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Radioactive water at Fukushima Daiichi: What should be done? (2018)

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Re: Radioactive water at Fukushima Daiichi: What should be done? (2018)

#51

Post by jessriedel »

AbrahamParangi wrote: post #31
jessriedel wrote: post #25

Earlier quoted context omitted.

No one knows with any confidence whether radiation levels below background levels are harmful or not. https://en.m.wikipedia.org/wiki/Linear_no-threshold_model

Sure but the assumption is that however infinitesimally bad it is, it’s not worse than what you’re already tolerating.

"Tolerating" might mean experiencing the normal levels of cancer, which is 2nd only to heart disease as a leading cause of death in the US. If we take a given amount of radiation, then, assuming the linear-no-threshold model, spreading that radiation around a giant population does not decrease the number of deaths induced.

Re: Radioactive water at Fukushima Daiichi: What should be done? (2018)

#52

Post by jessriedel »

throwaway5752 wrote: post #34
jessriedel wrote: post #25

Earlier quoted context omitted.

No one knows with any confidence whether radiation levels below background levels are harmful or not. https://en.m.wikipedia.org/wiki/Linear_no-threshold_model

Doesn't work that way if you ingest it, right? And obviously not all radiation is equal (alpha, beta, gamma) and even among those they have varying level of energy based on source. The concern here - if I understand correctly - is that it's ingestion and absorption of a low half live (more energetic) beta emitter.

No, I don't think the distinction between ingestion and external exposure is fredley's point. Indeed, a fixed amount of radiation is much more destructive when ingested.

But regardless, that's not the point I'm disputing. I'm disputing whether "the radiation has been reduced to background levels" necessarily means the negative effect of the radiation has been made negligible. Rather, assuming the linear-no-threshold model, the number of radiation-induced deaths will not decrease.

Re: Radioactive water at Fukushima Daiichi: What should be done? (2018)

#53

Post by throwaway5752 »

Animats wrote: post #50
throwaway5752 wrote: post #37

Earlier quoted context omitted.

Tritium undergoes beta decay and has a 12 year half life. Beta decay from a sign or your watch can only partially get through your skin (and skin is continuously shed and contains melanin). If you drink (or eat plants/animals in a tritium contaminated foodchain) then you bypass that protective layer and can damage organs that have far less resilience to radiation exposure.

Right. So put it in an oil tanker, take it someplace with permafrost, pump it out, and let it freeze. A few parts of Hokkaido are cold enough. In a century, it will have decayed enough to be a non-problem.

I don't think I'd want to bank on stable permafrost for a century. And one would probably want to put some care into site selection and construction as seismic hazards got us here to begin with. The residents of Hokkaido might reasonably not be warmly welcoming to this idea. I don't know enough about tritium impact to sublimation rates, but that would presumably be a problem. But point is taken about enclosed and chilled storage for 84-96 years.

Re: Radioactive water at Fukushima Daiichi: What should be done? (2018)

#55

Post by Symbiote »

jtms wrote: post #13
warmwaffles wrote: post #8

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?

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.

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.

Re: Radioactive water at Fukushima Daiichi: What should be done? (2018)

#56

Post by cpeterso »

fredley wrote: post #7

My old Physics teacher always said to put it on cornflakes. The surface area of all cornflakes in existence (back of the envelope) would result in totally harmless concentrations, undetectable above background. Of course getting the waste evenly distributed over all the cornflakes is another matter, one for the engineers...

James Lovelock (formulator of the Gaia hypothesis) suggested sprinkling radioactive waste through out wilderness areas. This would, in a way, also help preserve these areas because humans would be wary of entering them or building in them.

Re: Radioactive water at Fukushima Daiichi: What should be done? (2018)

#57

Post by adrianN »

marcosdumay wrote: post #42
adrianN wrote: post #9

Earlier quoted context omitted.

Tritium is quite weakly radioactive. It is effectively shielded by a few millimeters of air. As long as the crew doesn't drink the cargo they should be pretty save.

Evaporation may make it hard to insulate the crew from the cargo.

Evaporations from crude oil are probably more dangerous so I assume that oil tankers are equipped for this.

Re: Radioactive water at Fukushima Daiichi: What should be done? (2018)

#58

Post by keiru »

belenos46 wrote: post #32

Uhhh, culture a bunch of spores of radiotrophic fungus[0] and dump them all over the area? [0] https://en.wikipedia.org/wiki/Radiotrophic_fungus

Those are able to feed off radiation, but they don't shield other beings from it. It's not like oil-eating bacteria.

Re: Radioactive water at Fukushima Daiichi: What should be done? (2018)

#60

Post by pvaldes »

Lazare wrote: post #38
pvaldes wrote: post #26

Earlier quoted context omitted.

Hiding the problem under the rug. The sucessful human way of choice to manage radiation since the simpsons' first season Water currents would return it to home, or to somebody's home or kitchen. Fishes migrate also.

That's not how it works. It's dilute enough it's safe to just dump it on the coast already; dumping it at sea would just be a big PR production to make it appear even safer. There's no risk of "water currents causing it to return home". That's not even something that is physically possible.

> That's not even something that is physically possible.

Water currents move water masses, travel in closed loops and obey the laws of physics. Claiming that is not even physically possible that the same water pass two times by a point is an overstatement. Can be unprobable, but is perfectly possible with enough time.

Water in Fukushima travels to California and Alaska and then returns again to Japan, and then returns to USA in an endless loop. That's how it works. Ask an oceanographer.

Water masses with their own collection of animals and plants are traced far away of their point of origin. Is not a secret at all.

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