TEPCO Confirms Reactor 4 Spent Fuel Pool Is Now An Uncontrolled, Open Air Fission Process

Tyler Durden's picture

It had been a while since we had a factual update (as opposed to just lies and spin) from Fukushima. Courtesy of Kyodo, we now know that what was speculated by some as true, and rebutted by most as mere scaremongering, is in fact, fact. "Some of the spent nuclear fuel rods stored in the No. 4 reactor building
of the crisis-hit Fukushima Daiichi power plant were confirmed to be
damaged, but most of them are believed to be in sound condition, plant
operator Tokyo Electric Power Co. said Wednesday."
Naturally, in one month we will learn that most of them are damaged, and in two months, that each and every one has been demolished. "The firm known as TEPCO said its analysis of a 400-milliliter water
sample taken Tuesday from the No. 4 unit's spent nuclear fuel pool
revealed the damage to some fuel rods in such a pool for the first time,
as it detected higher-than-usual levels of radioactive iodine-131,
cesium-134 and cesium-137." These confirm an ongoing fission reaction. In a tremendously ironic development, the No. 4 reactor, halted for a regular inspection before last month's
earthquake and tsunami disaster, had all of its 1,331 spent fuel rods
and 204 unused fuel rods stored in the pool for the maintenance work. Unfortunately, the entire pool ended up being damaged following the quake and the subsequent explosion, in essence nullifying any protection that the containment dome would have provided. As the picture from the Asahi Shimbun below shows, the damage from overhanging structures which have subsequently fallen into the fuel pool likely means that there could well be an uncontrolled, if weak, fission reaction currently going on in the reactor 4 SFP (where the water temperature is currently 90 degrees) unprotected by the elements due to the complete destruction of the Reactor 4 shell.

(picture via of saposjoint)

More from Kyodo:

The cooling period for 548 of the 1,331 rods was shorter than that for others and the volume of decay heat emitted from the fuel in the No. 4 unit pool is larger compared with pools at other reactor buildings.

According to TEPCO, radioactive iodine-131 amounting to 220 becquerels per cubic centimeter, cesium-134 of 88 becquerels and cesium-137 of 93 becquerels were detected in the pool water. Those substances are generated by nuclear fission.

The government's Nuclear and Industrial Safety Agency said the confirmed radioactive materials were up to 100,000 times higher than normal but that the higher readings may have also been caused by the pouring of rainwater containing much radioactivity or particles of radiation-emitting rubble in the pool.

The roof and the upper walls of the No. 4 reactor building have been blown away by a hydrogen explosion and damaged by fires since the disaster struck the plant. The water level in the spent fuel pool is believed to have temporarily dropped.

In the meantime the latest drywell readiation reading in Reactor 1 is still "out of commission"

(Source: METI)

And lastly, a demonstration from Fairewinds' Arnie Gunderson who shows how the Zircalloy uranium pellets mostly likely melted and shattered, possibly penetrating through the floor of reactors 2 and 3.


Nuclear engineer Arnie Gundersen demonstrates how Fukushima's fuel rods melted and shattered from Fairewinds Associates on Vimeo.

(h/t Robert Breen)

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FilthyLucre's picture

I131 will increase your chances of thyroid cancer - but it has both a short radiological and biological half life so the exposure period is brief - unless of course the source is not contained and you are subjected to ongoing exposure. It is an alpha emitter and only causes localised cell damage.

Cs137 (and other Caesium isotopes) will increase your chances of all sorts cancers as it is deposited throughout the body - organs and muscles are the major places. It has a long half life and reasonably long biological half life - prussian blue can help to dispell it from the intestines but isn't a panacea. It is a gamma emitter and will cause cell and chromosone damage everywhere.

Sr90 (and other Strontium isotopes) will replace Calcium in your body and accumulate in your bones. It is a beta emitter and will damage bone marrow. It has a long biological and reasonably long radiological half life.

I131 and Cs137 can in no way be viewed as benign. The resolution rates for thyroid cancer are high, but do you really want to test this? The outcomes for the range of cancers caused by Cs137 not so good.

Isotopes of heavier elements such as Pu will not show the same rates of airborne dispersal as I131 and any heavy concentrations will likely be limited to local fallout. Dispersal of these heavier elements through the oceans should also be somewhat localised.

