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Earth Japan News

Fukushima Ocean Radiation Won't Quit 210

mdsolar writes with an update on how the oceans around Fukishima are doing. From the article: " The Fukushima disaster caused by far the largest discharge of radioactivity into the ocean ever seen. A new model presented by scientists from Woods Hole Oceanographic Institution in Massachusetts estimates that 16.2 petabecquerels (1015 becquerels) of radioactive caesium leaked from the plant — roughly the same amount that went into the atmosphere. Most of that radioactivity dispersed across the Pacific Ocean, where it became diluted to extremely low levels. But in the region of the ocean near the plant, levels of caesium-137 have remained fixed at around 1,000 becquerels, a relatively high level compared to the natural background. Similarly, levels of radioactive caesium in bottom-dwelling fish remain pretty much unchanged more than 18 months after the accident." The article suggests run-off from contaminated land and possibly a leak in the plant itself are to blame for the levels not dropping as expected.
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Fukushima Ocean Radiation Won't Quit

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  • by Antipater ( 2053064 ) on Wednesday November 14, 2012 @01:44PM (#41981947)
    A petabequerel is 10^15 bequerels. Someone didn't check when they copy-pasted the paragraph out of the article. Metric doesn't solve negligence.
  • Not unexpected (Score:5, Informative)

    by AmiMoJo ( 196126 ) * <mojo@wo[ ] ['rld' in gap]> on Wednesday November 14, 2012 @01:45PM (#41981957) Homepage Journal

    It is expected to take the better part of this decade to even get at where the leaks are coming from, let alone stop them. The problem isn't going away any time soon.

  • Re:mdsolar writes (Score:5, Informative)

    by rmstar ( 114746 ) on Wednesday November 14, 2012 @02:18PM (#41982413)

    Stopped reading right there. It's the Slashdot equivalent of "An article on Fox news..."

    You are being ridiculous. The article in question was published in nature, which is about as reputable and prestigious as it gets.

  • by Henriok ( 6762 ) on Wednesday November 14, 2012 @02:27PM (#41982521)
    1000 bq isn't that much. It might be much compared to the background radiation but to put it in context, recommended values in Sweden after Chernobyl is to not eat meat that radiates more than 1500 bq/kg. This radiation comes from Cesium-137 that mostly rained down over us. And 10 years after we could still kill game (mostly moose) with in excess of 4000 bq/kg. Many residential houses stand on granite that contains radon, and the limits for radiation from radon was 1000 bq/m^2,until 2009 when the EU lowered the limit to 200 bq/m^2. So.. We in Sweden lived with this kind of radiation for quite some time and we don't really consider this a problem. The halflife of Cesium-137 is about 30 years so the radiation is dropping steadily but slowly.
  • by vlm ( 69642 ) on Wednesday November 14, 2012 @02:29PM (#41982557)

    Short version is that weapons are optimized to use the absolute minimum fissionable material and reactors are optimized for an engineering reasonable heat flux per sq meter.

    The cost of building an ICBM to carry something "just 500 pounds heavier" is enormous. The motivation to make weapons lighter is intense.
    On the other hand PWRs need to keep heat flux low enough to not boil at a sane flow rate, and BWRs REALLY need to stay in nucleate boiling mode. This means a reactor is insanely heavier than a weapon.

    A normal human can pick up a modern weapons physics package. Well you have to be in .mil and lift weights occasionally, not your average people of walmart. But the point is the fun stuff is pretty light. A reactor core is made out of hundreds of modules each of which requires a rather heavy crane to lift individually.

    Another way to put it is if you want to light it off, it needs well under 100 pounds of the fun stuff. But if you want to reliably extract a gigawatt or so for a couple decades, there's some thermodynamic and materials science reasons that ANYTHING that can transfer a GWt over the long term is gonna be tons. Doesn't matter if the heat came from U or Pu or coal, its gonna take tons of metal to reliably transfer that heat into water. Kinda like if you wanna fire, a match isn't all that big, but a GW class coal electrical power plant, which also uses fire, is really heavy.

