IAEA informed in March that No. 1 reactor core started melting about 50 minutes after cooling stopped — Melted pile of fuel in 3.5 hours

Published: May 23rd, 2011 at 9:45 pm ET


Fukushima reactor had meltdown 3.5 hours after cooling system collapsed: U.S. researcher, Mainichi, May 23, 2011:

A meltdown occurred at one of the reactors at the Fukushima No. 1 Nuclear Power Plant three and a half hours after its cooling system started malfunctioning, according to the result of a simulation using “severe accident” analyzing software developed by the Idaho National Laboratory.

Chris Allison, who had actually developed the analysis and simulation software, reported the result to the International Atomic Energy Agency (IAEA) in late March. It was only May 15 when Tokyo Electric Power Co. (TEPCO) admitted for the first time that a meltdown had occurred at the No. 1 reactor at the Fukushima nuclear plant. […]

According to the simulation, the reactor core started melting about 50 minutes after the emergency core cooling system of the No. 1 reactor stopped functioning and the injection of water into the reactor pressure vessel came to a halt. About an hour and 20 minutes later, the control rod and pipes used to gauge neutrons started melting and falling onto the bottom of the pressure vessel. After about three hours and 20 minutes, most of the melted fuel had piled up on the bottom of the pressure vessel. At the four hour and 20 minute mark, the temperature of the bottom of the pressure vessel had risen to 1,642 degrees Celsius, close to the melting point for the stainless steel lining, probably damaging the pressure vessel. […]

Published: May 23rd, 2011 at 9:45 pm ET


Related Posts

  1. Gov’t Experts: Fukushima fuel rods were melting 75 minutes after tsunami; Reactor core not covered with water 10 minutes after power blackout — Worker: Before explosion, Unit 1 “filled with what looked like steam or dust… a series of large bangs… noise never heard before” (VIDEO) August 16, 2014
  2. Quake, not tsunami, may have caused damage that led to meltdown — Within 16 hours, No. 1 reactor core melted and made a hole in pressure vessel May 15, 2011
  3. NYT experts: “Danger of a wider radiation leak” — Cooling system may not work for fuel melted into concrete — Tepco “not worried” December 1, 2011
  4. New images show all melted fuel is “gone” from Fukushima reactor — Experts: Molten core may have reached outer environment, can’t tell if fuel is still contained — Official: “We presume fuel still in containment vessel… but we need to check one day” (PHOTOS & VIDEO) March 20, 2015
  5. Designer of Reactor No. 4 suspects Tepco cooked up simulation in attempt to deceive public December 12, 2011

126 comments to IAEA informed in March that No. 1 reactor core started melting about 50 minutes after cooling stopped — Melted pile of fuel in 3.5 hours

  • Rachel


    Sign this petition!

    Reinstate EPA Ongoing Testing For Radiation from Fukushima

    Target: President Barack Obama, United States Congress Members, Administrators of the EPA
    Sponsored by: Concerned Citizens

    • U235P239

      I think the best course of action would be to collect some samples and have them tested privately.
      That would at least give you some ammo in the fight to get testing re-instated.

      • Jack

        Yes! instead of revealing your name and address for any to see,
        let’s organize a Paypal donation site, to fund INDEPENDENT testing.
        Who wants to start a Rad testing paypal site?

    • dan

      I hope the petition works. But if they don’t want you to see the data, you probably won’t, unless you do it yourself. Even if they do agree to do it, if they don’t like it, they’ll just find a way to change the numbers.

    • U235P239

      In all reality there will be monitoring happening, if only to alert the big boys it’s time to enter the bunkers.

      • mark V

        JP Morgan said byebye Tokyo days after the earthquake, leaving $3 bn and keys in the door.

    • toots

      You can sign the Petition anonymously!!
      (and at this point, what more do you have to lose, anyway? Privacy in your radiation??)

      Having worked in govt., I can tell you that pummeling them to register your reasonable opinion DOES make a difference. It’s just fellow humans (warm-blooded & fallible) scheduling all those important priorities and meetings… These petitions help it stick in their head! Maybe our democracy is not in perfect form, but that does not mean we need to relinquish it!! To the contrary! MAKE IT WORK!!

  • U235P239

    If anyone was hoping for the IAEA to do something about Fukushima … don’t hold your breath.
    The IAEA haven’t been out to inspect Chernobyl yet 🙁

    • mothra

      When I need a nuclear paperclip, I think IAEA.

