Mitigating Fukushima's Dangers, 42 Days In

DrKnark writes "Tepco has released more information about their plan to stabilize the Fukushima reactors. They are basically facing 4 problems: ensure long term cooling of the cores; ensure cooling of the spent fuel pools; prevent release of radioactive material; and mitigate the consequences of the releases that will continue for a while."

Comments

No, thanks

[MichaelSmith]

Funny reading a post about people hacking up reactor cooling solutions with radioactive water pooling all over the place on a site called nuclearpoweryesplease.org

Re:No, thanks

[rrohbeck]

I just checked that site and you were right. No news there, just pages and pages on how reactors work. Wonders of technology. True, when they work and don't burn or explode.

Re:No, thanks

[MichaelSmith]

The subtext behind this issue of what source of energy does the most damage is control. Nuclear power plants are big, long term projects which require lots of investment from large Governments. Because of this they increase the reliance which people have for those Governments. You are locked in to both the technology and the political environment which brought it in to being. So people who want political independence on a smaller scale (state, local or individual) oppose nuclear power. They want technology they can control. They want it to be within their own reach.

Re:No, thanks

[mpe]

Those reactors are 45 year old technology, took a direct tsunami hit right after an earthquake that was in the top 3 worst ever recorded, exploded, caught fire, and resulted in a grand total of... zero deaths.

IIRC two people were killed at the plant by the earthquake. Both the earthquake and tsunami were of much greater magnitude than anything considered by the designers.
It's interesting that no attempt has been made to compare damage at this plant with that at other industrial plants in Japan. The press has also been silent on toxic chemical spills resulting from the earthquake and tsunami.

Re:No, thanks

[HungryHobo]

even if you count when things go wrong it still looks better than most of the alternatives.

For a parallel.
Many people are afraid of flying.
Why? it doesn't make a great deal of sense, you're more likely to die driving to the airport than while on the plane unless you live really close to the airport or you're going on a really long flight.
It's irrational.

But here's the thing.
When there's a plane crash hundreds of people die all at once.
When there's a plane crash it makes the news worldwide.
When you're on a plane it's someone else in control(the pilot).
Even when the plane doesn't crash if something goes wrong everyone hears about it.

Getting to your destination is still safer by plane by a wide margin if you're going long distance.
but people are still afraid of it.

Because you don't hear about all the road deaths.
They barely make the local news.
people don't die in their hundreds in car crashes.
they die less than half a dozen at a time.
In total vastly more people die on the roads but you only hear about the ones in your local area.
And people can convince themselves that they are in total control on the road, they ignore the chance of someone else doing something stupid and driving into them or something unexpected happening.

Nuclear is kind of like that.
It kills far less people per terawatt than most other sources even counting Chernobyl.
But when anything goes wrong it makes the world news.
It can kill lots of people when it goes wrong all at once but in normal operation it's vastly safer.
Other sources of power kill in ones or twos and only make the local news.
But they kill a lot of people per year.
a coal miner here a gas worker there and every now and then someone dies installing panels on their roof.

Plus there's the sexy aspect: radiation is scary and invisible, coal smog is boooring.

If I'm sitting watching the news beside someone who's terrified of flying as a story breaks about a plane crash am I wrong if I simply say
"It's still safer than the other options"
even if the person who thinks flying is more dangerous is pointing at it and saying
"look! look! I told you it isn't safe! Driving everywhere is the far safer way to travel! how can you say that after seeing that disaster!!!"

I'm in favour of nuclear because it's still safer than most of it's competitors.

It would be nice to be in control of your power generation but that's a pipe dream. If you don't live decently close to the equator solar panels on your roof are nothing but an expensive status symbol.

"Distributed" is a nice sounding word but in reality it doesn't make the problems with a flaky little grid based on dirty little community generators go away.

