Jeffrey LewisSubcritical Nuclear Test

The Department of Energy has released a video of a subcritical nuclear test.

A subcritical test results in no yield and would be permissable, even under a comprehensive test ban. Subcritical tests are used to determine the physical properties of fissile materials.

Of course, subcritical tests can raise suspicion, as Wolfgang Panofsky has noted, that a country is conducting concealable low yield testing. In 1997, Russian subcritical experiments appear to have coincided with an earthquake, leading to claims that Russia was conducting clandestine low-yield tests.

The decision to publish a film of a subcritical test is one that I think should be commended, rather than subject to demonstration.

Suzanne Jones and Frank Von Hippel proposed some transparency measures for subcritical tests.


  1. Pavel Podvig (History)

    It was 1997.

    [I’ve updated it, thanks…]

  2. MKH

    What do you think the marbles are for? Just packing material?

  3. Michael Mealling (History)

    But where’s the Kaboom! There was supposed to be an earth shattering kaboom!

  4. Darren Bane (History)

    I’m not an expert, but those marbles seemed to be made of glass. And vitrification is a good way to stabilise nuclear waste before you bury it.