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Fukushima Leak Traced To Overflow Tank Built On a Slope

Posted by ryuzaki0 on from the castle-built-on-sand dept.

AmiMoJo writes "The ongoing leak of radioactive wastewater at the Fukushima Daiichi nuclear plant has been traced to an overflow tank that was built on a slope. Because one side of the tank is lower than the other, water slops over the side when it is nearly full. TEPCO estimates that 430 litres of wastewater seeped outside the barrier around the tank and say some of this water may have flowed into the sea, about 200 meters away. They detected 200,000 becquerels per liter of beta ray-emitting radioactive substances in water pooled inside the barrier around the tank. The safety limit is 30 becquerels per liter. Officials say that a miscommunication with contractors led to the blunder."

12 of 76 comments (clear)

  1. You can't manage to build a level tank? by h4rr4r · · Score: 3, Interesting

    So they can't even manage a level holding tank and they are allowed to keep managing this clean up?

    How is this level of incompetence possible?
    Does Japan lack the technology to build level storage tanks? Or to inscribe a maximum fill line in the tank otherwise?

    1. Re:You can't manage to build a level tank? by intermodal · · Score: 3, Insightful

      It's not the lack of technology. It's the lack of geological stability. Fukushima is over 40 years old. The text provided on this subject here seems to convey a questionable assertion that it was intentionally built in its current position, but in a seismically active place like Japan, it is more likely that while the tank is built on a slope, it was built level. The shifting of the ground beneath the tank has probably caused the tank to lean a bit to one side.

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    2. Re:You can't manage to build a level tank? by Zeromous · · Score: 3, Insightful

      When you consider how rapidly and the fact there are hundreds of tanks, it is entirely possible that one tank out of a few was built slightly sloped.
      The deviation must be quite small to only let out 430 litres slip out. 430 litres is literally a drop in the bucket when compared to the size of these tanks.

      It's great news they were able to track this down.

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    3. Re:You can't manage to build a level tank? by AmiMoJo · · Score: 4, Informative

      They knew the tank was not level, and were careful not to overfill it. The problem is that this was not communicated to the contractors who then did overfill it.

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    4. Re:You can't manage to build a level tank? by khallow · · Score: 3, Insightful

      It's worth remembering here that the tank might have been nice and level in early 2011.

    5. Re:You can't manage to build a level tank? by intermodal · · Score: 3, Informative

      I'm not sure you bothered to actually understand the situation before you made any of your posts. We're dealing with a facility that was heavily damaged years ago and you're trying to imply they have no surveyors? As TFA notes, they have been keeping the level lower due to this being a known issue. A rainstorm made it overflow.

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  2. Re:Ah by durrr · · Score: 3, Informative

    It was 430 liters of wastewater with a comparatively low radiation level(0.2kBq, for nuclear medicine image studies you're counting mega-Bq and you're injecting it, for radionuclide therapy you're up in high and wild GBq numbers). So yes indeed no worries, really.

    Regarding the safety limit of 30 becquerel: that's two banana equivalent doses, meaning that a banana shake can exceed the safety limit. And 6 million bananas being equivalent to the total leaked value.

  3. Re:Just wondering... by bluefoxlucid · · Score: 3, Interesting

    Japan had its big catastrophe. Let me illustrate: observe March 10.

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  4. Re:Good work, PR Dept. by khallow · · Score: 4, Informative

    I question if gazillions of gallons of oil gushing into the ocean all at once is more or less bad than a little plutonium.

    I go with more bad.

    Plutonium is pretty fucking toxic.

    If you breathe it in under ideal conditions. Most sea life doesn't have lungs, the plutonium would all be chemically bounded up as salts or other compounds, the whole mess would be greatly diluted, and there wasn't much in the way of plutonium anyway - they're far more worried about radioactive isotopes of cesium or strontium.

  5. Re:Ah by AmiMoJo · · Score: 5, Insightful

    The limit is 30 becquerels per litre for beta radiation emissions. The potassium level in your body also remains fairly constant, so you will only have an elevated level for a few hours until it passes out. The stuff in this water can sit inside you indefinitely. Becquerels are an absolute measure of radiation, where as "banana equivalent dose" is supposed to be an "equivalent dose" based on how much harm it does the body and is not in any way directly comparable.

    Obviously the people who set these limits are not morons, they understand that it is perfectly safe to eat a banana or two. In any case, the level in this water is 200,000 becquerels per litre.

    I only wish I had the skill to draw an ASCII facepalm.

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  6. Re:Reminiscent of Titanic's "watertight" compartme by coolmoose25 · · Score: 3, Interesting

    IIRC, there was a show I watched on the sinking that took the premise of counterflooding and tested it. They built a scale model, and they were able to fairly accurately recreate the actual sinking, without counterflooding. They then tested what would have happened if they had counterflooded the ship to maintain its trim. Counterintuitively, the ship actually sank faster with counterflooding. I think they explained it by showing that while the out of trim condition contributed to the "ice cube tray" phenomenon that finally sank the ship, the counterflooding would not stop that. It wouldn't even slow it down. With the flooding in the bow from the strike of the glacier, combined with the negative buoyancy of the counterflooded aft, the ship was so low in the water at that point, it allowed the compartments aft of the comprised compartments to fill the adjacent compartments even faster, while the ship was now that much closer to sinking due to the negative buoyancy of the counterflooded aft. They also explored the stability of the ship in such a condition. They found that the ship became unstable laterally, and thus it would have risked a capsize as well. Overall, it was better not to counterflood.

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  7. Re:Ah by Tailhook · · Score: 3, Insightful

    scary

    430 liters is about 2x 55 gallon drums. It's nothing. The level of radioactivity is also rather low; 200kBq is literally 200,000 decay events per liter. A 7' long granite counter top radiates over 100kBq into your food.

    This is small and inconsequential. That it was even noticed is outstanding. The fact that the media has hysterical people like you in a lather is SOP.

    Don't worry; the hype has had the intended effect; the idiots are convinced TEPCO is destroying the planet. Yurts and Hobby Farms Now!!!11 herp derp.

    The fact that they're wasting resources to store water this clean is tragic. It should be pumped to the bottom of some ocean trench and the resources wasted storing it should be spent on useful work recovering the cores, spent fuel, etc. Instead, they're carpeting the area with water tanks in a monumentally stupid act of Nuclear Theater.

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