Database of radiological incidents and related events--Johnston's Archive

Novaya Zemlya nuclear test, 1969

compiled by Wm. Robert Johnston
last modified 24 February 2006

Date: 14 October 1969

Location: Matochkin Shar, Novaya Zemlya, Russia, USSR

Type of event: accidental radioactive release from underground nuclear test


At 07:00 UT on 14 October an underground nuclear test was conducted at the Matochkin Shar region in Novaya Zemlya. Three devices were detonated in two tunnels with a total yield of 540 kt: one device yielding between 20 and 150 kt along with one device yielding between 150 and 370 kt in tunnel A-7, at a depth of 500 meters; and one device yielding between 150 and 370 kt in tunnel A-9 at a depth of 520 meters. About one hour after the test a gas plume burst from the surface near tunnel A-9. Factors in the early venting included reaction with carbon dioxide in the surrounding rocks, thermal weakening of the cement plug around the nuclear device, and gas escape facilitated along a fault to the side of the mountain. Several hundred test personnel were in the vicinity and were not evacuated until 40 to 60 minutes later; the response to the accident was confused, compounded by the early departure of those in authority. On 24 October those more seriously exposed were transported to Moscow for examination and treatment. Over 80 people received doses of 40 to 80 rad.

Consequences: Unknown number of injuries.


© 2006 by Wm. Robert Johnston.
Last modified 24 February 2006.
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