4 ms·

Quick question / thought, why not run it through beds of sand that take some of the radiation and bury that sand somewhere? Eventually as you run the water thro

Quick question / thought, why not run it through beds of sand that take some of the radiation and bury that sand somewhere? Eventually as you run the water through the sand long enough it should become less and less irradiated right?

gnode 7y ago
The problem is that you have a large volume of radioactive fluid. The radioactivity is "low-level" but still poses a danger to health and life. If you store it somewhere, you have to be sure it will stay there. Additionally, if it turns out you stored it somewhere silly, you'd want to be able to get it back. The alternative is to dilute it down so that it's less harmful, but then you have a larger volume, and so containing it is a larger problem. If you dilute it to the point that its volume is the entirety of water on earth, then it's at a safe level (and a fraction of the natural level), and so isn't a containment problem anymore. Sand will not help the problem; the radioactive component is tritium, which is in the water molecules themselves. The sand will just mix with the water and give you a larger volume that has handling challenges of wet sand and evaporates and sweats radioactive water.
- Robotbeat 7y ago
  You don’t need to dilute it to the entire volume of the earth’s supply to make it safe. Remember, we build granite countertops and eat nuts and go outside in the sunshine, all of which have large amounts of natural radiation.
  - gnode 7y ago
    You don't need to in the general case, although the only practical way to do so in this case is via the ocean.
jtms 7y ago
I’m guessing if there were a way to filter out the tritium they probably already would have. The article states that they already removed other isotopes from the water, but not the tritium. This leads me to believe there is something particularly tricky about separating it from water. Hopefully someone with some knowledge can weigh in here as I am curious as well.
- gnode 7y ago
  Tritium can be refined, and is done for various applications (radiolabelling; nuclear weapons; nuclear fusion). However it's expensive, as is reflected by its cost of about $30k per gram. It'd be even more expensive to refine from a dilute solution. That said, an imperfect distillation may be cheaper, but the quantities of fluid here are still huge.
- Robotbeat 7y ago
  Tritium natural decays pretty quickly. Half life of 12 years.
  - beat 7y ago
    Which is a good point, but "half life" doesn't mean "all gone". It'll take some x cycles to get it down to some safe level y. So the water needs stored until then, if it's not being released somewhere. Meanwhile, it keeps accumulating, because the problem is caused by groundwater leaching into the contaminated reactor area. So at some point, accumulated volume p will probably exceed available storage area q, which seems to be where we are now. So it has to be dumped somewhere. The solution is almost certainly to dump it at sea, but I don't think they can get away with dumping it right on the coastline, politically.
    - pvaldes 7y ago
      > at some point, accumulated volume p will probably exceed available storage area q Maybe they should stack a second row of containers in the second floor then? (hey, we doubled the available space with only steel beams, some concrete and a welder! we can build upwards!, is like magic!)
      - beat 7y ago
        Gosh, why didn't they think of that? Every difficult engineering or social problem can be solved by the clever one-line idea of some dude on the internet.
- 7y ago

gnode 7y ago

The problem is that you have a large volume of radioactive fluid. The radioactivity is "low-level" but still poses a danger to health and life. If you store it somewhere, you have to be sure it will stay there. Additionally, if it turns out you stored it somewhere silly, you'd want to be able to get it back. The alternative is to dilute it down so that it's less harmful, but then you have a larger volume, and so containing it is a larger problem. If you dilute it to the point that its volume is the entirety of water on earth, then it's at a safe level (and a fraction of the natural level), and so isn't a containment problem anymore. Sand will not help the problem; the radioactive component is tritium, which is in the water molecules themselves. The sand will just mix with the water and give you a larger volume that has handling challenges of wet sand and evaporates and sweats radioactive water.

Robotbeat 7y ago
You don’t need to dilute it to the entire volume of the earth’s supply to make it safe. Remember, we build granite countertops and eat nuts and go outside in the sunshine, all of which have large amounts of natural radiation.
- gnode 7y ago
  You don't need to in the general case, although the only practical way to do so in this case is via the ocean.

jtms 7y ago

I’m guessing if there were a way to filter out the tritium they probably already would have. The article states that they already removed other isotopes from the water, but not the tritium. This leads me to believe there is something particularly tricky about separating it from water. Hopefully someone with some knowledge can weigh in here as I am curious as well.

gnode 7y ago
Tritium can be refined, and is done for various applications (radiolabelling; nuclear weapons; nuclear fusion). However it's expensive, as is reflected by its cost of about $30k per gram. It'd be even more expensive to refine from a dilute solution. That said, an imperfect distillation may be cheaper, but the quantities of fluid here are still huge.
Robotbeat 7y ago
Tritium natural decays pretty quickly. Half life of 12 years.
- beat 7y ago
  Which is a good point, but "half life" doesn't mean "all gone". It'll take some x cycles to get it down to some safe level y. So the water needs stored until then, if it's not being released somewhere. Meanwhile, it keeps accumulating, because the problem is caused by groundwater leaching into the contaminated reactor area. So at some point, accumulated volume p will probably exceed available storage area q, which seems to be where we are now. So it has to be dumped somewhere. The solution is almost certainly to dump it at sea, but I don't think they can get away with dumping it right on the coastline, politically.
  - pvaldes 7y ago
    > at some point, accumulated volume p will probably exceed available storage area q Maybe they should stack a second row of containers in the second floor then? (hey, we doubled the available space with only steel beams, some concrete and a welder! we can build upwards!, is like magic!)
    - beat 7y ago
      Gosh, why didn't they think of that? Every difficult engineering or social problem can be solved by the clever one-line idea of some dude on the internet.
7y ago