Re:No, thanks

[Kyusaku Natsume]

Well, nobody has followed up the story of the burning refinery of Cosmo Oil at Chiba, very close to Tokyo that burned for a week, or the other 2 refineries washed away by the tsunami in Miyagi prefecture, what stand was left to burn.

Re:No, thanks

[PopeRatzo]

The worst nuclear disaster of all time, Chernobyl, killed only 31 people.

Oh, come on.

I remember a little over a month ago, when we were hearing about how this Japanese disaster was no problem and how the reactors all handled the tsunami well and there was no reason for concern.

"Clean, Safe, and Too Cheap to Meter" was the slogan of the nuclear energy industry. It's turned out to be none of those things, and just because more people die from one of the other toxic sources of energy that rely on scarce, dangerous substances that happen to be under the control of a small group of transnational corporations doesn't mean that we should not discuss the very serious drawbacks to nuclear energy, only one of which is the possibility of disasters like this Fukushima one, now at "level 7" (at least for the time being).

I know nuclear energy is all high-tech-ey and stuff and cool but one thing for sure: as long as private industry is going to run the plants for profit there are going to be safety shortcuts and "unforeseen" accidents that are "unprecedented" and lots of people are going to die, either directly or indirectly 20 years later when they've got scores of tumors like so many of the workers from the "successful" plant at McMurdo, Antarctica (Raytheon).

Re:No, thanks

[Mindcontrolled]

The german poet Christian Morgenstern brilliantly commented on that kind of denial nearly 100 years ago - "weil, so schlieÃYt er messerscharf // nicht sein kann, was nicht sein darf". It should not be, therefor it cannot be. That's pretty much the hymn of the apologist.

Re:No, thanks

[Mindcontrolled]

Thanks for making my point.

Re:No, thanks

[SanityInAnarchy]

If you don't live decently close to the equator solar panels on your roof are nothing but an expensive status symbol.

Actually, small amounts of wind and solar can and do pay for themselves. It doesn't make you independent -- you still need the grid to compensate for a cloudy, calm day -- but when you generate an excess of power, your meter runs backwards and the power company pays you. Even if this doesn't happen, it's still reducing your power bill significantly.

Also, while I agree with your overall point,

a coal miner here a gas worker there and every now and then someone dies installing panels on their roof.

If we weren't dependent on coal and gas, maybe these could be avoided, but if people weren't installing those panels on your roof, surely they'd be doing something very similar. Maybe installing a satellite dish on someone else's roof.

It also makes your argument sound very, very weak when you complain that people react irrationally to one big, scary anecdote, but you haven't actually provided any statistics for how many coal, gas, or solar workers die every year, nor do you seem to be considering wind -- or even sources like hydro, which would make your point much stronger.

Re:No, thanks

[rubycodez]

In my country, the USA, all the reactors are 40+ year old technology (true in many other countries). And the core reason for the failure was backup power failure, which can happen by other means than Tsunami (considering most U.S. plants have exactly two backup generators per reactor)

Now I'm pro-nuclear, but the way in which we derive most nuclear power in the world is quite stupid and dangerous, with very, very long term risks.

Send in the robots

[Interoperable]

I guess that the primary reason that such duct-tape-and-cardboard methods are necessary is that people simply can't go into the reactor building due to high radiation levels. All the hardware required to cool the reactor is in place, it just needs repairs. It would surely be easier to perform those repairs than build a new cooling system, provided that access to the systems was possible.

I can't imagine that flooding the containment buildings was their first (or even second) choice but they must be restricted in terms of what systems they have access to from outside the most heavily contaminated areas.

Re:Send in the robots

[Mindcontrolled]

Yeah, you are probably right - but what does that tell us? They have no concept at all to handle a major failure mode in one of their reactors, none at all. All we are seeing is seat-of-the-pants level improvisation, because they have no plan. Why do we let those guys operate a reactor again?

