patrick.net

Nomograph says

pkennedy says

But that wouldn’t be dooms day enough for you though.

I think Troy used to live in Japan so perhaps he has more of a vested interest.
Terrideaner is just spreading histrionic paranoia.
Let other pens dwell on guilt and misery — Jane Austen

Did your shrink recommend that you handle information that threatens you this way?

And does the unpredictable, unknowable nature of the real world frighten you so much that you have to try so hard to disparage the topic of this thread?

"A foolish consistency is the hobgoblin of small minds" - Emerson

According to Wunderground.com, gusts of wind are blowing from the SE to the NW. (Away from Tokyo, but keeping it in Fukushima or Miyagi Prefectures now.)

My wife said the president of TEPCO was crying and apologizing on NHK yesterday. Did you see it, Troy? You are watching NHK even more than I am. (too busy checking multiple sources).

I read about that. And now they are reporting that radiation and fission isotopes have been found in milk and spinach from Fukushima Prefecture. Soon the horrible truth will be impossible to hide. He'll cry even more and maybe fall on his sword.

They've finally admitted that enough has been released that citizens near the plant will die.

pkennedy says

Translated to: ” I have no idea what it means, therefore it surely can’t be under control!”

I've been following this situation in the Japanese for hours every day. I understand it more than anyone (other than experts), and the experts differ about what's going to happen with Unit 4, eg "arclight" has said Kaku is wrong about being able to entomb the reactors immediately.

LA Times quotes chairman of NRC saying Unit 4 pool is empty, says there may be a breach, and quotes anti-nuke guy with UCS as there may be no solution.

http://articles.latimes.com/2011/mar/18/world/la-fg-japan-quake-wrapup-20110318

Pro-nuke guys are still saying there's no problem, there has not been a problem, death toll so far is microscopic compared to the tsunami up north, and coal pollutes more so don't worry we have this under control.

Here's a pic of Unit 4. The storage pool is in the upper left of what remains of this building. I can see why the chairman of the NRC said his information is that the storage pool is empty.

Here's what the Chief Cabinet Secretary last said about 3 and 4:

"There is immediate threat of radioactive nuclides release from the spent fuel pools of Unit 3 and 4, because of incapability of cooling these pools"

http://www.jaif.or.jp/english/news_images/pdf/ENGNEWS01_1300590001P.pdf

Complicating matters is that NHK is now reporting on the news that Unit 3's reactor vessel pressure is rising. They may need to vent that, and if they do they'll be venting who-knows-what since unit 3 has been running with the core only partially immersed for days.

Apparently the working environment now in front of units 3 and 4 is not as bad as Chernobyl. That was my main fear going into this week, that we would lose the ability to intervene (unless we got some robots in there).

What I don't know is what's going to happen with Unit 4. The experts differ about what will happen to the 276 tonnes of spent fuel as it continues to heat up. TEPCO has said recriticality is not off the table.

The storage pools in Fukushima had been re-racked:

Measures for increasing Storage Capacity

- Increase in the capacity of spent fuel pools by re-racking

http://www.nirs.org/reactorwatch/accidents/6-1_powerpoint.pdf

I don't know what's left to burn in Unit 4. Maybe the tonnes of fuel with its 2MW output will find a happy place and just cool down without venting or breaching the pool.

Whatever, the situation in Unit 4 and perhaps Unit 3 is not "under control" at the moment.

#3 and #4 both remain nasty question marks. And, as Troy pointed out earlier, the corroded pumps washed with seawater may or may not work when power is restored. I sincerely hope they will, but I have some doubts... but all is well, right???

From bbc asia-pacific:

2240: American investigative journalist and Japanese crime expert Jake Adelstein writes in his blog that: "the Japanese police are quietly beginning an investigation into TEPCO, the managing entity of the Fukushima Nuclear Reactor for charges of professional negligence resulting in death or injury." He says the investigation is still in its early stages and that nothing is official yet.

terriDeaner says

the corroded pumps washed with seawater may or may not work when power is restored

The pumps may not EXIST now.

http://www.youtube.com/watch?v=T_N-wNFSGyQ

Just saw this on twitter feed on the NHK steam:

圧力さげないと「ただちに」言えなくなる

Here's your Japanese lesson for today:

圧 -- 'atsu' -- 'pressure'. This is the same root in 'shiatsu' -- 'finger pressure'
力 -- 'ryoku' -- 'strength'
さげ -- verb stem of the transitive verb 'to lower'
ない -- negatory verb ending conjugation
と -- grammatical particle meaning 'upon/unless'
「 ただちに」 -- "for now"
言え -- verb stem of the potential form of 'say'
なく -- connective conjugation of negatory verb ending
なる -- 'become'

"unless the pressure is lowered 'for now' won't be able to be said" [when referring to radiation not being harmful]

The joke is if they don't bleed the primary containment, 50 tons of plutonium is going to be violently ejected all over the site via steam explosion.

