Vladimir Putin has confirmed  on July 4, 2019  that the top-secret submarine that suffered a deadly fire was nuclear-powered, but Russia’s defence minister said the nuclear unit had been sealed off and was in “working order.”  The incident, which left 14 Russian sailors dead,  The Russian government has been slow to reveal information about the incident because the submersible, thought to be a deep-diving vessel used for research and reconnaissance, is among Russia’s most secret military projects.  The fire aboard the “Losharik” AS-31 submersible began in the battery compartment and spread through the vessel…The vessel is thought to be made of a series of orb-like compartments, which increase the submersible’s resilience and allow it to dive to the ocean floor. Once there, it can perform topographical research and participate in rescue missions. It may even be able to tap and sever communications cables on the seabed.

Officials claim the submariners sealed themselves in one of the compartments to battle the blaze and toxic fumes…A Norwegian official told Reuters there had been no “formal communication” from Russia about an incident aboard a nuclear-powered vessel, but “we would have been happy to have been informed of such incidents”….Accidents aboard submarines invariably evoke comparisons to Putin’s clumsy handling of the sinking of the Kursk nuclear submarine in 2000, which left 118 dead and families desperate for information about their loved ones.

Excerpt Putin confirms fire-hit Russian submarine was nuclear-powerered, Guardian, July 4, 2019