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CGN(X) Nuclear Guided Missile Cruiser

The House Armed Services seapower subcommittee's portion of the fiscal year 2008 defense authorization bill directed the Secretary of the Navy to design and construct the next generation of surface warships with an Integrated Nuclear Power System. If the CG(X) is equipped with a nuclear power plant, which is an option being considered by the Navy, then advance procurement funding for the first CG(X) could have appeared in the FY2009 Navy budget submitted to Congress in early 2008, though it did not.

Electric Boat (EB) and Northrop Grumman Newport News (NGNN) are the two qualified nuclear capable private shipyards that can accommodate construction of surface ship nuclear propulsion plants. The two shipyards that have built all the Navy's cruisers and destroyers in recent years - GD/BIW and NGSS/Ingalls - are not licensed to build nuclear-powered ships.

Proponents argued that it made no sense at all to have aircraft carriers that carry 30 years' worth of fuel on board when the vessels that are necessary to protect them have to refuel every 5 days. Supporters of nuclear powerare are specifically looking at the CG(X) cruisers, which are to carry a large and powerful radar system and ballistic missile defense interceptors. The Navy has been conducting a wide-ranging design study of the ships. The nuclear power option is included in the study.

The Navy plans to build 19 of the cruisers starting in 2011. Equipping the cruiser with nuclear reactors could add an estimated $600 million to $800 million to the cost of each unit.

Addressing the nuclear power issue was a direct result of Representative Roscoe Bartlett (R-MD) making the committee aware of vulnerabilities to fuel, and the need for shipyard modernization again is a direct result of his efforts while he was chairman of the House Armed Services seapower subcommittee. Bartlett has been perhaps the leading member of the House of Representatives on the issue of peak oil and its implications. Congressman Bartlett is leading efforts to change U.S. energy policy to address the challenges of peak oil. US oil production peaked in 1970 and is in permanent decline. World oil production will also peak - perhaps disastrously soon. One of three scientists in the Congress, Dr. Bartlett is also a senior member of the Science Committee serving on two of its subcommittees, Energy and the Environment and Research and Science Education. Prior to his election to Congress, he pursued successful careers as a professor, research scientist and inventor, small business owner, and farmer. In 1999, the American Institute of Aeronautics and Astronautics (AIAA) awarded Dr. Bartlett its Jeffries Aerospace Medicine and Life Sciences Research Award. Dr. Bartlett's citation for the Jeffries award reads: "For pioneering contributions to aeronautical and aerospace medicine through more than 20 patented inventions on respiratory support and safety devices used by pilots, astronauts, rescue workers, pioneering NASA life-sciences space experiments, and over 100 publications."

Section 130 of the National Defense Authorization Act (NDAA) for Fiscal Year 2006 directed that the Navy provide a report on alternative propulsion methods for surface combatants and amphibious warfare ships. Section 130 identified several important and detailed matters to be addressed, including: the key assumptions used in carrying out the analysis; the methodology and techniques used in conducting the analysis; a description of current and future technology relating to surface ship propulsion; a description of each propulsion alternative and an analysis and evaluation of each such alternative from an operational and cost-effectiveness standpoint; a comparison of the life-cycle costs of each propulsion alternative; an analysis of when the nuclear propulsion alternative becomes cost effective as the price of a barrel of crude oil increases ("break-even" analysis); conclusions and recommendations of the study; and the Secretary's intended actions, if any, for implementation of the conclusions and recommendations of the study.

Guided by the Section 130 language, the FY 2006 Alternative Propulsion Study explored power systems in amphibious warfare ships, medium surface combatants (multi-mission air defense) and small surface combatants. Multiple ship/propulsion system concepts were evaluated on the basis of life-cycle cost and operational effectiveness. The study considered nuclear, gas turbine and diesel power sources, mechanical and electric drive, various types of propellers and podded propulsor systems, and other innovative concepts.  The study incorporated technology that is anticipated to be mature enough for transition to ship acquisition programs in the next twenty years.

The three types of ship concepts in this report do not reflect the requirements of any current or planned Program of Record ship.  Instead, they serve as boundaries of the analytical trade space for ongoing and future ship design efforts.

