Talk:Chernobyl disaster/Archive 5

This is an archive of past discussions about Chernobyl disaster. Do not edit the contents of this page. If you wish to start a new discussion or revive an old one, please do so on the current talk page.

Archive 1

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Archive 3

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POV

"There are two conflicting official theories about the cause of the accident. The first was published in August 1986 and effectively placed the blame solely on the power plant operators." Can not see much about the criminal negligence of those operators, the article seems to justify their actions. This can't be right. This is not a neutral point of view. Lantios 21:28, 7 April 2007 (UTC)

Causes

The sentence "There are two conflicting official theories about the cause of the accident" is misleading, as both theories in fact complement each other. The error of the power plant operators exposed the flaws of the control rods which in turn led to the explosion.

Controversy over fatality estimates

I feel that it would be best to put a down a range addressing the immediate death toll and the rates of cancer caused by the accident at the beginning of the article since all of these estimates seem to be fueled by lots of politics. You have on the one side those who make their livelihood off of nuclear energy, the International Atomic Energy Agency (IAEA). Of course they are going to present the rosiest picture imaginable so that we will pay for more research and the building of more reactors for them to play with. Then you have GreenPeace who want to end nuclear development and nuclear weapons, they seem to want to present it as most evil. No one seems to have come forth with reputable data on either side.

I was thinking maybe we could add a line before the estimates like "We will probably never know for sure how many people will be killed by the world's worst nuclear accident yet" This will let readers know about the uncertainty of the estimates and remind everyone that we are playing with fire when it comes to nuclear energy.

Frequently, someone with good intentions inserts, usually in the first section but also in various other areas of the article, a claim that the Chernobyl disaster fatalities are much higher or lower than an organization claims. I suggest that the controversy over fatality estimates be left in the Chernobyl disaster#Controversy over fatality estimates section. I think it is clearer and makes the article more professional, currently the WHO/IAEA figure of 9,000 cancer deaths (as opposed to the immediate deaths) is given in the third paragraph. I think that the WHO/IAEA figure is a good compromise compared to those who say that the only deaths caused were the several dozen immediate ones - the workers and some of the cleanup personnel- and those who say that hundreds of thousands will eventually die. The other estimates are still given in the controversy section. What do you guys think? -- Kjkolb 12:40, 20 July 2006 (UTC)

I think that sounds pretty fair, so long as we continue to make it clear, early in the article, that death isn't the only issue, and that many lives (thousands, I believe) have been blighted by non-fatal chronic health conditions. The IAEA are very poor at covering these "grey" figures. – Kieran T ^{(talk | contribs)} 14:31, 20 July 2006 (UTC)

I think that the 9000 dead estimate is an interesting theory, but not backed up by any firm data. In fact, no increase in cancer deaths has been found as of yet.WolfKeeper 15:41, 20 July 2006 (UTC)

Whilst it's valid for Wikipedia to report that no increase in cancer deaths has been proved, please remember, cancer deaths have been found, and some statistics (and the visual evidence for anyone who goes to a hospital in the area!) clearly show a high incidence of cancers. The problem is always going to be that it's just impossible to prove the direct cause of almost any cancer. And I'm the first to admit that "it's obvious" isn't encyclopædic. – Kieran T ^{(talk | contribs)} 12:57, 5 August 2006 (UTC)

However, nearly 20 years after the disaster, no increase in cancer has been found in the population.: is in the article. May someone please state (in the article) the source? If there is no source, well... there is no "information" Natmaka 16:05, 28 July 2006 (UTC)

Yes, I didn't like the way you deleted it out of hand- don't bother you with facts?. The Horizon that was on in the UK recently stated this; there have been no increases in Leukemia (this is the quickest cancer to manifest after an accident), and there's been no measurable increases in solid cancers either.WolfKeeper 17:11, 28 July 2006 (UTC)

I didn't like the way you deleted it: uh? Please show the diff where I deleted it. I did not delete your "contribution" nor like your false accusations.

As for the reference please state it fully (quote from the rules: "Articles should contain only material that has been published by reputable sources"). As far as I know the correct reference is here. It shows that your stuff comes from the infamous "Chernobyl Forum", which pretty proves the necessity of sourcing. Please place in the article whatever you find useful, but source it (who said/wrote it, when and where). You wrote However, nearly 20 years after the disaster, no increase in cancer has been found in the population as if it was the Pure Truth accepted by all observers. This is abusive because (even if most of the pertinent information is filtered) one can easily find facts reported from reputables sources proving that the "no more cancers" hypothesis is not a fact.

And please be careful with your accusations, as it is difficult for me to be friendly with supporters playing encyclopedists Natmaka 21:04, 28 July 2006 (UTC)

Why is the Chernobyl forum "infamous" Natmaka?

Read this chronology Natmaka 06:00, 10 September 2006 (UTC)

It is fairly well established that more thyroid cancers have been found in people exposed to radiation from Chernobyl - a point made in the Chernobyl Forum report. The question is whether more of other types of cancers have been found. Using a throwaway line in a news report, even one that appeared in the NYT, is not good evidence when there is a large pile of scientific literature that says otherwise. --Robert Merkel 08:02, 31 August 2006 (UTC)

Please read this. Quote: Elizabeth Cardis, a radiation specialist from the WHO's International Agency for Research on Cancer in Lyon, France, says that 30,000 to 60,000 cancer deaths is "the right order of magnitude". Her work was used by the Chernobyl Forum and she was responsible, during the Forum's research campain, for matters related to cancers. She even presented the 'Health' report during the Sept. 2005 meeting (read the chairman remarks and Nuclear News, 2005-10, page 46). Here are the figures published by WHO: By 2065, these models predict that about 16,000f cases of thyroid cancer and 25,000 cases of other cancers may be expected due to radiation from the accident and that about 16,000 deaths from these cancers may occur.. Is it clear enough? Also note: For thyroid cancers, the 95% uncertainty interval (UI) ranges from 3,400 to 72,000; for other cancers it ranges from 11,000 to 59,000. For the number of cancer deaths, the 95% UI ranges from 6,700 to 38,000. In a word: this work of an eminent WHO specialist (recognized by the Forum and IAEA) predicts deaths by various types of cancers.

(As a sidenote please read, in the New Scientist paper, Zhanat Carr, a radiation scientist with the WHO in Geneva, says the 5000 deaths were omitted because the report was a "political communication tool"...)

Let's check. In September 2005 an official IAEA press release started with A total of up to four thousand people could eventually die of radiation exposure from the Chernobyl nuclear power plant, meaning 4000, grand total. It was touted everywhere. In April 2006 the IAEA published much more discreetly 9000 people among the approximately 6.6 million most highly exposed, may die from some form of cancer (see the article, note #3. The original site leads to the [1] official document, which (page 106) ). This is is not equivalent to 4000, grand total. Then the quoted WHO-IARC report (April 2006) states that the cancer death toll will probably (.95) be in the [6700, 38000] interval and in an interview a WHO specialist recognized by the IAEA said "30000 to 60000".

The pile of scientific literature (you did not provide any reference...) may explain, as all papers do, that determining the cause of a given cancer is difficult. But serious work shows that Chernobyl induced-cancers (not only thyroid cancers) will very probably (.95) be fatal (maybe up to 38000 casualties). Natmaka 06:00, 10 September 2006 (UTC)

And more everyday, there is no way to tell. Anyone with common sense can look at this situation and say, billions and billions of pieces of radioactive...whatever were released into the water/air/ground and really, really shouldn't have been. This could be a long slow apocalypse here, sorry to use the a-word but who really knows what will come of this, its only been 20 years, thats not even a minute on the radioactive clock, not even a blip in history... all the IAEA seems to want to do is cover up for the industry and act like everything is running like clockwork over there and double as smooth here, I read their report on Chernobyl on their web page and they say something to the effect of, that could never happen in america, our reactors are too cool for school over here... I really have no reason to believe them. These are men who are profiting from this industry whose waste causes cancer and babies with their brains born outside of their heads, these are men with their finger on the trigger of something that could spell suicide for the entire race, and everyone knows it, and all anyone seems to want to do is set around and argue the details, he said she said, not productive. Anyway, just needed to vent that to people with their ear to the ground on this stuff.

Off topic parts on the TORCH report

In the section about controversy over fatality rates, the summaries of the WHO/IAEA and Greenpeace reports only included the material on death rates, whereas the bit on the TORCH report contained a lot of material on disease rates and other health problems. I removed some of this as it isn't really on topic and in context of the controversy regarding fatality rates. 83.108.157.39 23:11, 5 August 2006 (UTC)

You removed and I restored it; it is in 100% relevant section. `'mikka (t) 01:07, 6 August 2006 (UTC)

The torch report is dire, it is attempting to paint everything is the politics of the authors. It is common to compare radiation doses from occupational exposure to that from a X-ray examination. When the dose from Chernobyl was compared in the report with an 'average' chest X-ray the authors felt the urge to remind us that a chest X-ray might offer something useful to the person getting the dose while the accident offers nothing good. I think that unless the reader has been sitting in a hole for the past 25 years or living on mars then it is jolly clear that the chernobyl steam explosion and fire was a very nasty event which has done no good in this world. I would like to know why the authors of the torch report feel the need to waste ink on making a cheap political point. Anyway now I am going, you can estimate how many Cigarettes a chest X-ray is, I have seen one health physics experts estimate that 1 Cigarette = 1 chest x-ray = a 1 in a million chance of death. Will the next version of the TORCH report issue a table of the number of cigarettes each population (local general public, person drinking milk from backyard cow in Kiev, member of a clean up team....etc) would have to have smoked to have got the same risk ?

As there is no such thing as the standard chest X-ray or a standard cigarette then this is only a rough rule of thumb.Cadmium

Clean up

The sequence of events first described (in the paragraph labelled "Fatal Experiment") is 'directly negated' by the circumstantial evidence in the next section - that is to say, the article first proposes, objectively, that there were seven seconds between SCRAM and explosion, and yet one paragraph later it makes mention of a seismic event being recorded immediately before the SCRAM. I'm not a nuclear physicist, so perhaps there's some complicated, yet rational, reason why the seismic data has no conclusive bearing on the chain of events - but it seems to me that the article has been "sanitized" to compensate for the perceived feelings of the station operators. While this is a glowing success on humanitarian grounds, it's nonetheless a resounding failure in the field of unbiased academic reporting. --70.108.56.178 20:20, 14 August 2006 (UTC)

The article states that the sequence of events are not known exactly, and that there are several theories. As teh article states, teh siesmic event appears to support a theory different than the main one, but could possibly be unrelated. In my opinion the article does clearly state that the theory about what caused the accident is debated and somewhat controversial, and thsu I don't really think its much of a problem. 83.108.144.39 00:18, 15 August 2006 (UTC)

I think that the clean up template may be being applied too widely, which of the sub sections needs to be altered. I think for example that the subsection on the liberation of radioactivity by grass fires is OK. It is easy to understand and tells the unbiased truth. But other areas need some work.Cadmium 07:19, 16 August 2006 (UTC)

The "Contradictions" part summarises statements from this article: http://www.n-t.ru/tp/ie/ca.htm . The important claims there are: (1) There were two explosions, with 10-30 seconds interval. (2) The second one was more powerful. (3) Only one seismic event was detected. (4) Natuaral earthquakes in that area are not possible. => The event corresponds to the second explosion. => The AZ-5 had no impact at all, because by the time it was pressed, the reactor did not exist anymore. => The blame is on the operators, or on the designers of the experiment. --Whichone 17:48, 25 August 2006 (UTC)

In the second paragraph at the beginning, it says (47 accident workers, and nine children with thyroid cancer), does this mean the children already had thyroid cancer, or did they get the cancer from the accident? --Archonos 2 13:00, 10 April 2007 (UTC)

The children are attributed with getting thyroid cancer as a result of the accident. The radioactive isotope Iodine-131, when ingested (for example, from the milk of cows which have eaten contaminated grass), concentrates in the thyroid. Although all milk was supposed to be thrown out, some families had nothing else to give their children. Simesa 17:47, 10 April 2007 (UTC)

Deleted the "contradictions" part

According to the http://ru.wikipedia.org/wiki/%D0%A7%D0%B5%D1%80%D0%BD%D0%BE%D0%B1%D1%8B%D0%BB%D1%8C%D1%81%D0%BA%D0%B0%D1%8F_%D0%B0%D0%B2%D0%B0%D1%80%D0%B8%D1%8F (which is the article on the Chernobyl disaster in Russian, article http://www.n-t.ru/tp/ie/ca.htm is not reliable.