Re:Send in the robots

[maztuhblastah]

Yeah, you are probably right - but what does that tell us? They have no concept at all to handle a major failure mode in one of their reactors, none at all. All we are seeing is seat-of-the-pants level improvisation, because they have no plan. Why do we let those guys operate a reactor again?

Why do we let them? Because as much as we'd all love to see a form of electricity generation that uses only perfectly safe fuel, operates without any risk to its users, and emits no waste, the gods have not yet graced us with such an energy source yet.

And why do they have no plan? Well... because we can't plan for everything. We *did* have a plan for an earthquake. Then nature fucked us with a bigger one. We did know the risks of tsunamis -- but nobody thought of the possibility of a big one following a record quake.

For every disaster you plan for, there's always the chance of another one that makes the one you prepared for look like a tiny mishap. You plan for a quake at level X on the Richter scale, nature will throw an X+2 at you. You plan for tropical storms, nature will throw hurricanes at you. You plan for those, you'll get get a tornado. No matter what you plan for, there's always something that you didn't.

And then, after it's all over, and your otherwise-well-designed $PROJECT is a pile of smoking rubble, some asshole will come out of the woodwork and snort "How could those guys not plan for __________?"

Re:It's cooling down.

[beckett]

I'll wait until some unknown blogger says its ok, thank you very much!

Interesting radiation readings

[rrohbeck]

From http://theautomaticearth.blogspot.com/2011/04/april-20-2011-fukushima-review-of-ines.html:

On April 17th the same site had the following radiation levels recorded for units 1-3:

        Reactor 1
        Dry Well: 121.4 Sv/hr
        Suppression chamber: 97.5 Sv/hr

        Reactor 2
        Dry Well: N/A
        Suppression Chamber: 131 Sv/hr

        Reactor 3
        Dry Well: 253.2 Sv/hr
        Suppression Chamber: 103.9 Sv/hr
So that's going to take a while to cool off.

Re:Interesting radiation readings

[Fnkmaster]

Hehe, minor conversion error.

100 rem is 1 Sv, not the other way around. 1Sv of exposure is around the threshold for radiation poisoning and 8-10 Sv is considered untreatable with death guaranteed to follow shortly thereafter.

So a room at 100Sv/hour would give a guaranteed fatal exposure within about 90 seconds. Radiation poisoning would onset after 30 seconds of exposure.

So you can safely say that 100 Sv/hour is about the threshold for "instadeath".

Re:Interesting radiation readings

[Anonymous Coward]

Um, no, 1 Sievert = 100 rem, so in 5 hours you would get 50 k rem, and a normal lifetime dose in 9 seconds.
So according to the handy and authoritative ;-) XKCD radiation chart, the emergency workers would get a guaranteed fatal dose if they stayed for 5 minutes.
<handwaving>
Assuming the Iodine has already decayed by now, I thought the next most abundant decay products are Cesium and Strontium with half-lives of 30 years, if that's true then they could work for an hour until fatal dose in about 109 years time. ( 100 Sv/hr present / 8 Sv/hr lethal = 12.5; log(12.5) / log(2) = 3.64; 3.64 * 30 years = 109 years, if I didn't make any mistakes). Then they could work for 15 minutes until a "emergency radiation worker" 100 mSv dose after waiting for a cooling-down period of 239 years (log (100 / 0.1 / 4) / log(2) * 30), amirite?
</handwaving>

If they're not that patient then they have to use robots or something. Who's going to pay to keep the plant guarded from terrorists until the year 2250 until they can decommission it safely? Copyright doesn't even last that long (yet).
I find it very suspicious that nobody's even mentioned measured levels of Strontium-90 because it stores itself in the bones of people building new bone mass (i.e. children). They only talk about measuring Iodine and Cesium but Strontium should also be more than 5% of the fission products, almost as much as the measured Iodine (3%?) and Cesium (12%?)

Mitigating my ass.

