4 ms·

You seem to imply the ocean is a clearly better option — I’m not sure it is? Harm will come to us and other animals either way, the extent seems a bit hard to a

You seem to imply the ocean is a clearly better option — I’m not sure it is? Harm will come to us and other animals either way, the extent seems a bit hard to assess and depends highly on what one values.

eganist 6y ago
The water can stop beta particles far more effectively than the air (2in v. 10ft), which minimizes the risk to life forms save for those which directly interact with tritium water, but even then, there's far more water in the ocean for tritium water to dilute into. In the air, the water will still get invariably pulled into the water cycle, wherein it condenses into rain, enters streams and lakes, plants, life, etc. where it can't as effectively dilute. Would love for a nuclear or environmental researcher to fact-check me here. I'm out of my depth. I'm just applying the trivia that I know.
- skrause 6y ago
  This "what if" xkcd is somewhat relevant: https://what-if.xkcd.com/74/ https://what-if.xkcd.com/74/ The vast majority of water molecules in the oceans have never been drunk by any human ever.
- rnhmjoj 6y ago
  I'm just a physics student by incidentally I'm researching tritium right now. Tritium is one of the least toxic radionuclide because the β radiation it emits is very low energy, also the biological half life is only 10 days (it means it's quickly eliminated by the body): unless you ingest very large quantities of it, you're probably going to be fine. In fact, the range of the electrons is even less than you quote: around 5 mm in air and 6 μm in water, which means it's effectively stopped by the dead skin layer. If I were to decide, I would probably pick dilution in water over vaporisation.
  - eganist 6y ago
    > around 5 mm in air and 6 μm in water Interesting. My source re: beta radiation was (admittedly a nuclear promotion nonprofit) http://nuclearconnect.org/know-nuclear/science/protecting http://nuclearconnect.org/know-nuclear/science/protecting > β BETA – can only be stopped after traveling through about 10 feet of air, less than 2 inches of water, or a thin layer of glass or metal. Additional covering, for example heavy clothing, is necessary to protect against beta-emitters. Some beta particles can penetrate and burn the skin. I won't be surprised if you're right, but if a nonprofit getting government grants to promote the nuclear industry gets it wrong, I'd be pretty worried.
    - ascar 6y ago
      The problem is that the source is generalizing, which is fine for saying beta has usually shorter range and is less dangerous than gamma, but is too general to be applicable here. Beta radiation just describes a certain kind of radiation, namely emitting an electron (or positron). However it doesn't directly tell you how much energy that electron has. Wikipedia on Beta particles says that "Beta particles with an energy of 0.5 MeV have a range of about one metre in air; the distance is dependent on the particle energy." [1] Tritium beta decay just has an energy of 0.018590 MeV [2] and I wouldn't be surprised if reach isn't proportional but for example cubic (I don't know the formula) thus the huge difference in reach. [1] https://en.m.wikipedia.org/wiki/Beta_particle#:~:text=Beta%20particles%20with%20an%20energy,less%20ionising%20than%20alpha%20particles https://en.m.wikipedia.org/wiki/Beta_particle#:~:text=Beta%2.... [2] https://en.m.wikipedia.org/wiki/Tritium https://en.m.wikipedia.org/wiki/Tritium
      - eganist 6y ago
        Helpful, thanks!
    - perpetualpatzer 6y ago
      My understanding is that penetration depends on the energy associated with the the β particle [0] and tritium decay releases relatively lower-energy β particles [1]. The nonprofit isn't wrong... they're just saying "a .22 bullet can kill you" while parent is saying "tritium is like throwing the bullet instead of firing." [1] https://sciencedemonstrations.fas.harvard.edu/presentations/%CE%B1-%CE%B2-%CE%B3-penetration-and-shielding https://sciencedemonstrations.fas.harvard.edu/presentations/... [1] https://en.wikipedia.org/wiki/Tritium https://en.wikipedia.org/wiki/Tritium
ddingus 6y ago
Harm was going to come to us, post event, no matter what. Some argue we are not good enough at these things, meaning harm will come to us every time we generate energy this way. The only real question being us or future people, near or longer term harm. Say we set that aside as a matter of ambiguity and just focus on type of harm. (My own take is we will generate energy this way, so we may as well fund serious risk mitigation of all kinds.) We have only one option here longer term, and that is dilution. Normally, we have two, the other being containment. (And, given we do make energy this way, strong investment in containment makes a lot of sense.) And in this scenario, we have both contaminated water to deal with and a core likely to enter the water cycle itself at some point too. It will, at that time, irradiate water for a long time. Is the harm in the atmosphere greater than in water? It will go somewhere. IMHO, the water is a better shield and has far greater capacity to serve as a medium to dilute in than the air does.
garmaine 6y ago
The ocean is clearly a better option. First, water itself acts as an absorbent of the emitted radiation. So the only living things which take up the radiation are those which consume the water. Second, unlike heavy metals, the uptake of heavy water isn't especially driven by biology. They don't soak up and concentrate the radiation. Third, there is a lot more water in the ocean than the atmosphere. In the ocean it will dilute to nearly unmeasurable levels. In the atmosphere it will fall back down as rain and concentrate in our water supply, irrigation, and crops.

