5 ms·

Fukushima's surfers riding on radioactive waves

39 points by ofrzeta 8y ago

gus_massa 8y ago
It's not difficult to get a Geiger detector and measure the radiation level in the water, and compare it with the radiation level of water far away. IIRC the additional radiation level is tiny. Moreover, water is a good radiation shield, so you don't get the radiation from the whole sea, but the radiation from the nearby water. See https://what-if.xkcd.com/29/ https://what-if.xkcd.com/29/ [I'd recommend not drinking the water there, just in case there is some isotope that may accumulate. But I'd prefer to get a good analysis of this part before being to worried.]
- SmellyGeekBoy 8y ago
  Indeed. In fact, at a working power plant the spent rods are stored underwater because it's so good at blocking radiation.
  - hackerman12345 8y ago
    I would say the main reason they are stored underwater is mostly because they need a place to transfer heat to lest they melt and cause a critical mass of spent fuel.
    - godelski 8y ago
      They do it for both reasons. The hydrogens in the water molecules are good at absorbing neutrons. The control rods are also typically made of carbon, and will release x-rays, which the water is also fairly good at blocking. Not as good as gold, but who's got that kind of money.
- godelski 8y ago
  Here's a map of Japan's radioactivity [0]. For those unfamiliar 1 Sv (Sievert) of ionizing radiation equates to a 5.5% chance increase of eventually developing cancer. It is also the maximum allowed dosage to NASA astronauts over their career. Radiation dosages are also difficult to calculate and Sv's have a weighting factor for where the radiation is taken in. The Wikipedia article [1] has a decent introduction to how the unit works, but you should really consult a higher grade text. [0] https://jciv.iidj.net/map/ https://jciv.iidj.net/map/ [1] https://en.wikipedia.org/wiki/Sievert https://en.wikipedia.org/wiki/Sievert
  - tomatotomato37 8y ago
    For those also unfamiliar, a nano Sievert is one billonth a regular Schedule, and a reading of 8500 nSv/h, or 8.5 µSv/h, would take 4860 days of constant 24 hour exposure, or a bit over 13 years, to reach a single Sv of radiation exposure. 8.5 µSv is also equivalent to 85 bananas, or 1/5th the exposure of flying from NY to LA. Mind your units.
    - unsignedint 8y ago
      Here's the visual! https://xkcd.com/radiation/ https://xkcd.com/radiation/
  - hammock 8y ago
    Nice map. How about the water or the fish?
    - godelski 8y ago
      I don't have a map of the water, but I'd wager they are doing far better than those on land. For a few reasons. 1) radiation is heavy, so it sinks, but slow enough that the water would disperse it quickly. 2) Water is a FANTASTIC radiation shield. See above as well as any nuclear reactor. 3) The main concern are the bone seekers (isotopes that deposit within bones). Which have short half lives and aren't absorbed well. A rough number (towards upper bound) is that a fish eating it (directly it) would absorb 10% of it. A fish eating that fish would absorb 10% of that, and so on. And there wasn't much of those isotopes released in the disaster in the first place. So combine that with the good mixing from ocean currents and I'd say fine. I would happily eat tuna caught in Japan. Side note: short half-lives generally equate to more danger. That's because they are releasing their energy at a much faster rate (typically). Long half lives generally means they are decaying slowly (otherwise it'd be gone). I know this makes sense, but we frequently think the opposite. That isn't to say that you shouldn't be wary of long half life materials, but that the dangers are different. Radiation is a fairly complicated subject (unsurprisingly).
      - 8y ago
stillbourne 8y ago
That's pretty rad.
- bond 8y ago
  Nice :)
flareback 8y ago
I'm always amazed at how little attention the Fukushima disaster gets.
- SmellyGeekBoy 8y ago
  It got a huge amount of attention at the time. The situation there seems stable now though, I'm not sure what's left to report?
  - godelski 8y ago
    I'd argue that it even still gets a fair amount of attention. There's a post on HN at least every 6mo, if not more often.
- newnewpdro 8y ago
  VICE recently did a short Fukushima disaster piece: https://www.youtube.com/watch?v=yGWKL_PBUs8 https://www.youtube.com/watch?v=yGWKL_PBUs8

39 points by ofrzeta 8y ago

It's not difficult to get a Geiger detector and measure the radiation level in the water, and compare it with the radiation level of water far away. IIRC the additional radiation level is tiny. Moreover, water is a good radiation shield, so you don't get the radiation from the whole sea, but the radiation from the nearby water. See https://what-if.xkcd.com/29/ https://what-if.xkcd.com/29/ [I'd recommend not drinking the water there, just in case there is some isotope that may accumulate. But I'd prefer to get a good analysis of this part before being to worried.]

