Posted by
Roblimo
on from the sometimes-you-get-burned-when-you-play-with-fire dept.
Cy Guy writes "I'm sure there will be many more stories on this soon, for now, here is the wire story." An update sent in by cheetah: "It appears that someone mixed about 6 times too much uranium into a fuel processing tank. For the latest info click Here"
Just FYI, nobody is "prepared" for any disaster. The authorities conducted an evacuation and are evaluating the situation before taking rash action.
Contrary to widespread popular belief, a nuclear reaction is not in itself dangerous. Nuclear reactions are taking place all the time wherever there are radioactive minerals. The danger relates to the amount of radioactivity and the length of time of the reaction.
[There are dinner plates -- Fiestaware -- that were glazed back in the 30s with radioactive uranium. (Gave it a characteristic orange color.) They're decaying: a nuclear reaction, but it takes a very long time. You don't keep them in the house or eat off of them. But they're safe to own.]
In this case, a nuclear reaction was caused involving a certain amount of uranium with other amounts of water and nitric acid. The uranium in question would be decaying and emitting radiation as a matter of course; what happened here is that the material was concentrated enough that decaying particles from the uranium atoms strike other atoms and trigger a further reaction. This is simply a "self-sustaining" nuclear reaction.
This does not compare to Chernobyl. In Chernobyl, a reactor-sized pile of fuel was not only in a self-sustaining reaction, there was an explosion and fire. The damping system was permanently damaged. The roof was blown off the structure (this was one of the biggest errors made by the Russians: no containment structure). The fire was spewing radioactive ash high into the atmosphere. Without containment or control systems, stopping the fire was the only option. Even so, the way in which it was done (involving panic, local and army firemen with no training, and contradictory instructions from various levels of officials), and the criminal choice of not evacuating the town, were of greater importance.
This chain reaction in Japan, though, is simply exactly what Enrico Fermi caused to happen, for the first time, under the seat of the University of Chicago's football stadium.
What do you do when you have a critical mass that begins a self-sustaining nuclear reaction?
Well, two things, basically. You separate the material; or you insert dampers.
What they're doing here is a process of attempting to separate the material by draining radioactive water (not into the environment, of course, but into a holding tank). This way they can reduce the fuel beneath critical mass and the chain reaction will dissipate naturally.
No comparison with Chernobyl, really; more like other lesser accidents that have happened, such as Three Mile Island, or Windscale. In terms of human error and botched procedures, though, hopefully this will offer many lessons.
-- lake effect weblog {Network engineer in Chicago--looking for work!}
At the moment the best information that I have could (charitably) be called 'hearsay and rumour', but here's how I understand it so far:
1) This was a fuel processing facility, so comments like 'meltdown', 'China syndrome' and 'Chernobyl' are ridiculous.
2) It is reported that approx. 5 times the correct amount of Uranium was introduced into a chemical treatment vessel.
3) Two plant workers are 'seriously ill'. 30+ others were 'exposed'
4) Totally unconfirmed reports have been published of workers 'seeing a blue light' and feeling unwell.
5) People have been advised to stay indoors and wash off any rainwater they may have been in contact with.
Point 1: This facility is *not* a nuclear reactor. The worst that is likely to happen is a nasty, rather radioactive, chemical mess that will take a lot of time and effort to clean up. Even if the nuclear reaction (that may or may not have taken place) is still continuing, it will cool down on it's own. It is very difficult to design a reactor to keep a fissile reaction running for any length of time.
Point 2: It will be some time before we know why too much uranium was allowed into the processing environment. Let's not start blaming anyone until we know the facts.
Point 3: If you are listed as 'seriously ill' after an being involved with an event like this then you will be extremely lucky to live. My thoughts are with these people and their families.
Point 4: I don't know whether to believe this. The blue light sounds like Cerenkov radiation. If you start feeling ill just after seeing this, then you are certainly in the 'seriously ill' category. I doubt you'd be talking to reporters. It may have happened, but I'll wait for more information. You need a *lot* of nuclear activity for Cerenkov radiation to be obvious.
Point 5: Very sensible advice. If it was raining at or soon after the time of the accident, then the rain will absorb a lot of the 'nasties' from the air and wash them to the ground. In these conditions staying inside, closing the windows and avoiding contact with radioactive rain seems to be a good idea. Would you rather get in a car, sit in a traffic jam and wonder how much rain is in the car's ventilation systems? The instinct is to get as far away as possible, but a house is probably safer than a car.