If you ingest a small amount of I131 which results in you developing thyroid cancer and your outcome is bad - ie you die. Then *your* world is pretty much fucked up. Its all about statistical outcomes - if you are the statistic, then you are dead.

americanspirit's picture

glow little glow worm, glimmer, glimmer

life is an incandescent shimmer

when you gotta glow, you gotta glow

So glow Fukushima, glow (and blow)

FunkyMonkeyBoy's picture

Does this have the same electric atmosphere as a good Open Air Concert? Can we expect a 5 minute solo?

Dr. Porkchop's picture

Better than Zeppelin!


Black Swan


Hey hey mama Fukushima blew,

Gonna make you dead, gonna make you puke....

Lord Welligton's picture

Oh Shit.

"TEPCO Confirms Reactor 4 Spent Fuel Pool Is Now An Uncontrolled"

So trav7777 will say this is not "bad" news.

We always knew this was the case.

Look at the facts. Then let me persuade you that you are safe.

It's what sociopaths do.

Ignore the headline.

Ignore the man behind the curtain.

Everything is oki doki.

We have the information.

Go back to sleep.

Stormdancer's picture

I can't find anywhere Tepco has "admitted" anything like 4's SFP becoming an "open air reactor".

They've apparently admitted damaged fuel rods...belatedly of course...that was pretty well established a long time ago.  But, that's a far cry from active, ongoing fission reactions. Damaged fuel rods and the threat of further overheating and burning down even more of the fuel rods is horrific in and of itself.  If SFP 4 does descend in to new instances of fission we'll know it....and quick.

This is plenty serious without the exaggeration.  You've been Sapo'd on this one Tyler.  Take the time to read around a bit in Ivar's forum/blog and you'll see what I mean.

Lord Welligton's picture

“I can't find anywhere Tepco has "admitted" anything like 4's SFP becoming an "open air reactor".”

I can’t find anywhere that Tyler said that.

What I find is that Tyler’s strapline was “Open Air Reaction”.

A difference in language.

Or perhaps you also think everything is oki doki.

Stormdancer's picture

No, I don't think everything is oki doki and I think the language in the title is pretty obvious....and obviously incorrect.

Striving for accuracy isn't minimizing. 

Bicycle Repairman's picture

"If SFP 4 does descend in to new instances of fission we'll know it....and quick."

How will we know?  A report from NHK or BBC?  Perhaps people's hair falling out?

Stormdancer's picture

No, the volumious column of smoke and steam rising above a completely evacuated complex will undeniably tell the tale.  There will be no way to hide it.

Bicycle Repairman's picture

Steam?  Is there still water in there?  Suppose there isn't?

Stormdancer's picture

Well, with all the lying to date I suppose that's possible.  But, it would mean Tepco's lying has ascended to a new level since they just claimed they pulled a 400 ml water sample from that pool.

And it's a moot point anyway.  If SFP 4 went critical the smoke would probably be quite substantial all by itself even if little steam was present.



Bicycle Repairman's picture

#1 went critical, I believe.  I don't remember a column of tall column of smoke arisimg from it.

Stormdancer's picture

Yes, and those instances of fission occurred inside substantially intact containment.  SFP's are a very different circumstance.

Bicycle Repairman's picture

"SFP's are a very different circumstance."

Agreed.  There is no containment for the SFPs.

slewie the pi-rat's picture

Stormdancer: sorry, but the fact that you can't find something or understand the poss nature(s)/amount of fission and the vaporization of the poisons, does not make tyler wrong.  people on zH have been commenting about the evidence of fission in #4 since the roof blew off.  really.  very tentatively, at first, with many people warning about jumping to conclusions, logically, given the "facts" as we knew them.

more and more, the evidence and facts pointed to fission.  and we still don't know exactly what kind, or why, but there is quite a bit of fission in 4.  i would say that your words:  "ongoing fission reactions" is the best description of the reality there, too. 

even tho you seem to believe only in the impossibility of same. 

keep with it, ok?  so will tyler & slewie.

Stormdancer's picture

You are privy to info I haven't seen.  There has been substantial evidence that something has gone critical in one of the loaded reactors.  I haven't seen any credible evidence of criticality in SFP 4.

There is a huge difference between burning fuel rods and criticality.  Either one is horrible.  More of both is possible.  But stick with the facts.

samsara's picture

I haven't seen any credible evidence of criticality in SFP 4.


