Nuclear power for Cruisers and Destroyers

I do realize the cost in both the reactor and potential environmental issues is high, but I find myself wondering why the Navy went away from small nuclear reactors for surface combatabts.

Its reserved nowadays for submarines and carriers. But a Arleigh Burke class ship that could steam for years without refuling? What about the tankers that supply CBG's can you imagine how much they could offload if they did not have to keep thier own fuel bunkers?

As oil goes up and up, this may be a viable propulsion system in the furutre. Especially when the navy is talking about an all electric ship, rail guns etc.

What brought this on? One of my project this winter is scanning the 30,000 slides my father took since 1963. (12 at a time) and I came across this just now:


external image

Fleet week, San Francisco, 1965. What USN ship is it? This is pretty easy.



[edit on 1/16/06 by FredT]

The picture looks like the USS Long Beach. I saw it deactivated here at Newport News Shipbuilding. I also saw a number of the nuclear powered cruisers built here following the first three Nuclear surface ships built for the Navy These were designated CGN's The last one being the USS Arkansas CGN 41. Two nuclear power plants each. Two engine rooms, two screws.
As I recall these ships have since been decomissioned. Part of this is due to the fact that in those days they were built with Aluminum superstructures for weight savings. This metal was discovered to be very lacking in the Falklands Islands Wars of the early 1980s. Hence thier early retirement.
Also Fred T..cruisers with reactors are very expensive and I believe the Navy wants to save their uranium fuel for submarines and carriers. What is not known by most of the public is that almost half of a nuclear ships costs are due to the reactors if the design incorporates such.
What the Navy has figured out is that with Gas turbines they can get underway just as fast. Merging gas turbine technology with variable pitch propellor technology they can milk out the milage or go to speed very quickly. Also if you are ever able to see these ships in drydocks ..the screws ..or wheels are hugely out of proportion compared to the hulls. THis was not the case with the CGN cruisers. The CGNs had fixed blade wheels or screws.
If you can find it ..look for pictures of the USS Cole piggy backed on that salvage vessel carrying it back to the states for repairs after that terrorist attack in Aden,Yemen. They had to cut a hole in the deck of the piggy back vessel as the wheels are so large THe wheels would not clear with the available keel blocks underneath the Cole. THe deck had to be cut..the wheels are so large. THese types of cruisers are very fast...very. THey drink alot of fuel at speed but no doubt about their ability to get up to speed.
Another thing not known by most of the public...Cruisers more than submarines and carriers are considered expendable. They are there to protect the carriers...they are screening vessles ..designed to take the first hits.. Hence another reason not to put expensive nuclear power plants on them. This knowlege has not escaped the attention of other navys..they too are turning to this design ...gas turbines.
By the way Fred T...as I also recall the third of the first nuclear surface ships is the USS Bainbridge. CGN 25. As I recall she was classified as a frigate rather than a cruiser. As I recall these were early design reactors of which they had alot of teething problems taken care of in later designs. This means they leaked and wore out alot. Not cool in this buisness. Another reason they were deactivated. In the trades...the term for contaminated or spreading contamination do to leakage......is ...."crapped out.'
I have worked on the USS Enterprise several times. I dont care for it much for this reason..she is basically crapped out in different compartments..more so than the more recent carriers. This was the problem with early reactor plant designs over the long term. Think heavily about what this means.


Great post Fred T,
Thanks,
Orangetom

Yeah, to add to what Fred said, there's the simple fact that nuclear power's benefits become more attractive as size(and therefore fuel consumption) grow.
For cruisers and destroyers, they can pretty good range on their gas turbines, as the gas turbine design itself is incredibly efficient, the turbine has no "steam cycle" it powers the shaft more or less directly. So you can accelerate nice and quick, makes handling very nice.

For nuke power(or old "steam" power) you've got a huge steam cycle based around heating water to run your turbines. So you need a very large, bulky system which is actually very inefficient(but of course doesn't run out of fuel). For smaller vessels, where space is at a premium, it simply would not provide the same return on investment.

Also, gas turbines are much easier in terms of maintenance, and that's even when you ignore the radiation issues. Gas turbines are almost "plug and play" if there's a power failure, you pull into port and just swap it. For a steam cycle, I really wish I could show you some of the engineering diagrams I have seen, but trust me it is beyond belief due to mechanical complexity(lots of moving parts).
Oh, and gas turbines switch on faster. Nukes require a huge warming up period once they've been shut down, while a gas turbine is literally a flip of the switch and you're off.

