Russian AS31 sub and US ‘dark target’ that killed 14 returns to service

MOSCOW, RUSSIA — Russia intends to return to service the Russian AS-31 nuclear submarine in 2025. It is currently being renovated, which should be completed this year. In 2019, a fire in the submarine’s battery compartment killed 14 personnel.

Russian AS31 sub and US 'dark target' that killed 14 returns to service
Photo credit: Law in Action

The AS-31 is a nuclear-powered Russian submarine also known by its nickname Losharik. It was launched at the beginning of the new millennium in 2003. The AS-31 is a deep-diving submarine. It is powered by an E-17 nuclear reactor. During tests in 2012 in the Arctic Ocean, the sub dived to a depth of 2,000–2,500 meters (6,600–8,200 ft).

The AS-31 participated in Russian GUGI operations. These are Russian operations to deploy submarines, drones, autonomous vehicles, and sensors. The Russian GUGI fleet consists of eight specialized and covert manned deep-sea submarines. The AS-31 submarine has been defined by the United States Northern Command as a “dark target” whose movements and actions must be tracked.

Current renovation

AS-31 is under repair. This was claimed by the Russian state news agency TASS, citing a source close to the Russian military-industrial complex. According to the source, repairs will be completed in 2024, and in 2025, after passing trials and tests, the submarine will be returned to service.

Russian AS31 sub and US 'dark target' that killed 14 returns to service
Photo credit: AP

The source told TASS that at the moment the submarine already has a new active zone of the reactor. New hydroacoustic, navigation and special equipment are currently being installed. The previous equipment was destroyed in the fire in 2019.

According to the TASS source, the fire did not affect the titanium hull of the submarine. The source says the hull won’t change. According to some analyzes in the Russian media, the hull of the submarine will allow it to continue submerging at the same depths, but it is unlikely that it will. Due to the fire and the avoidance of possible risks, the depth of immersion will be reduced.

The fire

The fire on July 1, 2019, on the submarine AS-31 is of interest, not because of the fire itself, but because of the crew at the time. There were seven captains of the first rank on board the submarine – among them there were two awarded the title of Hero of the Russian Federation. There was one civilian on board, without specifying who, in what position, and to which Russian military department. The fact that such a senior officer was on board suggests that the submarine was most likely conducting a risky activity, either testing a new weapon or deep-water capability at that.

Otherwise, on July 1, 2019, a bomb exploded in the submarine, killing 14 personnel by suffocation by inhaling toxic fumes and smoke. The fire broke out at a depth of 300 meters. The fire started in the battery compartment. There were only five people on duty who managed to put on the portable breathing apparatus. The incident took place in Russian territorial waters.

According to sources, in addition to the fire, at least one explosion occurred on board. The fire was extinguished for 40 minutes. The fire broke out at 8:30 p.m., and the sub surfaced in the Gulf of Urrah an hour later.

The investigation

Immediately after the fire, the evacuation of the personnel, and the removal of the submarine to the dry dock, an investigation into the causes began. The Russian media disseminate the result of this investigation.

Russian AS31 sub and US 'dark target' that killed 14 returns to service
Photo credit: RMA

According to the information provided, a fire broke out in the battery compartment after a massive explosion. The presence of burning batteries fuels the fire. The batteries were lithium-ion. The AS-31 submarine is not designed to use lithium-ion batteries, but silver-zinc ones. The replacement of the batteries is a consequence of the deteriorating relations between Russia and Ukraine due to the outbreak of the war in Donbas.

According to some hypotheses of the investigation, the batteries may not have passed the necessary tests before they were put into service. According to other hypotheses, a short circuit on the submarine caused the batteries to become overloaded. There is also a third hypothesis – sabotage.

There are suggestions that Americans and Norwegians watched the incident. But they, as well as Moscow, are silent about it, due to the secrecy of the entire project.


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