I deleted the whole "contradictions" part as a POV.--Whichone 22:12, 7 September 2006 (UTC)

I agree. --Pinnecco 22:34, 7 September 2006 (UTC)

However not even mentioning about exotic version (for example local vertical energy blast, since Unit 4 was standing on between tectonical plates - the worst place possible, and Unit 4 personnel was told to suffer from quakes, asking Science Academy to test basement of the plant - it was planned for May, but reactor blasted in April). Be it heresy or not, but on should mention it IMHO. —The preceding unsigned comment was added by 80.249.152.137 (talk) 15:44, 27 April 2007 (UTC).

Grass fires

There is a graph accompanying this part of the article. The x axis is entitled Distance from fire (m). Can anyone tell me if the unit of measurement (m) is metres or miles? (comment by 195.92.168.163)

I made the title of this section lowercase. Also, please sign your comments by placing ~~~~ after them. My guess is that it is in meters, since I would expect larger drops if it were miles. The Pu-239/240 only falls from about 3 to 1 X 10⁵ over 80 units. It's hard to tell at a glance for the cesium and strontium since their scale is logarithmic and no intermediate numbers are given on the scale. -- Kjkolb 01:45, 16 August 2006 (UTC)

I am the editor who added the data about the grass fire experiment. The distance unit is meters.Cadmium

I don't understand the relevance of this section. I suggest it should be removed or rewritten. Joffan 00:09, 2 December 2006 (UTC)

500,000 deaths

Somebody put a sentence in the article claiming that "recent studies" had showed that there had been 500,000 deaths as a result of Chernobyl. They notably failed to cite these recent studies, hence it was removed. --Robert Merkel 04:30, 22 August 2006 (UTC)

⁴⁰K in soil

Please could someone tell me via my talkpage what the level of potassium in soil is, I would like to know the range which is normal for different soils. I can then work out the ⁴⁰K level. I fear that the TORCH report has been written in such a way that anything with a slight tracer of ¹³⁷Cs is classed as heavy contaminated. I think that the ⁴⁰K should be compaired with the ¹³⁷Cs in soils.Cadmium

TORCH Report cleanup?

The section on the TORCH report is getting very long almost justifying a separate article. In comparison, it is almost as long as the entire section on long term health effects. It is also unproprotionally detailed as compared to the reports from the chernobyl forum and greenpeace. I suppose you could consider it more credible ( tho I suspect this is highly disputed ) but hardly enough to warrant the overly detailed ellabouration on isotope concentration. I'd suggest that much of this material be moved to a separate page for the TORCH report, leaving the sumary of it's finidngs with regards to fatality estimates in the main article, as this would also bring it more in line with the sections dealing with the reports from the chernobyl forum and greenpeace. J.Ring 20:40, 30 August 2006 (UTC)

Yep. Please do so. --Robert Merkel 07:51, 31 August 2006 (UTC)

As nobody seems to have had any severe issues with it I moved the main part on the TORCH report to a separate page, sumarising it's finding in the Chernobyl disaster article. The new page should be here TORCH report. The references still need to be coppied but it's late and I'm tiered. J.Ring 22:08, 10 September 2006 (UTC)

I have added to the length of the section on the TORCH report, I think that it is vital that we should include some discussion of the different reports. I think that on Cs that the TORCH report is deeply flawed. According to my calculations it is viewing land as being contaminated by Cs-137 even when the level of the man made Cs-137 is much lower than the level of the natural radioactivity of the soil (K-40). What I would like is the following data to allow me to consider the problem in greater detail.

How much grass the average cow eats per day
How much milk the average cow makes per day
How much meat you can get from the average cow
How deep are the roots of the grass which the cow eats
What is the potassium content of beef
What is the potassium content of milk
- Belewu, M. A. and Aiyegbusi, O.F., The Journal of Food Technology in Africa, Vol. 7, No. 1, 2002, pp. 9-11 states that human, goat and cow milk have 210, 150 and 52 ppm of sodium respectivly and they all have about 1.6 ppm of potassium in them.Cadmium

With these things I can make a better accessment of the transfer of radioactivity (Cs-137) via a cow to humans. This will not be original research as the methods which I will employ are well established in text books. I have already made an accessment of the external gamma dose rate due to 4 KBq m^-2 and this is jolly low, I took a worst case where the activity was on the top surface of the soil. In real lfe it will slowly sink into the soil.Cadmium 08:20, 3 September 2006 (UTC)

Be careful, you're starting to verge into original research here. If you can't find a critique done elsewhere of the TORCH report, just trim that part down to a paragraph, about as long as the comments on the Chernobyl Forum report. --Robert Merkel 09:23, 3 September 2006 (UTC)

I would say that it is not original research to take the data published by others and then use that to calculate a dose assessment. If you look at the writings done on transmission lines by some of the electronics/physics community here you will see how at least one of them has made measurements (using standard methods in physics) on a length of coaxial cable to generate data which he is legally allowed to use in writing a wilikedpia article. I would suggest that the use of a standard method (already published by others) to generate contect is not original research. What do you think ? If you want I would dig out the details of the measurements which I think user:lightcurrent did on some RG213.Cadmium 09:48, 3 September 2006 (UTC)

Here is the work which the electronics community had done, which I think is important for deciding what is original research.Cadmium 09:52, 3 September 2006 (UTC)

== Cable impedance variation with frequency == Im pretty sure that OH lines do not act as high freq transmission lines at 50/60 Hz. When wL<<R and wC<<G, then the characteristic impedance of a TL is Z0= sqrt(R/G). At high frequencies where wL>>R, and wC>>G, Z0 =sqrt(L/C). So there are two distinct characteristic impedances for every line. Usually G is very small so the lf impedance is high, whereas the hf impedance is low. The break points in the impedance frequency graph are at w1 = G/C and w2 = R/L (where w=2*PI*f). If R/G>> L/C, it is obvious that w2>>w1. Between these two break frequencies the cable impedance decreases smoothly.

Example:

Take the case of a 50R coax with polyethylene dielectric. R is about 100mohm/m and G<20pS/m (based on measuremnets of leakage resistance in a 1m length). Using L=CZ^2, L can be calculated at about 250nH/m. So,

w2 = R/L = 200krad/s (f2=30kHz).

and w1= G/C= 0.2rad/s (equ to f1=30milliHertz).

At 100Hz the 50ohm coax will have an impedance of about 900 ohms only getting down to 50 ohms at about 30 or 40 kHz. The phase angle of the impedance between the two break frequencies has yet to be determined by me, but I strongly suspect that it is leading (ie cable looks capacitive). I will try to derive the phase angle when I get time.--Light current 16:47, 25 September 2005 (UTC)

OH lines seem to be inductive from what I can gather on the net, and shunt caps are used to compensate them. --Light current 00:22, 26 September 2005 (UTC)

Yes. Ive just confirmed this with my electrical eng friend from the local power company. He says OH lines are generally inductive, but it can depend on the exact configuration and interconnects etc. IOW they dont know what PFC to use until the systems up & running!--Light current 00:54, 28 September 2005 (UTC)

Thanks for this, Cadmium. While I think that this example is perhaps a little on the high side to act as an example of "not original research" for most of Wikipedia, I definitely agree with the general principle that arithmetic and plugging numbers into established equations (as for dosimetry) should not count as original research. Requiring simple maths about a topic to be published in a peer-reviewed journal is overkill. Wikisteff 03:30, 20 October 2007 (UTC)

Logarithmic graph for the Hiroshima comparision diagram

I noted that the graph for gamma radiation as compared to the Hiroshima bombing uses a logarithmic Y-axis. Seeing that this is relatively rare outside of scientific circles it would be nice if one could add a non-logarithmic version as well. As it is, the graph could easily be mistaken to show initial radiation levels half of thos of teh hiroshima bombing, while they are in fact orders of magnitudes lower. J.Ring 21:09, 30 August 2006 (UTC)

As the scientist resposnsible for calculating and drawing the graph, I will add a new version with a linear dose rate and log time scale. Both graphs are for a hypothetical site where fallout would have arrived shortly after the events. It is assumed that no separation of elements occured (this is not true in real life) and both graphs are normalised for the same yield of Cs-137. The problem with the inital dose rates is that they are not true estimates of the dose rates, the graph is to show that chernobyl fallout tends to be more long lived than a fission bomb's local fallout.Cadmium 12:40, 2 September 2006 (UTC)

Sweet! J.Ring 16:59, 2 September 2006 (UTC)

It is done, two new graphs which explain the difference in "average halflife" of the released activity have been drawn and added.Cadmium 08:12, 3 September 2006 (UTC)

Some confusion could be caused by the transposition of the colours used to represent the Bomb and Chernobyl in the graphs (It certainly confuses me). I question the relevence of this section at all. Comparisons are only relevent if done like for like. If Chernobyl is going to be compared with a totally dissimilar event merely because radiation is involved then why is there also not a comparison with the radioactivity released by atomic weapons testing which is of a much greater magnitude than that released by the Hiroshima bomb, and the radiation released by the luminous hands on my grandfathers pocket watch. 195.92.168.170 02:34, 6 September 2006 (UTC)

The campaign of bomb testing was rather long compaired with the half life of many of the isotopes so it is impossible to compare the chernobyl event with all the atom bomb tests done to date. The radiation released by a vintage watch is dirrect gamma rays from the radium, this is very long lived and is very different in terms of the isotopes in a fission product mixture. I will add some data for another release of radioactivity (from either a waste store or a reprocessing accident {I have not chosen which to use yet}) and then I will sort out the colours on the graphs.Cadmium 22:25, 6 September 2006 (UTC)

I have added graphs for both the Tomsk reprocessing accident where the feed for the second cycle of a PUREX process was ejected from a vessel. Also I have added a graph for a hypothetical accident where a single isotope (Ru-106, half life of about 1 year) is released. This has the same shape as a scrap metal related accident with either Co-60 or Cs-137. Does anyone want any other graphs showing dose rate as a function of time for either a real or hypothetical event ?Cadmium

Comparison to other nuclear disasters

In this article there are sections "Chernobyl compared to Hiroshima", "Chernobyl compared to Tomsk", "Chernobyl compared with the Goiânia accident", and "Comparison with other disasters", but in my opinion the comparisons should be listed on a separate page. There is a potential duplication of information, if we keep "Chernobyl compared with Goiânia" here, and somebody introduces "Goiâniav compared with Chernobyl" there. In fact, there is already a section "Comparison with other related events" in the Goiânia article.

Such a proposal has been implemented for Hurricane Katrina article. In this case, comparisons to other disasters (including comparison to Chernobyl) have been moved into Hurricane Katrina in historical context. --KPbIC 01:12, 12 September 2006 (UTC)

About the Chernobyl compared with XYZ sections, I do not think that duplication is the worst evil we can have here. I think it is better to have some duplication rather than leaving something out. Duplication can be ironed out of wikipedia, what we need to do is to safeguard the long term utility of it (Before the dups are combined they will both offer information on the subject). I have looked at the sections in the Goiânia article which compare it with other related events. All the related events described in the Goiânia article were lost source accidents where the source is either an external gamma photon source or ends up getting melted down into scrap. I think that these types of radiomisadventure (neogism ?!) are of a type which is very different to the majority of the types of events which I added the graphs for. The main point of the graphs was to show the difference in isotopic signature between the different events.Cadmium

The section is rather poor at the moment in my opinion. A lot of it looks much like original research, other bits seems to be far fetched in relevance. It is also a rather long section in an already long article. I say there are three options for cleaning up that section.