The primary results of this study are:

  • Ship displacement is not a good criterion for selecting the technology for power and propulsion systems.  Rather, lifetime and peak energy requirements drive the selection of power and propulsion systems.
  • Operational Tempo and Operating Profile significantly impact the break-even analysis of nuclear versus fossil fuel power and propulsion system alternatives.
  • Nuclear ship alternatives have higher ship construction costs (5th ship ~$600M - $800M premium in FY 2007 dollars) but have lower operating and support costs when fuel costs are considered.
  • Life-cycle cost break-even analysis ($70/BBL - $225/BBL) for Medium Surface Combatants displacing roughly 21,000 to 26,000 metric tons indicates that nuclear power should be considered for near term applications.
  • Life-cycle cost break-even analysis for Small Surface Combatants ($210/BBL - $670/BBL) and Amphibious Warfare Ships ($210/BBL - $290/BBL) indicates that life-cycle cost will not drive selection of nuclear power for these ships. 
  • Alternative fossil fuel power and propulsion architectures can reduce life-cycle cost over all current gas turbine plant architectures.
  • Ship vulnerability performance can be significantly improved with architecture improvements associated with zonal distribution, integrated power systems, and longitudinally separated propulsion equipment.
  • Nuclear powered ship alternatives provide operational benefits in surge to theater timelines and operational presence (time on station).
  • The amount of fuel required for transit and on-station operations of fossil-fueled ships can be reduced with use of more efficient propulsors, drag reduction, high efficiency prime movers and combined plants with boost prime movers.

The FY 2006 study analyses (for break-even costs and mission effectiveness) did include the impacts of significantly increased electrical loads including a consideration of future mission systems. In the particular case of the Medium Surface Combatant modeled, the significant increase in ship service loads is attributable to Theater Ballistic Missile Defense (TBMD) radar system requirements. Energy requirements for each ship type were based on Design Reference Missions (DRM's) derived from the DoD 2012 Baseline Security Posture (BSP) and the 2010-2014 MCO scenarios. These DRM's were comprised of Tactical and Operational Situations. These situations drove energy demand predictions based on mobility, survivability, and mission system energy demands. Warfare mission system loads that are continuously active drive the service electrical loads. Pulsed power weapons were not specifically modeled in the study as the energy consumption profiles and power system demands of future directed energy and electric weapons are not currently known.

The study modeled surge to theater (timeliness), operational presence (availability) and vulnerability (probability of loss of mission capabilities). Surge to theater was reviewed in terms of quantity of fuel and number of refuelings for high speed transits, plus maximum transit endurance without refueling. Systems that provide high-energy storage capacity and density, high energy conversion (i.e. engine) efficiencies and high thrust generation (i.e. propulsor) efficiencies improve performance relative to these metrics. Nuclear powered ships are superior to all fossil fuel variants in the transit scenarios modeled. Other technologies providing high levels of performance relative to the mission timeliness metric are diesel prime movers and single screw propulsors.

Operational presence was evaluated as the time a ship concept variant can remain on station while conducting missions in theater. DoD Defense Planning Scenarios provided the basis for the speed time profile and ship service electric loads modeled in the operational presence analysis. The nuclear powered variants are superior to fossil fuel powered variants in providing operational presence on station. Limiting factors for time on station for nuclear powered variants include ship stores and aviation fuel capacities. Fossil fuel plant variants with diesel prime movers have a significant advantage over gas turbine variants. The best performing small surface combatant fossil fuel variant studied is a mechanical-electric drive single shaft variant. This variant best captures the system efficiencies and flexibility provided by an Integrated Power System (IPS). Similar improvements in operational presence can be expected by employing hybrid IPS architectures.

Operational presence is improved through the inclusion of increased fuel tankage, albeit at increased acquisition and life cycle costs. The fossil fuel ships evaluated in this study were designed with fuel tankage capacities that are higher than traditional capacities. Nuclear ship options dominated these ships in surge and presence metrics, and would be even more dominant in comparison to current fleet ships.

Vulnerability is the probability of losing mission capability following damage from threat weapons. The vulnerability assessments demonstrated that both fossil-fueled and nuclear system architectures can be designed to similar vulnerability postures. Results of ship vulnerability assessment studies suggest that power and propulsion systems and architectures reduce ship vulnerability through redundancy, zonal distribution systems, separated distribution of propulsion systems, and flexible energy conversion systems providing for distributed conversion architectures.