Troy says

The pumps may not EXIST now.

http://www.youtube.com/watch?v=T_N-wNFSGyQ

Fuck. And it is pretty creepy at the end of that clip when the talking head is clearly scared shitless by the feed.

Troy says

The joke is if they don’t bleed the primary containment, 50 tons of plutonium is going to be violently ejected all over the site via steam explosion.

Not good. Any way this can be remedied remotely?

By the way, thanks for keeping up with the Japanese language websites and communicating them here. Much appreciated.

The latest on the death count is over 8,000 with over 12,000 more missing. At least 16-17,000 have actually perished, I assume.
Winds are blowing into Japan (Fukushima and Miyagi) but away from Tokyo. So far only on Tuesday have the winds really blown towards Tokyo. Tomorrow long rains are coming to Tokyo and Fukushima.

Other Japanese words in Chinese Characters/hiragana:

東京都 Tokyo city
福島県 Fukushima-ken
放射 radiation
核発電所 Nuclear power plant

American in Japan says

At least 16-17,000 have actually perished, I assume.

Yeah, when I saw the devastation of Rikuzentakata I told my mom the death toll was going to be at least 20,000.

Before then I thought this wasn't going to be too bad, but a wave that wipes out coast cities like an a-bomb is going to be a mass-casuality thing. Only thanks to the the several massive tsunamis in living memory probably will the death toll be under 100,000.

I know if I had been in fishing village I'd have felt perfectly safe on the third floor of a solid building.

May there be justice:

http://www.japantoday.com/category/commentary/view/bungling-cover-ups-define-tepco#show_all_comments

@Troy

"Only thanks to the the several massive tsunamis in living memory probably will the death toll be under 100,000."

As bad as it was, it could have been much worse. People were warned about the Tsunami ahead of time, so many moved up/inland.

It appears that one had to go much farther inland in many place, than with Phuket (I was there last summer). With Phuket people said that about 250m inland was enough.

Rain tomorrow for Tokyo and Fukushima. I don't want to be in that...

Another fairly good site:

http://japanearthquake.org/

Troy says

when you fly from Los Angeles
to Tokyo, you will be exposed to 5.5mrem (55uSv), so whatever we get from Japan
which is 5000 miles away will have no impact at all.

Goddamit this is the bullshit that they’re telling you and I for one am not buying it. This is how they’ve hand-waved the nuclear test era such that we don’t hunt down and kill the perpetrators who poisoned the shit out of this planet, and now who today defend the 60s and 70s nukes as a minimal risk that cannot ever ever create something as bad as Chernobyl.

Ingesting radioactive Cesium is totally different from the increased dosage up in the air!

You and terrideanner need to get a grip. There are thousands of people dead, millions in very serious danger of exposure, disease, and nuclear contamination. All you two can whine about is the one in a qaudrillion chance you may ingest a stray isotope from japan (as opposed to the billions of stray isotopes that float around the world already and you ingest all the time) that will have zero chance of increasing your risk of cancer. Unless you live in a lead lined room with a 99.9999% air filter puration system 24/7 you are getting radiation exposure every single day both externally and from ingestion of radioactive isotopes. Worry about real dangers like a car accident or falling in your bathtub. You guys must be lots of fun at parties.

bob2356 says

You and terrideanner need to get a grip. There are thousands of people dead, millions in very serious danger of exposure, disease, and nuclear contamination.

Responses like this lead me to believe that you have a reading comprehension problem. Please go back, and slowly read over some of the earlier entries... this time with your reading glasses on. Try not to just selectively leave out the parts that aren't convenient for your narrative.

I am concerned for all of the people affected by the earthquake/tsunami/nuclear crisis. The effects on the Japanese people have been horrific and very sad. But you need to understand that this crisis will have global effects, it is that simple. To what degree these effects are felt here are of great interest to me. If you don't care, then simply continue to ignore the information you don't like.

bob2356 says

All you two can whine about is the one in a qaudrillion chance you may ingest a stray isotope from japan (as opposed to the billions of stray isotopes that float around the world already and you ingest all the time) that will have zero chance of increasing your risk of cancer.