The point is SD, that from the track record of the last month,  Many of us believe that MANY MANY will DIE withOUT Ever getting 'Credible Evidence"  that they are dying.

Radiation doesn't really really give a shit whether 'YOU' have credible evidence or not.


slewie the pi-rat's picture

well, again, i haven't seen you here too much for the last 4.5 weeks, either, but i might have missed your inputs, too, ok?   but, you're sure here, now!

you question me on the facts.  the facts are not in dipute, are they?  tyler and i agree that the SFP went zircalloy melt, and you say:  "There is a huge difference between burning fuel rods and criticality."  

basically, as i said, many here felt the same way about two weeks ago.  not any more.  tyler gives the correct data for what the hell is/was in that SFP #4.  it went melt.  and started to intermittently fission, quite briefly, non-sustainable, in the mess, but overall, quite a bit of small chain reactions. 

you're from missouri.  you can't believe that 2 + 2 =4, you actually must count it, or have someone else tell you this is objective.  i don't care.  tyler's thesis explains much more than yours, imo.  you want "facts" but what we are saying is look at that building.  there was NO fuel in the reactor core.  only in the SFP.  shit, man, think!!!

thanks for yer input, too!  peace.

Stormdancer's picture

You don't seem to be able to discern the difference between "going melt" and "going critical".  Which is fine.  It's a serious situation with plenty of potential for getting much more serious.

Again, there is substantial evidence indicating reactor 1 or 2 or both have gone critical since the whole thing started.  No evidence that I know of that SFP 4 has done so.

Reactor 2 has a blown torus...known for a good while now.  A "core on the floor" scenario is pretty likely in reactor 1 and quite possible for 2 or 3.

I wouldn't want to be anywhere in Japan right now because of the open ended nature of this thing.  Tokyo is going to be 24hrs away from disaster for a very long time depending on subsequent developments and wind direction.  Not a good place to be.

slewie the pi-rat's picture

well, perhaps i wasn't clear.  i don't want to seem like i don't understand something.  there's a shitload slewie doesn't understand.  what i do understand is this:  there was no coolant in this SFP for quite some time.  the cladding freaking melted.  the hydrogen explosion from the zircalloy melt blew the freaking building to smithereens.  then we started getting chain and criticality.  i may be totally fuking wrong.  happens more often than i'd care to admit, ok? but if you can't understand me, don't blame me, ok?

MSimon's picture

Assuming you are talking about the SFPs this is where you went wrong:

then we started getting chain and criticality.

The only criticality I would bet on is reactor #1. It is possible that any of the SFP could go critical. But at this point I don't think they have.

Let me add that stormdancer knows his nuclear. And thank you storm for the atta boy above.


MSimon's picture

Fission products are not evidence of CURRENT fission. Unless the half lives are on the order of a few hours or less. I have yet to read a report about I-131being evidence of fission in pool #4. The closest to that was the DIFFERENTIAL amounts of I-131 in reactor #1 vs #2 & #3.



mick_richfield's picture

I think there was a recriticality inside #1 last Thursday after the 7.2 earthquake.

Shortly after the earthquake, the radiation levels inside #1 exceeded 100 Sv / hr, and temperature rose.  Then the radiation sensor became unresponsive -- or they shut it off, or quit reporting on it for a while.

Then, on Saturday and Sunday, Cesium deposition rates in Ibaraki went from 10 or 20 Bq/m^2 per day to 400 on Saturday and 800 on Sunday -- before they dropped down again.


Ident 7777 economy's picture

Shortly after the earthquake, the radiation levels inside #1 exceeded 100 Sv / hr, 

- - - - - - - - - - - - - - - - -

Could be instrumentation failure too, due to other factors (broken wire(s), heat, radiation, saltwater), so, we don't have all the facts on this either ...

Some verification I would expect could be made from outside the building, e.g. a higher than normal reading up next to reactor bldg #1.


Stormdancer's picture

Evidence for recriticality in reactor 1 preceeded the 7.1 by quite a bit.  It seems more likely to me that the dramatic increase in reactor 1's drywell radiation levels probably coincided with the pressure vessel failing and dumping some part of a molten core into the drywell. 

Lord Welligton's picture

"I can't find anywhere Tepco has "admitted" anything"

Just about the most truthful thing.

Go back to sleep.

trav7777's picture

So trav7777 will say this is not "bad" news.