      Note: TEPCo confirms two additional meltdowns today via Reuters

      • toots

        I don’t understand the tone of this UN project.
        They seem to be focusing on analyzing the history of this disaster, when they MUST FOCUS on NOW!! —how to deal with the pressing crisis NOW, to include warning and evacuating citizens properly!! EVERY MINUTE COUNTS!!!
        Put the response on FAST FORWARD!!!

    • 1111

      U235P239 re IAEA and the lot Unspeakable Criminals. Period

      10 plus weeks. If these things revealed now, were known by these criminals from the very beginning, what is a suggested appropriate punishment for such behavior and inaction?

      Unprecedented in the history of mankind !!

      The seemingly boundless wickedness of the money worshipers never ceases to amaze me. Speculation here but – given the stupendously evil track record – I’m starting to believe (well actually had suspicions some time back) perhaps a long “graceful ?” / gradual exit from the equity markets to avert price erosion mitigated negative revelations early on – but now – with short sales positions in place after requisite upticks – full blown ultimate panic disclosure continues to daily unfold – to drive equities toward zero value – so the short sellers can buy back the shares as prices drop toward -0- big money gains – no risk. Thumbnail sketch here – Sell paper you don’t have on happy news, say for $100 bucks, buy it later for $1 after All H Breaks loose and hand to buyer. Watch the “markets” in coming days / weeks. Make a note of this observation here and see how it plays out.

      Cheapest way to make the big fast money on the – now rapidly unfolding cataclysm. News control historically a popular instant cash mechanism for the Rothschilds and Bankster criminals.


  • ZP

    As I understand it so far…

    There is a clear “definition,”
    of stated problem.

    Where are the counter measures?

    ? ?
    ? ?

    ? ?

    • ZombiePlanet

      I know,
      I shall vote for that person.

      • ZombiePlanet

        Rather start my Grill. 🙂

        • ZP

          Can someone please point me to the correct petition,
          that so I may observe,

          the most correct procedure to follow?

          Ah, […]

          I thought so.

          • toots

            Just start calling all the offices involved, clown by clown…Better than nothing!! (& petition linked above)
            They’ve admitted reality, time to make it BITE!!!

  • charlie

    So the IAEA guys get well-paid for doing what, exactly? Fire them all. Dissolve the agency. Replace it with some engineers who are not close to the atomic old boys club.

    • tony wilson

      iaea are an elite boys club that promotes the nuclear atom at all costs.by hook or crook.
      people seem to believe it is some kind of international rescue made up of the most beautiful scientific minds in the world.
      they have known these old submarine reactors were lethal 40 years ago and did nothing to put pressure on general electric.

      what nobody has mentioned is if 4 reactors go full china syndrome,leading to a collapse in japan.what about the cooling of the 40 odd other nuclear reactors.
      it really sounds like a ballard novel 40 jets magma shooting in the air.as cores work downward.
      survival mode will not be an option with hundreds of meltdowns all over the world,you will need to be hanging out with barry liar obama to survive.
      keep an eye out for world leader movements..

  • beachbum

    Solutions at this time! Unfortunately, there may not be a lot of alternatives. We (humanity all over the world) are certainly in a serious learning experience. We could be observing a radiation fountain spewing this stuff into the air almost indefinitely.
    Peace out!

  • beachbum

    There could be three of these side by side all having a go at it! Wouldn’t that be a hoot? But how does that compare to Elenin? Now there’s a real serious situation! Doctor said to take a few months and call us before winter.
    Peace out!

  • Buck-O

    Physicist Michio Kaku is correct when he said,”it gives you a feeling Homer Simpson is in charge”, on one of his CNN interviews. They do a good job in the misinformation stage of this accident.

    Does anyone accurately know in what stage of the meltdown is? Do they know, outside of disaster stage.?

  • shockwave



  • Cindy


    The first news I’ve seen in weeks on Yahoo Home Page ..


    • Nevadan

      Cindy, I just read that article. In it they say there is no immediate danger from the site because the melted rods are covered in water and the radiation is far below dangerous levels.

      Works just like a sleeping pills for the masses. They are anxious to believe anything that tells them not to worry.

  • SteveMT

    The IAEA finally has updated their website to 5/18.
    Reactors 1-4 individually summarized.


  • NortBeam

    How neutron beam is in “news” creation … now Iceland ash is (again) oscillated up – to create a good crisis: 0b amao never lets em to go waste. (Like Gulf saboteur detonation was used to get US out, Soros Petrobrazz drilling)

    New 100x more powerful 6TeV Neutron Crisis Factory is in their plans…



  • Novamind

    How good are you?- What are we looking at? fog, steam, smoke?