We need to make sure that the Japanese authorities are given every possible assistance in dealing with this. Then we need to find out how it happened. Then we need to put measures in place to stop it from happening again. It has happened before on several occasions, at least once in US, once in UK and once in what was USSR.
Re:Luddite to the core, I see.
by
Tau+Zero
·
· Score: 3
You want guaranteed safety? Look at some of the designs for gas-cooled reactors with pelletized carbide fuel. They can be designed so that "thermal broadening" cuts off the chain reaction before the fuel gets near melting; if you turn off the cooling fans, physics would shut them off.
The only "technical solutions" I've ever heard of involve digging a really big hole, and I'm afraid that I don't trust the stuff to stay buried long enough.
Depends what you bury. Fission products (the actual waste) have half-lives of 50 years or less. You could bury that or keep it around at your option; the Pyramids are as old as 5000 years, and in that time all of the cobalt 60 and strontium 90 and other ugly stuff would have all turned cold. It isn't going away overnight, but it doesn't have to. Radioactivity is actually an advantage compared to chemical poisons which might not degrade for millenia, or elemental toxics like mercury which will be toxic forever.
-- Time is Nature's way of keeping everything from happening at once... the bitch.
Before you get all excited
by
konstant
·
· Score: 4
I have a feeling some of the more extreme technophiles/conservatives are going to chastise us for being alarmed by this sort of accident. Generally, after a nuclear mishap, the pattern goes like this:
1) BOOOM 2) a number of people are rushed to the hospital 3) liberals run around screaming "Look how awful nukes are!" 4) conservatives tilt their Laz-e-boys up a notch, puff on their pipes, and make devastating comments about "Luddites"
But look folks, nuclear technology really is a technology unlike most others. Only genetic modification has as much potential for literally wiping out the human race if somebody forgets to carry the two. We all know from experience that even experts make miscalculations, and that sometimes the results are hazardous. Generally, these are tragic but containable. They are what you might call "acceptable losses" on the path towards improving the lot of our species.
But I'll be damned if waking up each morning to a pitcher of radioactive milk is acceptable to me. Just a single reactor in Russia threw the world's food supply into havoc for months. And mistakes like Chernobyl have happened before and will happen again. Every once in a while somebody fucks up. It's just that, with nukes, the ramifications are so very large!
The reason that we don't see more accidents like this in Japan is not because nuclear energy is, on the whole, safe. It's because most people have extreme NIMBY reactions to nuclear facility proposals. People are scared of nuclear technology, and I think rationally so. The development of a clever scientific pet trick is not enough justification for its deployment. We do not have to do everything that we can do.
I'm sure that statement alone will be enough to moderate me down on slashdot;)
-konstant
-- -konstant Yes! We are all individuals! I'm not!
Re:Before you get all excited
by
cancrman
·
· Score: 3
You make it sound like nuclear technology is inherently evil. Ummmm....It's not. Yes it's true that it has its downsides, but so do a hell of a lot of other things. I'll just touch on a few here
Oil -> Air Pollution -> We all die slowly and eventually run out of fuel Coal -> Air Pollution -> We all die slowly and eventually run out of fuel Hydro -> Environment Damage -> Fish all die (& everything that eats those fish) Solar/Wind -> Not effective -> We all freeze Nuclear ->/Possible/ accidents -> We all die slowly
So, sure nuclear energy can fuck us up. But so can a lot of other things that we are already using. Nuclear power is a clean, cheap, & long lasting source of energy. Ok, I wouldn't want one in my backyard. But it is still a necessary evil at this point.
Pete I can see through time -Lisa Simpson
-- The sole purpose of the Internet is to get porn and bomb making plans into the hands of children.
Re:Before you get all excited
by
Jeffrey+Baker
·
· Score: 3
The amount of radiation released by this accident is tiny compared to the millions of tons of slightly radioactive fly ash spewed out of the smokestacks of coal-fired power plants in China.
China consumes ~25% of the world's coal production.
I know that I'm ignorant about what is going on over there right now, as I've only read the Reuters wire and a CNN report.
However, from this information it appears that Japan:
1. Is not prepared for this kind of disaster 2. Is not reacting to it in an aggressive fashion.
It is strange to me that given the repeated nuclear safety problems they have had over there that they do not have a plan in place to deal with a nuclear emergency. Why are they asking the US Military for aid? What kind of aid are they looking for? It seems like they don't even know what kind of help they need.