Slashing it down to a quick summary or list.
Moving it into a separate article
Deleting the entire section

Personally I'd go for the first option, but maybe the 2nd is preferable.J.Ring 01:37, 15 September 2006 (UTC)

I would reason that it is not original research as the consideration of the isotope signatures of the different types of events uses the normal method. It is important to understand the radiochemistry if you are to understand the events. If you read the literature on the subject you will see how the effects of different events depends on the isotopic signature. Also if you see the details on "Image:Bombvschernobyldoserateinopenair.jpg" then you can see the methods used, these are standard methods which are used in the accademic literature (hence it is not original research).Cadmium

I don't know. The problem with this is that we (ie the general public which does not understand these issues enough to evaluate your work) are taking your word for it that (a) you're using the right techniques, (b) using the right data, (c) making the right assumptions, (d) doing your calculations correctly and (e) providing us withethe right results. I have absolutely no reason to suspect you wouldn't do any of that, but the problem is I have no way to independently check it. That's why what verifiability, from external, mainstream sources (preferablly peer reviewed by people who can fact check) is a key feature of information in wikipedia and why what you're suggesting (or have done, I don't know where you're at with this) is clearly original research and, imo, shouldn't be included in Wikipedia. Please understand I am absolutely not suggesting bad faith here, I don't think you want to do anything except contribute to wikipedia in a meaningful way. But the policy against OR is applicable here. Psychobabble 22:55, 15 September 2006 (UTC)

If you want to see the method which I am using then please read T. Imanaka, S. Fukutani, M. Yamamoto, A. Sakaguchi and M. Hoshi, J. Radiation Research, 2006, 47, Suppl A121-A127. This ia a paper in which the gamma dose rate for bomb fallout is calculated. They got the same shape graph as me for a bomb fallout source. I created a copyright free version of this calculation for wikipedia. I adapted many of the assumptions which these authors used. I obtained the fission yeilds for U-238 and Pu-239 from the online Korean table of the isotopes (something which you can read for free). This allowed me to calculate the starting activitys of the different radioisotopes. I used only the isotopes (¹³¹I, ¹³³I, ¹³²Te, ¹³³I, ¹³⁵I, ¹⁴⁰Ba, ⁹⁵Zr, ⁹⁷Zr, ⁹⁹Mo, ^99mTc, ¹⁰³Ru, ¹⁰⁵Ru, ¹⁰⁶Ru, ¹⁴²La, ¹⁴³Ce, ¹³⁷Cs, ⁹¹Y, ⁹¹Sr, ⁹²Sr, ¹²⁸Sb and ¹²⁹Sb) which were accessed in the published paper which I used as a template..... Next using the simple maths for the decay of the isotopes I estimated the way that they would decay as a function of time.... Next I used the second edition of 'The radiochemical manual' to estimate the dose rate due to exposure to a point source of the isotopes (I used a slight fudge, by only considering the main gamma lines...many isotopes are not monochromatic gamma sources)...... So if you want to repeat my calculation, as long as you have a copy of excel and an education in the physcial sciences to 18 I think that you should be able to do it. I would welcome any attempts by a second person to repeat my calculation to see if they get the same answer.....So you would not then have to take my word for it. As all of the facts and ideas which I have used as in the public domain and are peer reviewed then I would reject the charge of OR. If you need help in doing the calculations, then please ask one of the wikipedia physics community or me for help I would gladly give advice on how to do it.Cadmium

Anyhow I think it is a bit overly detailed for the main article about the chernobyl accident. As an example, the part of the article describing the cause of the accident is written in a far more accessible manner. In it's current status the comparison diagrams are simply not accessible to many people who will read this article. Thus I'd say that the more detailed analysis should at least be moved to a separate page. Furthermore, if you are to argue that it isn't OR then those sections definately need more references. As an example, the listing of radioisotopes released is currently only referenced by the "According to the IAEA.." bit in the sentence preceeding it, and it woudl be virtually impossibel to verify without searching through IAEAs archives. In this case a direct reference is necessary. J.Ring 00:01, 16 September 2006 (UTC)

I can provide you with more references (I have added linked to the IAEA reports on both Tomsk and Goiânia) which are now in the section which compares the events, but I thought that the wikipedia was not ment to be a thing which is so covered in references that it becomes unreadable (like Jerry March's book on advanced organic chemistry).Cadmium

You may want to read up on Wikipedia's guidelines on references and verifyability. There is a good reason why it uses an automated reference system. 137.205.192.27 17:21, 16 September 2006 (UTC)

"...when the iodine-131 release is compared between the events (decay corrected to three days after the event) then Chernobyl released 25 times as much as the Hiroshima bomb." Does anyone know what "decay corrected to three days after the event" means? -- Kjkolb 17:15, 16 September 2006 (UTC)

A decay correction is used where a activity of an isotope is measured (or more correctly speaking estimated) some time after the event. For instance the Sr-90 level in a tree from near a WWII atomic bombing could be measured in 2005, then as it is known how quikcly Sr-90 decays it is possible to back calculate how much was present year after the bombing. This would be "decay corrected to one year after the event", the decay corrected values are not about what exists now... But in what existed at a given moment of time in the past. You may want to rewrite the part of the article to explain this.Cadmium

Images, Positioning

I have repositioned a lot of the images on the page and rearranged some of the sections. The reason for this is mainly that the left-aligned images quite break the position of the headings in a rather ugly manner. This is especially true when the height of an image exceeds the vertical length of a paragraph. I suggest we keep the images left aligned and small, except for where the image height exceeds the height of the section in which it occurs, where the image should be placed on a new line and centred, as to not break the heading beneath it. J.Ring 01:37, 15 September 2006 (UTC)

"nuclear explosion"

In the previous incarnation of this article, the intro sentence was this: "The Chernobyl disaster was a nuclear explosion and contamination due to an accident at the Chernobyl Nuclear Power Plant on April 26, 1986 at 01:23 a.m."

I changed to: "The Chernobyl disaster was an accident at the Chernobyl Nuclear Power Plant on April 26, 1986 at 01:23 a.m., consisting of an explosion at the plant and subsequent radioactive contamination of the surrounding geographic area."

I did this because I dislike the use of the words "nuclear explosion" in the previous version. People might disagree about this, but to me a "nuclear explosion" is something like a nuclear weapon detonation. In this case, the explosion was a steam explosion due to the malfunctioning reactor, but a similar explosion could have happened in any steam engine. I think "nuclear explosion" is misleading. Thoughts? SparhawkWiki 18:55, 6 October 2006 (UTC)

I agree with your change to remove the words "nuclear explosion" as none of the explosions at chernobyl were nuclear detonations. I hold the view that two explosions occured. The first was the steam explosion caused by over heating as a result of the thermal power surge in the core while the second was a hydrogen/air combustion. It is impossible to get a nuclear detonation in a power reactor such as a RBMK1000 becuase the insertion time (time required to go from subcritical to super prompt critical is too long when compared with the frequency of the generation of neutrons from the decay of minor actinides such as Cf). I am sure that in the moments before the power surge which damaged the core that the reactor was critical, so even if the core had been a solid lump of fissile matter the biggest fission release possible would have only been a fizzle (nuclear version of a damp squib).Cadmium

Thanks for the reply, always good to get some validation from an expert. SparhawkWiki 21:08, 18 October 2006 (UTC)

Duplication

Section "Causes" starts with:

There are two conflicting official theories about the cause of the accident. The first was published in August 1986 and effectively placed the blame solely on the power plant operators. The second theory, proposed by Valeri Legasov and published in 1991, attributed the accident to flaws in the RBMK reactor design, specifically the control rods. Both commissions were heavily lobbied by different groups, including the reactor's designers, power plant personnel, and by the Soviet and Ukrainian governments.

and ends with:

The IAEA's 1986 analysis attributed the main cause of the accident to the operators' actions. But in January 1993, the IAEA issued a revised analysis, attributing the main cause to the reactor's design.

Can someone move these paragraphs together? Adding references would be great too.

180-190 tonnes in reactor 4

The article says there were 180-190 tonnes in reactor 4, out of which most likely over half if not all was dumped to the outside environment. Why is there this much nuclear fuel present in any one place at any one time, in an active, reacting state? Can't there be reactor designs that work with say few hundred kilograms at a time? Even if more enriched, in case of a catastrophy the contamination to the environment should be less severe. I guess I should read up on how life is these days around Hiroshima and Nagasaki, or how much highly enriched material was dealt with there. If anything the core should should be chopped into 4, 16 or 32 pieces and separated by "neutron pipes" if there is such a thing possible (neutrons cannot be directed much by pipes-actually now that I read up on criticality accident, they mention some reflecting materials), and then if any one subsection goes kaboom, the rest would be in a physically distant and safe location to not participate and escalate the problems (at least 100's of meters far, or even if close to each other, shutting the neutron pipes by even breaking them with a hammer and bending them would be a way to stop the reaction as opposed to this "thermally deformed control rods" mechanism in use these days. At least some self sacrificing soul could run in and manually bust the pipes to save others, and you can't do such manual low tech things with a stuck control rod. Or ideally there would be reactors that extract/enrich 1 milligram of fuel, send it to the reactor to burn up in a minute, then reprocess the products, milligrams at a time should be easy, and this way only 1 milligram of explosive would be present in the world at any one time. I know this is wishful thinking by far, but the limits for dealing with a super low quantity and physically separating the fuel into very small quantities very far from each other should be pushed as far as possible. It's just seems like a prime strategic principle when dealing with critical mass. I remember reading that Richard Feynman had to be allowed to teach a plant's engineers and managers the reasoning behind creating tiny piles of radioactive material scattered all over a plant, making sure no pile was adjacent to another across a wall, which seems counterintuitive on logistics basis when you want to keep a material of one kind all in one place within a warehouse. But it's a prime principle when it comes to dealing with radiation materials, you have to scatter it as separate as possible, and put up with the logistic/tracking problems this creates, and this principle seems to be severely violated when reading such things as 180 tonnes of nuclear fuel expelled from reactor 4's core. Of course having reactors that are the size of a car engine would be a problem because of terrorism issues, but still, come on now, 180 tons? That's crazy beyond imagination. Make it 1 ton, if anything. Sillybilly 04:03, 3 November 2006 (UTC)

By the way, isn't there a way to combine fusion with fission, or at least consume some extra neutrons to breed fusion raw materials, or simply do fusion with neutrons alone? So neutron generation should be enhanced to the max, and if you had neutron-pipes you could divert a whole lot of the neutron "profit" to generate tritium and he3, and fission reactors could be running fusion in tandem. Without neutron pipes, a localized high abundance of neutrons in any core would be a supercritical situation, which needs control rods to get absorbed - basically in all current design the only way to control things is to eat up excess neutrons locally with control rods in a "reactor cooling" way, while if the mutual neutron sources were remote then a large fraction of them could be tapped for other uses. There just has to be a way to keep firing neutrons at low mass materials such as hydrogen, helium, lithium, beryllium and boron, and step up the atomic chain, and gain a lot of "hot" energy in a separate chamber while using neutrons instead of absorbing them in the initial chamber to gain an overall "cooling" effect as it's done in control rods. In this sense neutrons would be one component of a fusion fuel, find the best other component yielding the most energy, or most workable path, which would be something cheaper than the scarce uranium or thorium overall. Even if it takes a mile long pipe to irradiate something with neutrons because that something has a low cross section, but a lot of energy yield, it would still be a lot of energy yield per neutron consumed. The problem is still having proper neutron pipes that fully contain and bounce neutrons back without reacting. The current biggest problem with fusion is having to bypass the huge coulombic potential energy barrier, and if you used neutrons as one component of the fuel, that becomes a nonissue. To sum it up, basically you can't deal with too many excess neutrons in a fission reactor because that makes it supercritical, but if you tap the bulk of neutrons, and only send back a small fraction, and keep operating subcritically, you can turn fusion raw materials into energy without high temperatures, in a sense via "cold fusion", by stepping up the chain H+n+n+n+n+n, each time gaining some extra energy and extra heat. This setup would require at least 2, but preferably more, very subcricitcal cores communicating through a pipe, and the amount of neutron flux into each would be much easier to regulate just by shutting the pipe to divert the excess neutrons as opposed to using control rods in current designs. There could be many failsafe lowtech full pipeshutters along the pipe to stop the whole show, or even just busting the pipe with a hammer, as opposed to hightech requiring control rod actuating mechanisms where the control rods "get stuck" as in the Chernobyl case and everybody's out of luck then. Runaway thermal deformation made the control rods stuck, but with a pipe, such runaway deformation should stop the whole show. Sillybilly 22:04, 3 November 2006 (UTC)