Interesting estimates. Care to supply a source for these calculations?

bob2356 says

All you two can whine about is the one in a qaudrillion chance you may ingest a stray isotope from japan (as opposed to the billions of stray isotopes that float around the world already and you ingest all the time) that will have zero chance of increasing your risk of cancer.

You'll note that I haven't said a goddamn thing about dosing of the West Coast.

I'm only concerned about Japan, partially since I had plans semi-set to go back there later this decade, and the ongoing effects is an interesting academic exercise.

This is 4 reactors 'spitting the dummy' at once. I've read that Chernobyl's reactor core only had been in operation for 3 months, meaning the level of contaminants in its fallout was a lot less than what the current 3 reactors and 4 storage pools under stress contain.

The 3 scrammed reactors are still in the megawatt range WRT output and will be for months. They've been injecting seawater via the fire suppression pumps for days now, but either this seawater is evaporating in the reaction chamber -- leaving tons of radioactive salt behind, eventually gumming up everything -- or it is being dumped into the environment. Normally this would be just a "Bad Thing" (moderate contamination) but since all 3 cores lost cooling for hours it is quite likely primary containment -- the fuel rod cladding -- is compromised and this sea water is a contaminated with high levels of nuclear crap, including cesium and plutonium.

They've already said Unit 2's suppression containment is compromised, and anyone looking at Unit 3's explosion:

http://www.youtube.com/watch?v=T_N-wNFSGyQ

and resulting ruins of the facility:

might easily come to the conclusion that Unit 3's steam suppression torus is also compromised in integrity and/or functionality.

TEPCO has done a good job updating us with the microsievert level radiation leakage at the "West Gate" monitoring point, but has said absolute BUPKUS about what they're dumping into the ocean now, and none of the idiot reporters have been covering this.

Since Unit 4's storage pool was stacked to the full with 1535 fuel assemblies (including ~500 pulled out of service late last year) it is still outputting 2MW and will continue to do so for a great while.

I don't know what's going to happen from here. I half-expect things will get better from now on.

But I just don't know if & how the residual heat is going to be safely contained to avoid the creation of a continuous plume irradiating half of Japan over the next few months.

At any rate I do have hope that whatever challenges we still face we can meet them.

One problem is that the PTB's decision cycle has been rather slow. NHK is reporting this morning that they are only now sending an NBC-protected bulldozer:

that will start work clearing out the debris from the tsunami and last week's explosions. This is not very on-the-ball disaster management.

They're also bringing in two concrete tower-cranes today, too.

Troy says

I don’t know what’s going to happen from here. I half-expect things will get better from now on.

That's just it. It really does look like some stability has been achieved, and that the worst is over. However, the downside risk of having so much spent fuel around remains high.

The likely path forward at this point seems like continued bit-by-bit repairs to the remaining reactors over the next few weeks/months, with periodic releases of radioactive materials. Fortunately for all of us, we can expect far,far less radioactive pollution than if the spent fuel rods got out of control. Still, we don't know how much radioactive material will be released before this story is over. Probably (hopefully) very little on a global scale.

Now that this situation is coming under control, I hope that more foreign aid workers will be willing to go to Japan to help during the recovery period. The Japanese people have many difficult challenges facing them, and they will be compounded by dealing with ongoing contamination from the crippled plant. At a minimum, I hope this tragic experience will serve to teach the agencies responsible for public safety how to better anticipate and deal with catastrophic emergencies.

XKCD has a chart about dosages:

http://www.xkcd.com/radiation/

Vicente says

XKCD has a chart about dosages:
http://www.xkcd.com/radiation/
“Eagles are dandified vultures” - Teddy Roosevelt

Nice chart. What I'd like to see is the %increased cancer risk by radiation dose, and also a chart of %increased cancer risk versus concentration of ingested isotope (by type). I should do some digging... someone may have done these studies in a lab with mice or rats.

XKCD is just parroting the line about radiation is radiation.

For some reason most engineering types really want to defend the nuke industry to the death.

I think it's the romantic attraction to tapping the colossal forces of nature.

http://www.youtube.com/watch?v=0PfBYsII_Jw#t=34s

Troy says

For some reason most engineering types really want to defend the nuke industry to the death.