    • That is the effect from steam, leaving the reactors as fuel is vaporizing on contact with cooling efforts… it is highly contaminated. The fact that it is steam also indicates that it is making its way into the jetstream. so it should be a huge concern from international communities.

    • everything that steam touches raises the limits of radiation on site, hampering the efforts of tepco… this is well beyond human intervention. Eventually, even employees of tepco, wearing the most up to date safety equipment, will be limited to checking the radiation at 20km away. This is the situation I’ve been predicting. Once tepco and even robots are rendered useless to fight against these elementary circumstances… The situation will escalate globally…

  • yep. I bet tokyo hasn’t gotten a warning yet either. Though this has been happening for the last 2 months. The rad levels there must be alarming by now… 35million peoples healths at risk.

    • I agree. With the constant and multiple leaks the accumulation must be truthfully substantial, right? Isn’t that a reasonable conclusion?

  • I am sure its coming from reactors 1-4.
    Though in my estimations / models, reactor 1 goes first. then 3 then 2 then 4, though 5 and 6 will likely be going soon too.
    they are all beyond repair…

  • Novamind

    Visibility is reported to be 10KM.

  • icone

    I cant see where the fog -or steam- is coming from. Just a hint of a building now and then. But assuming its coming from a reactor since tacomagroove saw it start, what make this much steam? The corium hitting the water table?

    • J1

      That was my question also….water table reached?

      • I think its safe to assume this is due to the fuel pool in four. I feel that though this is a huge problem for tepco and tokyo, the fuel is likely still in a point of minute criticality. though that may change in opinion if this is what were seeing at noon (in 10 hours).

        • Either way. Its starting. Go buy water, your going to need it. Cnn is not going to tell you this.

          • J1

            Glad I loaded up on several 100 gallon containers, a katadyn filter and desalinator, and a handful of scepter 5 gallon containers. Looks like I’m about to get some mileage on em’.

          • The way I see it even if the fuel hasn’t breached the water table, these working conditions (not being able to see for instance). Are all too much for any chance in altering and or restoring the sites troubled reactors. There is nothing tepco can do at this point.

            I have a beautiful girl sleeping over today, and she is alone… so I am taking off for now… But as I said before. keep your eyes on the cam. keep your mind in peace, and start preparing the worst is yet to come…

          • J1

            Any other live feed channels you know of?

  • there is no known process to mankind in adverting this tragedy.

  • I should note, tepco may even be forced to abandon the site as of today. This is likely a deadly level plume of radioactive steam. The respirators on site are not going to be able to counter this amount of contamination.


  • noodles and cheese

    The weather for Fukushima is reported as ‘cloudy’. Might some of that be normal fog?

  • Jean Tanner

    Curiouser and curiouser.
    Here’s TEPCO’s live cam link

  • noodles and cheese

    Tacomagroove, I can find no information about boron’s time limit of efficaciousness against radiation. Could you please let us know where you got your information on the Godlike post (it is a quotation)? Thank you.

    • DuckNCover

      He will give you no citation on that “fact” because there is none. There is no boron time limit…
      Answer me this…boron control rods and blocks in a reactor…what is their “time limit”?? The life of the reactor…

  • The desperation has begun,…..:-(
    May 24th–“Japan will ask the European Union to ease import restrictions of farm products including those grown in Kanagawa Prefecture, southwest of Tokyo, farm minister Michihiko Kano said Tuesday. “Japan needs to make more efforts with patience to win foreign understanding that Japan’s farm and marine products are safe,” the minister of agriculture, forestry and fisheries told a press conference. (Kyodo)”

  • I wonder if this land would help in a pinch like this:

    S. Korean lawmakers visit Russian-held island claimed by Japan

    VLADIVOSTOK, Russia, May 24, Kyodo


  • Aji Jakarta

    They knew it … they knew it long before this day, that melt down process was happened to four reabtors…If they kept this information from public, hopefully because they all tried their best to find the way out ..Then, IF today they release the information … hopefully it is not because they can not find the good way to solve the problems …
    IAEA .., we all waiting for the good news …, after soo many bad news released day by day …

  • Major Domo

    Sorry tacomagroove, but I think you’re wrong, ‘it’ hasn’t started …yet.

    If a molten reactor core, Corium had dropped through the concrete and hit the water table, we’d most likely see much greater evidence of this, in the form of continuous steam release, and potential further explosions. What I see, is the same sporadic release patterns I’ve witnessed over the last weeks, which do appear to be occurring more often, with greater frequency, and with greater volume. Radioactive? Absolutely. Dangerous? Incredibly so. China Syndrome? Probably not.