Also, the action that appears to be taken so far seems to contrast starkly with the Russian firefighters who gave their lives to try and stop the Chernobyl disaster. Some officials are saying that they don't know whether or not the reaction will become self sustaining or not. It seems to me that if there is a chance this emergency could turn into something similar to a reactor meltdown people should go in there and do everything they can to smother the reaction before it becomes any worse. Taking a "wait and see" attitude with something like has the possibility of frigthening consequences.
Some people have questioned the value of telling people to remain indoors. This was probably done to avoid a widespread panic that would clog all the roads and hamper efforts to bring the situation under control.
Perhaps we'll get more useful information in the days ahead.
The way I see much of the controversy over nuke plants is that they directly compete with coal plants, coal mines, and the many jobs coal creates, or the more expensive alternative, petroleum fired generators. Humans have an affinity towards energy, so it looks like we will be generating it one way or another. Pick your weapon.
A coal plant is opening up 15 miles from where I live. This is good for me as my payscale suddenly shot up as they were looking for workers. Tell you the truth, I would rather have a nuke down the street. It all has to do with the air I breathe and the massive amounts of ground being dug that were a great habitat for wildlife and hunting.
Not that I'm complaining, electricity will be very cheap for manufacturing plants. Good paying jobs will be abundant and those who already are employed will see property values skyrocket. The price of land has doubled for the last few years.
Maybe I should stay under my bed till 0/0/00 :-P
by
Daniel
·
· Score: 3
Is it just me, or have we gotten..um..more disasters than usual this year? I mean..
-> Severe doughts on the eastern coast of the US. Floods in the midwest. Floods in the East from Floyd (a good bit of New Jersey and North Carolina was still underwater last I heard). -> Three major earthquakes almost on top of one another: Turkey, Greece, Taiwan. -> Political unrest and instability in Russia. Political unrest in the Middle East. Kosovo. East Timor. Other places that haven't gotten so much coverage (which I naturally can't remember) -> More stuff I've forgotten. -> This.
And the following events haven't even happened yet!
-> Massive civil disruption by Christian fundamentalists and cults of all descriptions who believe the end of the world is imminent. -> Computeres miscalculating the date and causing planes to fall out of the sky, eletricity to shut off. -> Microsoft releasing Windows '00.
Clearly these are Signs! The only thing for sensible people to do is to get a lifetime's supply of cookies and HIDE UNDER THE BED until the clock rolls over!
</SILLY>
Sorry, just trying to lighten the mood a little..
But in all seriousness this has not been a good year. I think the only disaster that hasn't happened yet is launching of nukes -- or perhaps a tornado in downtown NYC.
Daniel
-- Hurry up and jump on the individualist bandwagon!
Here's a brief description of the primary types of radiation and their relative harmfulness.
1) Alpha radiation. Alpha particles are helium nuclei, big and slow; they can be stopped by a sheet of paper, but if you inhale alpha emitters, they can tear up your lung cells. So don't do that.
2) Beta radiation. Beta particles are energetic electrons, and can penetrate a bit better than alpha particles, but you should be okay if you're in the next room.
3) Gamma radiation. Gamma rays are *very* energetic photons; these are the ones that'll get ya. You need a good amount of dense shielding to absorb these.
4) Neutrons. Energetic neutrons from radioactive decay both perpetuate the chain reaction, and cause direct damage like beta particles, only worse because they're heavier.
The people close to this one will probably have gotten a good zap of gamma radiation, and will be in a world of hurt. But unless radioactive *material* (such as the uranium itself) escapes into the surrounding air, nearby civilians should be okay unless there is inadequate shielding against gamma rays.
In a nutshell, this is Really Bad, especially for the people closest, but the Earth is not about to collapse into a molten ball...
Criticality in solutions of heavy isotopes
by
Anonymous Coward
·
· Score: 5
...is easier to achive than you think.
(Snarl, network here is on the fritz, apologies if this comes through multiple times - connection reset by peer before anything actually gets submitted, I'm assuming...)
Anyone working at a nuke plant, especially a fuel processing plant, knows this. This incident appears to have been caused by stupidity of truly mind-boggling proportions.
If you're ever working with heavy isotopes (i.e. fissionables) in solution, the water or other solvent in which the compounds are dissolved can act as a moderator, and the amount of uranium or other fissionable matter required for criticality drops precipitously.
