Fukushima Explosion Update: Core Presumed Intact As Sea Water Used To Bring Temperature Down, Radiation Level At 1015 Microsieverts/Hour

Tyler Durden's picture

The damage control to the Fukushima explosion reported earlier is coming fast and furious. According to CNN, "the explosion at an earthquake-damaged nuclear plant was not caused by
damage to the nuclear reactor but by a pumping system that failed as
crews tried to bring the reactor's temperature down, Chief Cabinet
Secretary Yukio Edano said Saturday. The next step for workers at the Fukushima Daiichi plant will be to
flood the reactor containment structure with sea water to bring the
reactor's temperature down to safe levels, he said. The effort is
expected to take two days." While the government is trying to play down the threat from the explosion, it has nonetheless double the evacuation zone radius from 10 to 20 kilometers: "Radiation levels have fallen since the explosion and there is no
immediate danger, Edano said. But authorities were nevertheless
expanding the evacuation to include a radius of 20 kilometers (about
12.5 miles) around the plant. The evacuation previously reached out to
10 kilometers." Next steps are to flood the reactor with salt water. NHK reports: "The
TEPCO Fukushima Daiichi nuclear power plant in Fukushima Prefecture is
believed to be exploded, and in order to prevent corruption, the
containment vessel will be filled with sea water to cool containers and
vehicles used by the SDF pump I. According to the Ministry of Defense,
work will begin at 8:00 pm, and that it expected to end around 1:00 am
on March 13 (or roughly 11 am Eastern)." And while containment efforts peak, the radiation level is reported to be in the range of 1015 microsieverts / hr. In the meantime, confusion in Japan is pervasive as up to a million people are without power. And while we hope the outcome of the Fukushima situation will be prompt and favorable, the economic devastation to the country will be pervasive for weeks to come.

CNN reports:

More damage control:

Radiation levels have fallen since the explosion and there is no immediate danger, Edano said. But authorities were nevertheless expanding the evacuation to include a radius of 20 kilometers (about 12.5 miles) around the plant. The evacuation previously reached out to 10 kilometers.

The explosion about 3:30 p.m. Saturday sent white smoke rising above the plant a day after a massive earthquake and tsunami crippled cooling systems at the plant in northeastern Japan. Four workers were injured in the blast.

The walls of a concrete building surrounding the reactor container collapsed, but the reactor and its containment system were not damaged in the explosion, Edano said.

Before Edano's announcement, Malcolm Grimston, associate fellow for energy, environment and development at London's Chatham House, said the explosion indicated that "it's clearly a serious situation, but that in itself does not necessarily mean major (nuclear) contamination."

Japanese public broadcaster NHK said the injured workers were in the process of cooling a nuclear reactor at the plant by injecting water into its core.

The Fukushima prefecture government said hourly radiation levels at the plant had reached levels allowable for ordinary people over the course of a year, Kyodo reported.

Earlier Saturday, Japan's nuclear agency said workers were continuing efforts to cool fuel rods at the plant after a small amount of radioactive material escaped into the air.

The agency said there was a strong possibility that the radioactive cesium monitors detected was from the melting of a fuel rod at the plant, adding that engineers were continuing to cool the fuel rods by pumping water around them.

Cesium is a byproduct of the nuclear fission process that occurs in nuclear plants.

A spokesman for Japan's Nuclear and Industrial Agency earlier said atomic material had seeped out of one of the five nuclear reactors at the Daiichi plant, located about 160 miles (260 kilometers) north of Tokyo.

"This is a situation that has the potential for a nuclear catastrophe. It's basically a race against time, because what has happened is that plant operators have not been able to cool down the core of at least two reactors," said Robert Alvarez, a senior scholar at the Institute for Policy Studies in Washington.

Alert.net quotes Chernobyl veterans who are scrambling to calm the public that this will not be a repeat of the Prypiat disaster:

Experts said pictures of mist above the plant suggested only small amounts of radiation had been expelled as part of measures to ensure its stability, far from the radioactive clouds that Chernobyl spewed out when it exploded in 1986.  

"The explosion at No. 1 generating set of the Fukushima nuclear plant in Japan, which took place today, will not be a repetition of the Chernobyl nuclear disaster," said Valeriy Hlyhalo, deputy director of the Chernobyl nuclear safety centre.  

