Russia has changed its mind about retiring its Akula ("Typhoon" in the West) SSBNs (nuclear powered ballistic missile subs). 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. 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 (Sea Launched Ballistic Missile), to be used on the new Borei SSBNs. The other two Akulas were put in reserve, but now they will be returned to active service, with their silos converted to fire the smaller (12.1 meters long and two meters in diameter) Bulava SLBM. The Akulas will remain in service at least until 2019.
The Akulas were built to complement, not replace, the existing the 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 558 feet (170m) long and 42 feet (13m) in diameter. Surface displacement is 15,000 tons, and 16 Bulava SLBMs are carried.
Work on the first Borei, the Yuri Dolgoruky, was delayed for several years because the first missile being designed for it did not work out. A successful land based missile, the Topol-M, was quickly modified for submarine use. This "Bulava" was a larger missile, cutting the Boreis capacity from 20 to 16 missiles. The boat also has four torpedo tubes, and twelve torpedoes or torpedo tube launched missiles. The Borei also sports a huge sonar dome in the bow.
The Boreis have a crew of 107 (compared to 163 on the Akulas), with half of them being officers (a common Russian practice when it comes to high tech ships like nuclear subs). Each of these boats will cost at least two billion dollars. This high cost, by Russian standards, is partly because many factories that supplied parts for Russian subs were in parts of the Soviet Union that are not now within the borders of present day Russia. So new factories had to be built. All components of the Boreis, and their missiles, will be built in Russia. A dozen (or eight) of these boats probably won't be completed for at least a decade.
The government has insisted that the Bulava will be made to work, no matter what it takes. Many Russian officials believed that the root of all these problems was the flight of so many skilled engineers and scientists from Russian defense industries after the Soviet Union collapsed (and sales promptly dropped over 90 percent). The smart people quickly found lucrative jobs in other industries, and there has been little new blood in the last two decades. The same thing happened on the manufacturing end. During the Soviet period, defense industries had the cash to attract the most skilled manufacturing staff. No more. And the dismal Bulava test performance is yet another result of this brain drain. The government apparently expects more delays in building the Boreis, thus keeping the three Akulas in service until the end of the decade provides some insurance against having no SSBNs in service. The Delta IVs entered service in the late 1990s, but have seen more time at sea than the Akulas.