[unity100]

Hear Dr. Michiko Kaku (yes, famous physicist) speak about fukujima. and what you hear wont ease your mind.

http://video.godlikeproductions.com/video/Japan_Nuclear_Crisis_Dr_Michio_Kaku_41311?id=5f6b79d071f3c70b40c

there are people STILL downplaying this, believing what industry shills are drumming like morons.

Re:Mitigating my ass.

[Anonymous Coward]

Sorry, but I ain't gonna pay much attention to a guy that can't count to 4: "There are 3 types of civilisation: Type 1, Type 2 and Type 3. We're Type 0."

Re:Mitigating my ass.

[Quantum_Infinity]

I do not respect this Kaku guy. He spends more time on TV than doing actual physics. He is a an attention whore. He is on every channel BBC, Science, Discovery, History and he has 'expert opinion' on everything. Moreover, he uses sensationalist language, often implying more extreme consequences of whatever he is talking about than is actually the case.

Re:Mitigating my ass.

[Mindcontrolled]

Nice. I don't like the message so I go straight to an ad hominem. Show you colors!

"Don't Panic" after 42 days

[Alain Williams]

With a review after 42 days I was expecting to read "DON'T PANIC" in large, friendly letters ....

Re:FTFA

[Mindcontrolled]

Reasonable people are demanding that we review our use of oil for years. What's your point?

Coal vs. Nuclear

[anchovy_chekov]

Ignoring all the "coal kills more people" vs. "Pu is forever" arguments, the fact remains that all these fuels are essentially nasty, polluting "fossil" fuels (albeit one from dead suns).

Maybe Fukushima and Deep Water Horizon will mark a recognition of the level of care we need to take when handling these very finite resources. I hope so.

Re:Coal vs. Nuclear

[gweihir]

Mercury is safe to eat in comparison to Pu. And Pu has a half-life that the distinction does not make a whole lot of difference. Also keep in mind that its half-life (24,100 yrs) the problem is not gone, but _halved_ and some other nice radioactive stuff created from it. Calling this "a while" is highly stupid. Also, it is quite possible (and done) to remove the mercury from the smoke.

Bottom line: Nuclear power is extremely expensive and deals with time-lines for containing its by-products that are far outside of what the human race can handle. The thing that really ticks me off is that by now it would have been cheaper to just shove all that money down the nuclear fanatic's throats and build up renewable energy source with what was left. And this stuff will continue to be expensive for > 100'000 years, a constant financial and ecological drain on humanity. Just so a few people without ethics could fill their coffers.

Re:Coal vs. Nuclear

[JSBiff]

But, there's one important difference - if used appropriately, every ton of Uranium has the energy equivalent of something on the order of a million tons of coal or oil. Also, don't forget about Thorium. Uranium is not the only nuclear fuel. Thorium is estimated to be at least 5 times more abundant than Uranium.

I've seen some analyses which estimate that, if we used fast breeder reactors (like the Integral Fast Reactor - search for that sometime, interesting reading) and Liquid Thorium Reactors, we have enough fuel supplies to last us at least 100,000 years. Also, both technologies solve the 'nuclear waste problem' by burning off the nuclear waste.

If we can extract Uranium cost-effectively from the ocean, we have enough Uranium to perhaps get us through a few billion years (and, over the course of a Billion years, more uranium will leach out of the earth's crust [there's all kind of uranium in the crust, but not concentrated enough for effective mining, but if it dissolves out, it might be recoverable] and into the oceans, making it an effectively renewable resource).

Nuclear power has it's challenges in terms of safety and economics. Fuel supply is not a real problem though. If you are *really* worried about a fuel supply which might run low in 100,000 years, I don't know what to tell you. I don't worry much about problems that far down the road.

Re:Coal vs. Nuclear

[cnaumann]

Ingesting very small amounts of Pu will (probably) not hurt you. The toxicity of Pu is grossly exaggerated. It is chemically toxic like most heavy metals, but there is nothing really special about its toxicity as a chemically. All isotopes of Pu are radioactive, the longer lived isotopes are less radioactive than the shorter lived isotopes. There is nothing special about the radioactivity from Pu 239 (half life of 24K years) that makes it more hazardous than any other radioactive material. If you are concerned about long half lives, the U-238 that is released from burning coal has a half live of 4.4 billion years.