    How close are we to that scenario? Could be that it’s just about to start, as you have suggested. There simply isn’t enough hard data out of Tepco to determine with any measurable amount of certainty. How thick is that concrete floor? Enough to withstand molten lava? For how long? Will the corium burn itself out to a point of semi-stability before it burns all the way through the concrete? Who knows? How will all the variables change, as individual scenarios play out from rector to reactor? There are too many unknowns. As far as I know, no one from Tepco has managed to survey beneath the reactors yet, or get close enough to install surveillance cameras, in an attempt to identify just how far this has progressed, with regards to explicit meltdown(s). And even if they did such evidence, would they share that data with the public?

    In Chernobyl, within 2 weeks of that accident, the Russians had already recruited miners to dig a huge tunnel under the reactor, and filled it with concrete, greatly extending the depth of the existing concrete floor. Imagine that, working while knowing there’s a melting reactor core just a few feet over your head. I wish Gorbachev was in charge here. What strikes me most about this whole disaster, is the difference between how the Russians handled it, and how the Japanese, are not. While the bravery of those currently working at the Fukushima plants cannot be questioned, it is the relative response, or lack thereof, of the powers that be to match the scale of this disaster with an appropriate level of action, that is questionable. Even though the Russians acted quickly, 25 years after the Chernobyl accident, the city of Pripyat remains abandoned. You have to wonder what Japan will look like 25 yrs from now.

    I think we run the risk spreading fear if we begin to make worst case scenario statements, without having factual information that reveals and supports the true status of the situation. We simply don’t have the full picture yet, and that’s the worst part – not knowing. A precarious and anxious situation to be in, especially for those living close to the evacuation zone. The truth is, the reactors, more specifically, the immediate areas under the reactors, are not accessible to determine the full extent or severity of the situation. I’m not saying that the situation is not dire, I agree that it is, and I think I have expressed that enough here in other comments. But I’m looking at the live cam feed now, things appear to be somewhat stable, in that I have seen no significant steam or other release from any of the reactor buildings today. If a core had dropped to the water table, the current scene would be less serene. Just another day in Fukushima.

    Even if I’m wrong, one has to wonder how an actual ‘China Syndrome’ would play out. First, we know the term ‘China Syndrome’ is an exaggeration. A core will not melt through the mantle of the earth. More likely, it will burn to a point, eventually “fizzling out”, while maintaining an unimaginable amount of radioactivity. How deep it drops depends on the temperature of the molten core, the amount of fuel, and the resistance of the earth itself, what lays in the molten core’s path. Will it actually create a huge explosion when they hit the water table? Or will they simply create steam, while continuing to sink through to the layers of earth and rock below? It might not be “pretty”, but perhaps hitting the water table will actually aid in burning them out? What is the composition of the land under the plants? How far down to the water table? Does anyone really know? Too many variables at play, and there is no precedent to compare with.

    One has to wonder, when looking at the lesser of two evils, if it might even be better for the cores to melt deep into the earth, and seal them off? Rather than continuing to spew radioactive steam into the atmosphere for eternity. Drop the cores deep into the earth, then seal it off. Bulldoze the whole site into the ground. Out of sight out of mind? Maybe not. One thing is for certain, at the very least, it would likely be a monumental environmental catastrophe, completely poisoning the water table, and spreading as far as the water travels, land, sea, for eons. What’s quite clear is that after examining the options, based on the limited evidence we have, the final solution may be a lesser of two evils.

    Of course, in the time it took to write this comment, the world has probably ended 🙂
    Just trying to remain positive. Not easy to do.

  • Nevadan

    Tacoma, keep up the good work. Without a doubt, we cannot sit around and wait for the ‘experts’ to come clean so we can stick to established facts.

    No, one of the main purposes of this discussion site is so that we can brainstorm, and glean hard-won information to try and piece together what is really going on. Different players bring to the table their observations and then we can discuss the logic of the idea.

    Do not be discouraged by those who insist on peer reviewed journal hard facts. We don’t have years to wait.

    Circumstantial evidence:
    (1) Russian radio announcement about major underground event at Fukushima on Monday…(nothing else heard so does that mean a false report or a continuing news blackout as has been the pattern?)
    (2) steam or fog obscuring the plant
    (3) steam seen rising in huge amounts from the roofs of the plant
    (4) more than one person observing the fog parting and still a massive amount of steam at the plant
    (5) fake still photo on the weather channel site (why the need to do that?)
    (6) the live feed on a loop instead of showing real time (again…why)

    Conclusion? We do not know, but it is WORTH TALKING ABOUT! Do not allow yourself to be muzzled by those who don’t appreciate discussion.

