"Should I Stay or Should I Go?"

Last updated Mar 17, 2011 10:35 am local time (9:35 pm EST)

Current situation as of morning of March 17. Tokyo radiation level remains within normal range.

JSDF helicopters attempted four successive water-dumps over reactors #3 and #4. The condition of those reactors is most troubling, as the spent fuel rod cooling ponds have evaporated and without refilling them, there is a high chance the rods will overheat, melt, and release radioactive material. The results of the water drops have yet to be announced.

Current situation as of evening of March 16. Tokyo radiation level remains within normal range.

Fukushima Reactor #1: in spite of explosion, containment housing believed unbreached, sea-water injection ongoing to lower temp of fuel rods, situation stabilizing.

Fukushima Reactor #2: leaked some amount of material, causing radiation spike this morning around 10am. Cause unknown. Rad level has been dropping steadily since.

Fukushima Reactor #3: vented what appears to have been steam earlier today. Suspicions that containment housing may be breached. Conditions preclude direct observation. There is a very high chance the pool containing spent fuel rods has completely evaporated and rods are melting, irradiating the area. A planned water-drop by helicopter had to be called off due to radiation counts exceeding safety limits for the pilots.

Fukushima Reactor #4: fire broke out this morning, since extinguished. Theory is that evaporation of spent fuel rod storage pool caused hydrogen build-up that caught fire. Fire occurred in area where seawater pump was placed, and radiation has slowed but not stopped efforts to add water to pool.

---------------------------------

It pains me to say this, but in the wake of the situation at the Fukushima nuclear power facility, there has been a lot of innuendo about the potential danger to the Tokyo metropolitan area. The following represents all of the current information released to date about the situation in Japanese press conferences and from other sources mentioned below.

I'm not a nuclear authority. I welcome all info, even contradictory info, so we can piece together a picture of what is happening without needing to sensationalize things. If anyone has data that contradicts any of the below, or sheds light on it, PLEASE comment so that I can amend it. 

The bottom line is, the Tokyo metro area seems to be safe for now and there is no need to panic or evacuate. There is no "fallout cloud" approaching Tokyo, as some media would have you believe. I base this on the following data points. They are collected from information announced in government press conferences and from other sources cited below.

Point 1: A sievert (whether milli- or micro-) is a measure of exposure, expressed per unit of time (in the case of info coming from Japan, by the hour). The effect is cumulative. This means that at a 2 mSv/h (millisievert / hour) level, you would need to be exposed to the source for 100 hours to be irradiated to the point that is considered clinical radiation poisoning (200 millisieverts, according to this chart translated by @gakuranman). But the current background radiation in Tokyo is somewhere around 0.3 microsieverts. That's something like three ten thousandths of a millisievert.

Point 2: As reported by NHK and corroborated by datafeed from the Hino monitoring station, metropolitan Tokyo radiation levels rose from a normal reading of around 20-30 CPM (0.2 - 0.3 microsieverts per hour) up to to 89 CPM (0.89 microsieverts per hour) for an hour, then dropped to close to normal background levels again. They remain normal as of this writing.

Point 3: Tepco released a graph showing a spike of 12,000 microsieverts (12 millisieverts per hour) at front gate of the Fukushima nuclear power plant. It has since dropped to below 2,000 microsieverts (2 millisieverts per hour) This seems to correspond to the fire at reactor #4, which has since been extinguished. 

Even still, again note @gakuranman's chart showing comparative radiation levels. Even one hour at 12 millisieverts (the max reading taken at the gate of the plant) is equivalent to less than 2 CT Scans. These readings were taken at the front gate of the nuclear plant in Fukushima. They decline rapidly with distance from the reactors. Again, metro Tokyo readings remain normal.

Point 4: The situation at the #1 and #3 reactors is under control, with seawater being pumped in now to keep the cores cool. There was no core breach. The situation at #2 is that water is being pumped in but the level is not rising. This needs to be watched closely. The fire in Reactor #4 was extinguished earlier today. A measure of radiation and some radioactive isotopes may have been released in this fire, but the release of radiation and material seems to have stopped with the extinguishing of the fire. The big issue at #4 now is a potentially dropping water level. But as stated above, radiation levels are corroborated by the Hino geiger counter datafeed.

