4 ms·

In an attempt to grasp how toxic the water is, wouldn't it be more effective to measure levels of cesium 137 instead of overall background radiation? I don't

In an attempt to grasp how toxic the water is, wouldn't it be more effective to measure levels of cesium 137 instead of overall background radiation? I don't care what background radiation the entire Pacific has, I care if the sushi I'm eating has ionized, cancer-causing particles in it. "Michio Aoyama’s initial findings were more startling than most. As a senior scientist at the Japanese government’s Meteorological Research Institute, he said levels of radioactive cesium 137 in the surface water of the Pacific Ocean could be 10,000 times as high as contamination after Chernobyl..." http://www.nytimes.com/2014/03/17/world/asia/concerns-over-measurement-of-fukushima-fallout.html http://www.nytimes.com/2014/03/17/world/asia/concerns-over-m...

tptacek 11y ago
Your analysis might confuse two different phenomena. When you mention TEPCO pouring "400 million gallons" into the Pacific, what you're talking about is them dumping contaminated cooling water from tanks into the ocean. The scale of that dumping is caused by (a) the ongoing need to pump water into the compromised reactor to cool it and (b) the large amounts of water they've already stored. However: that water is also filtered, to remove the (actually dangerous) Sr-90. What's being dumped into the ocean is HTO, not Sr-90 or Cs-137. On the other hand, the meltdown at Fukushima contaminated the entire area with Cs-137, most of which is in the soil, sediment, and sand. The Cs-137 contamination is much worse than the HTO contamination. However, it is also not ongoing; in fact, increase in cesium detected around the plant has fallen dramatically in the last two years.
- mrschwabe 11y ago
  Fair enough - though I'm not sure if I will just take your word for it that the potential for new releases of new cesium 137 is not an ongoing threat from Fukushima Daiichi. The only way we can know for sure I suppose, is through the efforts of independent researchers brave enough to get close to the facility. In the spirit of HN, it would be neat to see an open technology solution for the purposes of monitoring. Ie: if(waterSample.cesium137 > 0.001) return ALARM(waterSample)
  - gh02t 11y ago
    > it would be neat to see an open technology solution for the purposes of monitoring It's trivial to do so. Decay of Cs-137 releases a 662 keV gamma ray that is easily measured and the count rate is proportional to the source activity (or ultimately the total amount of Cs-137 present). You can calibrate an inexpensive NaI detector such that it will tell you how much Cs-137 is in a given volume of water. If you place it next to a pipe that has a constant flow rate, you can infer the average amount of Cs-137 in the liquid flowing through the pipe. It's something that you can build in an afternoon if you know what you're doing and have the equipment. This is pretty much how they monitor liquids for contamination in a real plant, except they use more detailed spectral measurements to monitor multiple isotopes. If you ever have the rare opportunity to go into a reactor control room, there will be a display somewhere that reads out this exact measurement.
    - mrschwabe 11y ago
      Good info! If the technology is cheap, as you point out, then the next logical step might be a collaborative project to get a network of inexpensive, miniature, buoyant craft's out to sea - for the purpose of actively measuring levels of cesium 137; sharing these results for everyone to see, to graph, and to check on at any given time of the day. One-time results from a fish is useful data but to have a whole swarm of devices actively monitoring levels in various locations would be ideal. Thinking ahead, the next hurdle could be the logistics of internet connection - maybe they could connect to each other in a mesh-network that daizy-chains back to an internet connection closer to shore. Oh, and power (solar panel maybe?). Navigation. Yeah - some challenges for sure, but it all seems within reason.
      - slapshot 11y ago
        Somebody did this. Before the experiment, they expected a background level of Cesium 137 of between 1 and 2 bq/M^3 (caused by 1950s nuclear testing, which released a ton of it). They found actual levels between 1 and 2 bq/M^3 across the Pacific with some small variation above and below: http://ourradioactiveocean.org/results.html http://ourradioactiveocean.org/results.html Think about it this way. Worst-case estimates are that 2-4 kilos of Cesium 137 were released. If it all ends up in the ocean, the total Pacific Ocean weighs on the order of 638,000,000,000,000,000,000 kilos. The total new Cesium 137 is: 0.000000000000000000627% of the ocean. At a 30 year half-life, that's one decay event per 70 liters per hour.

tptacek 11y ago

Your analysis might confuse two different phenomena. When you mention TEPCO pouring "400 million gallons" into the Pacific, what you're talking about is them dumping contaminated cooling water from tanks into the ocean. The scale of that dumping is caused by (a) the ongoing need to pump water into the compromised reactor to cool it and (b) the large amounts of water they've already stored. However: that water is also filtered, to remove the (actually dangerous) Sr-90. What's being dumped into the ocean is HTO, not Sr-90 or Cs-137. On the other hand, the meltdown at Fukushima contaminated the entire area with Cs-137, most of which is in the soil, sediment, and sand. The Cs-137 contamination is much worse than the HTO contamination. However, it is also not ongoing; in fact, increase in cesium detected around the plant has fallen dramatically in the last two years.

mrschwabe 11y ago
Fair enough - though I'm not sure if I will just take your word for it that the potential for new releases of new cesium 137 is not an ongoing threat from Fukushima Daiichi. The only way we can know for sure I suppose, is through the efforts of independent researchers brave enough to get close to the facility. In the spirit of HN, it would be neat to see an open technology solution for the purposes of monitoring. Ie: if(waterSample.cesium137 > 0.001) return ALARM(waterSample)
- gh02t 11y ago
  > it would be neat to see an open technology solution for the purposes of monitoring It's trivial to do so. Decay of Cs-137 releases a 662 keV gamma ray that is easily measured and the count rate is proportional to the source activity (or ultimately the total amount of Cs-137 present). You can calibrate an inexpensive NaI detector such that it will tell you how much Cs-137 is in a given volume of water. If you place it next to a pipe that has a constant flow rate, you can infer the average amount of Cs-137 in the liquid flowing through the pipe. It's something that you can build in an afternoon if you know what you're doing and have the equipment. This is pretty much how they monitor liquids for contamination in a real plant, except they use more detailed spectral measurements to monitor multiple isotopes. If you ever have the rare opportunity to go into a reactor control room, there will be a display somewhere that reads out this exact measurement.
  - mrschwabe 11y ago
    Good info! If the technology is cheap, as you point out, then the next logical step might be a collaborative project to get a network of inexpensive, miniature, buoyant craft's out to sea - for the purpose of actively measuring levels of cesium 137; sharing these results for everyone to see, to graph, and to check on at any given time of the day. One-time results from a fish is useful data but to have a whole swarm of devices actively monitoring levels in various locations would be ideal. Thinking ahead, the next hurdle could be the logistics of internet connection - maybe they could connect to each other in a mesh-network that daizy-chains back to an internet connection closer to shore. Oh, and power (solar panel maybe?). Navigation. Yeah - some challenges for sure, but it all seems within reason.
    - slapshot 11y ago
      Somebody did this. Before the experiment, they expected a background level of Cesium 137 of between 1 and 2 bq/M^3 (caused by 1950s nuclear testing, which released a ton of it). They found actual levels between 1 and 2 bq/M^3 across the Pacific with some small variation above and below: http://ourradioactiveocean.org/results.html http://ourradioactiveocean.org/results.html Think about it this way. Worst-case estimates are that 2-4 kilos of Cesium 137 were released. If it all ends up in the ocean, the total Pacific Ocean weighs on the order of 638,000,000,000,000,000,000 kilos. The total new Cesium 137 is: 0.000000000000000000627% of the ocean. At a 30 year half-life, that's one decay event per 70 liters per hour.