Comments on: Subcritical Testing at Lop Nor http://lewis.armscontrolwonk.com/archive/2239/subcritical-testing-at-lop-nor an ACW Network site Thu, 09 Feb 2012 09:41:05 +0000 hourly 1 http://wordpress.org/?v=3.3.1 By: Wm. Robert Johnston http://lewis.armscontrolwonk.com/archive/2239/subcritical-testing-at-lop-nor#comment-7105 Wm. Robert Johnston Sat, 04 Apr 2009 21:40:41 +0000 http://armscontrolwonk.com/?p=2239#comment-7105 Whether the UK has admitted to subcritical testing, the US has admitted it on their behalf. The DOE has announced that two subcritical tests at NTS were joint US/UK tests, Vito in 2002 and Krakatau in 2006: <a href="http://www.nv.doe.gov/library/newsreleases/KrakatauSuccessful_02232006.pdf" rel="nofollow">Krakatau Subcritical Experiment Conducted</a> Whether the UK has admitted to subcritical testing, the US has admitted it on their behalf. The DOE has announced that two subcritical tests at NTS were joint US/UK tests, Vito in 2002 and Krakatau in 2006:
Krakatau Subcritical Experiment Conducted

]]> By: peter Zimmerman http://lewis.armscontrolwonk.com/archive/2239/subcritical-testing-at-lop-nor#comment-7104 peter Zimmerman Fri, 03 Apr 2009 19:37:56 +0000 http://armscontrolwonk.com/?p=2239#comment-7104 Just a minor matter: by the convention of the CTBT negotiators in the US, “tests” involve nuclear yield and are prohibited. “Experiments” have no perceptible nuclear yield (i.e. remain subcritical) and are permitted. The demarcation, as far as close-up observers are concerned, between sub-critical and critical is pretty bright. It is difficult, especially if you haven’t conducted a lot of near-critical safety tests (in the US that means trying to keep nuclear yield below four pounds TNT equivalent) to go just barely critical and not go significantly critical. Yield goes up a lot faster than linearly with the compression beyond criticality. So I can believe that the Chinese made a costly mistake in a hydronuclear experiment, especially if it was designed to get close to critical or exceed the the threshold by a small amount. Just a minor matter: by the convention of the CTBT negotiators in the US, “tests” involve nuclear yield and are prohibited. “Experiments” have no perceptible nuclear yield (i.e. remain subcritical) and are permitted.

The demarcation, as far as close-up observers are concerned, between sub-critical and critical is pretty bright. It is difficult, especially if you haven’t conducted a lot of near-critical safety tests (in the US that means trying to keep nuclear yield below four pounds TNT equivalent) to go just barely critical and not go significantly critical. Yield goes up a lot faster than linearly with the compression beyond criticality. So I can believe that the Chinese made a costly mistake in a hydronuclear experiment, especially if it was designed to get close to critical or exceed the the threshold by a small amount.

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