Point 5: The biggest issue as of the the afternoon of March 16 is that the situation at the reactors has not improved, though it is not clear if it is worse. A fire broke out at #4 early this morning (since extinguished), while elevated temperatures were detected at #2 and smoke or steam issuing from #3. Elevated radiation levels were detected at the front gate of the plant but have since dropped. There was a brief rise in background radiation levels detected in Tokyo early this morning (apparently corresponding to the fire at #4) but it has returned to normal as of this writing. As of right now, the danger appears confined to the plant grounds itself. The repair/firefighting crews remain on-site and working. (Many foreign media are incorrectly reporting the plant was "abandoned." This is not true.)

Again, PLEASE comment if you have info that contradicts any of the above.

This is a fluid situation, and an environmental disaster around the reactor site, but Tokyo residents and those outside of the evacuation zone do not seem to be in immediate danger as of this writing. The people in the most danger are the workers inside the plant. By exposing themselves to higher than normal radiation levels, they are sacrificing their health to keep the rest of us safe, and are the unsung heroes of this potential crisis.

Thanks very much to Andy Szymanski for summarizing this data and co-authoring this article.

Comments

[D8beat]

Hi,

I'm also doing a post up on this and a commenter cross-linked to your site. I have an issue with your point #2 as it might be incorrect.

the graph shows a peak of 90 CPM, which translate to 6μSv/hr on a GM10, not .89. You can also see the conversion scale on the bottom of the page of the link you provided for that point.

Regards,
Sam
www.alternatesam.com

[Andy Szymanski]

Reading from Tsukuba city in between Tokyo and the reactor site:

4:49 PM 0.24 microseiverts/h

Very similar to background levels in Tokyo.

Source: National Institute of Advanced Industrial Science and Technology

[Andy Szymanski]

D8beat,

The site linked to (the Hino monitoring station) lists the conversion at approximately 100 CPM = 1 microseivert/h.

Are you saying this is incorrect?
I am asking simply because I don't have the knowledge.
Could you provide a link to a conversion method?

The Hino numbers seem almost identical to the government's numbers so I assumed they were correct at 100 CPM to 1 microseivert/h.

[FriedToast]

Had readings of ~15,000cpm at work this morning in Kaminokawa (Just outside Utsunomiya). Was 7500~8000 when I left work awhile ago.

According to this page:
http://park18.wakwak.com/~weather/geiger_index.html
100cpm = 1 microseiverts/hr

[Grrats]

Nice compilation.

Thought I'd share a small item that might shore up your argument (pun intended):

From the Stars and Stripes, the paper for the U.S. military, in a story about the US navy base in Yokosuka, which includes the following money quote:

"When asked by Stars and Stripes whether there was an evacuation plan in place if a catastrophe at the damaged reactors were to threaten the base, Wren (the commander) said the reactors were so far away that it wasn’t necessary to talk about it. “Fukushima can’t get big enough to drive us to an evacuation,” Wren told Stars and Stripes after the town hall meeting.'""

To put this in more perspective, a lot of the families back in the US who were freaking out after watching the US press reports were freaking out the naval staff at the base, and the commander was trying to get people to listen to reason.

[D8beat]

Hmm, it seems you are right in the Japanese translation:

15 CPM = .15 μSv/hr

=> 90 CPM = .9 μSv/hr.

Misread it to mean 15 cpm = 1 μSv/hr

my apologies!

[David Cook]

To summarize the articles posted above (and this is corroborated by a relative who has worked in nuclear power safety for 40 years):
Zero possibility of an atomic bomb-like explosion.
Virtually zero possibility of a Chernobyl-like explosion due to the much better design of the reactor.
Steam being vented off contains isotopes that contain very low levels of radioactivity and decay within hours/days. Nothing to worry about unless you are standing right next to the reactor for a long period of time.
The chain reaction in the reactor stopped a few seconds after the initial quake once control rods were inserted, but some heat is still produces for a few days.
Plant operators are trying to cool the rods mainly for economic reasons. If the rods melt things will be harder for them to clean up, but the vessel is designed to contain the rods even if the melt.
In the unlikely even of the vessel rupturing (1% chance according to the expert in that Financial Times article) the worst that could happen is some contamination that would be restricted to a small local area of a few hundred metres of kilometers.