It's also easier to measure and track the immediate effects of acute doses. How could you accurately measure the increased cancer cases (in humans) due to the open-atmosphere nuke tests last century? An appropriate control group would be impossible to assemble.

I think it's more because we can GAUGE the effects of say direct exposure to radiation, and to atmospheric carried particles. How can I gauge that you'll ingest a lot of foodstuffs carrying radionuclides and what that will do to you? I can't really, far too many variables.

Vicente says

I think it’s more because we can GAUGE the effects of say direct exposure to radiation, and to atmospheric carried particles. How can I gauge that you’ll ingest a lot of foodstuffs carrying radionuclides and what that will do to you? I can’t really, far too many variables.
“Eagles are dandified vultures” - Teddy Roosevelt

Exactly my point. But real dangers of ingesting radioactive particles persist, whether they are difficult to predict or measure.

Kinda sorta related. Just read that Stuxnet virus was found on computers in Japan. Hmmm sounds sketchy but you never know.

http://www.gilad.co.uk/writings/whatreallyhappened-stuxnet-found-in-japan-in-october-is-fuku.html

Troy says

bob2356 says

All you two can whine about is the one in a qaudrillion chance you may ingest a stray isotope from japan (as opposed to the billions of stray isotopes that float around the world already and you ingest all the time) that will have zero chance of increasing your risk of cancer.

You’ll note that I haven’t said a goddamn thing about dosing of the West Coast.

You are correct, my apologies. I thought you 5000 mile comment meant you were jumping on td's "oh woes me california is the center of the universe" bandwagon.

bob2356 says

I thought you 5000 mile comment meant you were jumping on td’s “oh woes me california is the center of the universe” bandwagon

I don't think there's any cause for concern WRT a brief episode of emission.

However, in terms of radioactive cesium, however, it is not clear which is worse, a nuclear test that creates cesium from a small amount of fissionable material, or a Chernobyl-like plume that carries literally tons of fission byproducts into the air.

Ie. if Fukushima 1 may have already contaminated a 5-10km area much more than the Hiroshima bomb did, just looking at the cesium angle, and given enough time and enough wind, this contamination can extend quite a long ways.

The Chernobyl plant was working from rather fresh uranium stocks, only in service for 3 months.

The #3 plant has 900kg of plutonium in its fuel pool, along with 90 tons of spent fuel rods.

TEPCO just announced their seawater venting results in 25X above regulatory limits for cesium, 120X for Iodine, which is not surprising given they are venting water directly from 3 compromised fuel cores.

bob2356 says

I thought you 5000 mile comment meant you were jumping on td’s “oh woes me california is the center of the universe” bandwagon.

Is that REALLY why you think I started this thread? What a narrow-minded, conceited fucking comment. If you haven't gathered by now that I am interested in local AND global consequences of what's going on, discussing this topic, and sharing useful information, then tough shit.

I'd ask again if you bothered to actually read the content above, but I already know the answer.

Troy says

TEPCO just announced their seawater venting results in 25X above regulatory limits for cesium, 120X for Iodine, which is not surprising given they are venting water directly from 3 compromised fuel cores.

I wonder how this will affect testing of Russian fish stocks... as of last week they were still in denial of any danger:

Russia tests Pacific fish for radiation
http://www.dawn.com/2011/03/20/russia-tests-pacific-fish-for-radiation.html

terriDeaner says

I am concerned for all of the people affected by the earthquake/tsunami/nuclear crisis. The effects on the Japanese people have been horrific and very sad. But you need to understand that this crisis will have global effects, it is that simple. To what degree these effects are felt here are of great interest to me. If you don’t care, then simply continue to ignore the information you don’t like.

Global???? All you talk about is what is happening in Japan and how it threatens California. I care a great deal about the horrific events in Japan. I care nothing about a non existent threat to the US. I do care a great deal about real threats to the US, things like hundreds of obsolete coal plants spewing untold tons of toxins and know carcinogenics into the atmosphere killing hundreds of people in the US every year. Of course that's downwind of CA so I can see how it wouldn't concern you. I'm concerned about things like poorly designed (to give them the benefit of the doubt, they were designed a long time ago with the known technologies of the day) first generation nuclear plants, just like the ones burning in Japan, that are still operating in the US but should have been shut down 20 years ago. Things like untold huge amounts of nuclear, chemical, and biological waste and pollution that exists on closed and current military bases. Things like undiscovered superfund type sites of illegally dumped industrial who knows what.

