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Fukushima and the dangers of going to Japan

  1. Mar 16, 2012 #1
    So I admittedly am not hugely knowledgeable about Nuclear energy and radiation which is why I decided to post on here. I am planning on moving to Japan at the end of September as I thought the area I'm going to was not threatened by radiation enough to be a problem based on information I found. Recently however somebody introduced me to two sources that not only say otherwise but one of them is saying that Japan as a whole is doomed and needs to be evacuated completely as the Fukushima reactors are impossible to stop. Sounds a little exaggerated but I cannot say for sure. the sources were fukushimadiary.com and enenews.com, I am unsure of the reliability of these sources and am hoping somebody here can tell me.

    My questions are is there any validity to the claim that the entire country needs to be evacuated due to radiation? I plan on going to Yokohama which is about 245 km from Fukushima, what is the risk of going there and should I reconsider? Lastly what do you find to be the most reliable sources on this?
  2. jcsd
  3. Mar 16, 2012 #2
    Here's an official, interactive radiation map provided by MEXT:


    And here's an official realtime radiation map:

    http://radiomap.mext.go.jp/ja/ [Broken]

    Yokohama is effectively unaffected. There shouldn't be any dangers involved in relocating to Yokohama. While contamination is a serious issue in Fukushima, Tochigi, Ibaraki, Chiba and Gunma prefectures, its impact on the rest of Japan is largely overrated. But there are spots with considerable contamination in the northwest of Tokyo, as can be seen on this map (or the interactive map if you play with the settings):

    http://radioactivity.mext.go.jp/ja/1910/2011/09/1910_092714.pdf [Broken]
    Last edited by a moderator: May 5, 2017
  4. Mar 16, 2012 #3


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    SW of Tokyo will be fine.

    I'd like to visit and spend time at Fukushima.

    Here's a map that indicates the areas of concern, but may not necessarily be that reliable.

    Here's another map, but source quality cannot be verified.
    http://eq.wide.ad.jp/files_en/110424map_1800rev2_en.pdf [Broken]

    Here is a more reliable source.
    http://www.anl.gov/Media_Center/News/2011/news111010.html [Broken]
    Last edited by a moderator: May 5, 2017
  5. Mar 16, 2012 #4


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    Complete idiocy.
  6. Mar 16, 2012 #5
    To make matters easier for you, here are two images taken from the official radiation map and showing the Tokyo region:

    http://i.minus.com/jIxjE0tqw4xyM.JPG [Broken] Contamination measured in thousand Becquerel per square metre.

    http://i.minus.com/jbuPF0sFkl0rfZ.JPG [Broken] Radiation measured in Microsievert per hour. Everything below 0.1 should be considered normal.
    Last edited by a moderator: May 5, 2017
  7. Mar 16, 2012 #6


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    Of the two sites you mention, I'm only familiar with ENE News, which has a habit of apocalyptic forecasts. There is also a loyal claque of doomsters that provide a chorus in the associated comments section. The 'Japan is doomed' comment is silly, there just is not enough radioactivity for anything like that kind of damage. But radioactivity does generate very visceral reactions, so it is perhaps to be expected.
    I think it is clear that much of Honshu, the central island, has been polluted with radioactive residue from this accident. The degree of pollution is measurable and is well above historic background, but also well below ambient natural radioactivity in places such as parts of India, China, Brazil and Iran. At Yokahama, your exposure is probably comparable to that at some relatively high level US site such as Denver. Do note that the deposition of contamination is very patchy, driven as it was by winds and turbulence, selectively deposited with rain and snow, concentrated in runoff.
    If you stay out of gutters, you should have no problems anywhere.
  8. Mar 16, 2012 #7


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    I've probably been exposed to more radiation than most of the general population. I'm still around and doing fine.

    Folks who fly a lot, particularly pilots and airline crews get exposed to a lot more radiation than the general public who spend most of their lives near sea level or less than 2000ft above sea level. One will have less exposure.




    It does help to be informed and put risk in perspective.
  9. Mar 17, 2012 #8
    What happens if Unit 4's fuel pool collapses? How far would the pollution spread with no containment? This is the scenario that i've read a few times in regards to Japan suffering widespread contamination. That along with the potential chain-reaction of nearby Nuclear plants being abandoned. Is this a completely unlikely scenario?
  10. Mar 17, 2012 #9


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    There is still some non zero risk of further problems, as there are still unknowns. But building a large scale doomsday scenarios around them is a pure fear mongering.
  11. Mar 17, 2012 #10
    Thank you everyone for the information, it was extremely useful and helped me to understand the problem better than I did and I appreciate it. This move is a big deal to me and so I'm glad to hear that there isn't any need for me to cancel it. One other thing that I have heard a lot of but not sure how much of an issue it is is the release of Plutonium and the release of MOX. Has there been a significant release of Plutonium? From what I remember people were talking about the explosions early on in the crisis shooting MOX fuel into the atmosphere which would cause wide spread radiation, or something to that effect. Is this true or is it just speculation at this point and how significant is that to the rest of Japan?
  12. Mar 17, 2012 #11
    There was some release of Plutonium, but it was not 'significant'. It's barely detectable.
  13. Mar 17, 2012 #12

    jim hardy

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    We "Baby Boomers" all lived through the years of atmospheric testing by Western powers . And more recent Chinese atmospheric tests. The latter showed up well on our monitors in the nuke plant.