[mjr]

Is this false?

http://search.japantimes.co.jp/cgi-bin/nn20110315z2.html

[D8beat]

Just to share, I don't know if you have heard anything about a 400 mSv/hr dose. So far after combing the sources, the only mention I get was from IAEA:

http://www.iaea.org/newscenter/news/tsunamiupdate01.html

15/3 05:15 UTC
Dose rates of up to 400 millisievert per hour have been reported at the site.

and then a clarification at 11:15 UTC
As reported earlier, a 400 millisieverts (mSv) per hour radiation dose observed at Fukushima Daiichi occurred between units 3 and 4. This is a high dose-level value, but it is a local value at a single location and at a certain point in time.

[Ruby Deevoy]

"The people in the most danger are the workers inside the plant. By exposing themselves to higher than normal radiation levels, they are sacrificing their health to keep the rest of us safe, and are the unsung heroes of this potential crisis." - Yes! Finally someone has said it. Apart from they are sacrificing their LIVES, not just their immediate health. I've found it totally disgusting how these people are being un-named and unrecognised as heroes, just so that government and nuclear officials can continue to lie about the severity of this crisis.

[Mr. S.]

The sad thing about the workers exposing themselves for the sake of the greater good is that the wrong heroes are paying for the hubris of the amakudari bastards who got the kickbacks for the construction of these wrongheaded reactors, and have already died a comfortable death. Leaving Tokyo is likely an overreaction, but on the other hand, I have three weeks off and a wife and nine-month son. I have a flight: it's my prerogative to overreact.

[gullevek]

Thanks, I also used this in my rant on my blod about this whole mess in the foreign media.

[Chris B]

Thanks for this Matt. It should do a lot to calm nerves.

We are going to the grandparents in Nagoya for a little while. We had planned to go down next week anyway. We are not panicking.

I don't disagree with your facts or intention.

For me, this as an information flow/comprehension issue. The main reason we are leaving is because it is very hard to have/comprehend enough information to make informed decsions on a tight time schedule - I understand that the risks are low, but I don't trust that I can catch it in time if things change.

Today illustrated this.

I was watching the Geiger counter in Hino (near where we are) go up and up around noon. Then, later on I saw the measurements from the spike (Ryugo Hayano's graph). So, like most other people, we were watching the low radiation blow in as it was happening.... If it had been dangerous, we wouldn't have had time to do much.

It looks like it takes around 3.5 hours to reach Tokyo (with a un-favourable wind). Being out West past Tachikawa, and given the state of the public transport system there would not be enough time for us to get to safety, or go anywhere if anything happened (I agree that the probability of this is low).

There's really no reason we absolutely need to be in Tokyo (we have no family here, and work can be done online), so we will try to leave - 4 extra days added to spring holidays at grandma's should not be a problem.

Orderly and calm retreat from danger areas when you can sounds pretty good, compared to the mayhem that would occur in Tokyo if everyone tried to leave at once.

Cheers,

Chris

[Mr. S.]

I believe the relative authorities in Japan have made the likelihood of panic higher by holding to the old paradigm of, trying to, control information: it teaches the public not to trust anything they hear from authorities (not a bad idea). The Japanese need to start electing, and promoting in industry, people young enough to have used the Internet. Give people the whole truth, even when some of it is worrying, and they won't presume you are hiding something very bad.

[kevin hutt]

Some information and other links.

Quite encouraging despite the name of the site.

http://forums.somethingawful.com/showthread.php?threadid=3396817

[Andy Szymanski]

Last update for now.

NHK is running a special on the radiation levels in the Metropolitan area (shutoken).

