Talk:Nuclear fallout
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The link to reference [1] is dead. Possible mirrors(?) are http://www.cddc.vt.edu/host/atomic/nukeffct/ and http://www.ciar.org/ttk/hew/nukeffct/ .
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[edit] nuclear fall-out
Hopefully somebody with real information will have a look at section 'Short term', as infomation there is very contradictory or confusing (stating first that a dose of 6 Gy is invariably lethal and later that a dose 30 Gy is incapaciting).
I know about this, the dose of 6 Gy absorbed over a short length of time will have a good chance of killing a person.... But the dose will take hours/days to kill the unlucky person. The US military consider that a dose of 80 Gy (gamma and neutrons) will instantly incapcitate the person and kill them. I have read that the higher the dose the quicker the radiation will kill a person, I think at high doses (cira 10 Sv) that the bigger the dose the quicker the person will get to the terminal stage of the acute radiation 'sickness'.Cadmium 23:08, 22 November 2005 (UTC)
Also Gamma radiation is mentioned in the article as being the most dangerous form of radiation and this is a Gross conceptual error. Gammas are particle radiation also known as photons, they have minimal mass, high amounts of energy and are nuetrally charged. They are however one of the most prevalent forms of radiation. Now this lack of charge and minimal mass causes a relatively low amount of interaction as the particle is traveling through material. Imagine a semi-truck and a ping pong ball travelling at the same speed through a crowd at a baseball game. The semi will hit many more people than the ping pong ball even without taking into consideration the geometry of particles. In actuallity the most dangerous form of radiation is Alpha radiation. Now an alpha particle is a He atom that has no electrons, thus giving it a much larger mass than a photon and a positive charge that is much greater than a proton.
[edit] Minor actinides
I think that a reference to this term should be included. In the science of spent fuel and advanced reprocessing, the transplutonium elements are known (along with Np) as the minor actinides. As some of the minor actindies were first identified in fall out from H bomb tests, I think that a mention of minor actindies should be made. The minor actinide page needs some more work, but it has been started.Cadmium 23:08, 22 November 2005 (UTC)
Data on Np-239, U-237, etc is at [1]:
"In 1958, W.J. Heiman of the U.S. Naval Radiological Defense Laboratory released data on the sodium-24 activity induced in sea water after an underwater nuclear explosion in which 50 % of the gamma radiation at 4 days after burst is due to Np-239. He found that Na-24 contributed a maximum of 7.11 % of the gamma radiation, at about 24 hours after burst (Journal of Colloid Science, Vol. 13, 1958, pp. 329-36).
"Hence even in a water burst, Np-239 radiation is far more important than Na-24.
"Perhaps the most important modification in the April 1962 edition of The Effects of Nuclear Weapons was the disclosure that the radioactive fallout from nuclear weapons contains substantial amounts of radioactive nuclides from neutron capture in U-238. This had been pointed out by scientist George Stanbury (who worked with data from nuclear tests, and had attended British nuclear tests to study the effects) of the British Home Office Scientific Advisory Branch in report A12/SA/RM 75, The Contribution of U239 and Np239 to the Radiation from Fallout, November 1959, Confidential (declassified only in June 1988). Both Mr Stanbury and The Effects of Nuclear Weapons 1962 found 40% of the gamma radiation dose rate from fallout is the typical peak contribution due to Neptunium-239 and other capture nuclides (e.g., U-237, which is formed by an important reaction whereby 1 neutron capture in U-238 is followed by 2 neutrons being released), which all emit very low energy gamma radiation, and are important between a few hours and a few weeks after burst, i.e., in the critical period for fallout sheltering. Because of the low energy of the gamma rays from such neutron-capture elements, which are present in large quantities in both Trinity-type fission bombs (with U-238 tampers) and thermonuclear bombs like Mike and Bravo, the fallout is much easier to protect against than pure fission products (average gamma energy 0.7 MeV). However, The Effects of Nuclear Weapons, while admitting that up to 40% of the gamma radiation is from such nuclides, did not point out the effect on the gamma energy and radiation shielding issue, unlike Stanbury’s Confidential civil defence report. This discovery greatly stimulated the “Protect and Survive” civil defence advice given out in Britain for many years, although it was kept secret because the exact abundances of these bomb nuclides in fallout were dependent on the precise bomb designs, which were Top Secret for decades." 172.141.71.168 12:25, 23 April 2006 (UTC)
[edit] Different types of bomb?