When you 'remove' the mercury from smoke, where does it go? It does not go away, it has to be put somewhere just like the waste products from nuclear power generation. The only real difference is scale. Nuclear produces only a small fraction of the toxic waste that is produced from burning coal, but that waste is a great deal more toxic. Which is easier to deal with? A billion tons of slightly toxic waste or a a thousand tons of highly toxic waste?

What are these 'cheaper' renewable that you are talking about? Do you really believe that there is some massive conspiracy to keep cheap, plentiful, reliable, and renewable power off the market? Or is this the renewable power that you are convinced that would surely be invented if only enough money were spend on it? If you have a way to produce electricty for a few cents a kilowatt hour using renewables, go for it. You have an unlimited worldwide market.

The roadmap document confirms a meltdown.

[Anonymous Coward]

From the roadmap document:

"Current Status [2] (Units 1 to 3) High likelihood of
small leakage of steam containing radioactive
materials through the gap of PCV caused by
high temperature."

The only way the pressure containment vessel could have a hole all the way through it 'caused by high temperature', which is leaking to the atmosphere, is if some of the fuel has melted and pooled. Units two and three show atmospheric pressure in the reactor primary containment.
See: http://atmc.jp/plant/vessel/?n=3 and http://atmc.jp/plant/vessel/?n=2

Quite possibly...

[denzacar]

Thousands of civilians killed? Yes.
Thousands of civilians killed by U.S.? Again, yes.

The IBC project released a report detailing the deaths it recorded between March 2003 and March 2005[72] in which it recorded 24,865 civilian deaths. The report says the U.S. and its allies were responsible for the largest share (37%) of the 24,865 deaths.

Thousands killed by DU ammunition? Possibly.
Thousands affected by the continuous effect radiation from DU ammunition? Almost certainly.
When you measure something in thousands of tonnes you can safely say that it WILL affect large areas of land and large numbers of people.
And 4.468 billion years is a long time.

The use of DU in munitions is controversial because of questions about potential long-term health effects.[4][5] Normal functioning of the kidney, brain, liver, heart, and numerous other systems can be affected by uranium exposure, because uranium is a toxic metal.[6] It is weakly radioactive and remains so because of its long physical half-life (4.468 billion years for uranium-238). The biological half-life (the average time it takes for the human body to eliminate half the amount in the body) for uranium is about 15 days.[7] The aerosol or spallation frangible powder produced during impact and combustion of depleted uranium munitions can potentially contaminate wide areas around the impact sites leading to possible inhalation by human beings.[8] During a three week period of conflict in 2003 in Iraq, 1,000 to 2,000 tonnes of DU munitions were used.[9]

Re:Quite possibly...

[Kyusaku Natsume]

The main trouble with depleted uranium comes from its toxicity, not from its radioactivity, you can see that since as you pointed out, the half life of U238 comes in a geological timescale.

Re:The supreme scrumpyolyness of delish!

[PopeRatzo]

WTF? Methinks you may have posted to the wrong story.

No, he posted to the story he meant to.

You'll see this kind of trolling, using brand new accounts and very very long off-topic or nonsensical posts whenever there is a story that may have implications that could negatively impact a corporation or industry sector. I believe they are intended to disrupt discussion of those stories. You'll see them very often in stories that discuss telecom companies or energy industry.

I believe they are paid trolls, from organizations like New Media Strategies (or their darker cousins) who, instead of astroturfing or writing positive things about their clients, exist only to disrupt serious discussions of things that could be construed to negatively impact their clients.

I could be wrong, but I've been seeing this pattern. You'll also see a pattern where an offtopic post is followed by a string of anonymous or very new accounts being very repetitive and responding to the original offtopic post, creating a long section that many people just won't bother to scroll through and will just abandon the potentially hot story.

