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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trav7777's picture

I cannot concur.  Far higher than normal levels of these isotopes are evidence.  They are not proof, nor are they conclusive.  They are merely evidence.

If there are stray neutron emissions, I would not wager these came from reactors that are in containers intended to provide neutron shielding (otherwise the things would kill everybody nearby).

I think "ongoing fission" is a gross misnomer.  There is at most sporadic fission in the nature of the types of criticality accidents which have periodically killed nuke plant workers over the years.  If the rods have been moved too close to one another and unborated water is introduced to the pile, fission is certainly not unexpected.  It happens sometimes even in the NORMAL mode of operation of these pools.

If you intend to say that these isotopes provide no evidence of "ongoing" or "current" fission, then I agree. 

Element's picture

If you intend to say that these isotopes provide no evidence of "ongoing" or "current" fission, then I agree

ah Trav, now you're engaging in binary thinking here.

Fission is not on or off, it's all about the concentration, not just the distance, or geometry, or transient enegy level.

As I expect you know, natural reactors have formed where natural uranium oxide ore was at a high enough deposition comcentration that it self-reacted and swapped neutrons for hundreds or thousands of years, and created significant natural plutonium in the process. (google Oklo reactor)

Recriticality is just the extreme-end of a spectrum of fission potentil that's occurring continuously if you have several tons homogenised in melt and poor moderation.

A hot highly homogenised melt of corium and concrete WILL still fission and make more heat above existing daughter product decay and activation decay. Every flash just activates more.

The danger is a system that is just dilute enough to not have recriticality states (much) but just sits there decaying AND making new daughter products, and thermal vibes, for years ... Like BWR foundation will provide.

If it's thermally insulated you have a big problem brewing because it can remobilise anytime water is re-introduced. If you keep flooding it indefinitely you get poisoned anyway.


MSimon's picture

It is the WATER in the reactors that does the shielding. No water (it only takes abouth 4 to 6 inches to do the job) between you and the neutron source, no shielding.

And yes recriticality has been intermittent. I would expect that from a pile of junk.

As you point out there is no conclusive evidence. So you may be correct. But at this point I doubt it. The only criticality I'd bet on is reactor #1 which appears to have core on the floor of a largely intact containment structure. I believe the reactor vessel there has melted through. With the top of the vessel (the cap) intact. That is indicated by the fact that it can hold some pressure (on the order of 100 psia).

Spalding_Smailes's picture

Fukushima nuclear power plant accident. Farms in the range of 10 kilometers 

Video link •

 Many cattle are dying ...


andybev01's picture

If those cattle are dying of starvation what does that tell you about the displaced people, and where is that video?

A sick and strange situation.

HK's picture

Are they dying of starvation or radiation?

CitizenPete's picture

lack of water - dehydated - systems shut down

Isotope's picture

Most likely dying of dehydration.

Lord Welligton's picture

The cattle are dead.

No farmer would have left them caged.

The farmer is dead.

wisefool's picture

agreed. But they are also probably irradiated. Or the butcher is dead too.

bob_dabolina's picture


Not gona lie, that is kinda' scary.

But it's ok John Paulson said this is bullish for Japan because they will rebuild the area.

For shits and giggles someone send that link to PETA

Lord Welligton's picture

Those cattle are not sleeping.

They are dead.

The cattle farmer did not leave his farm and leave the beast enclosed.

The cattle farmer is dead.

Bicycle Repairman's picture

Those cattle are not dead.

They are resting or perhaps they are stunned. Japanese cattle are known for taking a long nap after shagging.

They are prodigious shaggers.

The Profit Prophet's picture

Agree...you can clearly see more than one of them having a smoke. 

CitizenPete's picture

FUCK. what a waste

what a disaster 

Landrew's picture

When I saw isotopes other than Iodine I knew they had a core breach. I wonder why the Japanese government (heck the world) allowed the company to try and save the reactor complex for use? I would have buried all the cores and storage pools. Of course hindsight makes me a genius most of the time. The whole world will suffer now with the loss of nuclear power. Friends of mine at Muon's Inc. have been working on a Thorium reactor proposal a more than two years with little face time from DOE. Do you think they will answer the call now ha!

