Sunday, September 23, 2012

(Now They Tell Us) 1,590 Microsieverts/Hr in Futaba-machi, #Fukushima on March 12, 2011, Before Reactor 1 Explosion, and Vent, Not Explosion, May Have Caused High Radiation

So says the Fukushima prefectural government, after more than one and a half year since the start of the Fukushima I Nuclear Power Plant accident. Supposedly, it took them all these days to analyze the data that was retrieved from the 19 monitoring posts around the two nuclear power plants (Fukushima I and II), and only now the prefectural government is sheepishly admitting the radiation levels were much, much higher than it has been telling the residents.

What's more, though the prefectural government doesn't say it explicitly, the spikes in radiation levels correlate not to the explosive events but the vents, if you look at the charts published by the Fukushima prefectural government.

First, from Asahi Shinbun Fukushima Edition (9/22/2012):


On September 21, Fukushima Prefecture announced the result of air radiation survey conducted in March last year around Fukushima I Nuclear Power Plant. The reading in Kamihatori in Futaba-machi, 5.6 kilometers northwest of the nuclear plant, was 1,590 microsieverts/hour, highest so far outside the plant as the prefectural government knows.


The result was compiled from the data from March 11 to 31 last year that remained in the 19 monitoring posts installed near the nuclear power plant. In Yamada in Futaba-machi, it was 1,020 microsieverts/hour at 12AM on March 16, 2011, and it was 904 microsieverts/hour at 5PM on March 12 in Shinzan, also in Futaba-machi.


According to Fukushima Prefecture, the monitoring posts in the north of Fukushima I Nuclear Power Plant started to register higher radiation levels in March 12, and the monitoring posts in the south of the plant in Naraha-machi and Hirono-machi in March 15.


In the case of Kamihatori, the maximum level was recorded at 3PM on March 12, before the hydrogen explosion at Reactor 1 at Fukushima I Nuclear Power Plant. According to the prefectural government, it was probably because "radioactive materials had been leaking even before the explosion". The prefectural government says it will conduct more detailed analysis including wind directions and wind speed.

Now, for Fukushima Prefecture to pretend this was new information (that the radiation had been leaking even before the Reactor 1 explosion), that's highly misleading. Fukushima Prefecture started measuring radiation levels in the areas surrounding the two nuclear power plants (Fukushima I and II) as early as 8AM on March 12, 2011. The first measurement that would have shown them that the radiation level was already several times higher than normal (0.04 - 0.06 microsievert/hour) was that of Tomioka-machi (Fukushima II) at 0.18 microsievert/hour at 8:25AM on March 12, 2012. At 8:52AM on the same day, they measured 14 microsieverts/hour in Namie-machi. Reactor 1 had a hydrogen explosion at 3:36PM.

(All of these were disclosed long time ago - June 3, 2011 - by NISA of all people, and no one in the media said a thing. If you read Japanese, see my Japanese blog.)

But what's more interesting about the latest disclosure by the Fukushima prefectural government is that the spikes in air radiation levels coincide not with the explosive events but with the vents that TEPCO did or attempted.

From the data released by the Fukushima prefectural government (I put the English labels):

Kamihatori, Futaba-machi: The first spike of radiation occurred even before the first vent of Reactor 1 on March 12, 2011. The huge spike to 1590 microsieverts/hour occurred at 3PM, after the vent at 10:17AM and after the pressure of the Reactor 1 Containment Vessel dropped at 2:30PM.

Kamiyatori is located northwest of Fukushima I Nuclear Power Plant. On March 12, 2011, the areas that registered high levels of radiation were all located north and northwest of the plant.

Then, after the vent of Reactor 2 on 12AM on March 15, 2011 (which was a dry vent), huge spikes in radiation were recorded in the areas in Okuma-machi, Tomioka-machi, and Naraha-machi, which were located south of the plant.