He was quoted by Interfax news agency as saying Japanese reactors were better protected than Chernobyl, where just over 30 firefighters were killed in the explosion. The world's worst civilian nuclear disaster, Chernobyl has also been blamed for thousands of deaths due to radiation-linked illness.  

"Apart from that, these reactors are designed to work at a high seismicity zone, although what has happened is beyond the impact the plants were designed to withstand," Hlyhalo said.  

"Therefore, the consequences should not be as serious as after the Chernobyl nuclear disaster."   

We will continue following what appears to be nothing but a prolonged attempt at disaster spin as earthquake aftershocks continue.

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sharkbait's picture

This plant and the events thus far are nothing like Chernobyl.  Chernobyl was orders of magnitude worse.


Seasmoke's picture

worlds 3rd largest economy is coming to a stop for a long time

Turd Ferguson's picture

That they have been forced to use sea water shows that the backup diesel generators have failed. This is far from over. Pray.

AG BCN's picture

Don’t go all MC Hammer on us, focus Turd, we need ya

Careless Whisper's picture

and the discharged water is going... where?

OS2010's picture

I agree.  No matter what they do, this will not go away.

Cognitive Dissonance's picture

Sorry for grabbing a spot near the top but I thought these might interest ZH readers.

These are supposedly photos of Unit 1 after the explosion. Can't say if they are real so take them with a grain of salt. But compare them with the illustration of that type of reactor. Maybe the containment is still intact?

Though I seriously doubt the pipes and valves into and out of the reactor are undamaged after the explosion. I don't see the overhead crane in these pictures, which means it was either blasted away or more likely fell in onto the reactor.

New_Meat's picture

CD-good find and great cutaway of the Mk 1.  I doubt that the first two pix are of Daiichi-1 after the explosion.  Look more like secondary containment structure under construction.  Why?  The siding is so even and much higher than what I think I saw in the explosion video post explosion. 

The donutty thing at the bottom is the 'torus' that contains water to quench steam in the event of a reactor coolant system breach.  Reactor vessel in red.  Primary containment is the structure sorta' form-fitting around the vessel.  Steam comes out the top; rods inserted into the bottom.

- Ned

Spalding_Smailes's picture

They are showing the same pictures on the live broadcast now. A bit of twisted metal hanging in front .....

TBS News i Japan Live: TBS News i Japan Live

sushi's picture

In the second image we appear to be looking at the top of the steel containment vessel. If you count the floors on the cutaway with the floor immediately atop the torus as level 1 there are 4 floors plus a section of two heights of framework. In the photo images all the concrete associated with the top level floor is missing and we can see 3 segments of framework. So either the explosion removed a significant amount of concrete or you are correct and the photos are from the construction phase. A report elsewhere stated that one of the deaths was that of the overhead crane operator.

Cognitive Dissonance's picture

If you look at all the post explosion photos on the MSM they are all taken from a distance and you can't see the entire vertical height of the building, only the top third or fourth.

After studying high quality photos of all four buildings taken months or years before yesterday, you can see that the top third of the containment buildings all have a line about a third of the way down from the top that seems to demark a joint or connection. I wonder if these buildings were designed for the top to blow away in the even of a buildup of super heated gas, thus protecting the reactor itself to some degree.

Plus if you look closely at these photos, you will see much damage including debris hanging down and some of the steel structure is damaged, bent, twisted and a piece is missing at the top. The horizontal beam where the overhead crane runs on is missing or bent down near the top right. Plus the roof trusses aren't in place. They would never start siding the buildings until the roof was in place since the roof is an integral part of the structure.

Here is a better picture of Unit 1.

Second Photo appears to be after the tsunami in front of unit 4

Third photo is a high detail photo from a few years back.


davepowers's picture

thanks for posting this CG

there is a new TEPCO press release


This indicates something is going on a #2 and #3 as well. At least the status report is different than for #4-6.

Spalding_Smailes's picture

Now, all 3 live reactors are having problems ... The other 3 reactors were offline for maintenance ...



The emergency cooling system is no longer functioning at the No.3 reactor at Tokyo Electric Power Co's Fukushima Daiichi nuclear power facility, requiring the facility to urgently secure a means to supply water to the reactor, an official of the Japan Nuclear and Industrial Safety Agency told a news conference.

20 mins ago.


Also .......