SmellyGeekBoy 8y ago
Indeed. In fact, at a working power plant the spent rods are stored underwater because it's so good at blocking radiation.
- hackerman12345 8y ago
  I would say the main reason they are stored underwater is mostly because they need a place to transfer heat to lest they melt and cause a critical mass of spent fuel.
  - godelski 8y ago
    They do it for both reasons. The hydrogens in the water molecules are good at absorbing neutrons. The control rods are also typically made of carbon, and will release x-rays, which the water is also fairly good at blocking. Not as good as gold, but who's got that kind of money.
godelski 8y ago
Here's a map of Japan's radioactivity [0]. For those unfamiliar 1 Sv (Sievert) of ionizing radiation equates to a 5.5% chance increase of eventually developing cancer. It is also the maximum allowed dosage to NASA astronauts over their career. Radiation dosages are also difficult to calculate and Sv's have a weighting factor for where the radiation is taken in. The Wikipedia article [1] has a decent introduction to how the unit works, but you should really consult a higher grade text. [0] https://jciv.iidj.net/map/ https://jciv.iidj.net/map/ [1] https://en.wikipedia.org/wiki/Sievert https://en.wikipedia.org/wiki/Sievert
- tomatotomato37 8y ago
  For those also unfamiliar, a nano Sievert is one billonth a regular Schedule, and a reading of 8500 nSv/h, or 8.5 µSv/h, would take 4860 days of constant 24 hour exposure, or a bit over 13 years, to reach a single Sv of radiation exposure. 8.5 µSv is also equivalent to 85 bananas, or 1/5th the exposure of flying from NY to LA. Mind your units.
  - unsignedint 8y ago
    Here's the visual! https://xkcd.com/radiation/ https://xkcd.com/radiation/
- hammock 8y ago
  Nice map. How about the water or the fish?
  - godelski 8y ago
    I don't have a map of the water, but I'd wager they are doing far better than those on land. For a few reasons. 1) radiation is heavy, so it sinks, but slow enough that the water would disperse it quickly. 2) Water is a FANTASTIC radiation shield. See above as well as any nuclear reactor. 3) The main concern are the bone seekers (isotopes that deposit within bones). Which have short half lives and aren't absorbed well. A rough number (towards upper bound) is that a fish eating it (directly it) would absorb 10% of it. A fish eating that fish would absorb 10% of that, and so on. And there wasn't much of those isotopes released in the disaster in the first place. So combine that with the good mixing from ocean currents and I'd say fine. I would happily eat tuna caught in Japan. Side note: short half-lives generally equate to more danger. That's because they are releasing their energy at a much faster rate (typically). Long half lives generally means they are decaying slowly (otherwise it'd be gone). I know this makes sense, but we frequently think the opposite. That isn't to say that you shouldn't be wary of long half life materials, but that the dangers are different. Radiation is a fairly complicated subject (unsurprisingly).
    - 8y ago

stillbourne 8y ago

That's pretty rad.

bond 8y ago
Nice :)

flareback 8y ago

I'm always amazed at how little attention the Fukushima disaster gets.

SmellyGeekBoy 8y ago
It got a huge amount of attention at the time. The situation there seems stable now though, I'm not sure what's left to report?
- godelski 8y ago
  I'd argue that it even still gets a fair amount of attention. There's a post on HN at least every 6mo, if not more often.
newnewpdro 8y ago
VICE recently did a short Fukushima disaster piece: https://www.youtube.com/watch?v=yGWKL_PBUs8 https://www.youtube.com/watch?v=yGWKL_PBUs8