ConcernedScientist
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Mystytopia (talk) 22:47, 7 May 2007 (UTC) |
Bioremediation edit
Ey Up, There seems to be something a bit odd in the Bioremediation page. I left a note on the Talk page. Davy p (talk) 11:00, 6 June 2008 (UTC)
March 2009 edit
Welcome to Wikipedia. We welcome and appreciate your contributions, including your edits to Talk:Nuclear weapon design, but we cannot accept original research. Original research also encompasses novel, unpublished syntheses of previously published material. Please be prepared to cite a reliable source for all of your information. Thank you. Binksternet (talk) 01:46, 16 March 2009 (UTC)
Response to Binsternet Comment edit
Thank you for your response. I am aware that my comments upon the DISCUSSION thread of the associated article is not referenced in the sense which one would expect if it were to be added to the wikipedia article itself. Nevertheless, I cannot see anything in original research which prohibits the initiation of material which may be interpreted as original research UPON THE TALK PAGE (as I have done). At NO point have I actually interfered with the article. According to original research taking in conjunction with the TALK PAGE GUIDELINES, :
"Maintain Wikipedia policy
The policies that apply to articles apply also (if not to the same extent) to talk pages, including Wikipedia's verification, neutral point of view and no original research policies. There is of course some reasonable allowance for speculation, suggestion and personal knowledge on talk pages, with a view to prompting further investigation, but it is usually a misuse of a talk page to continue to argue any point that has not met policy requirements."
It is necessary to clarify : What is a reasonable allowance for speculation, suggestion and personal knowledge?
Given that there are wikipedia talk pages related to antimatter propulsion systems and interstellar travel, one might argue that whatever speculated aspects of my contribution are problematic must surely pale in comparison to the degree of speculation already allowed in relation to aforementioned articles to the self-evident extent apparent within them.
Is it also reasonable that no allowance for prompting further investigation has been permitted before your removal of the material? Does wikipedia policy permit the removal of such material without allowing the contributor a chance to provide additions or modifications to the problematic contribution so as to increase its quality and the extent to which it satisfies wikipedia policies?
but it is usually a misuse of a talk page to continue to argue any point that has not met policy requirements.
If the initial aspect of an argument is presented, though the argument is not carried towards completion (ie: so that the talk page contributions can be used within the article), I would argue that the 'reasonable man' would not see this as a continuation of the argument - but rather its termination, pointing out its weaknesses - though NOT deleting it. The phrasing of the Talk page policy is such that it is ALLOWABLE for the talk page material to NOT meet wikipedia policies to the SAME EXTENT that the article material should.
Given my comparison with antimatter propulsion systems, or other esoteric wikipedia pages, it would be surprising to me if the talk pages to such articles satisfied wikipedia policies to the same high degree as their articles might (assuming that their articles DO meet the lofty moral ideals of wikipedia policy).
PS - Please don't take my capitals in an offensive manner. They are only used for emphasis (Pretty please?......:)
ConcernedScientist (talk) 11:16, 16 March 2009 (UTC)
- The difference between your material and the material we have on antimatter propulsion and so forth is that those have been published in peer-reviewed scientific and engineering journals. The material you are posting so far does not match up with anything I have seen in physics or nuclear engineering journals.
- Original research is something you or others came up with and have not published in an independent, reliable, preferrably peer reviewed source. As far as I can tell you have not done so with your proposals.
- I am also concerned about the scientific accuracy of your claims - nanocrystalline matricies of fissile materials are all fine and good, but "annealing" is not a process to surround such microcrystals with a neutron reflector, and the best neutron reflectors have mean free paths of fission spectrum neutrons measured in centimeters, not nanometers, so even if you formed such a composite matrix the reflector isn't reflecting on distance scales within many orders of magnitude of the physical layout.
- You also mention that very high energy neutrons aren't likely to fission a Uranium nucleus. That is unfortunately completely false - fast fission is the operating mechanism of nuclear bombs, is well understood, is demonstrated by numerous unreflected and unmoderated criticality tests ranging from the original Godiva device in the 1940s through experiments performed today. Even higher energy neutrons, 14 MeV, originating in Deuterium-Tritium fusion, are used to "boost" nuclear fission primaries and to efficiently drive fission reactions in fissile tampers around secondary fusion elements in thermonuclear bombs.