Dear SillyBilly, thanks for your thoughts it was interesting reading them. Sadly a few things are a little different from the way in which you would like things to be. You commented in the large mass of fuel used, the fuel in a power reactor is low enriched uranium which is 5% or less U-235. The Little boy bomb droped on Hiroshima contained about 64 Kg of uranium-235. If the same amount of U-235 is dispersed in U-238 then the mass of the fuel would be larger. Also it is normal to run a power reactor with a much lower power density than a bomb, hence as each Kg of fuel has a much lower reactivity than that found in a bomb, a very large volume/mass is needed to get the required thermal output from the pile.Cadmium

Dear Cadmium, I do understand the need for a lot of material when the material is not very enriched, nevertheless the bulk filler material, U-238 is also very dangerous in case of a catastrophy, almost as dangerous as the U-235, because it's breedable, and almost as explosive during an explosion. And no you cannot use a different "filler" because the whole point is not to separate the U-235 from the 238 too much, for proliferation and energy cost reasons. So as opposed to 64 kg of highly enriched U-235(that consumes a lot of energy to get enriched) you have the equivalent of 190 tons of U-235+U-238, which, during an explosion it's about as bad as 190 tons of U-235, or somewhere in the ballpark. That's crazy. These guys at Chernobyl hosed the hole thing (SCRAM-d it) with neutron absorber rods that took quite a few seconds to do plus the rods melted (or at least thermally deformed but the picture in the article shows the fuel that's supposed to always be a solid molten into a magma), but still it seems they avoided a mushroom cloud because of having neutron absorbers present. There is no such thing as a naturally steady state nuclear reaction, it either wants to fully blow or do nothing at all, and you're always "tickling the dragon's tail" in commercial reactors when you tease it into that just 1.00 to 1.00 neutron chain reaction instead of one to 1.01 where it wants to blow or 0.99 where it wants to shut down. But technology makes it possible, just like fly-by-wire allows aerodynamically "ugly" but radarfootprintwise "beautiful" shapes to stay airborne. Still, this Chernobyl event was where fly-by-wire control rods got stuck, and I'm not happy with this hole idea. As I said above, the principles of critical mass teach to have nuclear materials separated for safety into sub-critical mass portions. If you can do that and just pipe the neutrons around, then you'd have better means of stopping the show by severing the links between two melting subcritical piles, as opposed to having to invade deeply with control rods prone to melt and get stuck into an about to blow already melting supercritical mass pile.

I'd also like to call your attention to the fact that, if you had good neutron reflectors that worked near 99.9999% efficiency, you could do a cavity setup like there is with a ruby laser based on an optical cavity, where the photons reflect back and forth between two mirror surfaces, a thousand times, but do this thing with neutrons if you find suitable mirrors, even if the mirrors end up being consumable items therefore considered "fuel", cost of doing business. Basically the rate of nuclear reactions is mainly dependent on neutron flux and less on the available fuel atoms present, and having to rely on naturally occurring U-235 decay to initiate and upkeep a chain reaction that is very lossy to the environment as a measure to sustain that 1.00 neutron to neutron multiplication state requires large amounts of U-235 present in single place at one time. If you had good means to bounce neutrons back and forth like you can photons between mirrors, then you could get away with very little nuclear material present at any one time, because each every neutron would pretty much be guaranteed to decay another uranium atom, and then only the nonneutronic decay mechanisms would quench the neutrons, whatever their proportion is, but there'd be no loss to the environment, such as boron control rods or reactor walls. In such case if you could get away with say 1 kg or 50 of fuel instead of 190 tons, in case that 1 kg or 50 kg blows it's still not 190 tons blowing up, meaning the environmental impact is a lot smaller in the worst possible case scenario, which is still quite an impact (100,000 acute deaths in the little boy) and you hope it never happens. Just in case someone wonders why we even deal with such things in the first place , tet me reiterate why we still keep tickling the dragon's tails (similar to why we fly fly-by-wire stealth bombers, it's because the payoff is so great), it's because 1 kg of U-235,238 equivalent to 3.5 million kg of coal in energy content. A few kilograms of fuel can heat homes and keep the lightbulbs lit in a whole city for quite a while. All new jetfighters have fly by wire because they are aerodynamically unstable at least on one axis, but true, the price of a fighterjet crash accident is a lot smaller than a nuclear plant's "hole to China", but you can argue the costs are in balance in view of the Iraqi war and coming energy wars.

If you had two or more subcritical piles of nuclear material situated in the foci of parabolic neutron reflectors, and they communicated through pipes, then you'd basically achieve a ruby-laser setup where the neutrons bounce back and forth between the mirrors and the fuel. For 3 pile design you'd need a central mirror that splits each beam, sending it 120 degrees, and behind the focus point of the parabola you'd need a smaller counterparabola to return the flux, with a small shadow on the incoming flux, like satellite-dish tv is done. In such setups SCRAMming, as in safety control rod axe man, or safety cut rope axe man could literally be done by somebody with an axe, by just severing the pipe link, possible through many many backup locations along the pipe via many different mechanisms that are highly unlikely to fail at the same time, as opposed to having a single mechanism at a single point type of setup with safety control rods, as done today in all supercritical reactors, commercial or submarine. If things fail and thermally deform, you're likely to have a mushroom cloud, as opposed to not having a critical mass in the first place, where if things go wrong, and the pipe deforms, the likely scenario is a self-shutdown, from such low-tech safety features as melting alloy supported pipeblocking mirrors. Note that you don't lose the option of control rods which can still be present, but you gain new showstopping mechanisms by having to rely on neutron sources external to the core to sustain any reaction.

There is the competing idea of a subcritical reactor based on externally generated neutrons, based on such things as particle accelerators or fusors, but these neutrons can be quite costly, as opposed to using the cheap naturally generated neutrons and just taking better care of them, as in a systems with better neutron mirrors for efficiency and safety, and neutron pipes for safety. In a 3 -pile reactor, 1 pile could be reprocessing and reducing nuclear waste that has the neutron absorbers chemically reprocessed out, while the other two provide the bulk of the energy in a pipe-based-safe way, having a central mirror system coordinating fluxes as needed, and many many neutron flux safetystops along the pipes. Also the need for the fuel to occupy a focus point of a parabola means that most malfunctions such as the fuel melting into a magma would make it flow away from the focal point through a supporting grid, unless the reactor is gas-cooled and run at 1500-2000 C where the fuel is a magma to begin with held in crucibles, but then too most thermal deformations or mechanical malfunctions would make the system "lose focus" instead of self-accelerate.

Note that while the energy payback is tremendous, and the cost of energy is on par with coal without greenhouse emissions and with less radioactive emissions than coal, the "tickling the dragon's tail" self-accelerate danger by neutrons overmultiplying is never remote by the simple nature of nuclear chain reactions, even in a pipe system, all one can do is improve the fly-by-wire negative feedback based on neutron flux/temperature monitoring and the SCRAM showstopping safety features, which in all current designs are limited to inserting neutron absorbing control rods into an unmolten undeformed solid brick pile. Still, stealth and nonstealth fighters are flown fly-by-wire, France derives 80% of its electricity without much incidents, and the Mobile-Chernobyl has been around for a while now, and so far all mushroom clouds in the world were intentional by humans. Some argue it's a matter of time only for a real accident, especially if the technology proliferates more and gets into untrained hands, but there are other things to put into perspective such as famine deaths of millions in third world countries as we speak, and conventional-energy based deaths in WW2, and such things as people living today in both Hiroshima and Nagasaki, that area hasn't been designated an off limit and sterile area for thousands of years. Ideally one would put all reactors deep into a mountainside far from any population and just carry the energy content away, whether by railroad or more wasteful electric wire, and then I don't think there'd be a problem finding workers willing to take the risks to go deep into the mountainside to provide energy that feeds us all, just like there are quite a few people willing to be astronauts even fully aware of the risks of dying, or people going down into coalmines and even to frontlines in a war where they believe it's a good fight and it makes a difference. Unfortunately these days most reactors are very close to highly populated areas because transporting electricity by wire to large distances is quite wasteful, but possible with decent efficiency as in HVDC designs, while allowing the "not in my backyard" to stand. The bigger problem is the need to be near large bodies of water, because up to 70% of nuclear energy is expanded as waste heat into the air through massive cooling towers, then the remainder into rivers and lakes, and rivers and lakes tend to be where most humans are located. Coal plants with their higher radioactive emissions are also next to rivers for the same reasons. Because of nearness to a large body of water, the pollution potential from leaks or fallout getting carried around is more severe. In a mountainside or out in nowhereland such as a desert there'd still be need for some water or huge heatsink-airfins, but if operating characteristics are improved by increasing reactor temperature to white-heat, then only 10-30% of energy would need to be rejected to the environment instead of 60-70% as done today.

BTW some modern designs have been proposed for the next generation of reactors which would be gas cooled and operate at very high tempertures. By increasing the temperture of the heat transfer fluid (at the point when it exits the reactor) a greater percentage of the thermal energy could be converted to electric energy. Also such a high temp. heat source could be used to split water into oxygen and hydrogen.Cadmium

Ideally humans could just switch to simpler lifestyles less energy greedy, sustainable by solar, wind and bio, but in the meantime while global warming and fossil fuel depletion occurs, the transition period could be eased by relying on nuclear, which is the only non-greenhouse energy source with high energy density and therefore "profitable" as defined by the unreasonably high expectations of today's business world. But there are very uneasy safety issues with nuclear that could probably be improved by orders of magnitude given enough effort. By the way nuclear is non-renewable in the sense that both uranium and thorium ore-grade reserves are limited, but there is tremendous trace-level of these materials is lower grade reserves, and if technology were available to extract it "profitably", it could supply the world's current energy needs for well over a millenium. Of course the "less profitable" solar and wind could supply it for millions of years, while being completely safe and emission free, and installable by the public near the homes and near where energy is consumed, and allowing a more distributed and more public ownership of energy resources as opposed to heavily centralized setups where the means of oppression are very severe.

Sillybilly 11:53, 11 November 2006 (UTC)

Dear Sillybilly,

Thanks for the mail, your eassy is rather long and a little hard to follow in places (I am just finding it a bit too large to digest)

you wrote

There is no such thing as a naturally steady state nuclear reaction, it either wants to fully blow or do nothing at all, and you're always "tickling the dragon's tail" in commercial reactors when you tease it into that just 1.00 to 1.00 neutron chain reaction instead of one to 1.01 where it wants to blow or 0.99 where it wants to shut down.

I would say in reply that that is not correct becuase of several things.

Not all the neutrons are emitted at the moment of fission, some of the neutrons are delayed. Hence it is possible for a system to be just critial in terms of prompt neutrons but slightly supercritical in tewrms of all neutrons. This is different to the superprompt critical state which a bomb has to enter.

