Nuclear security

US nuclear weapons: first low-yield warheads roll off the production line

The US has begun making a new, low-yield nuclear warhead for its Tridentmissiles that arms control advocates warn could lower the threshold for a nuclear conflict.

The National Nuclear Security Administration (NNSA) announced in an email it had started manufacturing the weapon at its Pantex nuclear weapons plant in Texas, as ordered by Donald Trump’s nuclear posture review (NPR) last year.

The NNSA said the first of the new warheads had come off the production line and that it was on schedule to deliver the first batch – an unspecified number referred to as “initial operational capability” – before the end of September.

The new weapon, the W76-2, is a modification of the existing Trident warhead. Stephen Young, a senior Washington representative of the Union of Concerned Scientists, said its yield had most likely been cut by taking away one stage from the original two-stage, W76 thermonuclear device.

“As best we can tell, the only requirement is to replace the existing secondary, or second stage, with a dummy version, which is what they do every time they test fly a missile,” Young said, adding that the amount of tritium, a hydrogen isotope, may also be adjusted. The result would be to reduce its explosive power from 100 kilotons of TNT, to about five – approximately a third of the force of the bomb dropped on Hiroshima.