Where is your outrage about these types real threats? Why are you so disturbed by the possibility of a non existent threat to CA? You are obviously rabidly anti nuclear and see this as a vindication your views, although I haven't seen where you are volunteering to do without electricity. I'm not pro nuclear or anti nuclear. All forms of energy generation have cost, benefit, danger trade offs. Since I'm willing to use the energy, then I have to accept the dangers involved. All we can do is hope that our elected representatives are diligent in making sure that the safety of the public is a high consideration. It appears that safety considerations were not taken nearly seriously enough for this particular reactor in Japan. Hopefully this disaster will implement a world wide evaluation of reactor designs and force changes on the ones that are in need of improvement. Or shut them down. The early cowboy days of nuclear plant design are long gone, but many of the early plants are still around.

If you really want to have your hair stand on end, read a book call "We Almost Lost Detroit". We really did almost lose Detroit as well as a substantial part of the rust belt. Believe or not in the 1960's there was actually a full scale operating breeder reactor (cooled by liquid sodium much, much more dangerous than a simple boiling water reactor, sodium explodes violently when exposed to water or air) 50 miles upwind of Detroit that had a partial meltdown and almost went totally out of control in a way that would make the Japan reactor fire look like a day in the park. Now that was stupid beyond belief even for the early days of nuclear power.

terriDeaner says

bob2356 says

I thought you 5000 mile comment meant you were jumping on td’s “oh woes me california is the center of the universe” bandwagon.

Is that REALLY why you think I started this thread? What a narrow-minded, conceited fucking comment. If you haven’t gathered by now that I am interested in local AND global consequences of what’s going on, discussing this topic, and sharing useful information, then tough shit.
I’d ask again if you bothered to actually read the content above, but I already know the answer.

I've read your comments. Someone else accurately described them as histrionics. I agree.

bob2356 says

Global???? All you talk about is what is happening in Japan and how it threatens California.

Not true. If it offends you so much that I have stated a thesis, and remain focused on evaluating it, go read something else. BUT just because I have taken this RATIONAL approach does not mean that I haven't considered AND ALSO COMMENTED on important issues related to the thesis (sigh... again..see comments above). Do you not understand that evaluating the question (the one posted at the top of this thread, not your straw man) involves gathering and contextualizing INTERNATIONAL news and information???

bob2356 says

I do care a great deal about real threats to the US, things like hundreds of obsolete coal plants spewing untold tons of toxins and know carcinogenics into the atmosphere killing hundreds of people in the US every year. Of course that’s downwind of CA so I can see how it wouldn’t concern you.

Why are you so disturbed by the possibility of a non existent threat to CA? You are obviously rabidly anti nuclear and see this as a vindication your views,

So you believe you can read my mind? I am not anti-nuclear, and nowhere above have I made that claim. In fact, similar to you I am neither pro- or anti-nuke. My goal is to try and to accumulate as much useful information as I can so that I can make rational, informed decisions. Why do you find that so threatening??? Because I refuse to toe your party line???

And you could have ASKED me at any time instead of trying to stereotype me, and stuff straw men, for the sake of your argument.

bob2356 says

All we can do is hope that our elected representatives are diligent in making sure that the safety of the public is a high consideration.

Keep hoping. Published today:

Nuclear Official Sees No Urgent Changes Needed for American Plants
http://www.nytimes.com/2011/03/22/world/asia/22atomic.html?hp

bob2356 says

I’ve read your comments. Someone else [Nomograph] accurately described them as histrionics. I agree.

Grow up.

I wrote this YESTERDAY:

terriDeaner says

It really does look like some stability has been achieved, and that the worst is over. However, the downside risk of having so much spent fuel around remains high.

And what is part of the remaining risk? Additional radioactive runoff from the plant. What was recently detected in seawater near the plant? SUBSTANTIAL radioactive contamination.

Obligatory Simpson's reference:

terriDeaner says

Additional radioactive runoff from the plant. What was recently detected in seawater near the plant? SUBSTANTIAL radioactive contamination.

I assume this is from the venting of the seawater cooling of the core.

There's a lot of nasty stuff in the core and this is what got TMI into trouble with regulators, they dumped IIRC 40,000 gallons of core coolant into the river.

This will be many many times worse before this is over.

In other news, they've released thermo imagery showing Unit 4 is not running hot, so if they can get water into the pool it should be OK now.

Unit 3 looks to be the bad boy now, running with higher pressure that may need to be vented again (just like TMI).

Troy says

I assume this is from the venting of the seawater cooling of the core.