Carlo Rubia was a very very bright guy and I think his muon catalyzed thorium reactor theory, that Chinese are building could be one of the great tools of the world ever.

Bicycle Repairman's picture

"I wonder why the Japanese government (heck the world) allowed the company to try and save the reactor complex for use? "

If this is true, it has not been emphasized enough.  This explains the stalling and the rest of the f#cking kabuki theater.  While people all over the world are being threatened and the Japanese people will be getting cancer, TEPCO is trying to save their investment.  Are you sh!tting me????

SparkyvonBellagio's picture

Those notes in Japanese read:



slewie the pi-rat's picture

well, pretty much this exact scenario and reasoning was inducted here, quite a while ago.  apparently, the earthquake cracked the spent fuel pool with all the spent and unused fuel rods.  no coolant.  no way to contain any hosed stuff.  cladding melt = H2 (hydrogen gas) explosion, blowing the living shit outa the top pf the building.

estimates of 5000 degree C.  temps.  reliable?  i can't prove it!

the chain reaction/nuclear fission was thought to be intermittent.  now, it is, perhaps intermittent in about 5 places in this mess, at once, and therefore "ongoing".  or, ironically, perhaps they hosed in boron water, which could, conceivably, have slowed the neutron escape and helped the mess to go critical.  don't know, but both ideas have come from sources which i now trust.

are they saying they repaired the SFP in 4?  or that it always held coolant?  and now, it's almost hot enuf in there to boil water?  really?   look at this place!  multiples of the Ce-137 vaporized in chernobyl!  2-3 X, at least!  90 degrees C.?  well!  isn't that special???

maybe others will chime in and help with the thinking.

recently there has been some renewed zH concern about reactors #s 5 & 6, also without coolant for long enuf to get more problematic than publicly acknowledged, even tho not producing electricity on 3.11.11.  "shut down".  and full of fuel and spent fuel,  needing to be cooled, and not having that need met.  the temps and damage go up pretty fast when the coolant goes awol.  see what they say, next. 

MSimon's picture

I haven't seen any evidence of current criticality at the SFPs. The last decent evidence was for intermittent criticality at #1.

It is bad enough. Which is very bad indeed. No need to make it worse without evidence.


slewie the pi-rat's picture

i understand your background and your innocent need for more evidence.  we've had many such posters, here, for over a month.  there are very few left, btw.  please excuse me if i'm wrong and just making this all worse than it really is, ok? 

if you've read the posts, here, over that time, good!  if not, please visit them.  you'll see some great interaction and interesting approaches to this enigma, in a riddle, with almost no one speaking the truth, ever.  here, again, we have a page with absolutely conflicting info put out by Tepco about #4.  same shit, different day.  the japanese are masters at propaganda and subtle clues about how to behave, and this had been happening, time after time, for over a month. 

if the information and the processes which lead to what tyler is saying and what slewie is saying do not meet your criteria for evidence, thank you for stating it so clearly.  that is fine with me.  please go back and review the articles and posts for the last month, if you haven't already.  you might understand the "circumstances" a bit more like me, if you do so.  i've already read them, and i haven't been shy about what i've been thinking, either.  neither has tyler.  also quite  a few others.  we have a permanent record of everything said, here.  enjoy!

MSimon's picture

I have been here since the beginning. Not all the threads. But most of them. I'm a newbie at ZH (18 weeks or so as a poster).

I must say that even with the hysteria of some of the commenters that this is the best major site for news. Tyler (even if his understanding is incomplete) breaks the news fast. And the links in the comments are outstanding.

slewie the pi-rat's picture

ok.  i've seen you around.  working hard, here, too, ok?  be careful with the labels, if you would, pls.  an honest diff of opinion or POV does not = hysteria.  #4 is totally fuked, imo.  no fuel in core!  the buiding blew up b/c of the SFP.  sorry if ya don't like the way that sounds, it's true!

HedgeCock's picture

 "an honest diff of opinion or POV does not = hysteria."

