4 ms·

One thing that grabs my attention is that the radiation levels in the contaminated zones are much lower than I thought they'd be. For context, the limit for a r

by struct 11y ago

One thing that grabs my attention is that the radiation levels in the contaminated zones are much lower than I thought they'd be. For context, the limit for a radiation worker in the US is 50 mSv. Obviously, I guess it depends on the radioactive isotopes released and what kind of radiation they release, but I'm still impressed.

ptaipale 11y ago
Another funny anecdote about Fukushima was that people evacuated the area of elevated radiation and left Japan to what was "home", for instance in the case of my countrymen, Finland. The end result: they left an area of lesser radiation to an area where there is more radiation (the natural background radiation here is higher than the elevated levels were in Japan). And when doing so, they took an airplane where the in-flight radiation levels are even higher.
- gggmaster 11y ago
  Maybe there are other things to concern about, such as a discredited government, peer pressure, etc.
  - ptaipale 11y ago
    Of course. And media hype, particularly social media rumors, combined with scientific illiteracy.
tptacek 11y ago
That's the limit per year. The figures you're seeing in this article are per hour. It's not immediately lethal, but it's drastically elevated.
- OscarCunningham 11y ago
  The figures are mSv/year or µSv/hour, i.e. harmless.
  - tptacek 11y ago
    Harmless? Doesn't 50mSv/yr imply a budget of 5.5uSv/hr? The numbers in the photos are higher than that. ... I mean, yes, they probably aren't statistically very harmful! Nothing like the Chernobyl exclusion zone, at least in the areas this person visited, and considering only ambient exposure. Still, over the limit, and, like I said, drastically elevated. Fukushima unquestionably harmed its surrounding area.
dfox 11y ago
The limit is 50mSv per year, not per hour. Sievert is cumulative unit that has to be either qualified by time or measured over entire lifespan to be meaningfully comparable. But on the other hand quantitatively measuring and comparing radiation effects is hard problem as there is essentially nothing that can be precisely measured and at the same time has any meaning as to biological effects, in practice the conversions between various units are just done using various experimentally determined constants that may or may not be relevant to given situation.
- e12e 11y ago
  Would appear that the limit is similar - the "red zone" is for "(> 50 mSv/y)" (note "more than") -- and the sign at the end "Leaving the zone" reads 4.9 mSV/h. That'd be about 42.000 mSV/year -- if we assume constant dose. Or put it another way -- stay an hour and you're at the (safe) limit of exposure for a year. As for all the comments on how nuclear isn't all that dangerous -- how much do we really know about people leaving 4-5 generations in an area with elevated radiation, eating produce etc? I guess we have some data from the Bikin Islands[1] -- but those levels might very well be much higher -- at least it's not an example of how we can live safely in a radiation zone. Speaking of [1]: "The special International Atomic Energy Agency (IAEA) Bikini Advisory Group determined in 1997 that "It is safe to walk on all of the islands ... although the residual radioactivity on islands in Bikini Atoll is still higher than on other atolls in the Marshall Islands, it is not hazardous to health at the levels measured ... The main radiation risk would be from the food: eating locally grown produce, such as fruit, could add significant radioactivity to the body...Eating coconuts or breadfruit from Bikini Island occasionally would be no cause for concern. Eating many over a long period of time without having taken remedial measures, however, might result in radiation doses higher than internationally agreed safety levels." IAEA estimated that living in the atoll and consuming local food would result in an effective dose of about 15 mSv/year." It will be interesting to see if removing topsoil in Fukushima will be enough for radiation to reach safe levels. Hopefully the water tables are safe. [1] https://en.wikipedia.org/wiki/Nuclear_testing_at_Bikini_Atoll#Return_to_Bikini_Island https://en.wikipedia.org/wiki/Nuclear_testing_at_Bikini_Atol...
  - 11y ago

by struct 11y ago

ptaipale 11y ago

Another funny anecdote about Fukushima was that people evacuated the area of elevated radiation and left Japan to what was "home", for instance in the case of my countrymen, Finland. The end result: they left an area of lesser radiation to an area where there is more radiation (the natural background radiation here is higher than the elevated levels were in Japan). And when doing so, they took an airplane where the in-flight radiation levels are even higher.

gggmaster 11y ago
Maybe there are other things to concern about, such as a discredited government, peer pressure, etc.
- ptaipale 11y ago
  Of course. And media hype, particularly social media rumors, combined with scientific illiteracy.

tptacek 11y ago

That's the limit per year. The figures you're seeing in this article are per hour. It's not immediately lethal, but it's drastically elevated.

OscarCunningham 11y ago
The figures are mSv/year or µSv/hour, i.e. harmless.
- tptacek 11y ago
  Harmless? Doesn't 50mSv/yr imply a budget of 5.5uSv/hr? The numbers in the photos are higher than that. ... I mean, yes, they probably aren't statistically very harmful! Nothing like the Chernobyl exclusion zone, at least in the areas this person visited, and considering only ambient exposure. Still, over the limit, and, like I said, drastically elevated. Fukushima unquestionably harmed its surrounding area.

dfox 11y ago

The limit is 50mSv per year, not per hour. Sievert is cumulative unit that has to be either qualified by time or measured over entire lifespan to be meaningfully comparable. But on the other hand quantitatively measuring and comparing radiation effects is hard problem as there is essentially nothing that can be precisely measured and at the same time has any meaning as to biological effects, in practice the conversions between various units are just done using various experimentally determined constants that may or may not be relevant to given situation.

e12e 11y ago
Would appear that the limit is similar - the "red zone" is for "(> 50 mSv/y)" (note "more than") -- and the sign at the end "Leaving the zone" reads 4.9 mSV/h. That'd be about 42.000 mSV/year -- if we assume constant dose. Or put it another way -- stay an hour and you're at the (safe) limit of exposure for a year. As for all the comments on how nuclear isn't all that dangerous -- how much do we really know about people leaving 4-5 generations in an area with elevated radiation, eating produce etc? I guess we have some data from the Bikin Islands[1] -- but those levels might very well be much higher -- at least it's not an example of how we can live safely in a radiation zone. Speaking of [1]: "The special International Atomic Energy Agency (IAEA) Bikini Advisory Group determined in 1997 that "It is safe to walk on all of the islands ... although the residual radioactivity on islands in Bikini Atoll is still higher than on other atolls in the Marshall Islands, it is not hazardous to health at the levels measured ... The main radiation risk would be from the food: eating locally grown produce, such as fruit, could add significant radioactivity to the body...Eating coconuts or breadfruit from Bikini Island occasionally would be no cause for concern. Eating many over a long period of time without having taken remedial measures, however, might result in radiation doses higher than internationally agreed safety levels." IAEA estimated that living in the atoll and consuming local food would result in an effective dose of about 15 mSv/year." It will be interesting to see if removing topsoil in Fukushima will be enough for radiation to reach safe levels. Hopefully the water tables are safe. [1] https://en.wikipedia.org/wiki/Nuclear_testing_at_Bikini_Atoll#Return_to_Bikini_Island https://en.wikipedia.org/wiki/Nuclear_testing_at_Bikini_Atol...
- 11y ago