Definitely possible - some of the vented material would stay airborne and the rest would precipitate in droplets as the steam condensed.

Is any of the wash water being collected after it percolates through the reactor ruins? It seems like this would be a likely source for large quantities of radioactive contamination.

I saw that thermal imagery, but had a hard time interpreting it without a better point of reference.

I'm starting to think what they are doing now, is just a holding action until they can move the equipment in they need to bury it. The lack of action report details may be misleading me into thinking there isn't much substantive going on. For example I see them bringing in power and able to deliver to some reactors. But not much about having sent someone in to assess the status of the critical cooling systems. Has anyone eyeballed the pipes & pumps for if they are intact? If so I'm not finding it.

@terriDeaner

I didn't think you had was a selfish reason for starting this, and I live in Japan.
It has rained for 1 1/2 days now so most of the radioactive elements are coming down, especially in the Pacific Ocean near Japan and in Fukushima Prefecture. Fortunately, winds have been away from Tokyo except last Tuesday.

The cesium-137 and plutonium are more of a concern than the iodine-131 since their half lives are much longer.
Still calm but alert...

Keep the information and links coming.

Yikes, looks like quite a lot if ending up in the sea:

[9:30 p.m. Monday ET, 10:30 a.m. Tuesday in Tokyo] High levels of radioactive substances have been found in seawater near the damaged Fukushima Daiichi nuclear power plant, its operator, Tokyo Electric Power Co. said Tuesday.

Levels of iodine-131 in the seawater were 126.7 times higher than government-set standards, the electric company said on its website. Its monitors detected caesium-134, which has a half-life of about two years, about 24.8 times higher than the government standards. Cesium-137 was found to be 16.5 times higher than the standard.

The electric company detected these levels in seawater 100 meters (328 feet) south of the nuclear power plant Monday afternoon. Radioactive particles disperse in the ocean, and the farther away from the shore a sample is taken, the less concentrated the contamination should be. Because of the huge amount of dilution that happens in the ocean, there's not much chance of deep-water fish being tainted, said Murray McBride, a professor at Cornell University, who studies crop and soil sciences.

http://news.blogs.cnn.com/2011/03/21/japan-quake-live-blog-u-s-military-families-in-japan-to-get-iodide-pills-monday/

I'd look for this to be an ongoing problem for the coming weeks/months. And IF entombment is the ultimate solution, it could go on for much longer.

BTW, odd choice for an 'expert'... I have a great deal of respect for Ag and soil scientists, but I would have thought an oceanographer or water chemistry specialist or fisheries biologist would have been higher on the list of candidates.

Because of the huge amount of dilution that happens in the ocean, there’s not much chance of deep-water fish being tainted, said Murray McBride, a professor at Cornell University, who studies crop and soil sciences.

American in Japan says

@terriDeaner
I didn’t think you had was a selfish reason for starting this, and I live in Japan.

It has rained for 1 1/2 days now so most of the radioactive elements are coming down, especially in the Pacific Ocean near Japan and in Fukushima Prefecture. Fortunately, winds have been away from Tokyo except last Tuesday.
The cesium-137 and plutonium are more of a concern than the iodine-131 since their half lives are much longer.

Still calm but alert…
Keep the information and links coming.

Hey, thanks AiJ. Glad you found some of this information useful.

Hopefully the rain scrubs out the bulk of the particulates. Don't discount the danger of I-131 just because it has a very short half-life, though. Remember that for the short-term the trade-off it is that it has a relatively energetic and intense decay period. Also keep in mind that it is concentrated by the body into a very small area (the thyroid gland). Effectively, this means you could get a very strong acute dose in a small area of your body over a very short time period after consuming a relatively small amount of it. How small of an amount is safe? I'm not sure...

From wikipedia:

Iodine in food is absorbed by the body and preferentially concentrated in the thyroid where it is needed for the functioning of that gland. When I-131 is present in high levels in the environment from radioactive fallout, it can be absorbed through contaminated food, and will also accumulate in the thyroid.

As it decays [I-131], it may cause damage to the thyroid. The primary risk from exposure to high levels of I-131 is the chance occurrence of radiogenic thyroid cancer in later life. Other risks include the possibility of non-cancerous growths and thyroiditis.

Stay safe!

And stay away from here:

URGENT: Radiation 1,600 times normal level 20 km from Fukushima plant: IAEA
http://english.kyodonews.jp/news/2011/03/80057.html