Talk:A4W reactor

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[edit] Useless Links

The reason I reverted here is because the links don't exist and in my opinion shouldn't, at least in Wikipedia. Those links are better suited in the Wiktionary instead. -- RevRagnarok Talk Contrib Reverts 12:50, 17 June 2006 (UTC)

It seems to me that the links could point to quite interesting articles, with a number of details about the fuel and core lifespans, and about neutron shields. I would hardly call them "useless links". modify 12:54, 17 June 2006 (UTC)

[edit] Mis-Information

The shaft horsepower does not have anything to do with the A4W reactor. The shaft horsepower is determined by the turbines that are on the various Nimitz class aircraft carriers. The specification that is on all of the US Navy VNimitz Class Carriers is 260,000, but even that is incorrect. I do not think that the Navy will disclose the actual #s, so citing reliable references is going to be nearly impossible.

The fuel lifespan is not set for each of the A4W reactors in the US Navy fleet. Most are rated at 30 years, but they all vary due to different designs. The reactors themselves do not have a rating for lifespan.

In the design section, I took out all of the metals and percentages because they are just plain wrong. The design of the fuel is not correct either.

I also do not believe that BAPL or KAPL actually built the reactors. I believe that Westinghouse actually built them, with technical input from BAPL and KAPL, but I can not prove that. Nly8nchz 11:24, 15 October 2006 (UTC)

In the past, we have -when possible- tried to put information on shaft horsepower in the reactor article. This is in part because while any particular reactor design may be used on a variety of ship classes, the reactor normally produces a certain amount of steam which is then fed into the steam turbines designed for that particular reactor. Hence why the D2G reactor produces 30,000 shp regardless of if it is installed on the Bainbridge, Truxtun, California, or Virginia class cruisers. As long as the information in question is properly cited and from a reliable source, I am sure we are fine. Thanks for removing the incorrect info on the reactor lifespans and composition. BAPL was operated by Westinghouse until 1999, when Bechtel took over the government contract. --Kralizec! (talk) 12:41, 16 October 2006 (UTC)

Kralizec, you are 100% wrong in your statement "This is in part because while any particular reactor design may be used on a variety of ship classes, the reactor normally produces a certain amount of steam which is then fed into the steam turbines designed for that particular reactor." The reactor does indeed exchange heat to make steam, but the actual SHAFT HORSEPOWER is dedicated to the steam turbines, not the Reactor. Shaft horsepower is driven from the design of the turbines, which any reactor can drive the steam production. This is not to say that just any reactor can keep up with the steam demands of the 140KShp that the turbines "might" make.

Please stop putting the power that the reactor can make. Not only is the # cited a guess, the website that it is supposed to cite does not even have a MW rating. The website that is cited only has the shaft horsepower referenced at 140KShp, it does not mention the power that the reactor can make.

Once again, the shaft horsepower HAS NOTHING TO DO WITH THE POWER OF THE REACTOR. If you are going to talk about shaft horspower, talk about the steam side of the power plant, not the reactor.

On another note, if you do the calculations, the 140KShp is not equal to the 550MW that was cited on this page. www.onlineconversion.com

The power that each reactor can produce IS NOT ON THE WEBSITE IN THE LINK. If you are going to cite references, make sure that the info on the website is actually there. I operated an A4W reactor for 4 years in the Navy, I know what I am talking about, but it seems that Kralizec does not. This is not a slam, just making sure that people do not put up information that is not properly cited.Nly8nchz 04:51, 24 March 2007 (UTC)

Note
71.118.174.88's edits to the above paragraph were reverted, but you may want to take a look at them, it was possibly a response. — RevRagnarok Talk Contrib 12:10, 25 March 2007 (UTC)

Nly8nchz, thank you very much for your work to ensure accuracy in this article. People working together on topics they have interest in is one of the best ways to improve our encyclopedia. However while I share some of your frustrations on this topic, I would caution you to remember our rules on civility. Statements like "Kralizec, you are 100% wrong" and "I know what I am talking about, but it seems that Kralizec does not" do nothing to resolve what is essentially a content dispute and only serve to ratchet up emotions on all sides.