"Because of its high "neutron flux" levels, the reactor pressure vessel can become embrittled and fail during accident conditions. A nuclear accident involving MOX fuel could cause a meltdown more serious than Three Mile Island or Chernobyl, because the levels of radiation inside a reactor using MOX are even higher than in a normal atomic reactor."


malikai's picture

Judging by the inflammatory language on the nirs site, I think this as a source of information is useless. If the language used was purely technical, you would not read sentences like this:

But using MOX as a fuel perpetuates the myth that plutonium is a commodity. Use of MOX would set up a reprocessing infrastructure that would allow continued use of plutonium as a fuel for centuries to come. Using plutonium in commercial reactors would be the first step toward the nuclear industry’s goal of recovering more plutonium from irradiated nuclear fuel by reprocessing. This option has been rejected time and again by the U.S. government as uneconomical, unsafe, and prone to nuclear weapon’s proliferation concerns, and so should be rejected again. NIX MOX!

One cannout count this as valid a source with such a strong political view on such a technical subject. Reading that site reminds me of reading Greenpeace circulars during the early 90s.

sushi's picture

Large schematic of this design plus elevation drawing.


There were other reports that on Unit #1 all the control rods were inserted except for 1 rod that did not insert properly. Is it likely that a single missing control rod would give rise to these problems?

New_Meat's picture

" Is it likely that a single missing control rod would give rise to these problems?"

No, part of the safety analysis that feeds back to the design.  One <anything> failing is part of the design.  Looks like the core shut down, then removal of decay heat is the next function to fulfill. They had (apparently) the emergency diesel generators working for like an hour until (unclear, the tsunami took them out?) the EDGs both failed.

Same happened at TMI-2, core shut down, decay heat rising, fubar the heat removal scheme.

- Ned

Cognitive Dissonance's picture


Both the cutaway above and this rough and crude schematic shows that the top fourth of the unit is clad with simple siding whereas the bottom three quarters show reinforced concrete. This would help explain only the top portion blowing away.

AUD's picture

Wouldn't the top of the building blowing off indicate that the reactor itself has exploded? Or if it was the 'pressure suppresion chamber' then the reactor would have taken the full force of the explosion anyhow? & probably disintegrated?

If there was any radioactive material in the core at the time it would now be everywhere else? No wonder radiation levels are down.



Ident 7777 economy's picture

Looking at the diagram above the path of egress for gases evolving from fuel rods in contact with the coolant in the Reactor Pressure vessel is:

1) up past the drywell head

2) into the Refueling cavity

3) and then up past the Concrete shield plug

4) into the area above the part labeled Reactor building



AUD's picture

But either way, whatever was in the 'lightbulb' shaped area, including the contents of the reactor vessel, is now part of the atmosphere?

Cognitive Dissonance's picture

The crude drawing doesn't begin to show the possible pathways to the top of the building nor does it show the vent locations for the reactor vessel. All we can surmise is that super heated hydrogen, once it is vented from the vessel, would attempt to rise to the top of the building.

Ident 7777 economy's picture

Just a question, CD, is your background engineering related; any work with drawings, schematics, technical sketches and the like? A number of us do this for a living (if one can call it a living at times!) and put a little more credance in a well-drawn info-packed sketch for its intended purpose of showing major delineated parts, chambers and enclosures, both sealed and unsealed etc ...

Just wondering.

Good job on getting some of these images/pictures together in one spot too.




Cognitive Dissonance's picture

There is no doubt that there are serious problems with the cooling of the reactor. The fact that the top of the building blew off doesn't mean the reactor itself also blew. In fact, the pressure release valves in the reactor vessel would probably let go long before the vessel or vessel top actually blew. That's not the real worry. The worry is an uncontrolled heat buildup with a subsequent melting of the rods which then breaches the bottom of containment eventually hitting ground water, then blowing by way of superheated steam.

What this most likely was was a hydrogen oxygen explosion from hydrogen produced as the fuel rod cladding broke down under extremely high temperatures of over 2000F. This is superheated hydrogen vented from the overheated reactor vessel into the containment building which would naturally try to flow to the top of the building where it mixes with the existing air/oxygen. At some point all it needed was an ignition source.

If the core itself was now scattered all over the site from the explosion the radiation readings would be through the roof and the authorities wouldn't be able to hide the fact for very long. And that picture of unit one with it's top blow off would never have been taken either.