You idiot ass...I was the one, more than a week ago, who said that neutron beams and radionuclide emissions were likely from SFPs.  I said that.  Nobody else did.  Me.

If you construe that as my having said it was not bad news, then you are a fucking idiot.

I have maintained since day THREE that the danger here was not reactor cores; in fact I said LET THEM MELT DOWN, they cannot be saved.  Spend all efforts on mitigation of SFP rods because there is NO CONTAINMENT for them.

I would not be surprised if sporadic criticality was occurring in these ponds as a result of mechanical displacement of fuel elements plus inclusion of unborated water.

There is argument upthread about silly shit such as "proof."  No, this is not proof in the OP, it is EVIDENCE.  It is what I said 2 weeks ago, there is EVIDENCE of ongoing criticality here and there, xenon isotopes downpipe, Cl36.  If they find Cl36 in the water, there you go.

The heavier than expected isotope concentration is evidence of there having been sporadic criticality at some point.  News flash- these events are the accidents which KILL plant workers.  Not exposures, not leaks, but criticality accidents due to moving some shit too close to other shit.

The premise is that SFPs have undergone some criticality during the aftermath.  It is not dispositive; there is no proof.  It is only a theory that tends to fit the facts.

slewie the pi-rat's picture

well, we did go balls to the wall about this shit, for days, here, it seems.  and there was a lot of very interesting stuff being shared.  yes, trav said that about the SFP's but others went into that, too.  almost a dozen, probably, certainly a half-dozen, easily.  what the hell?  can these SFP's be going critical or not.  theoretically, yes!  and, there are clues around, as you say.  arnie goes into this @ fairewinds.  shit!  no two people on earth see this the same way, as far as i can tell.  so what?  tell it like ya see it, and invite others to do the same.

Seasmoke's picture

water seems to be perfect for a bubble bath....

Abitdodgie's picture

Does this mean my electric bill is going to go up?

Bicycle Repairman's picture

Yes.  This is your fault.  You wanted electricity so you could play your "electric twanger".  Now you'll have to pay.

sangell's picture

A month into this thing and they still have no idea what the inside of that plant even looks like much less a method to remove and secure those spent fuel rods, if that can even be done.

Then they've got a dozen or so other reactors in the quake damaged zone. Just what surprises will those units unleash when they are brought back on line. I assume they are going to be brought back on line for the summer otherwise Honshu is going to be doing rolling blackouts forever.

hardcleareye's picture

It is going to be very difficult if at all possible to put the monster back in the pen, looks like they are working on it.


TOKYO, April 8 (Xinhua) -- Toshiba Corp. submitted a proposal to Tokyo Electric Power Co. (TEPCO) and the Ministry of Economy, Trade and Industry (METI) to decommission four troubled reactors at the Fukushima Daiichi nuclear power plant, local media reports said Friday.

The proposal filed by TEPCO and METI was drafted with the assistance of nuclear experts from Toshiba's Westinghouse Electric Co, Babcock & Wilcox Co. and Shaw Group, who gained invaluable knowledge from the cleanup following the Three Mile Island nuclear crisis in 1979.

According to sources close to the mater, the proposal sets out to level damaged buildings and structures at the Fukushima Daiichi complex without causing any more contamination to leak and will utilize robots to remove radioactive rubble caused by hydrogen explosions and the earthquake and tsunami that pounded the facility on March 11.

The proposal, which states it will take around 10 years to remove contained nuclear fuel rods and spent rods in storage pools from the four reactors, will be revised and updated as needs dictate, the consortium said.

They also said work would be undertaken to improve the condition of soil contaminated by radiation leaks.

TEPCO and METI will also look at a proposal to be submitted by Hitachi Ltd., which plans to liaise with General Electric Co., Bechtel Corp. and other utility firms and nuclear experts in a rival bid to decommission the the four reactors.

Bicycle Repairman's picture

"They also said work would be undertaken to improve the condition of soil contaminated by radiation leaks."

Do you think they will use some kind of Pu vacuum cleaner to do this?  Maybe Oreck makes one?

Plumplechook's picture

Just in on NHK - temp in reactor 4 SFP now up to 90 degrees celcisus:


The Tokyo Electric Power Company, or TEPCO, says the water temperature in the spent fuel storage pool at the No. 4 reactor in the crippled Fukushima nuclear plant has risen to about 90 degrees Celsius. It fears the spent fuel rods may be damaged.

