Talk:Pressurized water reactor

message: The reactor at Fukushima used PWRs... after the tsunami they couldn't get the backup generators to run in order to restore cooling. I'd like to know which PWR reactors have a robust backup cooling system... do any? 
Clarafury (talk) 18:34, 25 April 2011 (UTC)
thread_title:  Fukushima 

message: there should be a link on the bottom of the page to 'an article' about the different types of reactors - PWR, ..., ..., ... (if such an article exists)  —Preceding unsigned comment added by 76.104.195.115 (talk) 04:41, 17 March 2011 (UTC)
thread_title: link on bottom of page 

message: I'm planing to do some cleanup and/or rewriting of this article over the next few days. In particular I'm planing to remove a lot of the stuff that is already covered in nuclear reactor leaving the bits that distinguish a PWR from other reactor types ( this appears to be the trend in other articles on special reactor types ). Please feel free to replace any material I remove if you feel it should remain. J.Ring 17:55, 10 September 2006 (UTC)
replies: text: I'm going to remove the context tag as I think the introduction and general article is now a lot softer and more in line with other articles on various reactor types. J.Ring 20:19, 10 September 2006 (UTC)
thread_title: Cleanup / Rewrite

message: Quite a lot still to do on this page. For example, a PWR is *not* fully thermalised as this page currently claims. A CANDU is, and a graphite-moderated reactor is, but in a PWR or BWR the neutron loss from capture in the light water means that the core must be as compact as possible, so it's a compromise. Not quite sure how to put this simply.
Quite a lot of the information really belongs in the nuclear fission or nuclear reactor pages, as it applies to any reactor, not just to a PWR. Andrewa 06:19, 21 Aug 2003 (UTC)
replies: text: The VVER is basically just the soviet disign for a PWR like you said.  There may be small differences, but I am not sure what they are. Lcolson 19:25, 3 January 2006 (UTC)
replies: text: The VVER is classified entirely as a PWR by definition, like the AP1000 is a PWR as well.  It's just a matter different kinds of PWRs. theanphibian
I Have a question about reactors in general. I dont understand why the steam needs to be condensed/cooled before going through the cycle again. Really simple version of the entire thing, reaction heats water, water heats other water, steam goes to turbine, then gets cooled, that is the step I dont understand because if the water/steam is cooled there doesn't it just need to be heated again to go back through the turbine? I know going through the turbine it will cool down but why cool it more than it needs to be? doesnt this lower efficency of the reactor? sorry if this is a simple question just dont know much about it. Caleb rosenberg 05:12, 20 February 2006 (UTC)

text: The most ideal cycle possible is the carnot cycle, which when plotted on a T-s diagram is a box. In order for the greatest second-law efficiency to be obtained we want a real cycle to be as close to this "carnot box" as possible. In a real rankine cycle the condenser forms the "bottom leg" of the box (which is essential what a PWR cycle is). More to the point, by definition a rankine cycle is a heat engine, which must have a hot and cold side. In the rankine cycle the condenser facilitates the heat transfer for the cold side. In laymens terms, if you don't have a condenser the cycle will continue to heat up until something breaks. Not only that, but very little energy would be created from a process like this, because the water would have to remain superheated vapor for the whole cycle, which completely defeats the purpose of a rankine cycle. HTH! Wizard191 01:28, 23 February 2006 (UTC)

text: Turbines operate most efficiently when the pressure at the inlet is much higher than the pressure at the outlet. When the steam is cooled it condenses to a liquid which lowers the pressure significantly. Thus by lowering the temperature of the water at the outlet, you can dramatically increase the efficiency of the turbine. Also, no turbine can convert 100% of the heat produced into electricity, thus if the reactor is not cooled it would eventually melt. This is called a loss of coolant accident, or LOCA. Btw Wizard, supercritical water is actually a very good working fluid precisely because it doesn't undergo phase changes. For this reason there is much work on Generation IV reactors cooled by supercritical water. 137.205.192.27 21:58, 3 September 2006 (UTC)
replies: text: Pressure doesn't change as you condense the fluid.  And objectively you want the condenser to operate at as low of a pressure as possible, which yes, means that temperature is lower.  Now that pressure (the pressure of the condenser) is dictated by the temperature of your cooling water, colder coolant can condense water at a lower pressure, allowing for the use of a larger low pressure turbine.  And if you used that idea of not using a condenser at all, then you would have a mixture at the exit of the turbine that was less dense than that coming into the turbine and it would take more energy to pump it back into the reactor that you got from the turbine to begin with.  Believe me, EVERYONE has these questions when they take the first reactor heat transfer courses. theanphibian 06:01, 15 April 2007 (UTC)
thread_title: A lot to do

message: "This is an advantage for the BWR design because boric acid is very corrosive and the complex charging and letdown system is not required."
It is my understanding that boric acid is not all that corrosive (Boric acid calls it a mild acid), but that, over a long time, (very) tiny leaks in the CRDM nozzles (the Alloy 600 sleeves that the control rod drive mecahnisms move in) to the head drip enough boric acid to make a problem. Comments? 
--nbach 04:17, 5 April 2006 (UTC)
thread_title:  Boric acid 

message: "Since the mass of a water molecule is very similar to the size of a neutron..."  What on earth does this mean?  First, I don't see how "mass" and "size" can be considered meaningfully similar in the first place.  Second, a typical water molecule will contain eight neutrons and ten protons, which is obviously far heavier than a single neutron.  I don't know what the article is trying to say here, but unfortunately do not have the background knowledge to correct or clarify it. Egomaniac 19:22, 11 December 2006 (UTC)
thread_title: Huh?