AUD's picture

I dunno, that looked like a powerful explosion. Would the reactor vessel be designed to withstand that kind of force?

The top of the building looks like it was just cladding, doesn't look like the pressure would have been building up inside there, more likely under the concrete plug.

Cognitive Dissonance's picture

Nobody said pressure was building up in the top of the building. Just that hot hydrogen gas was flowing to the top of the building. Pressure inside the reactor vessel itself was vented into the containment building and the gas that was vented was steam, hydrogen and other gases. The hydrogen/oxygen mix was the explosive mix.

Have you ever seen the result of a gas leak explosion in a home or factory? Incredible force. It has nothing to do with pressure buildup at the top of the building, just a buildup of explosive gases. There doesn't need to be a buildup a pressure, just displacement or mixing of the existing air with the hydrogen. The explosion wasn't caused by pressure buildup, just explosive gas buildup.

fuu's picture

They were stating last night(CST) that the pressure inside the containment building was 2 times over the design limit. That would indicate to me that there was a lot of gas built up to explode when ignition occured.


I am curious, now that the containment building is broken is the hydrogen/oxygen just venting straight into the air?

New_Meat's picture

thx-and then no blast overpressure going down to primary cnmt. - Ned

Spalding_Smailes's picture


A new report released today in the Kremlin prepared for Prime Minister Putin by the Institute of Physics of the Earth, in Moscow, is warning that the America’s are in danger of suffering a mega-quake of catastrophic proportions during the next fortnight (14 days) with a specific emphasis being placed on the United States, Mexico, Central America and South American west coast regions along with the New Madrid Fault Zone region.



First quake almost 7 hours ago off the coast of California ...

Magnitude mb 4.3
Date time 2011-03-12 20:16:58.8 UTC

Magnitude mb 4.8
Date time 2011-03-12 17:54:27.0 UTC

Magnitude mb 5.3
Date time 2011-03-12 17:13:15.0 UTC)

Magnitude mb 5.4
Date time 2011-03-12 14:11:04.0 UTC

Magnitude mb 4.5
Date time 2011-03-12 12:03:42.0 UTC
Location 25.36 N ; 109.76 W

cossack55's picture

Gotta love Ken Ring.  BTW, I see a large disclaimer on www.spaceweather.com stating absolutely no relation between sunspots and earthquakes. 

Mr Lennon Hendrix's picture

It is the sun and the moon.  Tidal forces of nature, electro magnetism and even gravity affects us here on our tiny spaceship.

New_Meat's picture

infowarz has O taking over internet idz o' march 3/15 and endo' the world 5/21.  Let's see! - Ned

Spalding_Smailes's picture

Thanks C.C. .... Skepchick is a group of women (and one deserving guy) who write about science, skepticism, and pseudoscience.


A Conversation with My Dad, a Nuclear Engineer, about the Fukushima Daiichi Nuclear Power Plant Disaster in Japan


............... " My dad- Commander Mark L. Mervine, US Navy– is a nuclear expert who has worked on both nuclear submarines and nuclear power plants. I wanted to find out why my dad is so concerned about the Fukushima Daiichi power plant, so I called him up just a few minutes ago and recorded the call. I asked my dad all of the questions I had about the nuclear disaster. I hope this phone interview answers some of the questions you have. If you are at all concerned about the Fukushima Daiichi nuclear power plant disaster, you MUST listen to this conversation." .................


Podcast Link:

Interview with my dad


Blog Page:



dkny's picture

I wonder if these buildings were designed for the top to blow away in the even of a buildup of super heated gas, thus protecting the reactor itself to some degree.

My father, with experience in the chemical industry, mentioned that in that industry by design there are point of failures designed for the release of excessive pressure, as you don't want the energy to build up and then end up with a catastrophic release.

So, it probably blew up as it did by design.

Iam_Silverman's picture

Yup.  Those are blow out panels.  Designed to prevent excessive internal (seconday containment) pressure.  If I recall correctly, it is between 8 and 15 psid that they are designed to "pop".  I also recall them being chained so as not to become missile hazards.  Those panels appear to be gone - not hanging and swinging in the wind as a result of a passing tornado (been there, done that).

