Russia has again changed its mind about retiring its Akula ("Typhoon" in the West) SSBNs (nuclear powered ballistic missile subs). Two years ago Russia announced that at least two of the Akulas would be returned to service. But now that the Bulava SLBM (Sea Launched Ballistic Missile) has entered service and the new Borei SSBN has passed its sea trials, the risk of being with too few SSBN has passed. The Akulas are no longer needed and the remaining three will be disposed of.
Six of these 24,000 ton "boomers" (missile subs) were built in the 1980s, and three have already been scrapped. The others were to be retired because they were so expensive to operate. Two were retired, and these were the ones to be brought back into service. But in the last two years this was delayed as navy officials struggled with the huge costs.
These boats were the largest submarines ever built and each carried twenty of the huge (16 meters long and 2.4 meters in diameter, 90 ton) R-39 SLBNs. These missiles have all been retired from service. One of the Akulas had some of its missile silos converted to test fire the new Bulava SLBM, to be used on the new Borei SSBNs. The other two Akulas were to be taken out of retirement, with their silos converted to fire the smaller (12.1 meters long and two meters in diameter) Bulava SLBM. These refurbished Akulas were to remain in service at least until 2019.
The Akulas were built to complement, not replace, the existing Delta IVs and both classes are now to be replaced by new Boreis (which are closer in design to the Delta IVs). The Boreis are 170 meters (558 feet) long and 13 meters (42 feet) in diameter. Surface displacement is 15,000 tons and 16 Bulava SLBMs are carried.