  • by careysub ( 976506 ) on Wednesday November 14, 2012 @02:30PM (#41982569)

    The lead-in sentence is certainly incorrect in its current, broad brush form. Immediately after a nuclear explosion the decay of short lived isotopes creates levels of radioactivity astronomically higher than a leaking civilian power plant. But those short lived isotopes rapidly disappear. Eventually you just have long-lived isotopes with half-lives of decades or longer.

    Nuclear power reactors burn-up an astonishing large amount of fuel. The biggest fission yield of any nuclear test was no more than 15 megatons, which is the energy equivalent of 880 gigawatt-days (thermal) of nuclear reactor operation. Fukushima Da-ichi produced 29,891 gigawatt-days of power a year, a number 35 times larger. The amount of long-lived radioactivity (i.e. what you have left after several weeks) in Fukushima far exceeded any nuclear weapon.

  • by edxwelch ( 600979 ) on Wednesday November 14, 2012 @02:44PM (#41982745)

    It's no surpise that the sea is radiactive. Since the accedient there have been a series of leaks from the jury-rigged water purification setup:
    December 2011
    45 tons of water heavily contaminated with radioactive strontium escaped, of which 150 liters of water found its way into the ocean through a ditch connected with the beach
    26 March 2012
    80 litres radioactive water seeped into the ocean
    5 April 2012
    12.000 liters water with high levels of radioactive strontium escaped through a nearby sewer-system into the ocean

    On top of that the contaminated water lying in the basements is leaking into the ground water and out to the ocean. TEPCO are building a wall to contain that, but it won't be finished until 2014.

  • by Anonymous Coward on Wednesday November 14, 2012 @03:17PM (#41983165)

    One of the more difficult bits of the metric system is that it's case-sensitive. While bits and bytes are not SI units, it is customary to differentiate megabytes ("MB") from millibits ("mb").

    Remember also that "K" is short for kelvin, while "k" ("kilo-") is the prefix for one thousand.

  • by Luckyo ( 1726890 ) on Wednesday November 14, 2012 @03:28PM (#41983293)

    The latter can be prevented, but costs for plants that burn stuff are pretty steep. My father works for a burner-based power plant manufacturer (I've seen them make stuff ranging from burning coal to burning trash to burning the weird ass crap which is about 30% oil and 70% crushed rock), and one of the things he did was handle certification and maintenance of the new plants across EU that had to comply to rigorous norms.

    For example, the main cause of acid rains of the past, SO2 and NOx emissions are currently ZERO on some modern burner plants. Reason for this is extreme degree of burning process control (i.e. they can create burning conditions where certain gasses do not form, instead burning process forms far less harmful gasses such as CO2). Particles nowadays can be handled by filters which also have near-100% efficiency for particles they're responsible for. Basically they get particles out of the exhaust air and store it in a solid form which is then taken away to the appropriate dump.

    This stuff is really expensive though, so only new plants get the appropriate upgrades due to rigorous standards applied to them. Older plants still crap on the environment, same thing as old nuclear plants being far more risky when major disaster occurs then new ones.

  • by thesupraman ( 179040 ) on Wednesday November 14, 2012 @05:54PM (#41985209)

    The USSR has dumped over 39PBq in to oceans intentionally .
    The UK has dumped over 35PBq in to the oceans intentionally.
    A total dumping over all countries of 85PBq is known (ignoring of course military dumping, etc)

    So I assume by 'largest' they simply mean as a single event, certainly a lot more than that has been dumped, and there are single sights with more than that also..

    While we are at it..

    Weapons testing released 2,566,087 PBq also, just for reference (a lot of it not that far from Vegas..)
    Chernobyl released 12,060 PBq

    Also for reference, 1kg of coffee, and 1kg of granite also has around 1000 becquerels, the remaining number we are supposed to consider 'relatively high'
    So here is hoping no one has granite kitchen tops, or drinks coffee regularly..


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