Cognitive Dissonance's picture

They did not pop. They were exploded horizontally for hundreds of feet. Watch the video. Worse, you can see some of the steel structure missing and blown away as well as the entire roof structure, truss system and all. Plus the overhead crane is gone, either up and away or more likely down.

Ident 7777 economy's picture

I'm not so sure the crane is gone; take a closer look at the track (it is there, well, both tracks since the crane needs two actual tracks, one on each side. Hint: First look at the sketch to get an  idea of the track position) and follow it to the right kinda - looks like it might be at the right, or far side (from us) of the track. Oh yeah; some experience interpreting photo recon info on this end as well ..

Cognitive Dissonance's picture

Take a look at the beam the crane runs on and follow it to the right. It suddenly dips down at an angle. And I do have schematic and mechanical drawing drafting and reading experience as well as architectural.

Kaiser Zose's picture

Ned - if the top of the Reactor Bldg was blown away...the spent fuel pool is now possibly exposed to atmosphere.  Who knows what the integrity of the pool is...this pool has to be kept cooled to avoid problems with the spent fuel...which is probably pretty full as its a 40 yr old Rx and I don't think they use dry cask storage.  It takes days to boil off the spent fuel pool and there's usually 20+ feet of water on top of the fuel.  Unlikely they have cooling to the pool.  That's easier to flood with seawater though - just dump a fire hose in and start filling with ocean water.  Corrosion problems later are the least of their concerns.

Spalding_Smailes's picture

Found this: Reactor Details

Daiichi, Plant No. 1

Daini, Plant No. 2

ColonelCooper's picture

Dude.  You're on fire today.  Don't know how you're keeping up with any of it.

New_Meat's picture

KZ, yep, 'cept I don't think the spent fuel is kept above the reactor.  Gets moved and as you say, one could put a garden hose (was done at Browns Ferry BWR during their fire/thang back when) to get water where needed.

Spent fuel gets moved to its own special swimming pool--like the one that madeline albright talked about w/DPRK reactors spent fuel.  Then, well, it sits until all of the energetic halfs be energetic.

And I agree--corrosion is nay concern since the puppy is a) skoshi MWe and b) at end of design life.  OK, I gotta' say this: "Death Panel has decided to Sacrifice Daiichi-1 unit for the economic benefit of TEPCO and the Japanese economy."

same-same gee-eye.

[ed. you can see refuelling tramway in sketch lower right hand corner-rectangular thingie]

- Ned

zhandax's picture

Ned, I lived about 30 miles from Brown's Ferry when they had their little 'Nuclear Disaster by Candlelight' (what they called it on the Huntsville news that night) and they did cool it with the equivalent of a garden hose (5/8" pipe).  This means my garden faucet could cool one of these reactors in a dire emergency and TEPCO can't even manage that at three separate cores.  I will wager there has been a whole lot of arguing in the boardroom the last 24 hours about trying to save the 'investment' as opposed to securing public safety.  The roof explosion forced them to defer to public safety on the first core, and if no better alternatives appear and no one in the boardroom looses their shit (better likelihood in Japan than in the US), they will probably turn the saltwater pumps on the other two.

Iam_Silverman's picture

"KZ, yep, 'cept I don't think the spent fuel is kept above the reactor."

At the two BWR's I worked at in the past (Brunswick/Hatch) the fuel pools were indeed located at the upper level of the secondary containment building.  That made refueling go much faster - no upenders and transfer tubes to worry with.  You used only one refueling platform from the reactor vessel, through the "cattle chute" and then to the SFP.

Kaiser Zose's picture

Yes the SFP is a bit above the Rx Vessel...someone posted a diagram of a GE BWR Mk I (?) Rx Bldg in this thread on p1 if i recall correctly.  It shows location of the SFP relative to the Rx and it is slightly above.  At least the top of the SFP is a bit above the Rx.  In refueling the Rx cavity is flooded to equalize level between the pool and and Rx to that the refueling machine can be used to move fuel between the two...So I think that the level of the top of the SFP is essentially open to atmosphere now.

Odd Ball's picture

Great photos, CD.  I would say that those after-the-blast images are the real thing.  They match exactly my speculations several hours ago about the crane bay blowing off.  The crane looks as though it is still there - parked at the far end.  It runs on the two heavier beams that don't match up with the framework of beams that supported the metal cladding.  In a post further below you can see remnants of the cladding on the roof of another building.