Right you are slewie.  I'm getting sick of reading that word.  It is not "hysteria" to worry about the still living and not wait to cry over the dead.  

etudiant's picture

Have to say, this does not seem such a negative bit of info.

Bad news, the fuel rods are damaged. Of course, given the previous hydrogen fires and explosions, that was already known.
Good news, there is enough water in the pool to cover the fuel rods remaining. The water may be radioactive and overheated, at around 90 degrees C, but it indicates the pool is still largely intact.
So the problem likely is a pile of fuel pellets from the damaged fuel rods, collected in a heap at the bottom of the pool, overheating each other rather than getting cooled by circulating water.
Relatively speaking, that still makes pool 4 one of the safer sites in the plant. It is spitting a bit of iodine and cesium, but it is manageable with periodic water injections.

The pool is 4000 ton capacity, the daily water injection is about 200 tons, so it is staying pretty tight.

Bicycle Repairman's picture

How much damage do you think these 6 reactors will cause during the 30 years it will take to decommission them?  What do you think will happen if there is an earthquake and/or tsunami during that period?  How long do you think it will be before the excluded zone can be repopulated?

Thanks in advance.

slewie the pi-rat's picture

damage over 30 years? 7X chernobyl.  75 years for about 100 kilometers.  just guessing. 

there is an enormous amount of spent fuel which had been removed from the pools inside the reactor buildings.  there is a separate building, somewhere @ fuk_u, with spent fuel pools, probably 2, and everything is just hunky-dory, with every bit of it, of course. 

yeah.  wanna buy a bridge?  no evidence.  about 3 sentences, that i've seen, whatever that's worth.  when the first people re-conned the site, their was a "windows in outside storage building out" little blurb. 

The End.

MSimon's picture

When the monsoons shift there is a decent chance the radioactives could take out parts of Tokyo.

slewie the pi-rat's picture

well, i certainly would agree that it's gonna be bad news bears from the fallout.  many posts here following weather over the weeks, with a couple shifts putting tokyo downwind, already.  i think (not positive) in the days immediately after the 11th, tokyo was getting it pretty good. 

topcallingtroll's picture

A slow iodine leak that never stops is a big problem.

MSimon's picture

Natural decay will take care of I-131 in about 80 days. If there is no new criticality.

 It is the longer lived stuff that is the bigger problem.

slewie the pi-rat's picture

agreed. in cali, people are advised to let the milk sit till near the use by date to allow for I decay if they are worried. 

Bicycle Repairman's picture

Milk turns rancid before 80 days.  What should I do about cesium?

slewie the pi-rat's picture

w/ a 1/2-life of 24 years, that's what's bothering me, too!  like mercury, this stuff may be concentrated by the food chain(s).  not good!  i'm 65.  my kids are over 30.  my dad's 93.  he just outlived his dad, my grampa!  i'd like to see if i could make 93 myself!  this sure doen't give me extra confidence, but i'm not dead, yet, either! 

digalert's picture

Tomorrow Obama announces that the ceiling on debt and acceptable radiation will be raised as high as needed.

Barb Dwire's picture

I'm still surprised that none of the media has brought up the story of Jimmy Carter who commanded the team that help shutdown the runaway Chalk River reactor in the 50's.

Zero Govt's picture

the BBC (Bent Broadcasting Corporation) rolled out an 'expert' (crone) yesterday to say how under control Fukushima was and how "effective the response has been".

The response of Tepco and the Japanese Govt has been little short of a complete clown show who have not a fuking clue what to do one day after the other. Pissing on a melting nuclear reactor with a fire engine is not an "effective response", it's a desperate act to make it look like you're doing something when in fact you're all out of options

The bent rotten scum of the BBC continue their propaganda clearing house operations on behalf of Govts worldwide... fuk the fuking BBC

Jack Burton's picture

 I spent many decades using the old BBC as a touchstone to go to for news. As much as to use an old shortwave radio back in the technology stone age of the early 80s.

But NOW!  The BBC has become a voice of the corporate elite and the British intelligence community. They are whores made all the worse by their about face from honest news brokers to complete whore of the establishment.