As nuclear fuel and the moderator heats up some processes occur which tend to slow the fission process down. For instance when the graphite heats up the temperture to which it can moderate neutrons to increases. If you want super cool neutrons then a liquid hydrogen moderator is required to lower the neutron speed to a very low speed. Also in a system where water is the moderator if the water boils then less moderator is present in the system.

You wrote of the idea of a subcritical reactor, sadly such reactors have not be constructed on the industrial scale. At CERN a small scale test of some of the technology has been tested already. I am well aware of the ideas of using a proton beam (circa 1 GeV at a high beam current) to spallate neutrons from lead or some other heavy element, this neutron generation method is used already for creating the neutron pulses required for neutron diffraction (eg the ISIS source in england) such a neutron source would require a subcritical core to surround it. In this core actinides would be converted through fission to short lived fission products. Sadly such a reactor is much harder to build than a normal critical reactor, many good critcal designs exist, for instance the BWR is a supersafe reactor becuase it is a PWR which has been 'redesigned' to operate in a pipe burst fault an example of a LOCA event. If you had a very bad LOCA fault in a PWR then you could lose preasure and start to boil the coolant.

By the way if you see me making a dire spelling error, then please feel free to correct it. I will not take any offence from you correcting my typos.Cadmium

You say the tickling the dragon's tail in all nuclear power systems is not entirely true. Yes, there is some extra control - by delayed neutron release, and by moderators.

I don't completely understand how delayed neutrons are supposed to help, other than lessen the rate of things getting out of hand instead of instantaneous happenings, giving you some time to catch up and control things, and, perhaps allowing more time for the neutrons to escape or get absorbed by something else. If you have too many net neutrons generated per second that generate even more neutrons per second, you got a problem. If you got too little, you also got a problem. Perhaps you mean slight fluctuations get buffered out, a sudden excess is buffered by delaying, so there is no such sudden up or down drive away from the fine equilibrium of barely tickling the dragon's tail to get away with what we want but not tickling it too much to the point where it wakes up. What is the delay timescale we're talking about? 1 minute? 1 nanosecond?
Moderators increase reactivity because thermal neutrons are more likely to produce a reaction than escape. Therefore if moderation fails because of void formation, as in gas bubbles from boiling of liquids, it can provide a negative feedback and lessen the moderation which lessens the reaction rate, therefore self controlling to some degree, enough degree to make it commercially operable technology. However both high negative and high positive void coefficients are troublesome, as explained on the void coefficient page. This is only a mechanism with liquids in a reactor and thermal neutrons, however all moderator based reactors only allow 1% of the energy content in nuclear ore to be harvested, as opposed to breeder reactors based on unmoderated designs that allow 99.5% by breeding more fuel. That's a 100 fold increase, and better utilization of energy resources, and a subject of many future reactor designs, but it inevitably means that there is less moderator-provided safety feature present, which brings us back to the tickling the dragon's tail problems. I tend to look at all nuclear power plants as I look at stealth bombers: it's so ugly from an aerodynamic point of view, it would have no chance to ever fly if it weren't for the fly by wire, it would just do an ugly dive up or down, but it's very graceful with it's sophisticated sensors and computers, it seems unintuitive and unnatural, but it works. Inasmuch as you can keep a tight monitoring and control on what's going on, and have reliable sensors and a sane computer, it's fliable, but if your sensors data is wrong or the computer goes crazy, the stuff hits the fan, and what's your last of the last safety measures, where is your axe-man ready every second to chop the cord stopping the whole tickling the dragon show? Yes, some of the fly-by-wire is analog control, or built in analog response, and the lower tech and less complicated and more self correcting "by design" without human or software judgement intervention, basically without the need sensor data and decision making, but just natural behavior, such as boiling water, the better. Things like "if the temperature goes over the boiling pt of water (say 100C at 1 atm) then we will push this button" is a lot less safe than "it can't go over the boiling point of water because there is a ton of water there, and it would take at least 2 minutes for all that water to evaporate", which at least gives two minutes for stopping the whole show as opposed to seconds. I highly dislike the reading

"At 1:23:04 the experiment began. ...... At 1:23:40 the operators pressed the AZ-5 ("Rapid Emergency Defense 5") button that ordered a "SCRAM" — a shutdown of the reactor, fully inserting all control rods, including the manual control rods that had been incautiously withdrawn earlier."

I'm not used to seeing seconds where humans are in control. 36 seconds????? 36 seconds away from a mushroom cloud in your backyard? I know it was an experiment, poorly designed and run by not the most qualified, but what if somebody tripped in the control room, knocking over some control buttons, and spilling hot coffee on his coworker? How much time to they have to regain control and turn the knobs back to where they were supposed to be? This is crazy! We need more passive safety than that, such as less than critical mass cores! I know fly by wire stealth bombers do okay, and asking questions of "how many seconds are there to correct the flap motions up or down", the answer is none, probably 100 milliseconds, and these things fly around fine without being dependent on pilot intervention unless things go completely out of hand, but then there isn't much a pilot can do to keep the plane in control or emergency safe-land, while the SCRAM can sudden safe-land everything in a power plant. But a pilot flying a mission in a plane to me seems more acute and alert than a "security guard" reading a paper or asleep at the control knobs in a nuclear power plant, or at least bored out of his mind staring at the gauges and numbers. They are probably well trained and aware, but the atmosphere at first look does not suggest such an imminent and omnipresent danger to the second as when you are a pilot of a combat ship riding an unaerodynamic plane at low altitudes and extreme speeds hoping fly-by-wire works fine. Sillybilly 15:52, 11 November 2006 (UTC)

By the way I just read your above posting saying

"It is impossible to get a nuclear detonation in a power reactor such as a RBMK1000 becuase the insertion time (time required to go from subcritical to super prompt critical is too long when compared with the frequency of the generation of neutrons from the decay of minor actinides such as Cf). I am sure that in the moments before the power surge which damaged the core that the reactor was critical, so even if the core had been a solid lump of fissile matter the biggest fission release possible would have only been a fizzle (nuclear version of a damp squib).Cadmium"

Are you saying it's not possible for an unentriched fuel based reactor to explode, and all you ever get is a very hot and intensely radiating fizzle, because of insertion time and prompt critical constraints? If that's true, that's awesome! I'll sleep a lot better 50 miles from a nuclear power plant. Then all you need is a containment building to contain the fizzle, and making sure that supercritical piles never get "inserted" or "imploded" or "gunned together" by sudden steam pressures and similar explosions. I was not aware of this. Then the real problem is human intent, theft and lost material, as opposed to power plant operation, where many things have to go wrong at the same time, instead of one always omnipresent and imminent danger, that, if it gets out of control, the dragon wakes up. All there is just a pussy cat that wakes up and fizzles, which only turns into a dragon under very special circumstances (which are not that special where there is mechanical pressure.) Sillybilly 16:29, 11 November 2006 (UTC)

Yes I am saying that without taking a great deal of care to get the three conditions listed in the insertion time article that it is not possible to get a nuclear detonation. If you were to create an atom bomb where the implosion was too slow then the reaction would start too early, as a result the fuel (Pu metal fuel) would heat up early and it would start to fly apart (due to the heat) at a premature time. Even if the energy release is too small to vapourise Pu, it can terminate the fission (or make the system less critical) by causing thermal expansion. As it then goes subcritical the number of fissions which will have occured by that moment in time will be very small compared with the number which would have occured if the sphere had been crushed quickly and then injected with many neutrons rather than powering up early becuase of one or two stray neutrons. So you can sleep happy in the knowlege that a nasty big bang is not possible in a power reactor.Cadmium

So basically Chernobyl was as bad as it could get in a reactor? Since their control rods got stuck, the reason why the whole thing didn't explode in a nuclear way was not because they had neutron absorbers present, that got halfway stuck because of thermal deformation, but simply because radioactive stuff doesn't blow on its own. Basically the fuel melted down into a magma and thermally expanded/vaporized enough to keep it subcritical without ever blowing. The slight time delay you spoke of above can be very handy in such things. So even if the place had a containment building, the simple fact of the fuel needing to vaporize/expand without limits would have popped a hole on any containment building anyway, taking on whatever temperature (20,000C if that's what it takes) to build up the shockwave pressure necessary to pop anything. I'm curious, what kind of timescale are we talking about with delayed neutrons? That's gotta be the key parameter allowing thermal expansion without sudden blowing. Is it milliseconds?

I basically first wrote the above, then went on a reading spree. Now it's clear that there was no mushroom cloud in Chernobyl not because there were neutron absorbers somehow present, as said above, but because simply nuclear fuel doesn't explode on its own, contrary to what I've known so far. If it did, Chernobyl was as bad as it could ever get and would have pretty much resulted in a mushroom cloud.

From the critical mass page I read that critical mass is dependent on on the inverse square of density, so any thermal expansion will cut reactivity significantly. Suddenly increasing the density without stray neutrons present, and then suddenly shocking the critical mass with a lot of neutrons is the way to cause an explosion, because single stray neutron ignited stuff will just "fizzle out," basically heat up and expand faster and drop reactivity faster than the neutrons can multiply.

From the prompt neutron page I learned what you meant by delayed neutrons - the delayed neutron is not a delay in the decay of a U-235 or 238 just hit by a neutron, because that's practically instantaneous, but a delayed neutron is one resulting from the reaction fragments, such as cesium and iodine isotopes, and has a rough timescale of about milliseconds to 15 second half life.

From nuclear chain reaction one can read that fast neutrons travel about 10,000 m/s and take about 10 ns between generation and capture by a nearby nucleus. The delayed neutron fraction is typically less than 1%, but it's enough to keep the reactor subcritical prompt neutron wise, and allow the few second window for fly by wire controls to kick in and work their magic by moving controls rods slightly in or out. What I read makes me think that when a reactor becomes prompt critical, control by fly by wire is pretty much impossible, because the required response time is on the order 10 ns in face of exponentially increasing neutron flux. Moving control rods for any distances under 10 ns constraints is just too much mechanical inertia. If you had any other way to affect neutrons besides the strong force, such as electromagnetic means, sub 10 ns things might be possible for a neutron flux inside a conduit, and prompt critical reactions might be controllable, but definitely not by mechanical means as in control rods, they are just not fast enough to control prompt critical things. Compounding enough uncontrolled 10 ns yields the 3.6 millisecond number from below.

By far the most important and educational page was the SL-1 prompt critical accident page, where 3 people died, and 32 rescue workers got medals for entering massively radiating buildings and take on massive doses of radiation even with full protective gear many days later. This place too, just like Chernobyl, should have gone into a mushroom cloud if such a thing were possible with nuclear reactors. Basically the time constants were about 100 milliseconds for normal thermal expansion of solid components to cut critical mass by the square root density factor, and 6 milliseconds for water to start to boil and unmoderate the reaction, with the void coefficient method, dependent on the metal cladding thickness. Neither of these were effecitve because they were too slow because of the sudden increase into the criticality region by removing a control rod too far too fast. The prompt criticality went on increasing for about 3.6 milliseconds that set up a mechanically explosive/vaporizing thermal expansion and disintegration of the core by about 7.5 milliseconds, beating the unmoderating void coefficient shutdown by a few milliseconds. Basically a nuclear core disintegrates in under 10 milliseconds to become noncritical, and only some of the contained energy is released, and in order to have a mushroom cloud accident, it would either have to be kept together for far longer than 10 milliseconds to have the exponential growth of neutrons go on, such as under an explosive/imploding blanket, or, there needs to be enough neutrons suddenly generated in well under 10 milliseconds where even such self-disintegration would not be fast enough. To quote the article

"The accident also showed that in a genuine extreme accident both the vaporizing of the core and the water to steam conversion would shut down the nuclear reaction. This demonstrates in a real accident the inherent safety of the water moderated design against the possibility of a nuclear explosion.