Your right about the complexity of Nuclear steam systems. The engine rooms have very large and expensive reduction gears..same with conventionally/boiler fired steam systems. These gears are so expensive they often lease them ..they dont buy them. Gas turbines turn fast rpms too but they have a smaller reduction gear system between them and the shafting. Much less expensive.
Reactors take awhile to start from a cold start..but people are monitoring the reactors 24/7 from the first time the fuel is put in them to the time they are defueled. This never stops. This is a requirement. Temperatures are monitored and logged...if they have to get underway rapidly it can be done. Same with the engine room side...lubrication oils are mostly maintained at or near operating temperatures and moisture is removed from this type of system by centripital purifiers When ships are at the piers certified and ready to go..they are in a stand down condition but the engine rooms can be made ready quickly.
The main thing is the long term expense...over the cost of a reactor in a vessel designed to be hit first. Do we want to spend this kind of money and complications on a ship which will most likely be attacked first. In otherwords a disposable ship. These ships are planned with this in mind from the get go. They are there to be in the forefront of an attack on the carrier fleets as the front line in protective ships suffering attack from other aircraft or submarines.
The big change in the attack capabilities of these vessels is that they now carry Vertical Launch Tomahawk systems making their long range standoff attack capabilitys more potent, just as submarines now do the same.

Thanks,
Orangetom

Personally, I'd love to see more Nukes in our Navy. But, as mentioned above, putting a nuclear plant on a surface ship just isn't that easy. Carriers and Submarines make thier own special arguments, either that they need LOTS of fuel, or simply have to stay underway without refueling for vast periods of time.

One of the most effective Carrier groups in histroy was The maiden deployment of the USS Enterprise, accompinied by two nuke cruisers. (originally labled Frigates, due to missiojn, later classified as Cruisers, due to size) A battlegroup that can cruise the world at max steam, and that never needs to refuel, is a potent weapon of war. Or, as Moltke said, "an army which can fight on two fronts in a months time, effectively counts as two armies." (I think that's an accurate quote, I can't find the book:puz

It would be useful, but it's just not the most practicle way to do things.

It should also be noted that frigates and destroyers are the most likely vessels in the US Navy to be attacked. Do you really want small boats filled with explosives, seas skimming missiles or laser guided bombs anywhere near a nuclear reactor??????????

The larger vessels are inside the layered defense system and so are less prone to attack.



[edit on 17-1-2006 by paperplane_uk]

well, if your ship gets sunk and all your people are killed, it's typicly easy enough not to worry about what kind of mess got made in the process.

Great replies everybody.

Yes it is the Long Beach CGN 9.

I do realize the potnetial hazzards that a nuclear reactor entail esp. if one wer eto go down in a littoral area. However, given the huge demands the next generation naval ships will have in terms of electricity and given the rise in cost of fuel, A nuclear pwered DD-22 seems like the best of both worlds.

Nuclear reactors are expensive and complex, but given the safety record of the reactors powering the LA class and Ohio class subs .

The S6G reactor in a 688 class sub puts out 35000 shp
The S6W reacotr in the Seawold class puts out 52000 shp


The output specs on the navy's new (for the Virgina class) Transformational Technology Core Reactor are not avalible

By comparison
The LM2500 Turbines in an Arleigh Burke class DD-51 produce 25000 shp (4 for a total of 100000). in addition it also has a total of 7500 kw of additional generators (3) to powers its electrical system

Two reactor cores would supply this needed power quite nicely. I have no doubt the reactor cores would not be cheap but if you factor in a ships lifetime fuel costs it would be a sig. savings

Last I heard, the plan was for 7 of the Allison generators. So the power generating capacity should be around 17,500 KW.

Your last line is the real answer FredT. Short term costs. While in the long term cost savings would be significant, most people would only see the initial price tag, and hear the word "nuclear" and flip out. Radiation is Bad. That's all the average person knows, so if it's nuclear is Must be Dangerous. And there's no way the Navy could get the cost through for something like a fleet of nuclear destroyers or cruisers. People aren't interested in long term savings, they want an immediate return on their money.

Sorry it's a little rambling. It's 445am and I havn't slept yet, and only got a few hours of sleep yesterday.

[edit on 1/19/2006 by Zaphod58]

I'm not sure if that's entirely true.

