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View Diary: Extreme Levels of Cesium 137 Found Outside Exclusion Zone Around the Fukushima Plant (39 comments)

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  •  I-131? (1+ / 0-)
    Recommended by:
    Siri
    It's probable that more of these isotopes and others such as I-131 have been leaking out into the surrounding water over the months since the hydrogen explosions damaged the building structure and some or all of the rods in the pool.

    Huh? We've now passed beyond 21 half lives of I-131 since the accident. That means that only one in three million of these atoms is still around from the inventory inside the reactors that were operating during the earthquake.

    In the spent fuel pools, where the fuel had been removed from the core well before the accident, there is no I-131 left to "leak out."

    An idealist is one who, on noticing that a rose smells better than a cabbage, concludes that it will also make better soup.
    -- H. L. Mencken

    by bryfry on Wed Aug 31, 2011 at 07:23:54 PM PDT

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    •  Detection levels (3+ / 0-)
      Recommended by:
      oldhippie, rja, Siri

      There is still some I-131 in the spent fuel pellets, very little compared to the Cs isotopes which have a much longer half-life but it still exists and it can be detected by isotopic analysis. The other factor is that iodine is very mobile and will easily leak out of the fuel pellets into the pool water if the fuel rod jackets are damaged and especially if the pellets are allowed to heat up. Caesium is less soluble than iodine and melts at about room temperature but it doesn't vapourise until it reaches several hundred degrees Centigrade.

       The other isotopes of particular concern such as strontium 90 are much less mobile having much higher melting (769 deg C) and boiling (1384 deg C) points hence their paucity in the wider analyses of contamination levels around the Fukushima site and over the Forbidden Zone.

      •  Huh?!! (0+ / 0-)

        Detection has nothing to do with it. Your idiotic quoting of irrelevant facts from encyclopedias has nothing to do with it.

        I-131 has a half life of only 8 days. That means that after a little over 8 days, half of the inventory is gone ... doesn't exist anymore ... has become something other than I-131.  After another 8 days (a little over two weeks) 75% of the inventory is gone ... doesn't exist anymore.

        Now, drag out your pocket calculator (if you have one ... given the innumeracy you have displayed here, I suspect that you do not), and calculate 0.5 raised to the factor of 22. That's how much I-131 is left.

        This is virtually nothing.

        Is the level of scientific knowledge on this site so bad that your comment actually received two recommends?!

        An idealist is one who, on noticing that a rose smells better than a cabbage, concludes that it will also make better soup.
        -- H. L. Mencken

        by bryfry on Thu Sep 01, 2011 at 01:53:08 PM PDT

        [ Parent ]

        •  Virtually nothing and nothing (1+ / 0-)
          Recommended by:
          rja

          I did say there was very little I-131 left in any of the spent fuel rod pellets in the pools at Fukushima. By "very little" I mean maybe some milligrammes of the isotope in total in the several hundred tonnes of spent fuel in store there. That material can still leak out into the cooling pond's water and be detected using isotopic analysis, a much more rigorous process than the simpler energy-spectrum scintillator detectors used to monitor the much higher levels of residual contamination from, say, Cs-137. That sort of lab-based analysis is also used to determine the levels of Pu, radioactive strontium and some of the other members of the isotopic zoo that have been scattered over the Fukushima site and the surrounding area after the reactor explosions.

           The problem with isotopic analysis is that it also detects older contamination from, say, the Hiroshima and Nagasaki bombs, Tchernobyl, the Windscale release, Hanford, the assorted above-ground nuclear tests carried out by the Soviets, the French, the British, the Chinese and the US over the period of the Cold War etc. That's why the headline-grabbing reports of assorted levels of contamination in various places need to be studied with a careful eye before waving the bloody banner and proclaiming we're all DOOMED!

          •  No ... nothing! (0+ / 0-)

            Even when nuclear fuel is freshly discharged from the reactor it contains only a few grams of I-131 for each tonne of fuel. For anything sitting in a spent fuel pool, this small amount of I-131 would have decayed away long ago.

            The only plausible source of I-131 is from the fuel in the reactors at the time of the accident. By now, the amount of I-131 left is micrograms (not milligrams) per tonne of fuel.

            It's nothing.

            An idealist is one who, on noticing that a rose smells better than a cabbage, concludes that it will also make better soup.
            -- H. L. Mencken

            by bryfry on Thu Sep 01, 2011 at 02:42:39 PM PDT

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