Talk:Neutron moderator

message: I have just added the carbon dioxide  mention under the general wording "carbon compounds" because of the earlier mention of hydrocarbons and because it struck me that others, e.g. carbon tetrafluoride, might be realistic. That is, I can't rule them out, so I chose a wording that covers everything. However, this should really be firmed up, and more detail should be given about how carbon dioxide is used - I suspect in liquid or supercritical form for the density, in something like a CANDU arrangement or even an analogue of an Aqueous homogeneous reactor, but I don't know. I also suspect it would have to operate at lower, less efficient temperatures for pressure reasons. Even so, it might be enough cheaper than heavy water to be justified in research reactors or as a bridging technology to kickstart breeding a starter stock of fissile material for later thorium breeder reactors. All this is valuable information which must be out there somewhere, so I hope someone who knows can follow this up and flesh it out. PMLawrence (talk) 12:33, 17 October 2008 (UTC)
thread_title:  Carbon compounds 

message: The lede paragraph currently states:
In nuclear engineering, a neutron moderator is a medium which reduces the speed of fast neutrons, thereby turning them into thermal neutrons capable of sustaining a nuclear chain reaction involving uranium-235.
Is this correct?  If the purpose of the moderator is to reduce the speed of fast neutrons, wouldn't the intent be to render the material incapable of sustaining a nuclear chain reaction?  N2e (talk) 13:57, 23 October 2009 (UTC)
replies: text: Why don't you look at the graph of fission cross section which clearly shows that fission probability is highest for slow neutrons. Fast neutrons have too much energy to be 'captured' by a nucleus to cause a reaction. Kbrose (talk) 16:20, 23 October 2009 (UTC)
thread_title:  Clarification of the lede 

message: According to the graph a 1keV neutron has a Fission cross section of about 6 barns and a 1MeV neutron about 1 barn. But, on the Uranium-235 page the second paragraph contains the statement 
'Its [uranium's] nuclear cross section for slow thermal neutrons is about 1000 barns. For fast neutrons it is on the order of 1 barn.'
So either the y scale on the graph is supposed to be logarithmic (which it isn't at the moment) or there is some other problem with either.Pondermotive (talk) 23:26, 30 April 2011 (UTC)
replies: text: Actually I think I am wrong here, 1KeV is still much hotter than thermal temperatures, which are a about 1/10-1/100th of an eV for a neutron I think. The graph would be more useful if it extended to thermal temperatures as it would convey more information, perhaps marking on the range of common energies from neutrons emitted from a fission event and thermal energies for neutrons to give more intuitive reference points.  —Preceding unsigned comment added by Pondermotive (talk • contribs) 11:21, 1 May 2011 (UTC)
thread_title:  Erroneous/unclear graph of fission cross section in reactor moderators section 

message: There's a discrepancy between the top table and the first paragraph which lists, "regular (light) water (roughly 75% of the world's reactors), solid graphite (20% of reactors) and heavy water (5% of reactors)".  The table says there are 29 heavy water reactors (8%) and 29 graphite reactors (8%).  KenJackson.US (talk) 21:52, 25 November 2011 (UTC)
thread_title:  Incorrect Math 

message: I think moderator is common for all nuclear fuels even in breeder reactor (thorium). But in this article they mentioned only U 235 in first para. Moderator is also used in U-233 also. see this :en:Molten salt reactor.
In my view take that U-235 in first para may correct. Is it right?--தென்காசி சுப்பிரமணியன் (talk) 06:48, 1 January 2012 (UTC)
thread_title:  Common 

message: The Boltzmann constant (kB) should be identified in the first equation given in the "Moderation" section:
E=\frac{1}{2}mv^2=\frac{3}{2}k_B T        (k_B is the Boltzmann constant)
or something like that.
While we're at it, the rest of the parameters should be named as well.  It's ordinary good encyclopedic communication to describe the parameters in equations.  It's surprising how many people wouldn't know what m or v or T is without labeling or good context.  It's our duty to communicate, not to presume our own level of knowledge (nearly) on lay readers.
108.7.160.131 (talk) 16:36, 21 May 2013 (UTC)
thread_title:  Boltzmann constant 

message: It's a little over reaction to lock a page for sock puppetry, I think.  The guilty party is one person (and his socks), not the article.  Injunctive action should be toward that person, not the article.  And also, the editing by socks must be disruptive, or warring, etc..  If the editing by socks is good, the fact that it was done via socks is irrelevant.  I say this because the single reason given for the lock is "persistent sock puppetry".  In and of itself that ain't necessarily such a bad thing, disruption would need to go along with it to compel action.  Disruption may well be implied by "persistent sock puppetry" which would make it a reasonable reason for action, but still the action should be toward the disruptor, not the article. 108.7.160.131 (talk) 16:36, 21 May 2013 (UTC)
thread_title:  Misplaced locking 

message: \xi= \ln\frac{E_0}{E} and n=\frac{1}{\xi}(\ln E_0-\ln E) imply n=1. Something is wrong there. --Chricho ∀ (talk) 01:06, 28 June 2013 (UTC)
thread_title:  Formula for ξ 

message: If the purpose of the neutron moderator is to slowdown fast neutrons so they become thermal neutrons, and thermal neutrons are more susceptible to propagate a nuclear chain reaction, then it seems the purpose of the neutron moderator is to assist the continuation of the nuclear chain reaction, acting as an amplifier. What moderation is occurring? Is it the speed of the neutron that is being moderated and not the rate or sustainability of the nuclear chain reaction?  — Preceding unsigned comment added by 1.124.107.128 (talk) 12:18, 30 April 2020 (UTC)
thread_title:  Why label this part a moderator?