MOSCOW — A deadly explosion at a naval weapons testing range in northwestern Russia. A brief spike in radiation levels. An evacuation order issued, then rescinded, for a nearby village.
Last week’s mysterious accident on the White Sea, along with changing or contradictory information from Russian authorities, has led to speculation about what happened and what type of weapon was involved, and has even raised comparisons to the 1986 disaster at the Chernobyl nuclear power plant.
What is known and unknown about the Aug. 8 incident in the Russian region of Arkhangelsk:
A testing range was set up near the village of Nyonoksa, about 615 miles north of Moscow on the White Sea in 1954, when the Soviet Union’s missile program was still in its nascent phase. It has served as the main ground for testing a variety of missiles used by the Soviet and then Russian navy ever since.
They included anti-ship and anti-aircraft missiles of various types, as well as intercontinental ballistic missiles intended for the nation’s nuclear submarines.
The authorities have routinely closed various parts of the White Sea’s Dvina Bay during missile tests, and the approximately 500 residents of Nyonoksa have regularly been asked to temporarily leave their homes, apparently as a routine precaution during military activity.
The village is connected by rail to Severodvinsk, a city of 183,000 people about 19 miles to the east.
First word of the explosion came from the Russian Defense Ministry, which initially said the Aug. 8 blast of a liquid-propellant rocket engine killed two people and injured six others. It said in a statement that no radiation had been released, although the city administration in Severodvinsk reported a brief rise in radiation levels — a contradiction that recalled Soviet-era cover-ups of disasters like Chernobyl.
Two days later, Russia’s state-controlled nuclear agency Rosatom acknowledged that the explosion occurred on an offshore platform during tests of a “nuclear isotope power source,” and that it killed five nuclear engineers and injured three others. It’s still not clear whether those casualties were in addition to the earlier dead and injured.
The city administration in Severodvinsk, which has a huge shipyard that builds nuclear submarines, said the radiation levels there rose to two microsieverts per hour — approximately 20 times the area’s average reading — for about 30 minutes on Aug. 8. It then returned to the area’s average natural level of 0.1 microsieverts per hour.
Arkhangelsk region Gov. Igor Orlov said, “There is no evacuation,” and he claimed that some reports about the incident sought to sow panic.
Neither the Defense Ministry nor Rosatom identified the type of weapon that exploded during the test.