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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 th

by 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.
_nalply 7y ago
The difficulty of filtering out tritium from water is that tritium oxide is water and not some solution or colloid. Tritium is an isotope of hydrogen and reacts with oxygen to water, namely tritiated water. One way is distillation because the boiling point of tritiated water is slightly above that of normal water (101.5°C instead of 100°C), but this seems to be a lot more difficult than distilling alcohol.
Symbiote 7y ago
Normal hydrogen has one proton. We write H or ¹H. Deuterium (not relevant here) has one extra protons, giving two. We write ²H. Tritium has two extra protons. We write ³H. Water is ¹H₂O, or (showing the structure) ¹H-O-¹H. (Or ¹H-¹⁶O-¹H, since it's normal oxygen in all this.) One or both of those normal hydrogen atoms can be replaced with tritium: ³H-O-¹H or (rarely) ³H-O-³H. Chemically, both ¹H-O-¹H, ³H-O-¹H, ³H-O-³H, or for that matter ²H-O-¹H or any other combination are essentially identical. Any chemical process you might think to do on normal water will have the same result on tritium-water. To separate them, you must use physical properties: tritium-water is slightly heavier. This is how different isotopes of uranium are isolated — centrifuging to separate the heavier and lighter molecules — but it's likely to be extremely costly at the quantity being discussed.

by jtms 7y ago

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.

_nalply 7y ago

The difficulty of filtering out tritium from water is that tritium oxide is water and not some solution or colloid. Tritium is an isotope of hydrogen and reacts with oxygen to water, namely tritiated water. One way is distillation because the boiling point of tritiated water is slightly above that of normal water (101.5°C instead of 100°C), but this seems to be a lot more difficult than distilling alcohol.

Symbiote 7y ago

Normal hydrogen has one proton. We write H or ¹H. Deuterium (not relevant here) has one extra protons, giving two. We write ²H. Tritium has two extra protons. We write ³H. Water is ¹H₂O, or (showing the structure) ¹H-O-¹H. (Or ¹H-¹⁶O-¹H, since it's normal oxygen in all this.) One or both of those normal hydrogen atoms can be replaced with tritium: ³H-O-¹H or (rarely) ³H-O-³H. Chemically, both ¹H-O-¹H, ³H-O-¹H, ³H-O-³H, or for that matter ²H-O-¹H or any other combination are essentially identical. Any chemical process you might think to do on normal water will have the same result on tritium-water. To separate them, you must use physical properties: tritium-water is slightly heavier. This is how different isotopes of uranium are isolated — centrifuging to separate the heavier and lighter molecules — but it's likely to be extremely costly at the quantity being discussed.