Mukaihata, Okuma-machi, immediate south of the plant. Spike at 11PM on March 14, 2011:

Yonomori, Tomioka-machi. Spike at 2AM on March 15, 2011:

Yamadaoka, Naraha-machi. Spike at 3AM on March 15, 2011:

The plume that went past Okuma, Tomioka, Naraha reached Kitaibaraki City in Ibaraki at 5:50AM on the same day, registering 5.5 microsieverts/hour. The Japanese media reported it, as possibly caused by the explosion of Reactor 2 (here's Sankei Shinbun on March 15, 2011), and no one understood the significance of the news at that time. Hardly anyone knew what "microsievert" was.

Well, it may not have been the explosion that caused the spikes. It is likely to have been the vent - intentional release of radioactive materials to lower pressure to avoid explosions. Well the explosions or some explosive event (in the case of Reactor 2) took place at Fukushima I Nuclear Power Plant after they did the vent. So what was the vent for?

That the vent, not the explosions, caused the radiation levels to rise has already been stated by none other than TEPCO in its report. Again, when the report was released, the media paid no attention, and people didn't care (other than the familiar refrain of "TEPCO lies").

A Tokyo University researcher stated in his paper accepted by a peer-reviewed magazine that a huge spike of radiation was registered at Fukushima I Nuclear Power Plant after the Reactor 2 dry vent. Again, no one paid attention.


Anonymous said...

They still don't know what happened, or even what's going on now, and they tell us it's safe. I wonder how often reactors vent like that and nobody notices~

"Hey! Decapitating yourself is undoubtedly safe! I've never tried it, but the chance of death occurring from decapitation is rare, because hardly anybody uses decapitation anymore! Statistics show that out of a million people, only 0.01% have died from decapitation during the past century! See! It's perfectly safe!"

Funny how hardly anyone knew what a microsievert was. That's why I think it's ridiculous how we're using so much technology that almost nobody understands the basics of. I knew, because I'd read about Chernobyl several years ago.

My mother had never even heard of the Chernobyl disaster. They certainly never mentioned it when I was in school! They did focus heavily on a specific world war 2 atrocity, though! But how is studying that going to help our society move forward into the future? Oh wait, it doesn't.

Anonymous said...

The vent was necessary cause they thought the containment could have exploded, not just been breached.

Anonymous said...

Yeah, I understand that. But it's clearly still not safe either way. It was only necessary because we're not spending enough time and money trying out less risky alternatives.

I was also suggesting that if other reactors anywhere were ever forced to vent to prevent an explosion, would they actually tell us that?

"We narrowly avoided an explosion by venting high radiation into the atmosphere!"

Can you seriously imagine them telling us that? I can't.

arevamirpal::laprimavera said...

So they said. They didn't bother to warn residents. Okuma-machi residents were almost all evacuated, but not residents of Futaba-machi and Namie-machi, the wind was blowing in their direction. I remember reading that the plant manager (Yoshida) thought everyone within 50 kilometer radius had been evacuated. Would have been nice.

Atomfritz said...

Thank you LaPrimavera for this again-excellent analysis!

Two things make me think much:
1. What actually caused the radiation increase before the crew finally did the emergency vent? What and where was the damage to the (supposedly) tight containment, which caused these releases before the venting?
2. Did the prefecture government really write "Reactor 4 fire"? If so, could this be interpreted as admitting that there has been a (luckily probably very limited) spent fuel fire?

Anonymous said...

Fukushima used to be such a beautiful place, steeped in Japanese tradition. That image was forever destroyed in March 2011.

Nuclear power did this.

Anonymous said...

Would be nice if everyone was truthful in general. If they came out and said, "here's the situation, these are the facts, and this is what we need to do", there'd be much less confusion and everyone would be much more organized.

They had the systems in place, which is all great in theory, but when push came to shove, they decided to bullshit their way through everything instead. Brilliant, huh?

There's no way the media would bother telling us everytime nuclear reactors have hiccups, even if they're serious or not. If they did, everyone would have a negative impression of nuclear tech.