eganist 6y ago

The water can stop beta particles far more effectively than the air (2in v. 10ft), which minimizes the risk to life forms save for those which directly interact with tritium water, but even then, there's far more water in the ocean for tritium water to dilute into. In the air, the water will still get invariably pulled into the water cycle, wherein it condenses into rain, enters streams and lakes, plants, life, etc. where it can't as effectively dilute. Would love for a nuclear or environmental researcher to fact-check me here. I'm out of my depth. I'm just applying the trivia that I know.

skrause 6y ago
This "what if" xkcd is somewhat relevant: https://what-if.xkcd.com/74/ https://what-if.xkcd.com/74/ The vast majority of water molecules in the oceans have never been drunk by any human ever.
rnhmjoj 6y ago
I'm just a physics student by incidentally I'm researching tritium right now. Tritium is one of the least toxic radionuclide because the β radiation it emits is very low energy, also the biological half life is only 10 days (it means it's quickly eliminated by the body): unless you ingest very large quantities of it, you're probably going to be fine. In fact, the range of the electrons is even less than you quote: around 5 mm in air and 6 μm in water, which means it's effectively stopped by the dead skin layer. If I were to decide, I would probably pick dilution in water over vaporisation.
- eganist 6y ago
  > around 5 mm in air and 6 μm in water Interesting. My source re: beta radiation was (admittedly a nuclear promotion nonprofit) http://nuclearconnect.org/know-nuclear/science/protecting http://nuclearconnect.org/know-nuclear/science/protecting > β BETA – can only be stopped after traveling through about 10 feet of air, less than 2 inches of water, or a thin layer of glass or metal. Additional covering, for example heavy clothing, is necessary to protect against beta-emitters. Some beta particles can penetrate and burn the skin. I won't be surprised if you're right, but if a nonprofit getting government grants to promote the nuclear industry gets it wrong, I'd be pretty worried.
  - ascar 6y ago
    The problem is that the source is generalizing, which is fine for saying beta has usually shorter range and is less dangerous than gamma, but is too general to be applicable here. Beta radiation just describes a certain kind of radiation, namely emitting an electron (or positron). However it doesn't directly tell you how much energy that electron has. Wikipedia on Beta particles says that "Beta particles with an energy of 0.5 MeV have a range of about one metre in air; the distance is dependent on the particle energy." [1] Tritium beta decay just has an energy of 0.018590 MeV [2] and I wouldn't be surprised if reach isn't proportional but for example cubic (I don't know the formula) thus the huge difference in reach. [1] https://en.m.wikipedia.org/wiki/Beta_particle#:~:text=Beta%20particles%20with%20an%20energy,less%20ionising%20than%20alpha%20particles https://en.m.wikipedia.org/wiki/Beta_particle#:~:text=Beta%2.... [2] https://en.m.wikipedia.org/wiki/Tritium https://en.m.wikipedia.org/wiki/Tritium
    - eganist 6y ago
      Helpful, thanks!
  - perpetualpatzer 6y ago
    My understanding is that penetration depends on the energy associated with the the β particle [0] and tritium decay releases relatively lower-energy β particles [1]. The nonprofit isn't wrong... they're just saying "a .22 bullet can kill you" while parent is saying "tritium is like throwing the bullet instead of firing." [1] https://sciencedemonstrations.fas.harvard.edu/presentations/%CE%B1-%CE%B2-%CE%B3-penetration-and-shielding https://sciencedemonstrations.fas.harvard.edu/presentations/... [1] https://en.wikipedia.org/wiki/Tritium https://en.wikipedia.org/wiki/Tritium

ddingus 6y ago

Harm was going to come to us, post event, no matter what. Some argue we are not good enough at these things, meaning harm will come to us every time we generate energy this way. The only real question being us or future people, near or longer term harm. Say we set that aside as a matter of ambiguity and just focus on type of harm. (My own take is we will generate energy this way, so we may as well fund serious risk mitigation of all kinds.) We have only one option here longer term, and that is dilution. Normally, we have two, the other being containment. (And, given we do make energy this way, strong investment in containment makes a lot of sense.) And in this scenario, we have both contaminated water to deal with and a core likely to enter the water cycle itself at some point too. It will, at that time, irradiate water for a long time. Is the harm in the atmosphere greater than in water? It will go somewhere. IMHO, the water is a better shield and has far greater capacity to serve as a medium to dilute in than the air does.

garmaine 6y ago

The ocean is clearly a better option. First, water itself acts as an absorbent of the emitted radiation. So the only living things which take up the radiation are those which consume the water. Second, unlike heavy metals, the uptake of heavy water isn't especially driven by biology. They don't soak up and concentrate the radiation. Third, there is a lot more water in the ocean than the atmosphere. In the ocean it will dilute to nearly unmeasurable levels. In the atmosphere it will fall back down as rain and concentrate in our water supply, irrigation, and crops.