With the announcement that Russia has eliminated the last R-39 Rif (SS-N-20 "Sturgeon") submarine-launched ballistic missiles in September 2012, only one Typhoon remained in service, Dmitriy Donskoi, which was refitted with the more modern RSM-56 Bulava SLBM for testing.
Soviet – subsequently Russian – nuclear submarines are identified by the letter "K" followed by a number (for example, the lead boat of the Yasen class, the Severodvinsk, is K-560).
The sheer displacement of the Typhoon-class boats, comparable to several aircraft carrier classes, led to their classification as Heavy Cruisers (Тяжелый Крейсер).
Their primary weapons system was composed of 20 R-39 (NATO: SS-N-20) submarine-launched ballistic missiles (SLBMs) with a maximum of ten multiple independently targetable reentry vehicle nuclear warheads each.
The project was developed with the objective to match the SLBM armament of Ohio-class submarines, capable of carrying 192 nuclear warheads, 100 kt each, but with significantly longer range.
To accommodate this increase in range, Soviet SLBMs were substantially larger and heavier than their American adversaries (the R-39s is more than twice as heavy as the UGM-96 Trident I; it remains the heaviest SLBM to have been in service worldwide).
These ships – after the considerable engineering required to develop technologies to transfer oil from drilling platforms to the submarines, and later, to the waiting tankers – would then deliver their cargo world-wide.
In late December 2008, a senior Navy official announced that the two Typhoon-class submarines, Arkhangelsk and Severstal, that were in reserve would not be rearmed with the new Bulava SLBM missile system.
[citation needed] In late June 2009, the Navy Commander-in-Chief, Admiral Vladimir Vysotskiy, told reporters that the two submarines would be reserved for possible future repairs and modernisation.
The reasons for decommissioning the Typhoon-class vessels are the restrictions imposed on Russia by the Strategic Arms Reduction Treaty and successful trials of the new Borei-class submarine.