Our understanding of the world around us is based on the information we receive. If we don't receive any information, we naturally prefer to be happy and assume that everything's safe and good.

Most people don't even realize they do this, and always act extremely confident - as if their understanding of the world is perfect and omnipotent. It's that arrogant, ignorant attitude that's going to get us into deeper and deeper shit.

arevamirpal::laprimavera said...

Atomfritz, re your first question, no one knows after 1.5 year. Fukushima Prefecture was measuring tellurium-132 in the morning on March 12, 2011 as far away as Namie-machi and Minami Soma City.

Fukushima Prefecture doesn't say the nature of the fire. No mention of SFP. Fire was near the northwest corner, I think.

Anonymous said...

If I remember right, Unit 2 was being vented with all possible outlets, at the time, then a strong aftershock struck and loud noises were heard from Unit 2's containment immediately thereafter.

Those large tall vent towers were not fully operationally, if at all, due to the blackout and venting the units was done from inside and into each buildings' floors (so called secondary containment).

Since Units 1 & 3 & 4 self vented by spectacular explosions, fallout is/was shared with the rest of the world. Unit 2 popped a wall panel and vented itself to the immediate localized area (Japan) when it's containment blew and shares its poisons via leaking into the Pacific Ocean, for sure.

No power to make for functional tower venting with their so called filters and scrubbers could have trapped some of the radioactive contamination and released hydrogen in a safe manner but that was not to be as (3) melting cores vented directly to the outside air or caused explosions including Unit 4's fuel pool boiling off.

Same with Three Mile Island, they had to vent melted fuel core radiation directly to outside air but they claim fallout was at low levels, this is absolutely not true.

Anonymous said...

and now you know why TEPCO HQ was extra-reluctant to proceed with the venting.

Anonymous said...

also, the question you pose is perhaps the most important of all:


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Anonymous said...

It's so ironic that while the world is collapsing around us and for all we know we may soon become extinct, idiots are working hard to spam everyone with consumer advertisements.

"Who cares if everyone dies! Buy my product so I can take your cash to heaven!"

Anonymous said...

I think the radiation was kept quiet because they don't want people thinking about all the other times reactors have vented in the past. The venting at Three Mile island was "well below regulatory concern" even though the radiation detection system was "knocked" offline before the venting.

Anonymous said...

Could it be that the earthquake damaged the piping connecting the RPV to the turbines and radioactive steam started leaking ahead of any venting?
In this case we would have had a major radiation release as a consequence of a degree 6 earthquake even the plant had not experienced a station blackout and a flooding.

Anonymous said...

Wasn't there some indication that Unit #1 failed due to the earthquake before the tsunami struck? I seem to remember an article on this blog pointing in that direction but it was so long ago I'm not sure.

Anonymous said...

The paper reported that workers said they had seen cooling-water pipes bursting as they were evacuating from the nuclear plant following the quake at 2.52 pm on 11 March – before the tsunami struck about 45 minutes later.

It also quoted nuclear engineers who concluded from data released by TEPCO that coolant systems must have failed shortly after the quake.

It wasn't the tsunami that caused the nuclear crisis at Fukushima No. 1 in March. According to The Japan Times' translation of an article in the December issue Sentaku Magazine, evidence is mounting the meltdown was caused by the earthquake and by the use of a U.S.-made reactor that was unable to withstand such an event. Here are the details.

* Mitsuhiko Tanaka, a journalist who formerly worked as an engineer on the pressure vessel at the plant, has said Tokyo Electric Power Co. is afraid that revealing the earthquake as the direct cause of the accident will force the government to review its quake-resistance standards completely, the article reported. This would delay resumption of existing nuclear power stations by years.

(see more details at link)

La terra non ha uscite di emergenza. said...

IRSN version. February 2012

Atomfritz said...

Thanks to LaPrimavera and LaTerra for the links!

