The accident, which took place in the submarine’s bow section, killed 20 and injured 21. The injured were taken to a military hospital in Vladivostok. The reactor of the vessel was not damaged, said the Russia Navy, and the submarine was headed back to an undisclosed location in the Primorye region of Russia’s Far East under its own power, but accompanied by rescue vessels.

The vessel is widely assumed by experts and the media to be the Nerpa, a Project 971 Shchuka-B attack submarine, classified as an Akula by NATO, but Dygalo and other naval officials will not confirm this.

The navy said the vessel had 208 people – or nearly three times more than its usual crew – aboard when the fire extinguishing system was activated, resulting in large scale inhalation of frion gas, an antioxidant used to extinguish fires on submarines.

Alexander Nikitin, head of Bellona’s St. Petersburg office, a former submarine captain of the first rank and a former naval radiation inspector, explains how the accident could have occurred aboard the Nerpa, and how the fatal effects should have been avoided.

According to official data, said Nikitin, the construction of the afflicted submarine began in 1991 at the Komsomolsk-na-Amur ship repair and building yard. The boat was undergoing sea trials at the time of the accident, and had not yet been passed to the Russian Navy.

Sea trials, said Nikitin, are a part of the state tests that all vessels must pass after they have been built. The trials are carried out by the trial crew from the shipbuilding yard (which is a civilian crew). The Naval crew is present for the tests, as well as members of the state commission. It is usual during sea trials that up to three times as many people as comprise the usual crew would be aboard a vessel.

The contractor, a representative of the shipyard, is responsible for carrying out the programme of sea trials, said Nikitin. The submarine is commanded by personnel designated and cleared to operate a submarine, usually the most senior crew member aboard, such as the chief of staff or the brigadier commander, etc.

Bellona’s version of events
Those aboard the submarine on Sunday died as a result of volume chemical fire extinguishing system (or LOKh in its Russia abbreviation). According to information released, personnel located in the torpedo compartment, or bow section of the vessel died, said Nikintin. This compartment has a large volume, and if there are no weapons in it, as apparently was the case, then most of the trial crew can be located there during rest periods, as there are not enough bunks to accommodate them.

As the LOKh system is activated, the compartment is filled with a gaseous substance, an antioxidant – low toxicity Freon 114B-2 – which arrests oxygen and thus extinguishes the fire. The people located in the compartment should have immediately deployed their personal defence systems or should have hooked themselves up to one of the vessels stationary breathing systems, said Nikitin. If this does not occur within two to three minutes, then one is poisoned with toxic Freon vapour.

Most likely, personnel were equipped with their own individual defence systems when the submarine put to sea for trials, as vessels cannot put to sea unless the entire crew is equipped with such devices, said Nikitin. It is another question as to were these devices were located and if ther were enough of them in the bow compartment.

Secondly, if the accident happened when resting personnel were asleep, many may simply not have heard the alarm that accompanies the activation of the fire extinguishing system. Others may not have understood what was happening or how to react to the alarm. The cenral command of the submarine might not immediately have noticed or understood what was happening as such events, like the independent triggering of the fire extinguishing system, are rare. Therefore the crew had little experience. It must be taken into account here that this was a young and inexperienced naval crew and a young trial crew because the Komsomolsk-na-Amur shipbuilding and repair yard has not built a boat in 15 years.

How could this have happened?
1. Technical reasons: Spontaneous activation. When a submarine is under construction for more than 15 years, many technical installations and specific parts, for example rubber goods, gaskets, packing rings, and so on lose their qualities. And it is entirely possible in this case that the fire system was triggered spontaneously.

2. On third generation vessels, fire extinguishing systems are set up to work automatically in a given compartment in the event of a fire. It is possible that someone from the crew (the trial crew) decided to have a smoke in the bow compartment, which is strictly forbidden. The alarm and then the fire system could have been activate by the smoke. The system is built such that when it is activated, there is now way to quickly stop the chemical fire extinguishing process.

3. In 1977, the a watch officer of a compartment of a second generation submarine in a second generation submarine accidentally triggered the fire system in the compartment he was in. As they say, he “called the fire department on himself.” But he was alone in one of the rear compartments. In fright, he managed to jump to the adjoining compartment and batten down the bulkhead. The submarine then had to surface to ventilate the compartment. It is possible that yesterday’s accident may have happened in an analogous manner – that is, someone by mistake or for another reason managed to dump the fire extinguishing chemicals into a compartment where many people were located.

Conclusion
There are a few matters in yesterday’s accident that are disquieting.

In the given circumstances, nothing happened to the reactor installation (at least according to the official version). However, the technical condition of the “new” submarine we are talking about here can have affect the reactor installation.

Secondly – if the crew of the submarine together with trial crew slipped up and let such a massively lethal accident occur, then there are serious questions about the professional preparedness of the crew as well as the trial team.

The factors leading up to this accident could lead to more serious consequences because in the sea trial also includes in its programme more tests for weapons and work regimes for the nuclear reactor.