Yes, I'm paranoid. I believe paranoia is an appropriate reaction to life circa 2011.

Re:It's cooling down.

[CrimsonAvenger]

Without sounding like an idiot,

Too late...

quite a lot of their land was recently irradiated by exposed nuclear fuel burning,

I"ll bite. How much land was irradiated? And what's your evidence for your guess?

and they should really be evacuating about half of the fucking country.

Even assuming that the nuclear fuel was burning and freely releasing fission products, prevailing weather patterns mean that most of Japan was completely unaffected by this problem. Well, other than losing the 6 GW of electricity generation that they lost when the earthquake and tsunami screwed things up.

Re:It's cooling down.

[neokushan]

You're absolutely right, I made a major cockup. What I had in my head was the 50mile exclusion zone around the plant, which is obviously quite a lot larger than 50 square miles. I stand both corrected and ashamed.

Re:It's cooling down.

[TheRaven64]

They evacuated the exclusion zone because it would have been a PR disaster if some of the worst-case scenarios had happened and the press had said that all of those people could have been saved if they'd been evacuated early. Once it's completely under control, those people can return.

This is simple disaster management. You don't wait until something bad has happened before you start evacuating people, you evacuate them when the danger is only a potential. That way, if something does go wrong, you have a load of inconvenienced people, not a load of dead people.

Some of that zone has been exposed to radioactive materials, but they all appear to be things with short half lives, so they'll quickly decay back to normal background radiation levels.

Can we give up on the Coal vs Nuclear distraction?

[dbIII]

Except for in places where it isn't in the coal, which is just about everywhere outside of the USA because mercury really isn't all that common. Even when it is in the coal how is it going to get into your system when the flue gasses are scrubbed with water to remove the NOx and SOx which as a side effect very easily condenses the mercury removing it into ash dams or other pollution controls?
If you are going to say stuff like you do above in a public forum you really have a responsibility to say something tied to reality and know just a little bit about what you are talking about instead of just making shit up. When you are talking about a mercury threat a few orders of magnitude less than domestic light bulbs it really doesn't justify comparison with plutonium.
I'm aware that the plutonium is also usually very well contained so is usually also ignorable. We just happen to be discussing a situation where a significant amount of it may have escaped.
The "coal is dangerous" shit whenever nuclear is mentioned is getting very old. We all know it kills people, in fact there is almost a weekly death toll in direct mining accidents alone. However usually the comparison is brought up as a frankly very childish distraction along the lines of "little jimmy is being bad, why can't I be bad too". It's depressing and each time it is used I have to tell myself that the person who used it is a real human being and not just a juvenile lying weasel that thinks everyone else is stupid.

Option 3

[dbIII]

I didn't think of a typo instead of ignorance or deliberate misinformation. I'm sorry I went over the top a bit there.

Re:Option 3

[neokushan]

No harm done =)

Let that be a lesson to other people on slashot - sometimes it is possible to be wrong and there's no harm in admitting it.

Re:The supreme scrumpyolyness of delish!

[Securityemo]

Alternatively, someone is testing out software to spamflood the site (or similar) and needs to check what gets through the filters. That's obviously generated text combined with some random text from the internet, to have the structure of a real post while actually being nonsense.

Re:FTFA

[Mindcontrolled]

Well, I completely agree that we are dealing with just different levels of suck if we are comparing oil to nuclear - but that should be an incentive to massively research renewables and perhaps fusion. As to the competence of TEPCO - seriously? Five weeks after the incident, the best telemetry we get is a counter taped to one robot watched by a second robot's camera? A first year engineering student could hack something better in one weekend. They are bumbling fools. Discharging radioactive water into the ocean? Hey, we dump a couple of sandbags full of zeolith in the vicinity of the pipe, problem solved. Come on.