- Moderated nuclear reactions, where fission spectrum neutrons are moderated or thermalized down to a fraction of their original energy, have lower critical mass. But they also have timescales that are ten to one hundred times longer than those of fast fission reactions. The Operation Upshot-Knothole tests Ruth and Ray were tests of attempting to build highly tamped moderated nuclear bombs - they failed miserably, with yields of around 200 tons TNT equivalent (see Uranium hydride bomb). The Ruth and Ray yields are straightforwards to understand if you can model the moderated reaction in time and adapt the Serber efficiency equation to the longer timescales. Fundamentally, the energy buildup is too slow to avoid blowing the inertial tamper apart on yield timescales a couple of magnitude faster than chemical explosives, not a particularly highly efficient weapons system by nuclear standards.
- If you can point to any peer-reviewed publications of your theories or analysis, that would help. But without those, your contributions are going to fall afoul of our policies here.
- Thank you. Georgewilliamherbert (talk) 18:29, 16 March 2009 (UTC)
In what follows, I accept that most of the ideas here are conjectural (and view this as mostly a inquisitive discussion of potentially interesting ideas). I also accept that they are most probably to be developed into a workable weapon (though how probably is something which I am uncertain of). I have posted my response as a "point by point" response to your criticisms of the above referred to post and hope that some of the ideas presented here may have applicability somewhere.
The difference between your material and the material we have on antimatter propulsion and so forth is that those have been published in peer-reviewed scientific and engineering journals. The material you are posting so far does not match up with anything I have seen in physics or nuclear engineering journals.
> This point would seem to be of partial acceptability to a scientifically minded sceptic. Just because one may be aware that a phenomena (matter/antimatter annhilation) exists does not mean that one has a working design for application of that phenomena (matter/antimatter annhilation has never, to my knowledge, ever been used for rocket propulation on earth or in space). Thus antimatter propulsion as a wikipedia page is speculative as no experiments with antimatter as a propulsion energy source have ever been carried out (to my knowledge). Yet the wikipedia page is still there. Essentially, my criticism might be based upon a fear of mass delusion (which is not unknown), in which individual scientific facts have been verified in an above board manner, but there is no rational reason for supposing that such facts face up to scrutiny without an experiment (in relation to this, I think it fair to point out that even nuclear designers have been apt to alter the design of important weapons at very close time periods up until the actual testing of such devices for the reason I have just highlighted above – it can be very difficult indeed to determine whether a synthesis of ideas/principles can be invoked within a novel device successfully).
Original research is something you or others came up with and have not published in an independent, reliable, preferrably peer reviewed source. As far as I can tell you have not done so with your proposals.
> Accepted as being true (though I am not fully versed in the niceties of the objective standardisation used to determine the notions of “independent”, “reliable” or “preferrably peer reviewed” sources (it would always be nice to have axiomatically derived definitions of these : )
I am also concerned about the scientific accuracy of your claims - nanocrystalline matricies of fissile materials are all fine and good, but "annealing" is not a process to surround such microcrystals with a neutron reflector, and the best neutron reflectors have mean free paths of fission spectrum neutrons measured in centimeters, not nanometers, so even if you formed such a composite matrix the reflector isn't reflecting on distance scales within many orders of magnitude of the physical layout.
> I should admit that I have not done the mathematics on this (and that I would not seem to have as much of a background as your self, for whatever reason). However you state that :
i) “ "annealing" is not a process to surround such microcrystals with a neutron reflector”, BUT, according to annealing :
“In the semiconductor industry, silicon wafers are annealed, so that dopant atoms, usually boron, phosphorus or arsenic, can diffuse into “substitutional positions” in the crystal lattice, resulting in drastic changes in the electrical properties of the semiconducting material.” Clearly, it may be possible to introduce one of the potential choices for a neutron reflector into a Plutonium crystal lattice (my, limited understanding of the doping process is that the impurities have to be introduced so as to fit into the crystal lattice). Such potential choices include : (Be, C, H20, Fe, Ni, Pb, W) BUT I am currently uncertain of what preconditions must be attached in order to ensure that such materials would fit into the crystal lattice (though, in the case of diffusion annealing, this isn't necessary at all – and is so not a constraint).