As in my previous posts, levels across the board have lowered signigicantly.
Last measurement in Shinjuku was 0.08 microseivert/h.

They are also doing something very smart - showing people what these numbers mean in terms they can understand using a simple chart(i.e., compared to the exposure from a chest x-ray).

And to those who say don't trust the government: NHK also says that government information dissemination is lacking and they should be more proactive in determining policy.

[Ben]

One note - though I'm not an expert - you are right to point out that the radiation release in millisieverts, even at the plant, is not that threatening except to workers there, I believe the real threat to public health is the release of caesium-137 and iodine-121 - small amounts of these, if ingested, can cause serious long term effects. The radiation measures may give an indication of how much of these isotopes are passing by a given location - but I don't think they correlate fully. It seems important to know measurements of these isotopes in order to judge how serious the risk to public health in any region.

[try to help]

have a look here - there was a report in german tv, that some japanese people messure the radioactivity - and this is a live stream... take care - i pray for japan

http://www.ustream.tv/channel/geiger-counter-chiba

these are some more:

http://www.abovetopsecret.com/forum/thread674581/pg1

[Geek]

I have a geiger counter and I picked up 218cpm for over an hour as I was leaving the city. Levels tonight are still over 21cpm, over 2x normal. Still it's not dangerous but higher than reported.

[ML]

Info on most renown German News Magazine Der Spiegel - www.spiegel.de
Apparently Reactor 2 is not under control and radiation has increased to a level putting the 50 remaining workers there are risk for their health.
From this I deduct that there is a chance they will have to flee, leaving all the reators there without supervision or further interventions.

Follow the link below (German article though)

Whether or not Tokio is in Danger will depend on further development. If the reactors blow up - which cannot be denied for certain, it will mainly depend on the winds whether or not Tokio will be affected at all.

However - why take the risk?
A model calculation - numbers entirely made up, lacking any data - just to make a thought experiment.
If leaving the city for 10 days would cost you - say 10.000U$D and there is a 10% chance of massive impact on Tokio, statistics say, the expectancy cost for staying healthy is 100.000 U$D.
How much is it worth to you?

[ML]

to make it easier find the link
http://www.spiegel.de/wissenschaft/technik/0,1518,751020,00.html

[Matthew Grunewald]

I agree with all of this. In the current situation there is PROBABLY no reason to leave. That being said, has the hurricane past? On a good day in Tokyo you are sitting on a Ring of Fire... today, that ring of fire is smoking... I am not gonna look up the stats but I believe its something like a 70% chance of a 7.0 or higher in the next few days and the chance of major quakes in the next few days and weeks will remain high. What would a 7.0 do to those reactors or possibly a reactor that is closer to Tokyo? And if something does happen how do you get 30 million people out of Tokyo... you don't. If you leave you are safe, if you don't leave you might not be safe. I am from Florida and ignored hurricane warnings all the time and I am fine... The people in New Orleans ignored them and it all looked fine until a levee broke and than it was too late... I do not think Tokyo is in the clear yet as far as seeing another 'levee' break... Why take the risk if you do not have too especially when the situation is unclear. Take a two week vacation, get some R&R, evaluate the situation from a far... and head back when things are clear... there will always be other jobs.

[Dan S]

I think Chris got it right: "Orderly and calm retreat from danger areas when you can sounds pretty good, compared to the mayhem that would occur in Tokyo if everyone tried to leave at once."

Why taking chances? You can wait until you hear that something really bad happens, but then it's too late.

[k]

I get the feeling that ppl who say 'thank you I will stay' WANTED to hear that its safe to stay; a bit like preaching to the converted. None of us here are experts, but the fact that TEPCO has a history for coverups, the Fukushima plants are decades overdue for shut down, plus the potential afterquakes, are enough reason to get out while you can, only even if temporarily.

[JS]

Where is the post about the MOX FUEL?
Why are people avoiding that?
Tell me how is it safe? 4 Plants going into Melt Down...
MOX FUELLLLLLLLLLL

[JS]

GOOGLE MOX FUEL

[JS]

sorry for double post!