In addition to a sudden power surge, a nuclear explosion requires sufficient force to hold the reacting nuclear components together for a short but necessary time. This is achieved in a nuclear fission weapon by surrounding the core with a carefully engineered symmetrical inward-facing conventional explosion. This element is not present in nuclear reactors. Lacking such explosive compression to hold the vaporized core components together, the components fly apart as in this accident; the reaction ends, resulting in a steam explosion and a badly damaged reactor core, but not the type of explosion from a nuclear weapon."

That's very nice and reassuring to read. But I still have a problem - in this SL-1 accident they basically moved the single control rod 20 inches instead of the prescribed 3 inches, greatly increasing reactivity, but not by that much. I still have a problem with scenarios where there is a sudden burst of neutrons from having a highly supercritical reactor where even the self disintegration core metal vaporizing 20,000C thermal expanding with the speed of sound isn't fast enough. What if they pulled the control rod 100 inches, or some similar effect.

Good question, while I know something of the SL-1 event I do not have the details of the mechanics of the reactor design. For instance I do not know if the a part was 10 inchs or 30 inchs long. But I would to point out that the SL-1 event cayused a change in reactor design. It was understood afterwards that the design of a system where the removal of only one control rod could take a reactor from subcritical to supercritical was a very bad idea, so all designs after the SL-1 event have more than one control rod. Also even if the control rod was pulled all the way out then some limits to the reactivity of the reactor would exist.

The density of the fissile mater is lower than that in a bomb.
The fisile matter is diluted with some nonfisile mater which will absorb neutrons and reduce the number of fissions that each fission event can provoke. The U-238 will not fission when subjected to fast neutrons from a nuclear fission, to make U-238 undergo fission you require fusion neutrons from a reaction such as D-T.
As you have already commented the thermal expansion of the fuel will tend to retard the criticality
The lack of a tamper to hold the system together will allow the reaction to die out more quickly.
The moderator boils off as it heats up, if you read the recent review published in the US on crticality accidents then you will see how many of the process accidents were events which self-terminated when the water boiled away. In some of the events the reactivity was pulsed, the water boils and the reaction stops, the system cools and the gas bubbles from water radiolysis leaves the mixture and the thing goes critical again.

- "A Review of Criticality Accidents" by Los Alamos National Laboratory (Report LA-13638), May 2000. Coverage includes United States, Russia, United Kingdom, and Japan. Also available at this page, which also tries to track down documents referenced in the report.
- U.S. report from 1971 on criticality accidents to date

The fuel at the time of the event will not be, "pure" it will contain some fission products which are neutron poisons, in many power reactor fuels it is normal to add some burnable poison (B or Gd) the idea is that the neutron irradation removes the poison as the fuel is used, at the same time the consumption of the fissile isotope lowers the reactivity of the fuel. The two effects are ment to cancel each other out. The SL-1 fuel had some boron in it as a burnable poison. It is important to understand that the burning up of the poison can cause a reactivity transiant, it is thought that the sudden consumption of one of the xenon isotopes at Chernobyl contributed to the power surge.Cadmium

The nuclear chain-reaction page says supercriticality exponential growth of neutrons present is e^{(k − 1)t / g}, where k is the supercriticality constant, usually something like 1.01, t is the elapsed milliseconds, such as 3.6 ms in the above scenario, and g is the average generation time, that I don't really know what it means (is it 10 ns, the time a neutron travels to hit another nucleus?) If either k was instead of say 1.01 or even 1.05 or so as in the say the SL-1 case, say there was a steam explosion that blew all the control rods out of the core in under 10 ns that a neutron takes to travel, and you had a k of nowhere near 1, but say 10, or 100, is then the 3.6 or 7.5 millisecond vaporizing shutdown expanding fast enough to avoid a mushroom cloud? There is still something that feels very wrong with 190 tons of fuel present in a single place at one time. I still feel better now knowing that actually there were two separate "real" prompt critical accidents so far, one in Chernobyl and one in SL-1, and neither resulted in a mushroom cloud, but just a fizzle in both cases. There is still a danger of implosive steam explosions, or special circumstances such as sudden massive supercritical mass where the core disintegration isn't fast enough because even the vapor is dense enough for supercriticality, or just any sudden lasting explosive compression that greatly increases the core's density making it highly supercritical and keeping it that way long enough, such as terrorist attack airplane smashings. However the fly-by-wire tickling the dragon's tail that happens daily, where things go supercritical "smoothly", as opposed to sub 10 ns accidental control rod ejections or intentional attacks, such normal fly by wire where things go wrong "smoothly" by the reaction just slipping out of hand due to normal velocity control rod motions will result only in a core disintegrating fizzle. This lets me sleep a lot easier, because there is no dragon tail tickling going on. Now all that needs to be done is that all nuclear power plants have a decoy containment building, and the actual core be built somewhere hidden, underground, so that terrorists get to smash at the decoys. I'm still not happy with the whole 190 tons of fuel thing, but now I know that 190 tons is a relative thing, because critical mass is such a relative thing as opposed to being a fixed thing, theoretically you can have a 1 gram material explode under proper conditions, and then 190 tons not explode just fine, it's a relative thing, and it's hard to avoid being very far from the critical range that has not even a remote chance to be compressed into an explosion in any design, because simply power generation requires being in the neighborhood of criticality, if nothing else, by the less then 1% delayed neutron fraction. If we could process nanograms of fuel under a neutron flux, then even if the nanogram blew up from a terrorist attack it wouldn't be too much of a problem. You know solar panels aren't vulnerable to terrorists or intentional malice, even if very unprofitable. Sillybilly 23:19, 11 November 2006 (UTC)

True finished solar panels are quite harmless unless you bash someone in the head with one, I joke that almost any object is dangerous if you drop it on your toe. But the chemicals required to make silicon semiconductors are far from nice, and there is the possibility that someone might steal and misuse the reagents required for an industrial siliconchip plant.Cadmium

That's true. I've since read up on the Three Mile Island accident and the Goiânia accident and Pebble bed reactor. The Goiânia scenario highlights how dumb people can be, but such things will be very hard to completely avoid as long as there are medical uses for radiation, such as cancer therapies or even such things as a bone x-ray, radiation dangers at even a minimum level are probably here to stay forever in human society. As far as TMI goes, it highlights confusion generated by sensors and having to rely on people to make button pushing decisions, people are dumb and pretty much at loss when sudden decisions are needed, because they simply "don't know," but the timescale for things going wrong was surprisingly slow - hours. It's always easy to be wise after the fact, they say hindsight is always better than 20/20. Nevertheless it highlights the phase-change problem in all water reactors which is a sudden change in coolant properties. I just don't like the idea of people assuming they have liquid water in a pipe somewhere when it's all actually long gone and all you have is residual steam. The pebble bed reactor just seems so much better than anything current using control rods and water, because the control is not by partially inserted neutron absorbing control rods - where errors in mechanical motion such as moving it 20 inches instead of 3 lead to catastrophies - , but by that 100 ms characteristic time thermal expansion effect. Reactor output is throttled by withdrawing gas coolant flow and the thermal expansion from the core self heating to white heat drops the reactivity due to the inverse square critical mass law. In some designs if the coolant flow is completely stopped, the reactor heats up to an equilibrium temperature of 1600°C where the rate of heat generation drops to 1% full capacity, and the heatloss through the walls by conduction and radiation keeps the whole thing at this high temperature equilibrium balance, if the total bed size is sufficiently small, about 250 MW. The very high temperature helium cooling gas directly driving gas turbines gives a high carnot cycle efficiency (50% as opposed to 30% in current designs.) Also it can use any fuel, not just the less than 1% U-235. The downside is the designs are too compact, shippable around too easily, and there are some crazy proposals for powering hospitals, commercial ships, and even locomotives and airplanes with such things. I definitely don't want nuclear powered airplanes flying around, even if the weight to power ratio is favorable. Talk about proliferation made easy. You just can't trust the private sector where money and profit talks today, where is our bottom line, we'll deal with ethics later, without government oversight. Also, such compact things still pose a real danger of getting detonated in a mushroom cloud sense by sufficient explosives placed around them. It's very hard to keep this stuff safe from intent and malice, and sufficient knowhow. One the one hand having something too compact as 1 to 250 MW is a good thing, because if things go wrong, at least the effect is limited, as opposed to looking at that fallout map from 30,000 MW Chernobyl affecting Scotland, on the other hand compact things are more dangerous. There still should be designated nuclear plant sites where you can pile these small 250 MW units separated by enough distance, and then transmute the energy into something else, safer to hand to people like you and me, to people form Goiânia and the operators at Three Mile Island, whether as electricity, or some chemical energy storage (sulfur-iodine cycle hydrogen is mentioned a lot, but hydrogen has a lot of practical issues). This whole nuclear question reminds me of watching Startrek and the warp core issues, where the warp core is about to overload and go critical, and everybody has abandon ship before countdown to self destruct, but also this very warp core is what sustains life, powers the food replicators and the holodeck. There should be an episode where some refugees or even affected crewmembers protest the dangers of the warpcore and a court decides to order the captain to shut it down, and then they get to sit in relative darkness with little food and very little physical motion or speech allowed, but be very safe, the only power source being the solar panels receiving light from distant stars. They could slowly approach a star and a planet in about 10 years, build a battery bank that's 1000 times the size of the ship, charge it up with enough power while near a star to last through the darkness until the next stopover at the next star that will happen in another 10 years, and so on. If you have patience, such low intensity "green energy" completely safe from warp core incidents star trek is doable, because who says space is filled with Klingons when it's really just very empty, and nobody is gonna shoot at your huge load of battery bank "fat" you drag around in space. In fact why live and fly around in space at all when they can just settle the planet near a star, and live happily everafter there as foragers dressed in grass skirts, without needing any technology, and especially such things as a holodeck, who needs a holodeck when you got each other? Sillybilly 12:38, 12 November 2006 (UTC)

Chernobyl compared to Hiroshima Graphs

Just a thought that perhaps the graphs should retain the same colour lines for continutity throughout, if anyone has the expertise to edit and repost the graphs without the change in colour/site reference seen currently I think it would be a minor but important alteration.

Plant location

Two latitude/longitude locations are given for the plant, and they don't agree. Simesa 23:55, 22 November 2006 (UTC)

The article says 51°23′14″N 30°06′41″E / 51.38722°N 30.11139°E, but from following the links it seems like 51°23′22.39″N 30°05′56.93″E / 51.3895528°N 30.0991472°E is a better set of coordinates. There isn't really anything at the first set of coordinates. Does anyone have a justification that the first set is more correct? Wesino 22:15, 4 May 2007 (UTC)

...or maybe this set was intended to be the reactor complex? I've added the second one to the article as the coords of reactor 4, doublechecking appreciated. Wesino 22:22, 4 May 2007 (UTC)

Farming and Grass-fire sections

These sections appear to be general rather than related to Chernobyl. I suggest they should be deleted, unless the author wishes to rewrite them in a fashion which ties them more directly to the article. Joffan 06:15, 11 December 2006 (UTC)

Comparisons

I removed the comparison graphs to a separate article, linked from its previous location, because I felt that it diluted the article too much and because it overshadowed the ostensible content of that section, comparison to other disasters. I also admit I had concerns about whether it was truly encyclpedia material or whether it had strayed into being a kind of textbook exposition of radiation calculations. Not uninteresting or necessarily wrong, but as I say distracting from the focus of the main article. Joffan 22:26, 16 January 2007 (UTC)

Fauna

The fauna section's wording is suspect. Animals' thyroid glands disintegrated 6km away? VxP 01:07, 23 January 2007 (UTC)

I have edited this to improve the wording, based on the description of early effects on fauna from the IAEA International Chernobyl Project Technical Report (now cited). jts555 29 January 2007.

Aquatic systems

The contamination of aquatic systems was not covered in the article, so I have added a section to cover this.jts555 29 January 2007.

