Continuing with extracts and commentary from the book: "K-19, The Widowmaker" by the American author Peter Huchthausen.
"On August 12 2000 . . . the Russian super-submarine Kursk exploded and sank in 350 feet [about 100 meters] of water in the Barents sea . . . taking 118 Russian sailors and engineers to the deaths . . . Forty-nine top submarine officers, 36 more than the normal complement, were aboard the Kursk that day. They had come to observe a test firing of a remarkable new undersea weapon called the Shkval torpedo-missile. A super-cavitating missile capable of underwater speeds of more than 200 miles per hour [320 kilometers per hour] . . . The Kursk was testing an improved version of the Shkval that had a longer range and used liquid fuel, replacing the earlier solid-fuel system."
Liquid-fuel from the torpedo having leaked and reacted with other metals, causing a spontaneous fire with secondary explosions responsible for the loss of the Kursk.
As suggested an alternative theory the explosion of a conventional torpedo and not an improved version of the Skhval.
Mere firing of the Shkval torpedo creating an over-pressure within the torpedo room necessitating the opening of bulkhead hatches rearward in the boat, danger from accident that much greater, watertight
integrity of the submarine in a combat and in this case peacetime situation compromised.
That loss too of so many senior Russian submariners exacerbating the situation that much more! Such personnel hard to replace, years of institutional memory and experience gone in an instant!