I don't listen to a thing these ass clowns say. It is propaganda. They show their true colors by these useful idiots they trot out to tell us all is well at Fukushima.

toxic8's picture

I find the BBC to be an ass hair better than random MSM news here in the USA. At least, they have pretty pictures.

HedgeFundLIVE's picture

no story out on zerohedge yet about Goldman Sachs after the close here.  but we've been calling that obama will have at it with wall street again really soon.  guess it's happening.  smells like april 2010: http://www.hedgefundlive.com/blog/thursday-market-expectations-jamie-dimon-gave-us-a-hint-today

topcallingtroll's picture

Milk in little rock arkansas had the highest levels of radioactive iodine of all samples tested.

Three times the limit allowed for drinking water but under the limit allowed for milk which makes no sense to me. You can find this information online about U.S. government testing and results, but not a single newspaper in arkansas mentioned it.

I havent bought a newspaper in five years. They are worthless. Cover that pool you fucking slants! Radioactive iodine is a gas.

Aristarchan's picture

The info for milk contamination that is being misrepresented on some blogs is way wrong...the misinterpretation at least. Some of them are mixing up the water limits for milk limits (people intake more water over a lifetime than milk), and some are taking the numbers (24 pCi/L of Cesium in Hilo) as being above the limit. It is not. The FDA sets the intervention levels on milk, and they are set at 33,000 pCi/L Cesium (Cs-134 + Cs-137) for milk.

majia's picture

I've spent an hour and a half on the EPA webpage (and EPA reports) trying to find where it is stated that the exposure rates are based on lifetime estimates. Nowhere did I find this stated. Please provide me the link.

What I did find were statements like the one pasted below that do affirm that long-term exposure is factored into the risk models. However, the limits set for milk and water are not clearly delineated as based on any temporal frame. I'm still searching and will post what I find and would appreciate any links anyone else has found:

EPA: "Next we use mathematical models to evaluate potential solutions.

"The long lifetimes of many radionuclides,and the complex decay chains, means that in some cases, we have to project potential exposures for hundreds to thousands of years into the future. To make the extremely complex calculations that tell us what is likely to happen to radionuclides in the environment (potentially far into the future), we develop computerized, mathematical models. They take into account many factors:

·         decay rates of the radionuclides initially present

·         the behavior of these radionuclides in the environment

·         decay chain products, their decay rates, and their behavior in the environment

·         the type of environment (air, water, rock formations).



On another note, Arnie Gunderson has a new update and adds fuel to the debate about low-dose radiation by arguing that there significant health effects from TMI.


Aristarchan's picture

Here are some links I sent out earlier on twitter:




The EPA sets lifetime standards for radioactivity via human consumption, based on cumulative data and estimated consumption of a product (water consumption being much higher than milk). The most important standard is the FDA one, which is the single exposure limit (intervention limit) for a product. Also, one of these links is a Hawaii newspaper article that quotes EPA, one is EPA, the other is FDA.

majia's picture

Ok I checked the links. Water is based on lifespan exposure. No time frames are available for air or milk, just your FDA Intervention Level for diet and milk.

I also found a lot of criticism of EPA standards.

I'm interested in how do you respond to the following charges:

1. there is no safe level of iodonizing radiation (because of the damaging effects on DNA repairs). Tons of research on this plus the impact on pregnant bodies, embryos, susceptible individuals etc.

2. The EPA and NRC standards are based on the ICRP approach, which does not address the effects of internal emitters and assumes "energy is averaged across the whole body or a whole organ."

The alternative to ICRP.
ECRR's 19th March 2011 advice note on Fukushima - the European Committee on Radiation Risk

TrueSkeptic's picture

The short answer is that the nuclear industry, and therefore governments, don't really want clear actionable limits that an average citizen could understand and that are regularly checked and publicly disclosed.

You have to do your own research to educate yourself.  If you don't have a related background it will take a day of reading to understand the different measurement systems (becquerals, pico curies, sieverts, millisievers, microsieverts, Rads, etc), the type of radiation, rate of dose or accumulated dose, an internal (consumed or inhaled) or external emitter, etc.   ZH has been a great resource for links to explanations.

Ignorance and lack of concern are part of the control mechanisms.