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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)

#21

Post by tru3_power »

bitL wrote: post #10
adrianN wrote: post #4

So oil tankers can apparently carry some 300000 tons. Three or four oil tankers full would then be enough storage space for the onsite water. Couldn't we fill some tankers and have them release the water far away from any fishing grounds?

...and damage some preserved ecosystem in the process. Great idea!

That brings up a good point. There are a few nuclear zones that no one lives in right (Chernobyl came to mind after watching that hbo show)? Why don’t we at-least get some value out of of these sad situations and convert one to a nuclear disposal site?

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

#22

Post by Robotbeat »

gnode wrote: post #11
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?

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 cont…

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.

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

#23

Post by _nalply »

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.

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.

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

#24

Post by beat »

Robotbeat wrote: post #20
jtms wrote: post #13

Earlier quoted context omitted.

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.

Tritium natural decays pretty quickly. Half life of 12 years.

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.

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

#25

Post by jessriedel »

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...

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

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

#26

Post by pvaldes »

adrianN wrote: post #4

So oil tankers can apparently carry some 300000 tons. Three or four oil tankers full would then be enough storage space for the onsite water. Couldn't we fill some tankers and have them release the water far away from any fishing grounds?

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.

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

#27

Post by m4rtink »

VBprogrammer wrote: post #5
adrianN wrote: post #4

So oil tankers can apparently carry some 300000 tons. Three or four oil tankers full would then be enough storage space for the onsite water. Couldn't we fill some tankers and have them release the water far away from any fishing grounds?

I wondered that myself. I think the problem is that they first need to dilute it considerably before releasing it. If they do that before loading it onto the ship it might take too many journeys to empty the tanks. If they do it onboard the ship the you've got a ship full of radioactive water sailing about. I'm not sure how hazardous the water is but you might struggle to find people willing to sail on it.

Maybe just get an older tanker and sink it over the destination ? If you make holes big enough in the process it should take care of both dilution & the contaminated vessel.

It worked fine for ships full of chemical weapons in the past, so should be able to work in this case as well. :)

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

#28

Post by gnode »

Robotbeat wrote: post #22
gnode wrote: post #11

Earlier quoted context omitted.

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 cont…

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.

You don't need to in the general case, although the only practical way to do so in this case is via the ocean.

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

#29

Post by pvaldes »

gnode wrote: post #6
adrianN wrote: post #4

So oil tankers can apparently carry some 300000 tons. Three or four oil tankers full would then be enough storage space for the onsite water. Couldn't we fill some tankers and have them release the water far away from any fishing grounds?

This was my thought also, although it may not be trivial to just hire an oil tanker to transport radioactive water. Before dilution, there may be a significant risk of contamination to the vessel and crew. You'd probably need a special vessel, specifically designed to handle radioactive fluids. Even if an oil tanker is technically adequate, there's likely some costly certification / approval that would need to be don…

> it may not be trivial to just hire an oil tanker to transport radioactive water

I bet that this is not even legal, for good reasons

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

#30

Post by m4rtink »

tru3_power wrote: post #21
bitL wrote: post #10

Earlier quoted context omitted.

...and damage some preserved ecosystem in the process. Great idea!

That brings up a good point. There are a few nuclear zones that no one lives in right (Chernobyl came to mind after watching that hbo show)? Why don’t we at-least get some value out of of these sad situations and convert one to a nuclear disposal site?

IIRC this is already happening in Chernobyl - other than all the wildlife preservation & tourism there is a big solar power plant being built:

https://phys.org/news/2018-10-chernobyl-life-solar-power.htm...

The article says they aim for up to 100 MWe capacity in the future, which would be nice, yet still illustrates how very powerful nuclear reactors are, with each of the 4 now inactive Chernobyl blocks producing 1000 MWe (and 3x times as much heat!).

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