US Navy may get more nuclear powered

Research and development work on adapting the design of the Ford (CVN-78) class aircraft carrier nuclear power plant for use in a new Navy cruisers CG(X) and could be extended to amphibious assault vessels.

Congress in 2007 passed the National Defense Authorization Act for 2008, an annual piece of legislation that tells the Pentagon how it should spend its budget. Under the act all future aircraft carriers, submarines and battle cruisers have to be built with a nuclear power system at their heart.

The National Defense Authorization Bill for 2009, which the Senate has still to pass, aims to shift the process up a gear by adding various types of amphibious assault ships to the list of those that must be powered by nuclear reactors in the future. Amphibious ships come in various forms, from those that incorporate a dock for landing craft, to undersized aircraft carriers for helicopters and vertical take-off aircraft – or a mixture of both. The vessels’ position in combat can also vary – from a “stand-off” over-the-horizon location to being moored to a pier in a combat zone.

Equipping such ships with nuclear reactors would have another advantage in military operations, says Wright. “Assault ships are carrier escort vehicles and will no longer be holding up a carrier task force’s progress by having to be refuelled every three to five days,” she says.

There was a 2007 study on the use of more nuclear power in the United States Navy

A potential advantage of nuclear power postulated by some observers is
that a nuclear-powered ship can use its reactor to provide electrical power for use
ashore for extended periods of time, particularly to help localities that are
experiencing brownouts during peak use periods or whose access to electrical power
from the grid has been disrupted by a significant natural disaster or terrorist attack. The Navy has stated that the CG(X) is to have a total power-generating capacity of about 80 megawatts (MW). Some portion of that would be needed to operate the reactor plant itself and other essential equipment aboard the ship. Much of the rest might be available for transfer off the ship. For purposes of comparison, a typical U.S. commercial power plant might have a capacity of 300 MW to 1000 MW. A
single megawatt can be enough to meet the needs of several hundred U.S. homes,
depending on the region of the country and other factors.

The Navy is looking to install radar requiring 30 or 31 megawatts of power onto its new Cruiser.

A nuclear-powered CG(X) could cost roughly 32% to 37% more than a conventionally powered CG(X). The Navy estimates that building the CG(X) or other future Navy surface ships with nuclear power could reduce the production cost of nuclear-propulsion components for submarines and aircraft carriers by 5% to 9%, depending on the number of nuclear-powered surface ships that are built.20 Building one nuclear-powered cruiser every two years, the Navy has testified, might reduce nuclear-propulsion component costs by about 7%.

At a crude oil cost of $74.15 per barrel (which was a market price at certain points in 2006), the life-cycle cost premium of nuclear power is:
— 17% to 37% for a small surface combatant;
— 0% to 10% for a medium sized surface combatant; and
— 7% to 8% for an amphibious ship.

Newly calculated life-cycle cost break-even cost-ranges, which supercede the break-even cost figures from the 2005 NR quick look analysis, are as follows:
— $210 per barrel to $670 per barrel for a small surface combatant;
— $70 per barrel to $225 per barrel for a medium-size surface combatant; and
— $210 per barrel to $290 per barrel for an amphibious ship. In each case, the

lower dollar figure is for a high ship operating tempo, and the higher dollar figure is for a low ship operating tempo.

A 2006 Navy study states that for a medium-size surface combatant that is larger than the DDG-1000, an additional cost of about $600 million to $700 million would equate to a procurement cost increase of about 22%. If building a Navy surface combatant or amphibious ship with nuclear power rather than conventional power would add roughly $600 million to $700 million to its procurement cost., then procuring one or two nuclear-powered CG(X)s per year, as called for in the Navy’s 30-year shipbuilding plan, would cost roughly $600 million to $1,400 million more per year than procuring one or two conventionally powered CG(X)s per year, and procuring a force of 19 nuclear-powered CG(X)s would cost roughly $11.4 billion to $13.3 billion more than procuring a force of 19 conventionally powered CG(X)s. For purposes of comparison,the Navy has requested a total of $13.7 billion for the SCN account for FY2008.

UPDATE: The United States navy has 280 active ships The Aircraft carriers (12 current, 2 under construction, 2 planned) and submarines (70 now, 5 under construction or ordered, at least 9 more planned) in the US navy are nuclear powered already.

The US has 10 amphibious assault ships (helicopter carriers) and 11-18 amphibious transport docks.

Amphibious assault ships (small aircraft carriers for marines)
* Tarawa class (3 in commission, 2 decommissioned)
* Wasp class (7 in commission, 1 under construction)

Amphibious transport docks (200 meters long versus 173 meters for a cruiser)
* Austin class (9 in commission, 2 decommissioned, 1 converted to an auxiliary command ship)
* San Antonio class (2 in commission, 3 under construction, 4 more planned)

The US Navy has 22 cruisers and 52 destroyers with 3 under construction, 7 more planned.

Dock Landing ships
* Whidbey Island class (8 in commission)
* Harpers Ferry class (4 in commission)

So 32-50 ships in the amphibious and cruiser categories could become nuclear powered at about 2 at a time over 16-25 years from 2015-2040.

3 thoughts on “US Navy may get more nuclear powered”

  1. Yes, this type of tether is unstable. That may not be a critical problem. Bicycles are unstable. Airplanes are unstable. The question is, can this type of tether be stabilized at acceptable cost? I think it is likely, but not yet certain.

  2. Here’s the basic problem–horizontal tethers are unstable due to gravity gradient forces. So you can’t “drag” a tether out the back of a spacecraft like you would out the back of a car.

  3. Interesting. I had always thought that those high efficiency thrust mechanisms like ion propulsion were great for satellites and deep space probes due to their efficiency but limited for human space flight since they don’t get you the acceleration needed to achieve orbit but here you can use the efficient thrust on the orbital acceleration thingamajig. It is the best of both worlds if it can be made to work.

    It also makes those “x-prize” type sub-orbital space vehicles seem a lot less useless.

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