TEPCO took the temperature on Tuesday using an extending arm on a special vehicle. It found the temperature was much higher than the normal level of under 40 degrees.

To cool the fuel, TEPCO sprayed 195 tons of water for 6 hours on Wednesday morning.

The company thinks the pool's water level was about 5 meters lower than normal, but 2 meters above the fuel rods.

TEPCO believes the water level is likely to rise by about one meter after the water spraying on Wednesday.

The company also believes temperatures rose after the loss of the reactor's cooling system.

TEPCO says high levels of radiation at 84 millisieverts per hour were detected above the water surface, where radiation is rarely detected.

The company plans to continue spraying and to analyze radioactive particles in the pool to determine whether the fuel has been damaged.

The storage pool at the No. 4 reactor has housed all the fuel rods that were in operation at the reactor due to massive engineering work there.

TEPCO has sprayed more than 1,800 tons of water on the No. 4 reactor using fire engines and special vehicles since the March 11th crisis. The company feared that fuel rods could cause evaporation of water and put workers at risk of exposure.

University of Tokyo Professor Koji Okamoto says the temperature of 90 degrees indicates that cooling is continuing, although some of the water in the pool may be boiling.

Okamoto says high radiation indicates the possibility of radiation leaks from damaged fuel, and called for the evaluation of water sampling to determine how the situation should be tackled.

The professor says that to prevent further damage to the fuel, it's important to continue cooling the pool while minimizing water leakage from it.



Bicycle Repairman's picture

Thanks for the information.  Just curious, how far do you think the Pu these reactors are spewing can travel? Fukushima? Tokyo?  Jet stream?

Thanks in advance.

divide_by_zero's picture

A link to the Berkley Nuclear Monitoring site, under teh air sampling apparatus they use a Rigid brand industrial vacuum for air filter sampling



Bicycle Repairman's picture

If we rely on testing from a nuclear engineering school, and the results of their tests may eliminate the need for the school, what will the quality of the testing be?

wisefool's picture

-Henry Ford. But engineers know going in they are expected to be peer reviewed like Doctors, even without the pay. So the majority are going to tell the truth even if that means they ending up a draftsman for a plumber putting bidet in a glass tower for an investment banker at goldman sachs. Those dudes make even more money than doctors and get peer reviewed by former GS employees who work at the FDIC, SEC, Treasury and IRS.

Somebody should actually go dig up Mr. Ford and put him on the investigation into the financial collapse. Another one of his famous quotes was "no problem is exceedingly difficult if you break it up into smaller peices" I.E. Who made money from both the run up and collapse? What was thier part? 

divide_by_zero's picture

This isn't some bullshit like the existence of AGW, the radiation and it's efects exist and will require study either way; cleanup or creation.

avonaltendorf's picture

Unit #4 spent fuel is the least worrisome problem at Fukushima Daiichi. #1 is running hotter, no longer being monitored or data being hidden. No access to #2 and leaking radioactive water as fast as they pump it in. #3 was the MOX core, almost certainly a puddle of corium that breached the pressurized steel vessel (my guess).

The proposal to demolish the containment buildings without additional release of radioactivity is complete bullshit.

tortola trader's picture

Al`Gore(bechev)???  Why, I believe he's busy getting a massage right now....

LostWages's picture

Unlike Gore's massage, this story does not have a happy ending.

Misean's picture

So, what has been confirmed? That the author believes that some information released by TEPCO proves a suspision the author has? That's it then?!?

Nice headline though...


Bicycle Repairman's picture

"The firm known as TEPCO said its analysis of a 400-milliliter water sample taken Tuesday from the No. 4 unit's spent nuclear fuel pool revealed the damage to some fuel rods in such a pool for the first time, as it detected higher-than-usual levels of radioactive iodine-131, cesium-134 and cesium-137." These confirm an ongoing fission reaction.

Did you read that part of the article?  Do you think it indicates something else?  How do you feel about the detection of abnormal levels of radiation in children's milk here in the USA?

MSimon's picture

Go to the top an read my critique. None of those isotopes is evidence of a current criticality AT THIS TIME. 

If we see I-131 two months from now that would be evidence. Or I-134 now -  which has a half life on the order of an hour.

Bicycle Repairman's picture

Any thoughts on the isotopes present in American children's milk?

Stormdancer's picture

Umm....it's not a good thing? :)