I did a few summer terms at a research reactor at a university. This reactor was often used to create compounds for medical use as well as other research. Preventing this type of incident was discussed in one of the most heavily-underlined-and-boldfaced sections of text in the book.
Any time you have to work with heavy unstable isotopes in solution, it's imperative that you know exactly what you're dealing with. That means you need to know both the nuclear (cross-sectional) and the chemical properties of both solvent and solute, AND the shape of the container, AND the concentrations expected at any stage in the dissolution.
Those latter two are particularly counterintuitive - but are glaringly obvious in hindsight, as they're significant factors in the mean distance (i.e. free path) between particles of the heavy isotope in the solution, a key determinant in criticality.
To give an example of what can go wrong - take a beaker of water and drop in a spoonful of brown sugar. Pretend the sugar is fissionable.
At the start, you have a subcritical mass of brown sugar. Safe enough to hold in your hand. At the end, the sugar is distributed evenly enough through the water that even with the water's moderating effect, it's subcritical. Safe enough to work with.
Walk away from the beaker and come back in 5 minutes. Observe that there are regions in the beaker of varying concentrations. At least one of these concentrations will be the "right" concentration to minimize the mass required for criticality. If the volume of that region is large enough, it goes critical in that region and it's game over.
For an even better version of this game, imagine you can stir it quickly enough so that this is never a risk. Mix it in a baking pan, so that the liquid is never deeper than 1cm, and most of the neutrons fly out the top and bottom of the pan. Give it to your friend, who pours it into one of those nice flasks with the spherical bottoms. The spherical shape allows many more neutrons to be absorbed. Your last thought is that "Safe enough to work with" only means "safe enough to work with in this container". Game over.
Or just carelessly leave the pan under the fume hood over the weekend. Or toss it in the freezer, and discover that as it freezes, the capacity to hold the material in solution changes, and some of it precipitates out. In either case, don't expect to get any work done on Monday morning, though.
Of course, now that I've gone through the hard ways to have this accident (about which anyone working in this environment would still know), putting seven times as much solute in the solution would also be a good way to screw it up.
Scary thought: If they could see the Cerenkov radiation - and weren't looking at the tank - it means the radiation flux through the fluid in the eyeball was high enough to cause a visible blue glow. That's a lot of radiation.
Remember all those "how to build your own atomic bomb" plans, that all worked out to "this won't give you a nuclear detonation, but it'll make one unholy hell of mess"?
The Japanese have just become the test case. While we're not talking about levelling cities or nuclear explosive yield, in terms of the physics involved - an uncontrolled chain reaction in a critical mass - the Japanese have arguably just nuked themselves, in the same sense that the Americans nuked them twice earlier this century.
It's a banner week for Darwinian Stupidity in the sciences, folks. First we lose a $125M space probe because two engineering teams didn't know the difference between metric and Imperial measure, and then a couple of Japanese fuel processing guys manage to top our blunder by accidentally building and activating something that's the fundamental equivalent to the core of an atomic bomb.
The Blue Light is Cerenkov radiation.
by
Tau+Zero
·
· Score: 3
Nobody's gotten this entirely right yet... the blue light is Cerenkov radiation, which is created when charged particles like electrons (NOT neutrons) move through a medium faster than light travels through it. (Obviously this cannot be done in free space, but it can in water, in glass, and other media.) Much like an object moving through air faster than the speed of sound creates a sonic boom, a charged particle going faster than the local speed of light creates a "photic boom". Just FYI, some electronic devices such as Travelling Wave Tubes work on not-dissimilar principles.
How do the electrons get moving so fast? When a gamma ray bounces off an electron, the electron can recoil at high speed. This phenomenon is called Compton scattering, if I'm not mistaken.
-- Time is Nature's way of keeping everything from happening at once... the bitch.
Slashdot Mirror
Just FYI, nobody is "prepared" for any disaster. The authorities conducted an evacuation and are evaluating the situation before taking rash action.
Contrary to widespread popular belief, a nuclear reaction is not in itself dangerous. Nuclear reactions are taking place all the time wherever there are radioactive minerals. The danger relates to the amount of radioactivity and the length of time of the reaction.
[There are dinner plates -- Fiestaware -- that were glazed back in the 30s with radioactive uranium. (Gave it a characteristic orange color.) They're decaying: a nuclear reaction, but it takes a very long time. You don't keep them in the house or eat off of them. But they're safe to own.]
