About the beginning of the program SSBN-X or Ohio Replacement became known in 2008 year, when it was announced about preliminary research on the appearance of a promising submarine missile carrier. At the end of August 2012, it became known about the completion of the formation of common requirements for new submarines. 31 in August at the Washington Navy Yard shipyard (Washington, DC) a package of documents was signed concerning the requirements for the SSBN-X project, and a week after that the appearance of the necessary boat was approved by the command of the naval forces.
USS Louisiana SSBN-743 arrives at the first home port at Kitsap Base in Bangor, WA, October 12 2005
According to reports, the Ohio Replacement boats should be about the same size as the Ohio. At the same time, however, at the expense of a slightly larger case diameter, the full displacement of SSBN-X will be approximately two thousand tons more and amount to 20,5-20,8 thousand tons. The prospective submarine will be equipped with a nuclear power plant, electric motors and jet propulsion. Driving characteristics of the new submarines should not be lower than that of the “Ohio” project, with the need to reduce noise. The main feature and the main difference from the original Ohio Replacement Ohio will be the composition of weapons. Prospective boats should carry the Trident-16 version D-2 5 intercontinental ballistic missiles.
According to the current plans of the Pentagon, SSBN-X submarines will have to be in the ranks of the US Navy from the 2025-30 to the 2070-80 years. Achievement of such service life will be possible due to some changes in the structure of the onboard equipment. First of all, they relate to the reactor. A new nuclear power plant must have a service life of at least forty years, which coincides with the required service life of the boat itself. Thus, SSBN-X will not have to be removed from service for long-term maintenance and repair of the reactor, as was the case with all previous US nuclear submarines. It is worth noting that these requirements for Ohio Replacement in comparison with Ohio look quite severe: the Ohio project boats need to recharge the reactor and prevent all systems after twenty years of service.
Another technical problem concerns the armament of promising submarines. The United States Navy wants to get a submarine equipped with a modular system of mine launchers. The unified CMC (Common Missile Compartment) launch complex will have a modular structure. Since the UK is taking part in the SSBN-X project, this approach will allow us to equip promising boats of both countries with identical launchers and missiles, which will directly affect the cost of each individual submarine. According to the current plans of Washington and London, a CMC launch complex with sixteen mines will be placed on American submarines, and a reduced version of eight “cells” on the promising British submarines of the Successor project. The reasons why Britain is actively involved in the development of the CMC system are interesting. The fact is that the first of the English boats of the Vanguard project in 2024 will reach the age at which it should be written off. Americans, in turn, will begin to write off their "Ohio" three years later. Thus, the British naval seamen, wishing to continue the operation of the Trident family of missiles, are interested in the soonest completion of work on the CMC topic, so as not to be left without strategic submarines. Because of this, since 2010, the UK has covered a large part of the research and development costs.

The characteristic problem of the Ohio Replacement project, even at the design stage, was the constant fluctuations in the cost of finished submarines. After several years of disputes, the US military agreed to reducing the SSBN-X series of boats to 12 units. At the same time, the cost of the program is constantly becoming the object of criticism, above all, of congressmen. At the beginning of the program in 2008-09, it was planned to spend billions of dollars on the construction of each of the submarines at 7-8. Subsequently, under pressure from the financial structures of the Pentagon and Congress, the command of the Navy had to agree to a reduction in the maximum cost of new submarines to 4,8-5 billion apiece, with corresponding losses in quality and performance. At the same time, over the past months, naval military leaders have had to “fight” with contractors too. According to several calculations, the cost of each SSBN-X submarine can be reduced to 5,5-5,8 billion without any significant loss in capabilities, which still exceeds the amount required by Congress.
In March of this year, the Control and Financial Department of the US Congress published an interesting report. According to analysts of the Office, while maintaining the current financial trends, the total cost of the Ohio Replacement program may eventually exceed 90 billions, of which about 12 will be spent on design work, and the rest on the construction of the ships themselves. To this we should add a few more billions of service during the service and the indignations of the congressmen will be clear: the SSBN-X project is quite expensive even for the United States. For comparison, it is worth mentioning the economic indicators of the Ohio project, each boat of which cost 2-2,5 billion dollars.
The financial problems of the Ohio Replacement project so far have led to several serious consequences. Thus, difficulties in forming an acceptable cost for ready-made submarine missile carriers caused the purchase of the lead boat, previously planned for 2019, to be transferred to the 2021, which may lead to a shift in delivery dates for the entire series. In addition, to further reduce the cost of each submarine to the required five billion Pentagon, you may have to change the hardware requirements, or look for alternative ways to ensure the required characteristics. One of the ways to do this may be the creation of a modular architecture of onboard systems and equipment, which in the future will make it relatively easy and cheap to replace obsolete units with modern and advanced ones.
Anyway, the main problem of the SSBN-X project continues to be its financial side. The complexity of the development of new technologies and the creation of promising technology in this case "intersect" with the constant reduction of the defense budget. As a result, even the current plans for the construction of the head of the submarine for the 2021 year may not come true. In this case, the US Navy will have another problem: the ending resource of the existing Ohio boats and the impossibility of replacing them quickly and fully.

On the materials of the sites:
http://lenta.ru/
http://vpk-news.ru/
http://globalsecurity.org/
http://articles.janes.com/
http://cbo.gov/
http://fas.org/
http://navy.mil/