Longitudinally separated propulsors as enabled by IPS and hybrid propulsion plants were the single largest discriminator among surface combatant variants in the vulnerability analysis. Since the life-cycle cost analysis did not significantly discriminate between IPS and mechanical drive plants, future surface combatant designs should consider IPS and hybrid propulsion plants, both fossil and nuclear.

Nuclear and conventional propulsion systems for Navy ships and submarines have been improved in recent years. Nuclear power plants are now simpler and smaller with reduced maintenance and personnel requirements, and their life span has also been increased. These improvements have eliminated the need for refueling newer submarines, such as the Virginia class submarines. Improvements have also been reportedly made to conventional propulsion systems, such as the Integrated Power System, which produces electrical power for both the propulsion system and ship's support systems.

Life-cycle cost break-even analysis for Medium Surface Combatants displacing roughly 21,000 to 26,000 metric tons indicates that nuclear power could be considered for near term applications under a range of assumptions about future oil prices, ranging from $70/BBL to $225/BBL. Although the price of oil briefly exceeded $100 per barrel in late 2007, US government forecasts of future oil prices do not anticipate such high prices in the future. In November 1998 the Energy Information Administration released a forecast of World Oil Prices out to the year 2020. At that time, oil prices were some of the lowest since the early 1970's, and that even by 2020 oil prices in real 1997 dollars were expected to reach only $22.73. The EIA's "International Energy Outlook 2005" was released in July 2005. It projected that, from anticipated high levels throughout 2005, world oil prices decline gradually through 2010 to $31 per barrel (in 2003 dollars). The Annual Energy Outlook 2007, released by the US Energy Information Administration in February 2007, predicted that crude oil prices would fall to less than $50 per barrel [in constant 2005 dollars] by 2013, before nearly $60 per barrel [in constant 2005 dollars] by the year 2030.

The AoA Oversight Board (OSB) for CG(X) consists of Flag and General Officers and Senior Executives from Office of Secretary of Defense (Acquisition and Program Analysis), Deputy Assistant Secretary of the Navy for Ships, Deputy Assistant Secretary of the Navy for Integrated Warfare Systems, Naval Sea Systems Command, Naval Reactors, Navy Staff, Program Executive Offices (Ships and Integrated Warfare Systems), Joint Staff, and Aegis Ballistic Missile Defense Office. The OSB assists the Analysis Director in assessing the validity and completeness of key program issues, alternatives, assumptions, measures of effectiveness (MOEs), integration and interoperability issues, international participation, process redesign approaches, scenarios, concept of operations and threat characteristics.

The Maritime Air and Missile Defense of Joint Forces (MAMDJF) Initial Capabilities Document was reviewed and validated by the Joint Requirements Oversight Council (JROC) on 01 May 2006. As part of the effort on CG(X), the Next Generation Cruiser, the Under Secretary for Defense (Acquisition, Technology, and Logistics), Kenneth Krieg directed, on June 16th, 2006, that an AoA examine the capabilities and cost of a range of options to address the gaps as defined in the MAMDJF. Additional AoA clarification was specified recently by the Secretary of the Navy who stated in the cover-letter for his Report to Congress on Alternative Propulsion Methods for Surface Combatants and Amphibious Warfare Ships, dated January 12, 2007, that "The ongoing Analysis of Alternatives for the Maritime Air and Missile Defense of the Joint Force capability, which will include recommendation of a CG(X) platform alternative, is incorporating the methods of this study, and is examining both fuel efficient fossil-fueled power plants and nuclear power alternatives. Again, the selection of power plant architecture for a particular class of ship must include analysis of the cross-program considerations described above."

In response to Representative Taylor's question to the Secretary of the Navy on the study dated January 12, 2007, the Secretary responded that the AoA "includes efforts to review the potential use of nuclear propulsion. The AoA is scheduled to be completed this year, and will address the physical possibilities of incorporating a nuclear plant, the cost versus operational effectiveness, the value and need for increased electrical power to allow for future technologies, and impacts to the logistics force." When the CG(X) AoA was complete, it will provide the foundation for the Milestone A decision, initially scheduled in late 2007 by Secretary Krieg, thus beginning the Technology Development Phase.