Which doesn't refute all that you say (as you allow for the possibility that some type of matrix of Plutonium and neutron reflector can be formed – perhaps also allowing for the preservation of the crystal structure of the material), but would appear to be a type of process which enables the construction of a matrix of reflector material. (I doubt that surrounding microcrystals with neutron reflector is a respectable idea, and so I do not believe that I would have suggested it – however, without a mathematical analysis, discounting any potential utility for that idea would require further rationale).
The next counter-argument provided to the design improvement suggestion is the following :
“ and the best neutron reflectors have mean free paths of fission spectrum neutrons measured in centimeters, not nanometers, so even if you formed such a composite matrix the reflector isn't reflecting on distance scales within many orders of magnitude of the physical layout”
This confuses me slightly as the sentence could perhaps do with a little more work. But what I gleaned from the above was the following :
>>That the best neutron reflectors will only ever produce reflected neutrons which have a mean free path of, say, x cm. This seems odd to me as the mean free path is the path length covered by a neutron within the plutonium material on average before its next collision. You seem to be saying that neutron reflectors can not reflect neutrons with with a mean free path of a few nanometers. But surely the mean free path of a neutron source/ray/beam depends upon the momentum-position characteristics of the neutrons which make up that beam, as well as the density of the material (Uranium/Plutonium) which those neutrons have to pass through. This seems to me to be independent of the issue of a neutron reflector – whose purpose is to reflect neutrons (albeit with a certain efficiency and energy profile changing set of caveats imposed upon the reflected beam/beams/diffuse source of neutrons).
You also mention that very high energy neutrons aren't likely to fission a Uranium nucleus. That is unfortunately completely false - fast fission is the operating mechanism of nuclear bombs, is well understood, is demonstrated by numerous unreflected and unmoderated criticality tests ranging from the original Godiva device in the 1940s through experiments performed today. Even higher energy neutrons, 14 MeV, originating in Deuterium-Tritium fusion, are used to "boost" nuclear fission primaries and to efficiently drive fission reactions in fissile tampers around secondary fusion elements in thermonuclear bombs.
>> Ah, yes, my statement was : “This is unimportant as, when modelling the nuclear explosion under conditions of criticality, we are primarily interested in an integral measure of neutron kinetic energy and momentum distributions (very high energy neutrons DO pass through uranium atoms, but they are NOT likely to induce a further neutron-progeny creating fission within such uranium atoms as, informally, they pass through the uranium atoms too quickly to induce fission – a higher number of lower energy neutrons emitted within the annealed material would be more likely to result in a larger proportion of progeny-creating fissions – which is where the integral measure comes in, the “mean free path” that a neutron will have to travel before inducing a fission, something which is infinite for neutrons which have TOO lower an energy-momentum distribution).” The way that I read this (admittedly long) sentence is that there exists an energy point for neutrons at which the likelihood of (progeny-creating !) fission being induced within a Uranium atom (say) drops off and becomes lower/insignificant. THIS COULD BE COMPLETELY FALSE, as I am not aware of information which indicates how the probability of fission of a U235 atom varies with the momentum-position characteristics of any incoming neutron radiation *** in a mathematically precise way. However, I believe that the point you make is correct, HIGH ENERGY NEUTRONS ARE TO BE WELCOMED in a chain reaction.
- In particular, the position being referred to would presumably be the position (relative to the nucleus centre) at which the U235 atom is impacted by the neutron. Intuitively, one imagines that a low energy neutron hitting the centre of the U235 atom will not likely fission it, whereas a high energy neutron hitting the centre would. But what about a Relatively low energy neutron hitting the centre (with sufficient fission inducement energy), and a high energy neutron hitting the edge (thus, potentially, passing through/not inducing a fission).
Here, we are not considering the complexities of whether much energy is released from the fissioning of nuclear by-products by the general internal neutron spectrum – but this would have to be considered for a fuller comprehension of the situation.
In what follows, I ACCEPT your above criticism near-completely, I have stated that there are perhaps situations in which it may be beneficial to use cool neutron reflector impregnated within the material to slow fast neutrons down. My intention was that it would be feasible to take a larger number of extremely high energy neutrons and use the impregnated neutron reflector – fissile matrix to bring those extremely high energy neutrons to a lower energy level which would be of utility for the purpose of inducing fission (this would require numerical analysis – and I imagine at this point that even EXTREMELY high energy neutrons will induce a fission, making my point above quite useless and of little application within a nuclear weapon).
