Japan Nuclear Experts: Fears corium not totally covered in water at Reactor No. 1 — May only be 15 inches deep, even lower than No. 2

Published: May 22nd, 2012 at 9:44 am ET
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Excerpts from a May 22 report in the Tokyo Shimbun translated by EXSKF:

Analysis by the Japan Nuclear Energy Safety Organization (JNES) has revealed the possibility that the water inside the Containment Vessel of Reactor 1 may be only 40-centimeter deep, despite 6 tonnes/hour water being injected [into the Reactor Pressure Vessel]. The water level inside the Reactor 2 Containment Vessel has been measured by an actual survey to be about 60-centimeter deep. It shows how severe the damages to the Containment Vessels have really been.

[...]

There is also a fear that the fuel debris [corium] may not be completely submerged in water. But the JNES researchers say, “The temperature inside the Containment Vessel is not that high, at 30 degrees Celsius. The fuel debris is considered to be submerged and cooled.”

[...]

JNES Conclusions

  • There is a hole several centimeters in diameter on the pipe that connects the Containment Vessel and the Suppression Chamber
  • The location of the hole is about 40 centimeters from the concrete floor of the Containment Vessel
  • The injected water is leaking from the hole in great quantities
  • There is no water [in the Containment Vessel] above the hole

New York Times on the JNES: The Japan Nuclear Energy Safety Organization, which is supposed to provide a second layer of scrutiny, is understaffed and largely an advisory group. Masatoshi Toyoda, a former vice president at Tokyo Electric who, among other jobs, ran the company’s nuclear safety division, said the organization should be strengthened.

See also: NHK: Water level "far lower than previously thought" at Reactor No. 2 -- Just two feet deep -- Anticipated it was 5 times higher -- Decommissioning reactor could be "much more difficult" (PHOTO)

Published: May 22nd, 2012 at 9:44 am ET
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Related Posts

  1. *NEW Dec. 1 Yomiuri* Gov’t Study: Reactor pressure vessel may be “tilted” after corium melted through concrete floor up to 200 cm deep November 30, 2011
  2. Report: Reactor No. 2 has multiple 4-inch holes in CONTAINMENT VESSEL May 24, 2011
  3. Hardly any water in Reactor No. 1 after flooding effort — “Containment vessel is likely to be broken and leaking” May 12, 2011
  4. NHK: Molten nuclear fuel “could be exposed from the water” at Reactor No. 1 (VIDEO) December 23, 2011
  5. Japan researchers believe Reactor No. 1 filled with steam — Gas leaking from upper part May 23, 2012

20 comments to Japan Nuclear Experts: Fears corium not totally covered in water at Reactor No. 1 — May only be 15 inches deep, even lower than No. 2

  • patb2009

    it's okay that the water level is likely only 40 CM in the Containment vessel because the corium
    isn't in the Containment vessel.

    It burned it's way out a long time ago.

    Now how much is in the basement and how much is in the Ground water 400 Meters down,
    hard to say. I'd guess half.


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    • Sickputer

      I agree Patb. There is just a surface film left in the entire leaking reactor vessel. The weight of 100 hot tons of nuclear lava burned through long ago via the control rod tubes. Probably took a five foot diameter of stainless steel out as it left. Might a crust left behind holding in that tiny bit of water. But hey! It's in "cold shutdown condition"! Tepco whitecoats cheerfully intone nonstop that mantra while the 100-ton alien bus burns on down to its destiny. Methane layer perhaps? Meanwhile…somewhere in Finland a red-suspendered man sits on a bench pondering the same thing. ;-) maybe….


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  • aigeezer aigeezer

    "The fuel debris is considered to be submerged and cooled" is not the same thing as "The fuel debris is submerged and cooled".

    What people consider to be happening – especially if agenda driven – is irrelevant.

    Also… "There is a hole several centimeters in diameter" coupled with "6 tonnes/hour water being injected" – are those concepts compatible? (I don't know – anyone know details about water flow rates?)


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  • BreadAndButter BreadAndButter

    "The injected water is leaking from the hole in great quantities."

    Where to? Simple answer.


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  • Hemisfear311 Hemisfear311

    Even the best build dams cannot withstand the power of water leaking through even very small crevices. The water will erode its way through the best manmade obstacles if it is allowed to continue to flow.