    If it worries you, take a few rolls of photographic film and have one developed every week until you get feeling comfortable.

    After TMI they got the film from local drugstore shelves and developed it to assess whather there'd been exposure to the town. The film was not fogged and it had sensitivity of about 5 mr, which is a very low amount.

    That's something easily within your power to do and it might make you feel less apprehensive .

    Hmmm no Kodachrome anymore - i guess you'll have to use Fuji.
  14. Mar 17, 2012 #13
    Film is going the way of the dodo. Assuming it becomes largely unavailable in the near future what's the next best way of doing this?
  15. Mar 17, 2012 #14
    I'm curious for someone to answer the question as to what happens if Unit 4's fuel pool fails before they remove the fuel rods, how bad will the contamination be? Could it wipe out Tokyo?

    I think it's a reasonable question to ask if someone is thinking of moving to Japan. Its not like any of us would be surprised if another big quake hit and took out the fuel pool, it's in fairly bad shape.
  16. Mar 17, 2012 #15


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    Did the risk of future earthquakes in Japan disappear? I assume you won't want to fly to Japan as that would expose you to radiation enroute. There is also a non-zero risk the plane would crash. Then there is the risk of driving to the airport or taking a taxi in Japan - a truly life threatening experience. Perhaps it is best to hug a radon detector and hide in the basement.But even there would still be at risk from nuclear weapons and asteroids.

    My point is not to belittle your fear of radiation, it is to try to remind you that you can't get away from risk unless you are already dead.
  17. Mar 17, 2012 #16


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    I'm sure TEPCO is working diligently to prevent further degradation of the pool and fuel. The pool seems to be intact, and the plan is to cover it with special shielding in order to allow personnel to examine and move the fuel while minimizing exposure.

    If the pool failed, there could be additional contamination locally. With time, the fission gas decay, so rod internal pressure should decrease, along with a reduction in decay heat.

    The incidence of large quakes is few and far between, but such large quakes are, of course, unpredictable. More likely, they will experience Mag 5-7 quakes in that area, which have already occurred, and the pool is still intact.
  18. Mar 17, 2012 #17

    I see your point, and I wouldn't say I have a fear of radiation so much as I want to ensure I'm informed about the realities of the situation and how these things truly work so I don't find myself giving any sort of credibility again to the claims that brought me to make this thread and ask these questions in the first place.
  19. Mar 17, 2012 #18
    With all due respect, I would advise you to read a more wide variety of sources of information. Fukushimadiary was a blog started by a young man in Japan (Yokohama, I believe) who was convinced that Japan is irredeemably contaminated, and was convinced that his own health problems were a result of Fukushima. His blog started to get some attention from outside of Japan, from people who were prone to believe conspiracy theories, and so there formed a symbiotic relationship of the supremely paranoid. That blog embraced every wild rumor and prediction that he became aware of, and in turn he began to attract more and more hysterical submissions and posters. Enenews was a site that similarly embraced wild speculation and lurid headlines. Actually enenews is just a news aggregator, and the news it chooses to focus on is news with eye-catching, apocalyptic headlines.

    The problem is, these sites early on were leading people to believe Fukushima was magnitudes worse than Chernobyl, and when that scenario failed to materialize, they needed to come up with deeper conspiracy theories and stories of cover-ups to justify their extreme positions.

    The story of unit 4 is a great example. The foreign press gave voice to some who suggested the spent fuel pool of number 4 was obliterated, and bits of spent fuel were dispersed around the surrounding countryside. This story persisted for several months, despite Tepco showing video footage of intact fuel bundles in #4. Then, a rumor started to spread that the entire building of # 4 was leaning, and was in danger of collapse, and this rumor was of course embraced by the conspiracy theorists. And yet, #4 still stands.

    I'm not saying that these sites didn't have any value. However, if they are your exclusive source of information you will be as misinformed as you would be should you choose to listen to Tepco exclusively.
  20. Mar 17, 2012 #19
    I'm not quite sure what you are saying here, would the fuel pool catch on fire? Would the fuel rods melt/combust or are they safe with no water? I'm trying to get a feel for the difference in contamination between the current situation and an exposed fuel pool with no water and fresh fuel rods. Obviously the situation would be worse, but how much worse?

    Recently in NZ, Christchurch a second big earthquake caused most of the actual destruction a year after the first one gave everything a rattle.
  21. Mar 17, 2012 #20
    Speaking of dangers, how dangerous is contaminated food in the long term?

    The present limit is 500Bq/kg, soon to be lowered to 100Bq/kg. Rice crops are affected, and with rice being staple food in Japan, we will probably see a significant increase in radiation intake from food compared to pre-disaster levels. Is it a concern?

    If I eat 1000Bq of Cs-137, how does it translate into the internal radiation dose over my lifetime?

    I found a conversion table for ingestion in this PDF (page 156) following a link from Wikipedia, but I am not sure I understand it correctly. It lists the conversion factor for Cs-134 as 1.98E-8 Sv/Bq, and for Cs-137 as 1.35E-8 Sv/Bq. How can that be??? The isotopes should chemically be almost identical, and Cs-134 has a shorter half life, so it should have a lower conversion factor, not a higher one.
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