Relationship”.
  3. ^Russia’s Nonstrategic Nuclear Weapons, by Dr. Jacob W. Kipp, Foreign Military Studies Office, Fort Leavenworth; published in Military Review May-June 2001
  4. ^“The Myth of Russia’s Lowered Nuclear Threshold”. 22 September 2017.
  5. ^“The Elusive Russian Nuclear Threshold”. 26 November 2019.
  6. 6 Kristensen, Hans M. “Germany and B61 Nuclear Bomb Modernization.”FAS, 13 November 2012.
  7. S. National Archives
  8. Nuclear Security