message: Look, I can't find anything here, in the article on nuclear power, or the article on nuclear plants that states the typical cycle time between refueling outages.  THIS IS IMPORTANT.  I will add later possibly, but either I just can't find stuff well or this is completely unacceptable to not include.theanphibian 17:41, 31 March 2007 (UTC)
thread_title: Time between refueling

message: I appreciate the comparison to Chernobyl to illustrate the safety advantages - but does a CANDU reference belong here? (I cleaned it up so it correctly says positive void, not temperature coefficient). Given that there is no refence to BWRs or gas reactors, etc. it is my opinion that this is not needed, as it is covered under the void coefficient page. This is the PWR article, and I'm not sure other designs belong here unless we're going to do a full-run comparison. I'll leave this a bit for comment, but I plan to remove this line in a few days if nobody feels strongly otherwise. Revr J (talk) 20:44, 4 July 2008 (UTC)
thread_title:  Moderator - other reactors 

message: This claim doesn't look right - the delayed neutron fraction is only a percent or two, so the amount of fissile material would only have to increase by a comparable proportion, making this not a powerful safety feature. I think what is meant is that PWR fuel is not enriched enough to go critical without a moderator, unlike fast reactor fuel which must be around 20% fissile.
:It's a safety feature but for a different reason.  Reliance on delayed neutrons for criticality results in power and reactivity swings low enough to be controlled easily.  Shutdown status without a moderator is a static safety feature, consider this more of a dynamic feature. Protonk (talk) 13:42, 8 September 2009 (UTC)
replies: text: Yes, no doubt that delayed neutrons are a safety feature, what I'm questioning is the statement "do not contain enough fissile uranium to sustain a prompt critical chain reaction". It's not particularly the quantity or enrichment of the fuel that allows reliance on delayed neutrons. It's an inherent property of the fissile material and neutron spectrum. --JWB (talk) 15:12, 8 September 2009 (UTC)
replies: text: Well, Beta is a function of the fuel choice.  The DNF can change based one state of the reactor (kinda beside the point I guess).  Let me take a look at the statement again. Protonk (talk) 16:00, 8 September 2009 (UTC)
replies: text: thoughts?  I'm a little rusty so please change as needed if I've made a grave error. Protonk (talk) 16:04, 8 September 2009 (UTC)
replies: text: I think this gets rid of what I was objecting to (it might still be somewhere else in the article, not sure) though it wouldn't hurt to actually say beta is a function of the fuel nuclide and neutron energy, and not of enrichment, if that is the case. --JWB (talk) 17:52, 8 September 2009 (UTC)
replies: text: I don't know how much we want to go down that road.  Beta is a function of the fuel choice.  Beta_eff is a function of the fuel choice, load and geometry (because we have to consider absorption and other cross sections).  Like I said I'm operating on distant memory right now.  I'll try to have something more authoritative to say later. Protonk (talk) 18:27, 8 September 2009 (UTC)

text:  I think that gets the point across (along w/ reminding me that the link is through effective neutron lifetime). :) Protonk (talk) 01:10, 9 September 2009 (UTC)
replies: text: OK, I think that is a well phrased description of how it works - but is it a particular characteristic of PWRs (or LWRs or thermal reactors in general) vs. some other kind of reactors? In this section, would expect comparison of PWRs to others. --JWB (talk) 02:45, 9 September 2009 (UTC)
replies: text: Ah.  That's a good point.  It's probably more of a characteristic of the fuel load, which isn't necessarily unique to PWRs. Protonk (talk) 02:51, 9 September 2009 (UTC)
thread_title:  Less fissile material than required for prompt critical 

message: Some of the material in this article applies to LWRs in general. At least if highly detailed, we should move it to that article and retain WP:Summary style here. --JWB (talk) 18:55, 10 September 2009 (UTC)
replies: text: Are you thinking of working on the BWR article as well? --JWB (talk) 20:11, 10 September 2009 (UTC)
replies: text: No, I wasn't. Protonk (talk) 20:16, 10 September 2009 (UTC)
thread_title:  Could move General LWR material to LWR article 

message: There is an error contained in the subtitles of the animation video featured in this article (An animation of a PWR power station with cooling towers). There is mention of fusion whereas in a PWR (as for other nuclear reactors) the proces is called fission.
I hope signaling this helps in improving the quality of the article.  — Preceding unsigned comment added by 109.130.183.62 (talk) 20:54, 6 May 2014 (UTC)
thread_title:  Error in subtitles animation movie 

message: The pressure in the primary coolant loop is given as 15-16 megapascals but I question this. If the water is not to boil, wouldn't the pressure have to be above the critical point of 22 megapascals? Biscuittin (talk) 14:01, 25 December 2014 (UTC)
replies: text: I think I understand. The water actually does boil, quote: "localized boiling occurs and steam will recondense promptly in the bulk fluid". Biscuittin (talk) 14:10, 25 December 2014 (UTC)
thread_title:  Pressure in the primary coolant loop 

message: Could we have a list of PWR grid power plants ? - If not in this article then where ? - Rod57 (talk) 13:45, 28 April 2019 (UTC)
thread_title:  Could we have a list of PWR grid power plants 

message: Could we have a list of licenced PWR designs - eg the Westinghouse 4-loop (used at Watts Bar), the three coolant loop Hualong One design, and any others ? - Rod57 (talk) 13:48, 28 April 2019 (UTC)
thread_title:  Could we have a list of licenced PWR designs 

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thread_title:  A Commons file used on this page or its Wikidata item has been nominated for deletion