[JayJay]

Great article.
I created a comprehensive explanation on how to interpret radiation fluctuations according to live streaming geiger counters in Tokyo and Chiba and I also linked to this article.

https://www.facebook.com/note.php?note_id=205415829470134

[Markus Leach]

These articles go into detail about the spent fuel rods, which seem to pose the most serious threat....

http://www.nytimes.com/2011/03/15/world/asia/15fuel.html?_r=1&emc=eta1

http://ca.news.yahoo.com/japan-radiation-leaking-directly-air-iaea-20110315-013445-640.html

[dsf]

It's Sievert not Seivert

[Leonardo Boiko]

I agree, the current situation resembles a lot the thing about “frogs in boiling water”… which is a urban myth, no more than false information spread by rumors.

http://www.snopes.com/critters/wild/frogboil.asp

[malien]

Not sure really what this means, but CNN said most people are exposed to 2-3 milliservierts per year as normal background radiation. So 2 per hour would seem to be a lot.

[Bruce Lewis]

Don't panic: these radiation levels are low and not dangerous. Radiation at the levels reported in your area is well within normal limits in many areas. In the United States, adult workers in the nuclear industry may receive a whole body dose of up to 5000 milliSv per year, and you guys are getting much less than that.

(The sievert [Sv] is a unit measure of radiation dose -- that is, of how much energy is deposited in tissue per suit of time. It is equivalent to the old unit, the rem [1 r = .01 Sv]. Since physical effects like minor blood changes from radiation exposure are not expected until a person receives 25r or more in a short period of time, I'd say you're perfectly safe.)

Note: I am a former naval nuclear power worker. Although I flunked out of nuke school, I did work in a real nuclear power plant aboard ship.

[dottydo]

Think of the boiling frog.
Leap out and assess safety from a safe distance.
Muddling in a muddle doesn't say survivor.
Think.

[David Cook]

Useful Q&A on the BBC website about Fukushima.

http://www.bbc.co.uk/news/mobile/world-asia-pacific-12732015

[Prof David Cope]

Here in western Tokyo, on a family visit, I happen to have a rather accurate geiger counter with me - brought it along out of interest to measure the dose on the flights out and back over the arctic.

My readings confirm what you posted.

Normally, background levels here are about the same as in London, where I live - around 0.2 microsieverts/hour.

Around 11am yesterday I noticed this had risen to about 0.4 and then to 0.7 inside the house. Going into the street, I was getting 1.5.

This continued for about an hour and then subsided to normal background, where it is now.

None of these levels is any cause for concern, of course.

As this seems an informed blog area, I will post any future abnormal readings here.

Best to everyone involved.

[Roy Berman]

I've been continuing to post updates all night but need to sleep now.

http://www.mutantfrog.com/2011/03/15/radiation-safety-update/

[Prof David Cope]

Just a small point - it's important to be alert not to type m for 'micro' - I have done it in the past in haste. There's 3 orders of magnitude difference of course.

In the main, we are talking µsieverts/hr here, not msieverts.

You can get µ if you have num lock on by holding down alt key and typing zero-one-eight-one, as I have just done to type it at the start of this paragraph.

Just to update from this part of wesern Tokyo - radiation remains at normal background level.

All the best to everyone.

[Durf]

I know some people who are going, or at least sending their families farther away. All radiation concerns aside, if staying here puts them through a lot of stress, that isn't helpful to their physical or mental health, and should be taken into consideration as they decide what to do.

My family and I are staying put. Much more worried about continuing quakes than about Fukushima fallout.

[dave merrill]

Thanks for 'splainin' things in a clear and understandable fashion, Matt (and Andy). Stay safe!

[Terri MacMillan]

Thank you for this. I can't afford to leave, anyway, so I'm making the best of staying and doing things around the house and nearby. I'll be ready to help as I can when things are a bit more clear in Tohoku.

[MattAlt]

I think I managed to fix all of the misspellings of "sievert." Thanks for pointing that out.