The 2007-2008 Center for Naval Analyses Analysis of Alternatives (AoA) was said to have looked at two possible nuclear powerplants based on existing designs: either a pair of the single-reactor Seawolf SSN 21 submarine plant, and or one of the two-reactor nuclear carrier plants. Doubling the 34 megawatts of the Seawolf plant would not even match the 78 megawatts of the Zumwalt. Halving the 209-megawatt plant used in nuclear carriers would yield a bit more than 100 megawatts, enough for power-hungry BMD radars plus an extra measure for the Navy's contemplated future directed-energy weapons and railguns.

The fiscal 2008 defense authorization act required the Navy to power its future classes of cruisers with nuclear reactors. The House bill contained the nuclear power provision, and was favored by House Armed Services Committee Seapower Subcommittee Chair Gene Taylor, D-Miss., and ranking member Roscoe Bartlett, R-MD. The Senate version of the bill did not express a view.

SEC. 1012

a) Integrated Nuclear Power Systems- It is the policy of the United States to construct the major combatant vessels of the strike forces of the United States Navy, including all new classes of such vessels, with integrated nuclear power systems.

(b) Requirement to Request Nuclear Vessels- If a request is submitted to Congress in the budget for a fiscal year for construction of a new class of major combatant vessel for the strike forces of the United States, the request shall be for such a vessel with an integrated nuclear power system, unless the Secretary of Defense submits with the request a notification to Congress that the inclusion of an integrated nuclear power system in such vessel is not in the national interest.

(c) Definitions- In this section:

(1) MAJOR COMBATANT VESSELS OF THE STRIKE FORCES OF THE UNITED STATES NAVY- The term `major combatant vessels of the strike forces of the United States Navy' means the following:

(A) Submarines.

(B) Aircraft carriers.

(C) Cruisers, battleships, or other large surface combatants whose primary mission includes protection of carrier strike groups, expeditionary strike groups, and vessels comprising a sea base.

(2) INTEGRATED NUCLEAR POWER SYSTEM- The term `integrated nuclear power system' means a ship engineering system that uses a naval nuclear reactor as its energy source and generates sufficient electric energy to provide power to the ship's electrical loads, including its combat systems and propulsion motors.

Details of the Center for Naval Analyses Analysis of Alternatives (AoA) remained closely held, but sources confirmed that the analysis examined dropping the Kinetic Energy Interceptor (KEI) from the CG(X) program. The KEI is a large ballistic missile-defense rocket under development by Northrop Grumman as a ground- or sea-based weapon to intercept ballistic missiles in their boost, ascent and midcourse flight phases. The KEI is much larger than the SM-3 Standard missile developed by Raytheon which arms Navy cruisers and destroyers for the BMD role. The 40-inch diameter KEI is nearly 39 feet long, while the 21-inch diameter SM-3 stands just over 21 feet tall. Both missiles use a kinetic energy warhead, intended to ram an enemy missile. Reportedly, a the missile launch tube for a KEI would need to be so large it would take the place of six SM-3 launch cells.

In July 2007 Christopher P. Cavas reported in Navy Times that the Center for Naval Analyses Analysis of Alternatives (AoA) may recommend two different ships to form the CG(X) program. "One ship would be a 14,000-ton derivative of the DDG 1000, an "escort cruiser," to protect aircraft carrier strike groups. The vessel would keep the tumblehome hull of the DDG 1000 and its gas turbine power plant. The other new cruiser would be a much larger, 25,000-ton nuclear-powered ship with a more conventional flared bow, optimized for the ballistic missile defense (BMD) mission. In all, five large CGN(X) ships and 14 escort cruisers would be built to fulfill the cruiser requirement in the Navy's 30-year, 313-ship plan, which calls for replacing today's CG 47 Ticonderoga-class Aegis cruisers and adding a specially designed sea-based missile defense force."

Two types of cruisers would allow one with SM-3 and the other with the KEI.

By mid-2008 the Analysis of Alternatives remained incomplete, and it was unclear whether it would be completed before the end of the year.

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Page last modified: 07-07-2014 19:41:04 ZULU