In this case, a nuclear reaction was caused involving a certain amount of uranium with other amounts of water and nitric acid. The uranium in question would be decaying and emitting radiation as a matter of course; what happened here is that the material was concentrated enough that decaying particles from the uranium atoms strike other atoms and trigger a further reaction. This is simply a "self-sustaining" nuclear reaction.
This does not compare to Chernobyl. In Chernobyl, a reactor-sized pile of fuel was not only in a self-sustaining reaction, there was an explosion and fire. The damping system was permanently damaged. The roof was blown off the structure (this was one of the biggest errors made by the Russians: no containment structure). The fire was spewing radioactive ash high into the atmosphere. Without containment or control systems, stopping the fire was the only option. Even so, the way in which it was done (involving panic, local and army firemen with no training, and contradictory instructions from various levels of officials), and the criminal choice of not evacuating the town, were of greater importance.
This chain reaction in Japan, though, is simply exactly what Enrico Fermi caused to happen, for the first time, under the seat of the University of Chicago's football stadium.
What do you do when you have a critical mass that begins a self-sustaining nuclear reaction?
Well, two things, basically. You separate the material; or you insert dampers.
What they're doing here is a process of attempting to separate the material by draining radioactive water (not into the environment, of course, but into a holding tank). This way they can reduce the fuel beneath critical mass and the chain reaction will dissipate naturally.
No comparison with Chernobyl, really; more like other lesser accidents that have happened, such as Three Mile Island, or Windscale. In terms of human error and botched procedures, though, hopefully this will offer many lessons.
lake effect weblog
{Network engineer in Chicago--looking for work!}
At the moment the best information that I have could (charitably) be called 'hearsay and rumour', but here's how I understand it so far:
1) This was a fuel processing facility, so comments like 'meltdown', 'China syndrome' and 'Chernobyl' are ridiculous.
2) It is reported that approx. 5 times the correct amount of Uranium was introduced into a chemical treatment vessel.
3) Two plant workers are 'seriously ill'. 30+ others were 'exposed'
4) Totally unconfirmed reports have been published of workers 'seeing a blue light' and feeling unwell.
5) People have been advised to stay indoors and wash off any rainwater they may have been in contact with.
Point 1: This facility is *not* a nuclear reactor. The worst that is likely to happen is a nasty, rather radioactive, chemical mess that will take a lot of time and effort to clean up. Even if the nuclear reaction (that may or may not have taken place) is still continuing, it will cool down on it's own. It is very difficult to design a reactor to keep a fissile reaction running for any length of time.
Point 2: It will be some time before we know why too much uranium was allowed into the processing environment. Let's not start blaming anyone until we know the facts.
Point 3: If you are listed as 'seriously ill' after an being involved with an event like this then you will be extremely lucky to live. My thoughts are with these people and their families.
Point 4: I don't know whether to believe this. The blue light sounds like Cerenkov radiation. If you start feeling ill just after seeing this, then you are certainly in the 'seriously ill' category. I doubt you'd be talking to reporters. It may have happened, but I'll wait for more information. You need a *lot* of nuclear activity for Cerenkov radiation to be obvious.
Point 5: Very sensible advice. If it was raining at or soon after the time of the accident, then the rain will absorb a lot of the 'nasties' from the air and wash them to the ground. In these conditions staying inside, closing the windows and avoiding contact with radioactive rain seems to be a good idea. Would you rather get in a car, sit in a traffic jam and wonder how much rain is in the car's ventilation systems? The instinct is to get as far away as possible, but a house is probably safer than a car.
We need to make sure that the Japanese authorities are given every possible assistance in dealing with this. Then we need to find out how it happened. Then we need to put measures in place to stop it from happening again. It has happened before on several occasions, at least once in US, once in UK and once in what was USSR.
Time is Nature's way of keeping everything from happening at once... the bitch.
I have a feeling some of the more extreme technophiles/conservatives are going to chastise us for being alarmed by this sort of accident. Generally, after a nuclear mishap, the pattern goes like this:
;)
1) BOOOM
2) a number of people are rushed to the hospital
3) liberals run around screaming "Look how awful nukes are!"