Re:Can we give up on the Coal vs Nuclear distracti

[Xyrus]

Plutonium and Uranium are non-volatile nuclear fuels. The only way they escape a nuclear reactor is a raging inferno capable of over 6000 F, a massive explosion that shatters the fuel rods and disperses the particles, or (to a much lesser extent) damaged fuel rods with exposed surfaces flacking the material into reactor water. Neither of these two fuels have escaped in any significant quantity.

The biggest concern with nuclear accidents isn't even the fuel, it's the fission by-products. Nuclear fuel is not very radioactive, and due to it's low volatility it doesn't disperse very well outside of extreme events (Chernobyl). The real danger comes from the volatile, highly radioactive, products of nuclear reaction like Cesium and Strontium (Iodine has a half life of 8 days, so is only a short term concern).

You also have a responsibility for factual honesty. Mercury is only one of the contaminants in coal, and even the best scrubbers do not remove all pollutants. But other than mercury, there are also heavy metals, toxic compounds, and radioactive elements as well. This is why waste products like fly ash is treated as a serious environmental pollutant. If a major coal depot or coal plant had a major disaster, it would just as effectively turn the surrounding area into a toxic wasteland. The same goes for oil refineries (which are under even more stringent regulation than nuclear plants due to their potential of becoming an ecological disaster).

The point being, of all of our current power sources, nuclear ranks as one the safest in regards to both pollution and mortality. Fossil fuel sources are ranked as they deadliest. I would much rather live next to a nuclear power plant (and have) than an oil refinery (which is actually illegal) or a coal plant.

The Plutonium Monster is a myth

[MichaelKarnerfors]

I'm sorry but I just have to nip this nonsense in the bud because I'm sick and tired of this completely unscientific fear-mongering that takes place. The Plutonium Monster is a myth.

Plutonium has about the same chemical toxicity as cadmium and caffeine. And unless you intend to grind the stuff into powder and snort it, it's not going to do you any recognizable harm. It's next to insoluable in water when in its oxide forms and not volatile... it doesn't go anywhere in the environment.

People make a big fuss and say "oh but it has such a long half-life... 24 100 years!". Well the thing is: a substance's radioactivity is inversely correlated to the half-life. Radioactivity comes from decay. Less decay means longer half-life... and conversely longer half-life therefore means a less radioactive substance.

The big worries are the short-lived ones. Iodine-131 is biggest worry of all, because is hot, it's plentiful and it's very volatile and mobile in the environment. With a half-life of 8.02 days, it falls apart so fast that even a trillionth of a kilogram falls apart at a rate of 4.6 MegaBecquerels. That's the big worry in the short run... and that is what caused the cancers from Chernobyl. 4000 cases of thyroid cancer, because the Soviet authorities didn't screen for and didn't stop contaminated food: they let the kids drink milk that was contaminated with I-131, even though it was completely preventable.

In the longer run it is the medium length half-lives that are a nuisance. I-131 falls apart fast and from Fukushima we're already down to 1 in 40 left of the original inventory from when the reactors shut down. In the long run Cesium-137 and Strontium-90 are the top contenders of being trouble. They have a half-life of around 30 years, which makes them hot enough to be a bother, and long-lived enough to remain a while. They are also - just like I-131 - rather volatile and mobile in the environment.

Plutonium - in comparison - is a not a big worry. Its specific activity is low and it doesn't get around. If it falls out of the reactor is stays put near the accident site. Now I know alot of you have been listening to the scare-mongers and tabloid news... and if you did: the joke's on you. It's just that "Plutonium" is a charged word... "Iodine" and "Caesium" isn't... so waving the Plutonium Monster around is an efficient way of making a buzz.

I'm not saying this to downplay anything. I-131 and Cs-137 are big problems in an accident like this and they need to be dealt with. Just focus on the right stuff, ok? Plutonium is not the major worry here.

/Michael, co-founder of Nuclear Power Yes Please