[Miss Helenc]

The French, Swiss and German Embassies have advised their citizens to leave. The French Government have graded the severity of the nuclear situation at a level 6 (7 having only ever been given when Chernobyl went off in 1986). I'm getting good info from reuters btw.

I left Tokyo. Actually the reason was because I couldnt handle any more shaking. I didn't have room in my head to think about nuclear threats but they don't seem to be entirely in control. Life is too short to take risks in my opinion. Good luck guys.

[Steve Harrison]

Showing my ignorance, when did we switch from Rems to Seiverts?

All my charts and such are Cold War vintage.

[MattAlt]

Miss Helenc, what is your source of info about the embassies? Would like to read it for myself -- thanks in advance!

[Prof David Cope]

This is from the French embassy web site - and for those of you who can read French you will see that it talks about "dans l’hypothèse d’une aggravation importante de la situation" for the advice it gives, which is then to move to the "south" of the country, or to return to France, for those whose presence is not indispensable.

A titre préventif, mais aussi afin de faciliter la tâche des autorités japonaises, dans l’hypothèse d’une aggravation importante de la situation, un éloignement de Tokyo (et plus généralement des régions relativement proches de la centrale de Fukushima) vers le sud du pays, ou un retour en France est recommandé à tous ceux dont la présence n’est pas indispensable sur leur lieu de résidence et de travail.

[Benjamin Cole]

The Federation of Electric Power Companies of Japan (FEPC) Washington DC Office reported that at 10:22AM (JST) on March 15, a radiation level of 400 milli sievert per hour was recorded outside secondary containment building of the Unit 3 reactor at Fukushima Daiichi Nuclear Power Station.

http://lewis.armscontrolwonk.com/archive/3663/new-fepc-statement

An X-ray of your spine will give you a dose of 1.5 millisieverts. A CT scan of your stomach and pelvis will give you 15 millisieverts.

The amount reported by FEPC is 25 times those levels. The question of whether Tokyo sees high level of exposure is a valid one, but it is clear that the risk is much larger than your mention of 0.2 - 0.3 microsieverts in Tokyo or even 12 millisieverts at the front gate of the plant.

[MattAlt]

The reports of "millisevert level" radiation detected at the gate are in error. They were microsievert level. The spike is still not a good thing, but the level is MUCH smaller than originally announced.

[Keith]

http://finance.yahoo.com/news/Japan-abandons-stricken-nuke-apf-3314845701.html?x=0&sec=topStories&pos=main&asset=&ccode=

Japan suspended operations to prevent a stricken nuclear plant from melting down Wednesday after a surge in radiation made it too dangerous for workers to remain at the facility.

Chief Cabinet Secretary Yukio Edano said work on dousing reactors with water was disrupted by the need to withdraw.

The level of radiation at the plant surged to 1,000 millisieverts early Wednesday before coming down to 800-600 millisieverts. Still, that was far more than the average

"So the workers cannot carry out even minimal work at the plant now," Edano said. "Because of the radiation risk, we are on standby."

____________

Matt,
It seems conditions are not improving and since the heat causes more decay of the physical structure and fuel rod, the conditions seems to get progressively worse. There are two possibilities: it is improving or it is getting worse.

Using logic to decide to leave or not. Currently Tokyo does not have adequate supplies, resources, or energy to sustain its population. Resource have to be allocated to bring supplies in. These resources can be use at area closer to the damage area. The only way to decrease resource needed for Tokyo is to reduce its population. Thus leaving will help out the more damaged areas. Also if the situation gets worse, leaving now means there will be less people to evacuate later. Think of Katrina, if more people have left early, it would helped those who had to remain since they will have more resource and less people to rescue.

Now what happens if it improves. You have just taken a vacation or perhaps see some friends. If it doesn't improved, you have just helped out a lot of other people by not consuming valuable needed resource.

[MattAlt]

Your facts are in error. Those readings were in the MICRO sievert level, and the crews in fact remain on site.

If you have the means and desire to leave, I don't think anyone will fault you for doing so. But based on the news I am seeing, and I agree the situation at the plants remains quite serious, I see no NEED to evacuate. Everyone has their own decision to make here.