Nevertheless, there is perhaps a details worthy of note (from Nuclear fission) : In particular, IS IT THE CASE THAT Very fast neutrons can pass through a fissile material without inducing fission (if the answer is NO, then this stops the idea dead in its tracks, so dont bother to answer the subsequent questions, if the answer is YES, then DO answer the following questions)? At what energy level does this occur? What proportion of neutrons have an energy above such a hypothetical points.
NOTE : There COULD still be potential utility gained in using impregnated neutron reflector within a spherical ball of Uranium or Plutonium IF the number concentration gradient of the reflector could be altered precisely with the radius of the fissile material, as this could alter the mean free paths (or should I say, velocity?) of the neutrons in a direction dependent way (though the alteration would only be statistical as the whole chain reaction process is a statistical one). THIS WOULD REDUCE THE CRITICAL MASS OF MATERIAL NEEDED FOR THE DEVICE AND COULD EVEN BE USED TO CREATE A NON-SPHERE/OBLATE DEVICE AS (I *think*), such a distribution of neutron reflector would reduce the tendency of neutrons to escape for the spheroid mass and leave the nuclear device.
Moderated nuclear reactions, where fission spectrum neutrons are moderated or thermalized down to a fraction of their original energy, have lower critical mass. But they also have timescales that are ten to one hundred times longer than those of fast fission reactions.
The Operation Upshot-Knothole tests Ruth and Ray were tests of attempting to build highly tamped moderated nuclear bombs - they failed miserably, with yields of around 200 tons TNT equivalent (see Uranium hydride bomb). The Ruth and Ray yields are straightforwards to understand if you can model the moderated reaction in time and adapt the Serber efficiency equation to the longer timescales.
>Given the position relating to the applicability to 'dispersed' neutron reflectors within such a device – is it the possible that these ideas would find application within nuclear power generation? This is a purely hypothetical point, which I thought I should raise. This is an incidental point in relation to the general thread of my responses to your response.
Fundamentally, the energy buildup is too slow to avoid blowing the inertial tamper apart on yield timescales a couple of magnitude faster than chemical explosives, not a particularly highly efficient weapons system by nuclear standards.
> The key idea here (I *think*) being that the chain reaction needs to proceed within a relatively slow chain reaction window. Too quickly, and the reaction causes the fissile materials to blow apart before an appreciable amount of them have had time to fission. Too 'slowly', and the (presumably reflective neutron) tamper is blown off the device before the tamper has a chance to reflect neutrons back towards the device for the purpose of reducing the critical mass required from it in order to induce fission (of course, this is all subjective as we haven't indicated what is meant by 'slowly' or 'quickly' – and, in fact, I am not even certain that my interpretation of the points above is even remotely correct - I garner that "Serber efficiency equations" are perhaps slightly specialised snippets of knowledge). The issue of the Serber equation is something I will have to read up on in order to determine what it implies in relation to nuclear chain reaction rates and the like.
> Also "[Ruth] and [Ray] failed miserably, with yields of around 200 tons TNT equivalent". Did they fail MISERABLY? In terms of economic cost and efficiency - what were their quantitive yield (of course, 0.2kT does sound quite impotent, but this is dependent upon the amount of material used, as well as its cost, especially if not enriched).
If you can point to any peer-reviewed publications of your theories or analysis, that would help. But without those, your contributions are going to fall afoul of our policies here.
> Unfortunately, I cannot do this. But I thought that I should at least give some response as I'd guess that these ideas have already been thought about and that they might have some applicability somewhere.
Thank you. Georgewilliamherbert (talk) 18:29, 16 March 2009 (UTC) Retrieved from "http://en.wikipedia.org/wiki/User_talk:ConcernedScientist"
FINALLY, apologies for not presenting any mathematics. However, even if I had - what possible application would there be for any of the above?
ConcernedScientist (talk) 11:06, 28 March 2009 (UTC)
I've been doing some tidying up here. I notice your section from 2008 and kinda left it alone, but it seems to me overly wordy and I should like to attempt to simplify it. Nobody ever responded to you on the talk discussion, so first I will post here to get your attention. Then I will suggest some revisions. I think it is worth having, but labours the point somewhat. OK? Thanks and good WP'ing SimonTrew (talk) 21:34, 13 April 2009 (UTC)