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

Nyonoksa explosion, 2019

compiled by Wm. Robert Johnston
last modified 26 August 2019

Date: 8 August 2019

Location: Nyonoksa, Russia

Type of event: explosion of experimental reactor


During offshore tests of what is believed to have been Russia's 9M370 cruise missile its nuclear reactor exploded. Testing of the 9M370 Burevestnik intercontinental-range cruise missile (Western designation SSC-X-9 Skyfall) was announced by Russia in 2018, and it was stated that it used a nuclear reactor for propulsion. On 8 August 2019 a missile, likely this missile, was being tested offshore from the Nyonoksa test facility near Severodvinsk. Apparently the reactor exploded on the test barge, causing casualties among the test engineers, some of whom were thrown from the barge into the water. Two reportedly died of radiation injuries within hours before they could be transported to an airport to fly to Moscow for treatment, implying extremely high doses (>10,000 rad). Three were transported to a civilian hospital in Severodvinsk with limited efforts to control radiation exposure by transporting responders. At least two individuals died at the hospital despite treatment; Russian authorities later removed medical records from the hospital. Russian authorities reported 5 killed and 3 injured, though some early reports indicated 3 to 7 killed and 15 injured, including 8 seriously (2 of these 8 are likely those that died at a Severodvinsk hospital). Seven injured were taken to Severodvinsk and Arkhangelsk hospitals; 6 were taken to a hospital in Moscow for treatment of radiation injuries (it is unclear if these numbers overlap).

Airborne contamination from the explosion was detected in Severodvinsk about 3 hours after the explosion as well as in the village of Nyonoksa. Information on the Severodvinsk radiation levels was removed from the city web site on 9 August. Residents were ordered evacuated from Nyonoksa (population 500) on 12 August, but this order was rescinded a few hours later (this evacuation order may have been unrelated to radiation issues). Part of Dvina Bay where the explosion occurred has been ordered closed to shipping for a month. About 60 civilian hospital staff involved in treating the injured were taken to Moscow for radiation testing; at least one doctor was found contaminated by cesium-137, and cesium-137 contamination at the hospital was significant. Analysis of the contamination in Severodvinsk showed several short half-life isotopes that had to have been recently produced in nuclear reactions (including barium-139 and strontium-91), confirming that the accident involved a nuclear reactor and not an RTG as some Russian statements have claimed.

Consequences: 5 fatalities (at least 4 due to radiation), 13 injuries (at least 6 with radiation injuries)


© 2019 by Wm. Robert Johnston.
Last modified 26 August 2019.
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