A few items of note on this issue:

  • The "550 MW" number was added to the article by an anonymous editor [1] earlier this month and no one caught the vandalism. Before that change, the article listed 104 MW, which is the correct metric conversion of 140,000 shp.
  • Official wikipedia policy (WP:VER) is verifiability, not truth. The power produced by the A4W reactor is properly cited from the Federation of American Scientists website, which clearly indicates that the "power per reactor" is "140,000 shp."
  • You stated "I operated an A4W reactor for 4 years in the Navy, I know what I am talking about." While I have no doubt that you are an expert on A4W reactors, please remember that official wikipedia policy states that original research (including personal experience) is strictly forbidden. Wikipedia articles should only contain verifiable content from reliable sources.

Thanks again for your interest and hard work on the article. Between the two of us, I am sure we will make this article the best, most accurate article it could possibly be! --Kralizec! (talk) 13:47, 26 March 2007 (UTC)

[edit] Ratings

First, let me point out why rating a reactor's power by Shaft Horsepower, as is done on the FAS website, is fallacious. How many reactors do NIMITZ-class carriers have? Two. How many shafts does it have? FOUR! So simply converting SHP to watts and multiplying by two reactors just does not work. Furthermore, the reactors provide steam to many other loads besides the main engines. There are turbine-generators for shipboard electrical power, steam-powered pumps, steam catapults, and so on. The reactors must generate much more power than that which is required for propulsion. This means that not only is 104 MW an incorrect power rating for the A4W plant, it is not even in the right ballpark. I would think that it would be better to have no number than an obviously incorrect number. Second, to say that the fuel lifespan is not set for naval reactors is incorrect. Each reactor core has a certain amount of fuel and burnable poison, and the laws of physics determine very clearly what the end-of-life of any given reactor will be. A reactor core lifespan is expressed in units of Effective Full Power Hours, and this is very closely monitored during reactor operation. The problem in determining exactly how long -- in years -- a naval reactor core will last, is that the reactor power varies greatly during its lifetime. Very rarely is a naval reactor actually operated at 100% full power. So while it is easy to calculate how long a reactor will last if it is run at full power all the time, it is not a practical or useful value. Only operational experience can determine the lifespan of a NIMITZ-class carrier reactor, and that has been shown. In a book published by RAND corporation's National Defense Research Institute, for the U.S. Navy, titled "Refueling and Complex Overhaul of the USS Nimitz (CVN 68): Lessons for the Future," I found the following quote in the summary (p. xiii): "At some point, the nuclear reactors that power an aircraft carrier run out of the fuel with which they were provided when the carrier was built. For the current Nimitz-class carriers, fuel depletion occurs after about 23 years." 129.6.122.174 02:00, 21 September 2007 (UTC)

Thank you for pointing out that oversight- you beat me to the punch there! Not to mention the fact that the max core rating stated in the various manuals is with the throttles cracked wide open and Average Coolant Temperature at the top of the band. Seeing as the reactor doesn't always operate at that temperature (and during sea trials on the Reagan, we ran the full power speed trial at an even higher elevated band personally approved by NAVSEA08, who was onboard at the time), there's even more evidence to shoot down the argument above. A note about the lifetime of the cores- while fuel depletion for Nimitz, Ike, and Vinson was around 23 years, with the increased tempo of operations of the CVN fleet (surges, longer, more frequent deployments, etc), shouldn't that be reflected in the article as well? Rumor in the fleet is that TR and Lincoln have been put on restricted EFPH because they're nearing the end of their core lives too fast for NGNN to be able to keep up with the pace of carriers requiring refueling. Anybody have any word about that?

Tspencer227 02:21, 16 November 2007 (UTC)