4) conservatives tilt their Laz-e-boys up a notch, puff on their pipes, and make devastating comments about "Luddites"
But look folks, nuclear technology really is a technology unlike most others. Only genetic modification has as much potential for literally wiping out the human race if somebody forgets to carry the two. We all know from experience that even experts make miscalculations, and that sometimes the results are hazardous. Generally, these are tragic but containable. They are what you might call "acceptable losses" on the path towards improving the lot of our species.
But I'll be damned if waking up each morning to a pitcher of radioactive milk is acceptable to me. Just a single reactor in Russia threw the world's food supply into havoc for months. And mistakes like Chernobyl have happened before and will happen again. Every once in a while somebody fucks up. It's just that, with nukes, the ramifications are so very large!
The reason that we don't see more accidents like this in Japan is not because nuclear energy is, on the whole, safe. It's because most people have extreme NIMBY reactions to nuclear facility proposals. People are scared of nuclear technology, and I think rationally so. The development of a clever scientific pet trick is not enough justification for its deployment. We do not have to do everything that we can do.
I'm sure that statement alone will be enough to moderate me down on slashdot
-konstant
-konstant
Yes! We are all individuals! I'm not!
I know that I'm ignorant about what is going on over there right now, as I've only read the Reuters wire and a CNN report.
However, from this information it appears that Japan:
1. Is not prepared for this kind of disaster
2. Is not reacting to it in an aggressive fashion.
It is strange to me that given the repeated nuclear safety problems they have had over there that they do not have a plan in place to deal with a nuclear emergency. Why are they asking the US Military for aid? What kind of aid are they looking for? It seems like they don't even know what kind of help they need.
Also, the action that appears to be taken so far seems to contrast starkly with the Russian firefighters who gave their lives to try and stop the Chernobyl disaster. Some officials are saying that they don't know whether or not the reaction will become self sustaining or not. It seems to me that if there is a chance this emergency could turn into something similar to a reactor meltdown people should go in there and do everything they can to smother the reaction before it becomes any worse. Taking a "wait and see" attitude with something like has the possibility of frigthening consequences.
Some people have questioned the value of telling people to remain indoors. This was probably done to avoid a widespread panic that would clog all the roads and hamper efforts to bring the situation under control.
Perhaps we'll get more useful information in the days ahead.
The way I see much of the controversy over nuke plants is that they directly compete with coal plants, coal mines, and the many jobs coal creates, or the more expensive alternative, petroleum fired generators. Humans have an affinity towards energy, so it looks like we will be generating it one way or another. Pick your weapon.
A coal plant is opening up 15 miles from where I live. This is good for me as my payscale suddenly shot up as they were looking for workers. Tell you the truth, I would rather have a nuke down the street. It all has to do with the air I breathe and the massive amounts of ground being dug that were a great habitat for wildlife and hunting.
Not that I'm complaining, electricity will be very cheap for manufacturing plants. Good paying jobs will be abundant and those who already are employed will see property values skyrocket. The price of land has doubled for the last few years.
Is it just me, or have we gotten..um..more disasters than usual this year? I mean..
-> Severe doughts on the eastern coast of the US. Floods in the midwest. Floods in the East from Floyd (a good bit of New Jersey and North Carolina was still underwater last I heard).
-> Three major earthquakes almost on top of one another: Turkey, Greece, Taiwan.
-> Political unrest and instability in Russia. Political unrest in the Middle East. Kosovo. East Timor. Other places that haven't gotten so much coverage (which I naturally can't remember)
-> More stuff I've forgotten.
-> This.
And the following events haven't even happened yet!
-> Massive civil disruption by Christian fundamentalists and cults of all descriptions who believe the end of the world is imminent.
-> Computeres miscalculating the date and causing planes to fall out of the sky, eletricity to shut off.
-> Microsoft releasing Windows '00.
Clearly these are Signs! The only thing for sensible people to do is to get a lifetime's supply of cookies and HIDE UNDER THE BED until the clock rolls over!
</SILLY>
Sorry, just trying to lighten the mood a little..
But in all seriousness this has not been a good year. I think the only disaster that hasn't happened yet is launching of nukes -- or perhaps a tornado in downtown NYC.
Daniel
Hurry up and jump on the individualist bandwagon!
Here's a brief description of the primary types of radiation and their relative harmfulness.
1) Alpha radiation. Alpha particles are helium nuclei, big and slow; they can be stopped by a sheet of paper, but if you inhale alpha emitters, they can tear up your lung cells. So don't do that.
2) Beta radiation. Beta particles are energetic electrons, and can penetrate a bit better than alpha particles, but you should be okay if you're in the next room.
