h2g2 The Hitchhiker's Guide to the Galaxy: Earth Edition

That *is* that link though I'm not surprised it isn't working. Half a mo and I'll see if I can find another.

http://www.elenaschernobyl.com/

There you go - that one should work ...

Oops, sorry Mort Both of those work now

(I saw somewhere that the original site stopped hosting her pages after a short period of time and they then got mirrored to various sites - she was appealing for funds at one point)

I think that is the case, webspace has been donated from various places so there are different links.

There is a forum on it being a fake. (off topic I know but thought I would post the link anyway)

http://www.cre8asiteforums.com/viewtopic.php?p=70706

Just a small clarification - I wasn't expecting a comparison of death tolls, just a comparison of radiation levels - something that would make people appreciate what x millisieverts means etc.

Woodpigeon

Very well-done entry!

Minor quibbles/notes ...

Footnote 4: a half life does not imply anything about the stability of the decay products. A half life is simply the time it takes for half of the material to decay radioactively.

First item in list under "The RMBK reactor" section should probably read, "1. High availability due to ability to refuel without shutting down the reactor" instead of "...within shutting down the reactor."

The rest of this article was tip top! Nicely done.

For what Woodpigeon asked, the explanation might be a bit more involved than expected. There are three sorts of general units talked about in the "nuclear world" so to speak. What one has to realize is the different things that they measure. A becquerel is simply a measure of disintigrations per second. A becquerel is derived from frequency, or 1/s. However, becquerels are unhelpful for measuring the *effects* of radiation and radioactive materials on various physical objects - often the real question that people are concerned with in safety and environmental concerns. For this, the unit gray (Gy) is used to express the energy absorbed from a dose of radiation. A gray has root units of J/kg. Grays are useful for expressing a large energy absorption from a sudden radiation flux, as in what someone or something might receive from a certain sort of nuclear accident. Just to complicate things further, the way that wonderful and complex system known as the human body is affected by radiation is expressed using yet another unit - this one is the sievert, or Sv. A sievert is a derived unit that attempts to express an equivalence of absorbed dosage taking into account biological harm. A dictionary might define Sv like this: "A unit of ionizing radiation absorbed dose equivalent obtained as a product of the absorbed dose measure in grays and a dimensionless factor, stipulated by the International Commission on Radiological Protection, and indicating the biological effectiveness of the radiation." Of course, Sv, Gy, and Bq are all SI units. The US version of all of these are, respectively, rem (Roentgen Equivalent in Man), rad (Radiation Absorbed Dose), and curie (Ci) or sometimes Rutherfords (both measures of disintigrations/s, but in more convenient orders of magnitude).

It is naturally then, quite difficult to understand in real world, common man terms what doses like 2 mSv versus 4 mSv or even 100 mSv means. The topic of "what level of radiation is bad for the human body" continues to be hotly debated all over the World, with obvious politicical ramifications. To be honest, no one really knows for sure.

So. To sum it all up, people are a problem. No really, that's more or less the summary. There's no simple way to convert between Bq and Sv without talking about the exact specifics of the people involved, the amounts and types of materials, the chemical form of the materials, the type of accident, when/where/how ... the list of things one must consider grows longer than even I can go on about. I know, I can hear you all saying, "Thank God!"


- JD

Whew, my head is spinning after that one! Thanks JD!

Correctamundo JD - thought of submitting that last post to Peer Review?

I'd second that - amazingly helpful

Two small comments. Excellent entry.

1) Finland is planning a new reactor.

2) How about something on contamination of food sources in the wider area - some foodstuffs are still being checked, and others were off limits for a long time.

sprout

Mort/TT - thanks for the links.

Woodpigeon - I've expanded the dosages bit slightly.

JD - points taken, thanks for that. Perhaps you could check the dosages bit and footnotes (2nd paragraph under "The Casualties") and suggest any clarifications. Your explanation should definitely be submitted to PR, then I could just link to it!

Sprout - Damn, I was hoping no-one would notice it was a bit thin on the food contamination side. I'll need to do a bit more research on that one . I'm not sure Finland *planning* a new reactor alters the wording at all; shoot me down if I'm wrong.

Top notch stuff!

I wasn't sure how to interperet this at first, maybe it's just me being thick:
--The incident happened early morning on 26 April
--Evacuation of nearby town complete within 2.5 hours on 27 April
This means the town wasn't evacuated until the next day? At first I read it that the evacuation was within 2.5 hours of the accident and thought you had the date wrong. If this seems misleading could it maybe be slightly reworded?

Couple of typos:
'Immediate Aftermath', last paragraph: Predicably >> Predictably

'Chernobyl Since': East of Chernobyl >> east of Chernobyl

Footnote 8 appears to be in a sentence by itself. Also, should the footnotes follow a sentence structure whenever possible? Most of them do, but a few don't.

Very nice.

Wow! I guess that explanation made some sense, eh? Thanks for the positive feedback on it folks, I guess I'll have to go and write that up into a real article now.

As for that paragraph you have describing dose estimates, Dave, I think it's accurate enough. I'm not privy to the mounds of data that have been gathered by those involved with the Chernobyl disaster, so I'd have to trust sources, same as you. I, personally, wouldn't debate the validity of phrases such as, "a single dose above 10mSv poses a significant threat to the human body," though I think there are some who would. It's really a terribly complicated subject, and as a safety engineer (not a health physicist or physician) one which I am not entirely qualified to discuss. Everything else in there looks right-on.

So, I'll get to work on the "Measurements of Radiation" entry here. One thing that makes it so hard to understand that I didn't mention earlier is that the units rem and Sv are dependent on the pathway of contamination by the substance (such as eating contaminated food, breathing contaminated dust, or just standing right in front of a large neutron source, God help you - actually, rem/Sv are rarely used for that last case, it's usually time to just use Rad/Gray at that point ... viz recent massive dose received by Japanese workers who inadvertently caused a criticality in their solutions work at a power plant facility). I'm getting ahead of myself. I'll work on it, put up a placeholder for it for now.

- JD

Just a little something for interest sake:

Revelation 8:11 - "And the name of the star is called Wormwood: and the third part of the waters became wormwood; and many men died of the waters, because they were made bitter."


Much was made of this verse in some circles after the accident because of a mistranslation of Chornobyl as 'wormwood' (it actually means 'mugwort'.


see, for example http://ryanj1678.tripod.com/christianity4today/id37.htm which accepts the mistranslation and goes on to conclude that we're already in Hell or something.

*nudge*

Researcher PSG

small point on units, switching from using milliSieverts to mSieverts, I know they are the same up possibly more readable if one is used consitantly.

Really intrested in the entry, liked it

Brief flashback to GCSE geography. I put in my mock exam that the reason welsh sheep are kept on the far fields, away from the farm house is because after Chernobyl the sheep glowd so much it kept the farmers away.

I'm not sure if this is true or not, but I got a mark for it. Ain't it great having teachers who feel they can't tell people they're wrong !!

Or maybe you got a mark for giving the teacher a good laugh!

* joins the choir *

for an entry very well done!

All I can add is that 'predicably' is still there, and that you can link to:
A812800 Hollywood's Laws of Life, Physics and Everything
A600940 Endless Loops
A476723 How a Nuclear Plant Works



Bossel