    At block #1 they continue to add 6 tonnes of water every hour. What used to be small cracks in walls and floors last year is now gaping holes. More than 400 days into the disaster means that 57+ kilotonnes of water has had its way on structures that were never build to withstand such stress.

    It is a terrible dilemma. Inject more water and the building collapses even faster due to erosion – stop injecting water and the corium (or what's left of it) will heat up with all the consequences that have already been discussed here for more than a year.


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  • Sharp2197 Sharp2197

    Please note the 2 different uses of vessel.

    They are pumping into Reactor Vessel
    Water level in Containment vessel

    The water is leaking into the basement and then going elsewhere.
    Most likely into the earth.


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  • glowfus

    they dont know where the melted fuel is but they do know that there is water above it. this is probably true, but whos water? there's or the oceans?!


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  • fireguyjeff fireguyjeff

    One major problem here.

    If a loaded SFP can boil soon after the cooling water stops circulating, then it seems reasonable that the term "corium" and "cool" just don't go together.

    They have molten fissionable material and at the same time hedge as far as they can with "The fuel debris is considered to be submerged and cooled.”

    Why say "considered" unless they have no idea just WTF is going on??!!

    The language out of these guys is just so beyond pathological.


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  • glowfus

    gravity does exert a force on radiation so i suppose as the water and melted fuel gravitate toward the center of earth the "photon divergence" would increase as per inverse sqaure.


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  • PhilipUpNorth philipupnorth

    Fuku has taught the world that GE Mark I Containment Vessels are not built to CONTAIN nuclear fuel in event of a meltdown. Why not? Design flaws. They also cannot even CONTAIN the gasses reactors generate, and have been retrofitted with pressure release valves that vent directly into the atmosphere. All Mark I nuclear reactors worldwide must be shut down before further accidents happen.

    Containments 1 & 2 have little water. News: Containment 3 will also be found to have little water. And Reactor 3 was using MOX fuel. Coriums 1,2,&3 are mostly below the Containments, and perhaps even below Buildings 1,2,&3. The world needs to know where Coriums 1,2,&3 ARE. If TEP.gov can't find these missing Coriums after a year of assuming incorrectly that they were safely under water in the Containment Vessels, then TEP.gov needs to step aside and let international teams deal with the situation. This level of incompetence is intolerable!


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  • AGreenRoad AGreenRoad

    Once Pandora's Box is opened, all kinds of vipers come out…

    Dr. Helen Caldicott MD On Nuclear Weapons, MAD/Nuclear Armageddon; via A Green Road Blog
    http://agreenroad.blogspot.com/2012/04/dr-helen-caldicott-md-on-nuclear.html


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  • This would all have some level of importance if the fuel in reactor 1's primary containment was within its containment vessel.


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  • Longjohn119

    JNES has to be wrong about the hole, it's MUST be considerably larger than "a few centimeters" because there is no way under the Laws of Nature to push 6 tons of water per hour through a hole a few centimeters in diameter via gravity … But OBVIOUSLY that's what is happening, it's flowing out as fast as it's going in so the hole(s) must be considerable in size.

    Someone with even a little training in hydrology should be able to estimate the total size of all the holes with a fairly simple calculation based on amount of water in versus amount of water lost (Which seem to be one and the same)


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  • Longjohn119

    “The temperature inside the Containment Vessel is not that high, at 30 degrees Celsius. The fuel debris is considered to be submerged and cooled.”

    Well of course the temperature in the containment vessel is only 30 degrees Celsius, there is no core in there anymore …. it's below the vessel probably by several meters after a year

    What they need to do to measure the actual core temperature is find the hole in the bottom of the containment chamber (Which really shouldn't be too hard since it's big enough to leak SIX FREAKING TONS OF WATER PER HOUR) and drop the thermometer into the hole until it reaches the core … If they do that I can almost guarantee they'd see a quite significant rise in temperature


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  • Insight

    With a complete inital meltdown and a reported 3,000 tons of contaminated water in the basement last year, this containment vessel/basement no longer holds the nuclear material.
    I think it has burned through the floor and melted into the underlying lava rock forming multiple radioactive lava tunnels flowing into the ocean. It could be that the heat they are measuring is a result of evaporation of the water they pump in, creating the source of an electrical charge; friction of steam against the containment walls of the tunnels, not the decomposition of water.`


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