However, the declared number of casualties and the seniority of the deceased personnel is unclear. It is assumed the tragedy occurred onboard the AS-12, which has an estimated crew of some 25 officers.

All these special-purpose submarines are assigned to the 29th “deep water” Submarine Division based at the Gadzhievo submarine base on the Kola peninsula.

Formally assigned to the Russian Northern Fleet, the “deep-water” submarine division is under the direct control of the Russian Ministry of Defence’s GUGI Directorate, which oversees covert marine and naval activities ranging from deep-sea oceanographic research to covert testing of advanced sea-based combat systems, to undersea special operations.

Covert trials of a nuclear-armed torpedo?   While official word suggests the submarine was undertaking scanning of the seabed in one sector of the Barents Sea, the actual mission being undertaken may be different.It is possible the submarine was taking part in the covert sea trials of the Poseidon sub-sea strategic combat system (a large calibre nuclear torpedo) .

The tragedy would be the first reported large-scale fatality sustained by GUGI’s secret force.

But it cannot be compared with previous disasters involving Russian nuclear-powered submarines such as the RFS Kursk Oscar II class catastrophe back in 2000 or the incident onboard RFS Nerpa Akula IIclass back in 2008.

This disaster has happened within a unit designed specifically to operate in extreme physical environments where the safety and professionalism of the crew is a key to survival and success.

The crew comprises only middle-to-senior rank officers…….

Was a nuclear disaster averted?

It is understood that the fire onboard led to the fatal intoxication of more than half of the crew — about 14 out of some 25 onboard — and serious injuries of another four or five onboard.

Any submariner would concur that a fire onboard a submarine on deployment poses a serious risk. Fire onboard a nuclear-powered submarine is even worse.

While it is unknown what triggered that fatal fire, a mechanical failure or a human error, the fact is clear: the crew, at the cost of their lives, prevented a potentially major environmental disaster if the DSV had sunk to the bottom of the ocean, or exploded…… https://www.abc.net.au/news/2019-07-03/russias-nuclear-submarine-disaster-test-vladimir-putin-navy/11274964