The fire that killed 14 people on Monday in a Russian military submarine in the Arctic started in the battery compartment, without touching its nuclear reactor, the Defense Minister said on Thursday.
"The main cause has been established. This is a fire in the battery compartment, which then spread"said Sergei Shoigu in a report to President Vladimir Putin, transcribed on the Kremlin website.
"The nuclear reactor of the apparatus is completely isolated and compartmentalized. The crew has implemented all necessary measures to protect the facility, which is fully operational", continued Sergei Shoigu.
It is the first time since the tragedy that the Russian authorities acknowledge that the submarine, the type of which was not revealed, operated on nuclear energy.
Sergei Choigou said he hoped for a "short while"to repair the submarine and put it back in the water.
According to a military source cited by the Kommersant newspaper on Thursday, the fire was able to start from a short circuit in one of the dashboards, turn on cables or oil, ventilation then drive the smoke through the submarine compartments.
At the time of the fire, the submariners were resting and had no time to protect themselves, according to the same source, adding that only five members of the crew survived by controlling the fire and making the submarine surface.
According to the newspaper, the submariners, who were then on a training mission near the Russian coast, had no real experience in the fight against fire.
According to the official version of the Russian authorities, the 14 submarines killed, highly qualified officers, were after the inhalation of toxic fumes during the fire. The accident occurred in Russian territorial waters aboard a plane described as a research submarine in the closed military port of Severomorsk, in the Arctic.
The Kremlin said on Wednesday that it would not provide detailed information on the accident on behalf of the "state secret".
According to the Russian press, the submarine in question is the AS-31, a modernized version of the AS-12, also called "Locharik", a secret trade for special operations or research and can dive up to 6000 meters deep.