Comment on Tobacco Quote

Apologies for not discussing this properly (I'm a newbie), but I'm not sure I like the following quote, and especially not the emphasis given to it by inclusion within the opening section:

"Dr. Peter Boyle, director of the International Agency for Research on Cancer, put the discussion of the figures into perspective: "Tobacco smoking will cause several thousand times more cancers in the same [European] population."[2]"

It seems to trivialise the accident. The fact that it may be true is irrelevant. Afterall, tobacco kills so many people that the above quote could be used to trivialise 'any' event. For example, in the opening paragraph of (say) the 9/11 attacks, I could "put the figures into perspective" by saying "tobacco smoking will cause several thousand times more deaths in the same [US] population".

Plus - the quote is very deceptive by referring to "European" population. Seems a bit arbitrary. If the speaker had compared the impact of Chernobyl vs Tobacco upon the "Northern Hemisphere" population, then Chernobyl would appear more trivialised, whereas if he had compared the impact upon the "Belarus" population, then Chernobyl would appear less trivialised.

In summary, I'm going to leave any editing to other people (I'm a newbie, and it's not really my thing), but I just thought it might be an idea to point out my concerns about the above type of quote.

Cheers, Steve

—The preceding unsigned comment was added by 135.196.169.250 (talk • contribs) 00:18, 12 February 2007.

Hi Steve. Your point has indeed caused some unease before, in an older, archived section of the talk page, here. What we have now probably reflects consensus from that discussion. The statement as it stands probably reflects the figures available from the quoted source, rather than worldwide figures. Your suggestion that "The fact that it may be true is irrelevant" might seem as a bit unencyclopedic to some editors!

Thanks for the contribution, and welcome to Wikipedia. Please don't be discouraged by grumpy editors, and stay around! --Old Moonraker 09:59, 12 February 2007 (UTC)

I too think the "tobacco" comment trivialises the whole disaster too, and is completely misplaced. The 9/11 comparison by Steve is very apt. Worse still, the tobacco sentence also receives undue prominence in the opening section, when it could better be included in the relevant section below. There is also bias in taking that sentence from the source listed but not including the IARC conclusion that "concluded that about 16,000 people across Europe could die as a result of the accident." from the same BBC Horizon source, claiming instead that it is difficult to make an estimate. 212.64.98.189 19:39, 18 February 2007 (UTC)

The sentence about smoking originally was with the paragraph "Other studies and claims" in Chernobyl disaster#Controversy over human health effects, with the other claims made in the "Horizon" article on the BBC website. It would perhaps be reasonable to put it back there and away from the lead, as suggested by 212.64.98.189. We are going over already well-trodden ground here. Old Moonraker 20:41, 18 February 2007 (UTC)

Afterthought: The IARC report does have its own para in the same section. It bases its conclusion on the "linear no threshold model", which "Horizon" does not accept. By reverting the sentence under consideration back to its original position the two opposing points would be adjacent. (Here I find myself defending something I'm not too happy with; I thought it out of place when it was moved to the lead ~~article~~ paragraph, but that seemed to be the consensus of the time.) Old Moonraker 20:55, 18 February 2007 (UTC)

I would agree to move it back with all the other arguments. I don't think it's right to pick and choose certain quotes and put them in the leader. 212.64.98.189 00:41, 19 February 2007 (UTC)

OK, it's done. --Old Moonraker 07:40, 19 February 2007 (UTC)

Not to stir this up again, but in my opinion the quote is talking of the amount of cancer the disaster will add, not the amount of deaths. So sure you cuold use it when talking about 9/11 but it does not have the validity that it holds because there is no massive increase in cancer as a result of 9/11. Shotmenot 07:41, 21 March 2007 (UTC)

I've gone back to the citation and you are right: The IARC director is referring to the incidence of cancers, not deaths: He is putting the supposed onset of cancers from Chernobyl into the context of the cancers supposedly caused by smoking, not comparing fatal or non-fatal outcomes. However, is this not implicit in his statement? It's interesting that, a few lines above, the European Committee on Radiation Risk is accusing IARC (among others) of deliberately misleading the public to protect the vested interests of the nuclear industry. I think having the two statements in the same section enhances WP:NPOV --Old Moonraker 08:32, 21 March 2007 (UTC)

Excelent article on Chernobyl - published one week after the disaster

Here is the link for an article (IN PORTUGUESE) about the accident, which was published one week after the disaster. It explains Sweden's first reactions, the USSR answer, how people in Europe reacted to the news, etc.

http://veja.abril.com.br/idade/em_dia_2001/reportagens/reportagem_chernobyl.html

--Pinnecco 10:22, 25 February 2007 (UTC)

Release version nomination

Hello

I failed this article on a quality basis, as it needs a serious cleanup. The prose is disjointed and the lead is too long. Feel free to renominate this article here once you've fixed up the criteria that failed your article. Social Studiously ^{My Editor Review! -} 10:45, 29 March 2007 (UTC)

Revamping Chernobyl disaster entry

I made some changes to the article. Here is a quick summary:

double sections were deleted (e.g. material covered under Chernobyl disaster effects)
reorganized for logical flow (e.g. chronology then causes, not vice versa)
cut See Also list; it is counterproductive to keep it so large. If you feel that something else should be included and is not feel free to add those, but let's try to keep it short and tidy. Note that some entries will lead to others so it is not necessary to include both.--Riurik ^(discuss) 15:22, 18 April 2007 (UTC)

Poland

I am pretty sure that the article fails to mention that parts of southern Poland were also evacuated after the disaster and citizens went through a decontamination process. —The preceding unsigned comment was added by Tetty2 (talk • contribs) 20:02, 26 April 2007 (UTC).

Source: My friend Mike and his brothers and parents who were evacuated from their fishing trip and put through decontamination.

I and others (I'm sure) would be interested to hear more about this-find a citation from a provable reliable source that is written somewhere and we could include a section on what types of decontamination processes was/were used.--Read-write-services 23:55, 12 August 2007 (UTC)

Spin-off proposal: section on controversy over effects

I think the "effects" section is too long and the main article can benefit from spinning it off, as I hastily tried to do here. I think Chernobyl disaster should discuss effects, but it is extra to include such a detailed and extensive summary of the controversy over findings in an entry about the disaster itself; the controversy discussion seems to better belong in a separate article Chernobyl disaster effects (already there). A pithy summary of the recent studies is in order of course and I have nothing against that. If agreed then, the task is to provide a general summary and include the link to the main article. Your thoughts?--Riurik^(discuss) 04:27, 18 May 2007 (UTC)

As the editor who reverted your first attempt (I hope that I wasn't acting too hastily as well) I support the principle of your action, with a "pithy summary" and link, as you suggest. I look forward to the result!--Old Moonraker 06:44, 18 May 2007 (UTC)

No haste perceived. I spliced up a summary for the health effects studies section. Feel free to revise if something was not included, etc. Regards, --Riurik^(discuss) 22:33, 19 May 2007 (UTC)

Animals being able to survive/Americas not affected by radiation and chemicals?/Will Chernobyl be abandoned for GOOD?

If you haven't heard or known this, certain animals have been living in the surrounding area of Chernobyl and the Chernobyl NPP for some time. (They are in the surrounding area, not like, inside of the Plant or near it.) Somehow, they are able to survive, but how are we humans not able to survive like them? Will the radioactivity not affect the animals and show "Evolution-like" changes in them? I think animals like Horses and dogs have been able to survive there solely on the fact that: Humans aren't around there (Unless some beefheaded "Scavenger" wandered into the zone, suddenly being cooked by the radiation and chemicals in the air.) On another note, how has the U.S. not been affected by the radiation? Around a week or two after the incident, large clouds of the chemicals were over parts of the U.S., but somehow, those states and peoples were not affected by it. Again, another question. After the certain time Chernobyl had for the many deadly chemicals and radiation to "go away", will Chernobyl, Pripyat, and the surrounding areas be abandoned for good? Of course, over that time the Chemicals and Radiation should have SOME sort of affect on the living animals in the area. Will it be abandoned for good? Because all of that junk could just as well be hiding in the deep soil just waiting to be dug up. What will happen to the Charnobyl NPP after all of the time has passed? — Preceding unsigned comment added by 151.197.57.145 (talk) 05:16, 8 June 2007 (UTC)

There are people and animals living near the Chernobyl reactor, but many of them are ill, have genetic defects, etc. The death rate is high and life expectation is low. Yann 15:57, 9 June 2007 (UTC)

I think that Yann is taking a over grim view, the vast majority of the radioactivity has already decayed away. The main remaining threats are due to ⁹⁰Sr, ¹³⁷Cs these will decay away over the next 300 years to very low levels. If the alpha emitters (actinides) are well controlled (by the sealing of surfaces and other measures) then the area will be safe for the majority of human activitys.

The ability of radiation to induce genetic changes which progress from one generation to the next in most animals are oftein exagerated by the average member of the general public so I wuld not expect the area to have three headed dogs, cats which fly or any of

the other gross changes which the gutter press and the general public expect. It is normally only a 1% chance per Sv in humansCadmium

Request for feedback

Please provide feedback on the article at request for feedback.--Riurik^(discuss) 21:34, 15 June 2007 (UTC)

Thanks to Adrian M. H. for providing feedback on the entry as of 18:37, 24 June 2007 (UTC).--Riurik^(discuss) 03:58, 26 June 2007 (UTC):

...it is a very well written article indeed and could be a strong FA candidate, I believe, with a few improvements. As you probably know, the references need to be increased in some sections, including Immediate Crisis Management and Causes. The Grass and forest fires sub-section has a group of embedded URLs that need to be changed to footnotes. It looks very difficult to trim the length, as it does not have anything that is not essential or at least very worthwhile, and because of this, the Effects of disaster section would probably have to be the main target, since it has a full article. I'm not sure how much could actually be removed from this section without leaving it incomplete, so it may even require restriction to a See also link. If that doesn't work, then the length will probably have to remain unchanged. As WP:SIZE says, length has to be judged on a case-by-case basis, because there are circumstances in which an article has to be very long. There are no rules about this, as such. My advice would be to put it through an FA candidate review and see if the length is among the issues raised. You may well be able to justify it.

Chernobyl

Hi Riurik, I have made some edits to the chernobyl accident page recently. I think that the subject is a bit of a political football, I think that a need exists for a honest discussion of the topic. That is why I added the report of the dose estimates which have been made. I know that lots has been written about the events in april/may 1986 but some of what has been written has been found to patent nonsense (like the motorbike ride of Elena Filatova). I do not think that the section on the dose suffered by the general public is too technical, if you want I can add a rough guess at the likelyhood of getting cancer as a result of those doses.