The article doesn't seem to distinguish at all between different types of bomb, although they differ greatly in the amount and type of fallout. This is surely the main 'factor affecting fallout'?? The current discussion seems to be mainly for the old-fashioned fission bomb. --Tdent 10:52, 25 May 2006 (UTC)
As far as I can tell, the fallout is mainly influenced by the bomb yield and placement (ground, air, underground, water, etc.) Sure you can get bigger yields from the thermals, but that's not the point. The point is, as far as I can tell, any radiological differences would be pretty localised and short lived, especially compared to the other factors. --Elgaroo 19:07, 8 June 2006 (UTC)
[edit] Effect Of Fallout On Material Properties
One topic I was hoping to see covered here alongside the expected ones is the effect of fallout on material poreprties. The reason I am interested in this (and I uspect it would be of interest to quite a few other readers) is that I have heard mention that nuclear fallout has had a long term impact upon the manufacture of steel. For specialised applications, what is known as 'pre-fallout steel' is harvested (plates from sunken World War I battleships are one such source) because its paterial properties are, I am told superior for those applications than steel made after the appearance of fallout in the atmosphere. Unortunately, attempts to Google the topic throw up lots of references to computer games (sigh). I'd certainly like to know more on this, including the reasons why fallout has affected the engineering properties of steel made after 1945, but sadly trying to find references to this topic is proving to be an uphill struggle. Any offers? Calilasseia 15:34, 25 July 2006 (UTC)
- The low radioactivity steel is normally used for things such as radiation detectors, by lowering the radioactivity of the steel the background of the detector can be lowered.Cadmium
[edit] Better explanation of this graph.
Hi, I know nothing about phyiscs or nuclear fallout, so I'd appreciate this graph being better explained:
It seems to me that the Chernobyl fallout as shown here is completely flat, or possibly non-existant.
OK, here is my understanding of it: the Chernobyl graph is like the tail-end of the bomb graph – hence it is relatively flat. This is because the Chernobyl release would not contain high proportions of short-lived radionuclides which are characteristic of the early stages of fallout from a nuclear bomb.
Inside a reactor radionuclides are created gradually in a controlled reaction over an extended period of time. Consequently any short-half life isotopes would decay in hours or days before there is a significant build-up. In contrast, a nuclear bomb creates all its resulting radionuclides in one quick event. Hence the proportion of short-life radionuclides is high. The shorter the half-life, the more radiation is emitted per unit of time. So the bomb graph shows a high initial dose of radiation, which decays rapidly as the short-lived radionuclides decay over a matter of days. In contrast radioactivity from Chernobyl is from longer-half life (less radioactive) materials which persist for years.
Of course, there was more material in Chernobyl than there would be in a typical bomb. So the graph is really like the tail-end of several bombs added together. In approximate terms, it is like the radiation from large nuclear bomb a year or so after detonation when all the short-life radionuclides have decayed.
[edit] source data
The plots look great, but I haven't seen explicit references to the source data and/or formulae used to generate them. If the data are in the public domain, I believe they can be uploaded to the Commons and linked to from there. If they're not, I'm not sure how the derivative copyrigit applies in that case. Also, a plot with no source data might be construed as original research. Ojcit 21:22, 28 September 2006 (UTC)
[edit] 10kt+ into stratosphere?
Regarding the line about bombs larger than 10kt reaching the stratosphere, I'm pretty sure I read somewhere that only the very largest bombs (500kt+) actually loft dust into the stratosphere. This would seem to imply something like a 20kt bomb wouldn't, which contradicts what's written here.
Anyone have a source? Gigs 13:49, 10 October 2006 (UTC)
[edit] What kind of radiation is it?
This article doesn't say what kind of radiation it is. Is it gamma radiation? This must be made clear. 64.236.121.129 (talk) 18:20, 9 January 2008 (UTC)
[edit] Proposed External Links addition
I suggest that the following address be added to the Nuclear Fallout page, External Links: http://old-elf.tripod.com/fallout.html Article by John Hanna (activist - Environmental Life Force), Micronesia Service Committee, Bulletin, March 1979. The article describes his first-hand observations on a 1974 visit to Rongelap Atoll with the AEC medical survey team. —Preceding unsigned comment added by 216.110.210.6 (talk) 18:31, 2 April 2008 (UTC)