3) Gamma radiation. Gamma rays are *very* energetic photons; these are the ones that'll get ya. You need a good amount of dense shielding to absorb these.
4) Neutrons. Energetic neutrons from radioactive decay both perpetuate the chain reaction, and cause direct damage like beta particles, only worse because they're heavier.
The people close to this one will probably have gotten a good zap of gamma radiation, and will be in a world of hurt. But unless radioactive *material* (such as the uranium itself) escapes into the surrounding air, nearby civilians should be okay unless there is inadequate shielding against gamma rays.
In a nutshell, this is Really Bad, especially for the people closest, but the Earth is not about to collapse into a molten ball...
(Snarl, network here is on the fritz, apologies if this comes through multiple times - connection reset by peer before anything actually gets submitted, I'm assuming...)
Anyone working at a nuke plant, especially a fuel processing plant, knows this. This incident appears to have been caused by stupidity of truly mind-boggling proportions.
If you're ever working with heavy isotopes (i.e. fissionables) in solution, the water or other solvent in which the compounds are dissolved can act as a moderator, and the amount of uranium or other fissionable matter required for criticality drops precipitously.
I did a few summer terms at a research reactor at a university. This reactor was often used to create compounds for medical use as well as other research. Preventing this type of incident was discussed in one of the most heavily-underlined-and-boldfaced sections of text in the book.
Any time you have to work with heavy unstable isotopes in solution, it's imperative that you know exactly what you're dealing with. That means you need to know both the nuclear (cross-sectional) and the chemical properties of both solvent and solute, AND the shape of the container, AND the concentrations expected at any stage in the dissolution.
Those latter two are particularly counterintuitive - but are glaringly obvious in hindsight, as they're significant factors in the mean distance (i.e. free path) between particles of the heavy isotope in the solution, a key determinant in criticality.
To give an example of what can go wrong - take a beaker of water and drop in a spoonful of brown sugar. Pretend the sugar is fissionable.
At the start, you have a subcritical mass of brown sugar. Safe enough to hold in your hand. At the end, the sugar is distributed evenly enough through the water that even with the water's moderating effect, it's subcritical. Safe enough to work with.
Walk away from the beaker and come back in 5 minutes. Observe that there are regions in the beaker of varying concentrations. At least one of these concentrations will be the "right" concentration to minimize the mass required for criticality. If the volume of that region is large enough, it goes critical in that region and it's game over.
For an even better version of this game, imagine you can stir it quickly enough so that this is never a risk. Mix it in a baking pan, so that the liquid is never deeper than 1cm, and most of the neutrons fly out the top and bottom of the pan. Give it to your friend, who pours it into one of those nice flasks with the spherical bottoms. The spherical shape allows many more neutrons to be absorbed. Your last thought is that "Safe enough to work with" only means "safe enough to work with in this container". Game over.
Or just carelessly leave the pan under the fume hood over the weekend. Or toss it in the freezer, and discover that as it freezes, the capacity to hold the material in solution changes, and some of it precipitates out. In either case, don't expect to get any work done on Monday morning, though.
Of course, now that I've gone through the hard ways to have this accident (about which anyone working in this environment would still know), putting seven times as much solute in the solution would also be a good way to screw it up.
Scary thought: If they could see the Cerenkov radiation - and weren't looking at the tank - it means the radiation flux through the fluid in the eyeball was high enough to cause a visible blue glow. That's a lot of radiation.
Remember all those "how to build your own atomic bomb" plans, that all worked out to "this won't give you a nuclear detonation, but it'll make one unholy hell of mess"?
The Japanese have just become the test case. While we're not talking about levelling cities or nuclear explosive yield, in terms of the physics involved - an uncontrolled chain reaction in a critical mass - the Japanese have arguably just nuked themselves, in the same sense that the Americans nuked them twice earlier this century.
It's a banner week for Darwinian Stupidity in the sciences, folks. First we lose a $125M space probe because two engineering teams didn't know the difference between metric and Imperial measure, and then a couple of Japanese fuel processing guys manage to top our blunder by accidentally building and activating something that's the fundamental equivalent to the core of an atomic bomb.
How do the electrons get moving so fast? When a gamma ray bounces off an electron, the electron can recoil at high speed. This phenomenon is called Compton scattering, if I'm not mistaken.
Time is Nature's way of keeping everything from happening at once... the bitch.