I have added some data which has come without any discussion to the article, I think that the grass fires are very important. They are as important as the possibility of a further collapse, while if the building fell down next week it would result in a dramatic release of radioactive dust it is an event which can only occur once, but grass fires could occur each summer. I have read that fires have already occured within the exclusion zone, so I think that a discussion of the fires is important and should be included in one of the articles on the accident.Cadmium

Agree, the entry is definitely very political and attracts excessive number of vandalism (often very random stuff as you probably noticed), which does not help with overall quality level. As for the level of technicality, it is undoubtedly a subjective call. I will be honest that I am not familiar with mSv, such as its nature and how it works (e.g. what is a lot mSv what is not, etc). Now, this information is still probably very useful to those who are familiar. With this in mind, I added it at the top of the "Chernobyl disaster effects" entry. If you think it can be very useful, perhaps you would be willing to incorporate a quick reference sentence under Chernobyl disaster entry and leave the crust under the C. D. effects entry. The same goes for the grass fires data. You provide good reasons for their inclusion under Chernobyl disaster entry (i.e. that they have occurred already and are very dangerous); this info needs to be included, however the bulk should still go under the "Effects" article rather than under the "Disaster" which is already so huge and needs to be stabilized. See you around the editing space.--Riurik^(discuss) 00:22, 18 June 2007 (UTC)

Dear Riurik,

Thanks for your thoughts, I think that the Chernobyl page should be subjected to some protection to prevent the anon editing which oftein adds gibberish into it. Regarding the mSv it is a unit of radiation effect in living things, the dose in terms of energy alone is in Gy but after a quaility factor is applied (different forms of radiation have different abilities to cause harm to living things) the dose in Sv is calculated. Sv is the modern SI unit which is a replacement of the cgs system unit rem.Cadmium

Thanks for the info; i incorporated it verbatim as a ref under the "effects" article.--Riurik^(discuss) 01:55, 20 June 2007 (UTC)

Image

Is it possible to use the image of the control room second from the left on the top row of the images on this page? I think it would be quite informative. SGGH ^speak! 19:35, 11 August 2007 (UTC)

Rontgens

should rontgens in this article be replaced by grays? grays are the SI accepted unit. however, rontgens were the unit historically used during the accident. is there convention in this situation?--Snideology 21:33, 11 August 2007 (UTC)

To be honest I'm not sure what the actual policy states however,I believe that the general population is more familiar with the term roentgen and roentgen-equivalent-man etc. In saying this though, I would imagine that the SI unit should be used. Good question though.--Read-write-services 23:45, 12 August 2007 (UTC)

Text under Test Plan

The line 'An RBMK-1000 reactor requires water to be continuously circulated through the core, as long as the nuclear fuel is present.' should be replaced with 'An RBMK-1000 reactor requires water to be continuously circulated through the core, as long as the nuclear reaction is taking place.' One would assume that even with this design, the control rods would be inserted in the cae of a loss of CW flow' [Russell 15th August 2007]

AGREED. Perhaps you could just add this.Cheers--Read-write-services 01:55, 15 August 2007 (UTC)

Cloud Seeding

The History Channel has said that the Soviet Government used [cloud seeding] (a technique that causes rainfall) to cause radioactivity to discend over rural Ukrane and Russia rather than reach Moscow. I don't know if the History Channel is considered a reliable source by Wikipedia, or how to cite the History Channel, but if this is true and verifiable, I think it should be mentioned in this article. It certianly plays into the narrative of an insane Soviet Government. 64.108.200.238 04:06, 2 September 2007 (UTC)

Comment

The opening sentance says that the disaster " is considered to be the worst accident in the history of nuclear power". Is the considered part neccessary? It was the worst accident, was it not? Ostap 04:15, 3 September 2007 (UTC)

Flawed Design Theory

"The reactor also had been running for over one year, and was storing fission byproducts; these byproducts pushed the reactor towards disaster."

This point is not clear. Why were the byproducts pushing the reactor towards desaster? Explanation needed! 160.228.120.4 12:00, 5 September 2007 (UTC)

One of the things which contributed to the power surge was the consumption of the xenon, one of the xenon isotopes is a strong neutron poison. It is normally only present in a switched on reactor at a low level becuase it is destoyed by neutron capture and it is formed by the decay of some of the fission products. The problem is that if you run a reactor at high power and then turn the power down (by lowing the reactivity) the xenon isotope will form by the decay of the precursor isotopes. It can then build up in the core thus poisoning the reaction. If the control rods are pulled out a long way to get the reactor critical again, then the xenon will start to be comsumed by the neutrons. What will happen is that when all the xenon has been consumed that suddenly the reactivity of the core will increase. This can lead to a power surge in a reactor, the bad design of the RBMK1000 (the worst sin is the use of water as a cooling agent and graphite as the moderator, this leads to a postive void coefficent) can then cause a small power surge to become bigger than the same xenon related surge which could happen in a BWR or PWR. The results of the chernobyl power surge was lots of damaged fuel and a steam explosion which lifted the lid on the reactor.Cadmium 18:39, 25 September 2007 (UTC)

Health effect section (PoV)

This section seems highly contentious. Particularly statements such as:

Exaggerated reports by anti-nuclear power protest groups and irresponsible journalists [42], based on speculation rather than evidence, have contributed to the anxiety and depression of people in the fallout zones. These include the TORCH report, the Greenpeace report, and the April 2006 International Physicians for Prevention of Nuclear Warfare (IPPNW) report.

"Exaggerated"? "Irresponsible journalists"? The supporting documentation includes the actual articles which the author of this section has determined to be exaggerated and irresponsible. The claim may be true, but it looks like PoV of the worst kind right now. CMacMillan 14:07, 25 September 2007 (UTC)

Worse still, this section claims that the more recent UNSCEAR report revises the initial estimate of 'up to 4000 thyroid cancers'. It does no such thing. In the summary of both reports, they say that it is likely that a "large fraction" of the 4000+ diagnosed thyroid cancers were caused by the disaster. I am thinking this section should be mostly deleted and reworked unless someone can provide an explanation. Alkrensel 10:31, 3 October 2007 (UTC)

The UNSCEAR report goes on to say:

"There is a tendency to attribute increases in the rates of all cancers over time to the Chernobyl accident, but it should be noted that increases were also observed before the accident in the affected areas. Moreover, a general increase in mortality has been reported in recent years in most areas of the former Soviet Union, and this must be taken into account when interpreting the results of Chernobyl-related studies."

This is certainly notable. Lwnf360 20:05, 16 October 2007 (UTC)

I have removed some weasel words and included a long quote from the UNSCEAR report which talks about 4000 cancer cases, and then goes on to say that there are essentially no other attribituable effects. I do still agree that this section needs work, and incorporation with the other section about health effects. The emphasis should be on the controversy/lack of consensus and the difficulty at attributing effects to the accident. I also changed the flag to indicate the nature of the dispute here. Lwnf360 20:33, 16 October 2007 (UTC)

Helicopter crash

Why does this article, let alone any of Wikipedia, not mention the Mi-8 helicopter crash during the cleanup effort?

Hello, unsigned. Be bold, cite a reliable source, and make the edit yourself. We are all editors, here! :-) - Ageekgal 07:11, 26 September 2007 (UTC)

Controversy

Why not link to a controversy page? —Preceding unsigned comment added by 86.21.224.201 (talk) 16:05, 28 September 2007 (UTC)

Statement about graphite fire most likely faulty.

The article states:

After part of the roof blew off, the inrush of oxygen, combined with the extremely high temperature of the reactor fuel and graphite moderator, sparked a graphite fire. This fire greatly contributed to the spread of radioactive material and the contamination of outlying areas.

This statement is most likely faulty since graphite does not ignite in air. In fact, graphite is used as heat shields on for instance the Space Shuttle.

Here is an example of an article that directly contradicts the statement about the graphite burning:

http://gt-mhr.ga.com/7nuclear.html

The 'red glow' observed during the Chernobyl accident was the expected color of luminescence for graphite at 700°C and not a large-scale graphite fire, as some have incorrectly assumed.

So... what do we do about this? --J-Star 08:51, 8 November 2007 (UTC)

Was the temperature so hot that graphite could have ignited? The way to resolve this is see the original reference for that statement above and if it and the one you found still contradict then perhaps both can be incorporated (although one or the other is likely to be closer to the truth, it either burns or doesn't). However, the link you provide is commercial, not scholarly (peer-reviewed journal); this is problematic. Is there a scholarly source that makes the same claim as the .com site?--Riurik^(discuss) 18:15, 8 November 2007 (UTC)

Well the thing is I don't find any report that goes beyond simply stating "The graphite burned". None of them references anything else. We don't really know *what* kept the heat going... if it was residue heat from the 30 GW power spike; self-sustained criticality; burning graphite; something else burning... or a combination of some or all of the above.

As far as I can conclude though: graphite needs extremely high tempetarures to burn in air if solid. Temperatures of up to 1500C won't cut it alone. See |this link for an example of how stable reactor graphite is. The graphite would have had to be pulverized in order to burn on its own. This is enough to put serious doubt as to whether there really was a graphite fire.

Until anyone can find any link that conclusively proves the graphite was burning, I'm afraid we only have unsourced claims of that at the moment. --J-Star 22:49, 8 November 2007 (UTC)

J-Star, here is a link to NEA. According to them, graphite seems to have burned; it sounds incredible, but that's the source we were missing.--Riurik^(discuss) 04:19, 9 November 2007 (UTC)

Ok, maybe I'm just paranoid in the extreme... but where did NEA get this information? Bear in mind that the accident happened many years before the Soviet Union fell.

But ok, let's have one trail of thought that agrees that the graphite did burn (because I'm seriously starting to doubt the dissenting website by now). How did that happen? What was the source? If the graphite fire didn't happen immediately but rather some time later, after the other fires had been extinguished, what happened that started it? Did the molten core becomes so hot and was the graphite shattered so badly that the fire started from that? Did the combination of graphite and radioactive materials (with their radiation) have special proeprties that allowed the graphite to catch fire more easilly? --J-Star 07:07, 9 November 2007 (UTC)

I agree with the IAEA view that the graphite did burn, the IAEA have stated that a graphite fire did occur (http://www.iaea.org/NewsCenter/Features/Chernobyl-15/cherno-faq.shtml). A report from the USA on the subject of if/how graphite can burn states that at chernobyl "Graphite burned for many days supported by asphalt fires and decay heat from the buried fuel". This is on page 53 of the document (page 4 of the pdf). http://www.iaea.org/programmes/inis/aws/htgr/fulltext/26045231.pdf. This comment in the USA report suggests to me that J-Star was right to think about the radioactive nature of the fuel, but rather than the used fuel having some special effect becuase of the emission of alpha. beat and gamma rays it was special becuase it would have stayed hot becuase of decay heat.Cadmium (talk) 14:01, 25 November 2007 (UTC)

Wrong death tolls

Ignorant right wingers are trying to down play death toll . DO not remove my accurte well documented changes —Preceding unsigned comment added by 207.197.96.93 (talk) 19:57, 15 November 2007 (UTC) my accurate commentay wass removed by the right wing fringe. Right wing exxtremeists shoould stay not delete my accurate information

Ignorant right winger Dawn Bard is now trying to spin the story. Well known facts dont need documentation —Preceding unsigned comment added by 207.197.96.125 (talk) 19:59, 19 November 2007 (UTC)

I have deleted b.s right wing death toll figures and replaced them with accurate information —Preceding unsigned comment added by 207.197.96.125 (talk) 20:11, 19 November 2007 (UTC)

Please don't delete my comments from the talk pages, or attack me personally. I was just trying to tell you that your edits keep getting reverted because you are failing to provide sources for them. (They also tend to be badly spelled and ungrammatical, but that's really a secondary issue.) Also, you should always sign your comments on talk pages using four tildes (~~~~) --Dawn bard (talk) 20:20, 19 November 2007 (UTC)

This is the last warning you will receive for your disruptive edits.
The next time you vandalize Wikipedia, you will be blocked from editing. Your edits are vandalism, if you continue your IP address will be banned from editing Wikipedia. Lwnf360 (talk) 08:00, 27 November 2007 (UTC)

My mistake for not doing his talk page first! IP has been blocked for 1 week as of 19, November 2007. Lwnf360 (talk) 08:03, 27 November 2007 (UTC)

B.S death toll deleted

Ignorant right wingers need to stop messing wiht my accurate facts

* * *

Excellent article that all sides of this argument should read at: http://www.spiegel.de/international/world/0%2C1518%2C519043%2C00.html

71.219.65.237 (talk) 14:34, 26 November 2007 (UTC)James

PBq?

The article currently reads 18 million Curies (670 PBq) What is the prefix P in this case? (The p that comes to mind for me is lower case for pico and that doesn't seem right). RJFJR (talk) 20:42, 26 November 2007 (UTC)

The P is for peta, is rare SI prefix meaning 10¹⁵, I am going to change the enery to use TBq, it will look a little more ugly but more people have heard of T than P.Cadmium (talk) 20:31, 27 November 2007 (UTC)

Cancer Data no where to be found

The pro-nuke cabal is clearly trying to downplay the danger of nuclear power —Preceding unsigned comment added by Layla27 (talk • contribs) 05:23, 27 November 2007 (UTC)

POV