Tellurium seems quite relevant in nuclear forensics, as it seems highly volatile at conditions to be expected in the molten Fuku reactors (according to [*]), even more than cesium.

The comparison with the IRSN estimate of 108 PBq of released tellurium-132 [see link of LaTerra above] (almost 3 megacurie!!) with the NISA estimate [**] of 760 TBq shows there is much uncertainty how much was released. IRSN's estimate is almost 150 times higher than NISA's estimate. And IRSN are _very_ probably no fearmongers.

As tellurium and its chemical compounds have an extraordinarily low boiling point (below 1000 degs C) it's quite clear that Tellurium is one of the first radioactive elements being dispersed in case of a developing nuclear meltdown.

When looking at Table 4 of the NISA document (FP release ratio) one can see that NISA expected about 10 times more tellurium release than cesium release. This might explain why at the very beginning there was found more tellurium than cesium.

And further, looking at Table 5 of [**], we notice that the reactor 1 Tellurium release was about 50 times higher than reactor 2 release, while reactor 3's Te-132 release was allegedly almost negligible.
So, according to NISA's estimate, about 97% of Tellurium-132 release originated from reactor 1 !!

Conveniently tellurium decays beta-wise, and so isn't easily detected by "normal" dosimeters. Iodine-131 did most of the gamma damage in the first weeks after the releases, and Tellurium was its quasi-counterpart in the "beta trade".

So, the tellurium findings together with the data that Fukushima prefecture government released demonstrate that the Fuku-I reactors leaked radioactivity into the environment long before the venting.

So I quote anon 12:28:

The sad answer seems to be "yes".

Could the damage leading to the releases even have been caused by the earthquake itself instead of the consequences of the station blackout?

This is a question the nuclear industry doesn't want to be asked, of course, because this would nullify their "assertion" that nuke plants are earthquake-safe.

So, let's all sing the shill song "It was only the tsunami!", as this saves us from thinking about what lessons to learn from the accident.

[*] :
[**] :

La terra non ha uscite di emergenza. said...

La terra non ha uscite di emergenza. said...

An inventory 3 Fukushima cores here. 257t, 3,7% enrichment. Medium 23GwD/t burnup.

Anonymous said...

Apart from pipes bursting there is also the flange at the top of the pressure vessel, which is designed to leak once the pressure goes over some limit.

Atomfritz said...

Thanks for pointing at this, anon 6:43.

This would mean the vapors would rise up the reactor pit, get around the big yellow cap and rise into the floor 5 room through the seams of the concrete reactor lid.

So we have always to keep in mind that actually the drywell "containment" is only partial, as there is no such "containment" in the upward direction.

All pictures showing the reactor enclosed by the drywell don't show this important detail, thus suuggesting the reactors are fully enclosed by the drywell.
This gives a (wrong) feeling of safety.

As we have seen strange and unexpected things like open equipment hatch doors and the like, it's still a mystery which release path was "used" by the early releases that occurred before venting. So the cause(s) could be even another thing that nobody yet anticipates.

A link of anon 8:06 (thanks) link to a very interesting Independent article talking of burst pipes and early release alarms:

arevamirpal::laprimavera said...

It could have been a broken pipe or two from the earthquake, it could have been the flange. But the post I've been trying to write is about the TEPCO teleconference video on the first 5 days, and if that's what actually transpired, I now think that the whole thing could have been completely avoided. Reactor 1 building may still have blown up, but core melt may not have happened in any of the reactors.

There are still so many things I want to write. Professor Hayakawa has been giving me a subtle pressure to translate his latest map. I wish there were 36 hours a day, so that I can write this blog, write my Japanese blog, and still have time to try to earn some money to keep roof above me and food on the table.

Anonymous said...

"Well below regulatory concern" just means "it's not for all you consumer peons to be concerned about."

Yeah, the strategy to keep everyone working so hard that they have no time to do anything else is clearly "working" (pun not intended).

Anonymous said...

What does translating prof. Hayakawa map entail? I might be able to help.

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