In addition to the other cons listed before, nuclear reactors are sometimes more trouble than they're worth. They require periodic evals, and are much more maintenance intensive...requiring much closer attention to detail in maintenance. Furthermore, the gas turbine electric system on the DDX is very quiet, giving it acoustic stealth. The quieting measures for a nuclear steam driven system would be far more extensive.

Nuclear also brings up weight. And it's also not even necessary to run all the gas turbines at once. The Spruance class achieves high 20 knot performance running on just one of its two turbines to power both shafts. You don't need to run everything at once. Nuclear would also bring up crew requirements, as you need a specialized reactor team. It also increases personnel costs, as reactor personnel require more training. It would also affect SWO officer qualifications as well. The Navy is ALWAYS looking for new qualified nukes, even under today's personnel crunch. SWOs usually qualify on all their ship's systems...are they going to have to qualify for nuke systems as well? This would cause a huge revamping of naval personnel training and would likely change recruitment requirements as well.

It would be a big change, let's just say that. The small boys are considered expendable as well in a major war. They "take one for the team" if need be.

did the US just built new small ractors for cruisers and destroyers?

I dont know if the cost went down or not but would this new ractor type be able to be put in the ships?

They might just manage to shoehorn one into another large cruiser class, but nothing smaller will ever have a nuclear reactor. The numbers just dont add up

Agree with your assessment. Good to see you on here again.

And for Char2c35t and others...yes there are a number of new reactor designs out capable of being put into ships...small ones too. But the costs of them have not gone down...they have gone the other way. Much more expensive. Hence they are very choosy about how they would use them.
There are significant changes coming in shipboard propulsion and engineering support systems.....keep a eye on this. It has been coming for about ten years now...and still developing.
Any of you actually know how much raw unprocessed uranium is available in the world... or even processed stockpiles...together..both..??? Something to be considered!!! I would expect that even this resource is scarcer than oil over the long run.

Thanks,
Orangetom

Thought i had something to add then realised i did'nt.

Stellar

[edit on 20-1-2006 by StellarX]

Good memories. I served on that ship from '87 to '90.

Slept 200ft from a nuclear reactor!

DR

Originally posted by paperplane_uk
They might just manage to shoehorn one into another large cruiser class, but nothing smaller will ever have a nuclear reactor. The numbers just dont add up

Not true. The beam on a virgina class SSN is about 33 feet, 40 for the Seawolf. A Arleigh Burke is 50-60 feet. There is plenty of room. Heck even Perry Class Frigate has a beam of 45 feet. There should be plenty of room.

Cheers orangetom, it's been a while! You wernt suggesting they are near perfecting the mythical "all electric ship" were you??????lol

frigates and destroyers are the most space intensive vessels in existance. They barely have room for everything with the current CODEG (COmbined Diesel Electric and Gas) sytems. They are NEVER going to have a nuclear reactor on board. There just is no room.

ps. looking at just the beam of a vessel is a very poor way of judging their size.

You know paperplane..I worked a weekend on one of those frigates named the USS Gettysburg. I was quite shocked to learn that internally they have not much more room than a submarine. Crews berthing is quite cramped...the galley was the most spacious area I noticed while on board. Engine rooms just as packed full as subs too. The Gas Turbines were small and enclosed in a kind of sound dampening box. Yes they are quite space insensitive. In my ignorance I thought that being a surface ship they had noticably more room than a submarine. I was wrong.
While it is not necessary to go into any details there are reactor designs which will fit handily into the size of a destroyer. Once again it is just not practical for many of the reasons well stated by others on this thread.

As to the all electric ship..I do know that they are working in this direction but as of yet have alot of breakthroughsdifficultys to overcome. No doubt that motor technology has taken great leaps in the last twenty years as also has propellor/propulsion technology. I was quite surprised to step down into a dry dock under a ocean liner and get my first good look at one of these Aziopods.


Thanks,
Orangetom

So,
what happens when somebody Sinks one of These nuclear Babies?

If Argentinian Air Force sunk British Destroyers in Falkland War with free fall bombs, I am sure that Nuclear Cruisers and Destroyers are sinkable.

The Navy really enjoy the Pleasure of conducting combat operations in WATER, for if something goes wrong, it Sinks to the Bottom and nobody ever knows about it. Just like Numerous Soviet and American Submarine Accidents during the Cold War - nuclear reactors and possibly nuclear warheads sleeping on the bottom of the Ocean, slowly spreading their Deadly cargo.

I wonder what kind of Fish swim in those Oceans...