    • ya I didn’t place a large bet on that one, 300am and tired lol, thanks for the post:)

    • DuckNCover

      Yes, nothing like a scoop shovel full of doomsday scenarios and wild speculation compared to hard facts.

      • Jack

        Hey Duck….you getting paid to be here?
        Just funnin’…
        Did you see the other thread where the lady in LA is detecting
        500 millirem as she walks around the city?
        Wild Speculation?

        • DuckNCover

          No, I missed that….but I did see where they are moving about 170 of the 400 cattle out of the evacuation zone. Fresh, pre-cooked burgers at your local McD’s.

          • hey duck.n.cover. it states well before my reply on this thread: May 24, 2011 at 4:49 am · Reply

            That was my question also….water table reached?

            May 24, 2011 at 4:52 am · Reply
            I think its safe to assume this is due to the fuel pool in four. I feel that though this is a huge problem for tepco and tokyo, the fuel is likely still in a point of minute criticality. though that may change in opinion if this is what were seeing at noon (in 10 hours).

            Its harder to admit to you that before this threaders reply, and I even tactfully replied to the situation earlier. That you both failed to notice how I addressed this specific issue. Though I assume hard facts are something you like to have at hand I enclosed the reply with the time so you can scroll up and see it there well above yours… Why you did make this comment only in attempt to insult me is of interest to others. While you surely only made ground in insulting your self while making a baseless argument in a high school level demeanor.

    • Major Domo

      @Nevadan If you’re in any way suggesting that I am attempting to ‘muzzle’ or discourage conversation here, or that I’m insisting on ‘peer reviewed journal hard facts’, in some sort of effort to downplay the severity of this gross situation, you couldn’t be more wrong. I am merely attempting to throw out a balanced and unbiased view based on what we do know, rather than relying on unscientific speculation, hearsay, fear-mongering, conspiracy theories, or anyone promoting any specific agenda. And to make myself perfectly clear, I am NOT suggesting anyone in particular here, including tacomagroove, is guilty of any of that. On the contrary. We’re all in this together, and are fortunate enough to have a community where we can discuss these issues as level headed adults, unlike many of the conversations I see going on in other communities where these topics are discussed.

      The truth is, we have little knowledge of the current state of the reactors in Fukushima. We only get little bits of information trickling out of Tepco, much of it inaccurate, or inadequate to explain the full scope and status of the disaster. We can be reasonably sure from evidence, that one or more reactors is either in a state of meltdown, or has already melted down. To what extent, is something that even the world’s greatest minds are having a hard time agreeing on.

      Is it ‘WORTH TALKING ABOUT’? Absolutely, and that’s entirely my point. I asked a lot of questions, mixed with my own opinions in order to invite open discussion, from the community, and specifically tacomagroove, who’s perspective and comments, I do appreciate and sympathize with. Not an attack on anyone else’s view or thesis. The buildings are mess, looking at them could only lead one to assume the worst. But we do not know don’t know what’s lurking beneath. And not knowing more than 2 months in, is unconscionable, unforgivable. I would like to see whoever it was that decided building multiple reactors on a fault line was worth the risk, with their head on a stick.

      My personal view? I remain skeptical, accepting nothing as truth from Tepco, MSM, Governments, or any Nuclear industry body. I trust my own eyes and ears, and rely on myself to make informed decisions based on the information I have gathered, through the very same process that has us all convened here. I simply feel we’re better off with a balanced approach, one which does not attempt to diminish the severity of the current situation, but one which is based on fact. It’s not my intent to try and “smooth things over”, or make a shit sandwich more palatable. If the Shit hits the fan, we’ll all be eating it. In my wildest dreams, I never thought I’d own a Geiger counter. I own one now, and I feel better knowing I can trust my own readings, with my own eyes, rather than relying on dodgy EPA stats. We’re all here with our own eyes, and our own opinions. To each his/her own

  • Jack

    Wow, they ought to get Entrepreneurial and start selling Unique Beef
    NukeBurgers! $100.00 a pound!

  • jed

    Is time travel possible? Is Time Linear? What is Time! One thing I do know is that this is our “TIME”

    Question 1. How did one of the most successful bands in the world “The Killers” write and release a song about the Tiger Woods saga well over a year before the story broke???


    Question 2. How did the biggest band in the world, “U2” write a song over 20 years ago about Tokyo Electric Co?
    “Earthquake 4. Nice and Slow. Useless scenes in old Tokyo. Useless scenes near Tokyo”


    After the Rain the Sun comes out!!!!