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A comment on Japan’s plan to dump nuclear waste into the pacific ocean may not be safe. Parent comment

Re:Japan’s plan to dump nuclear waste into the pacific ocean... by pvaldes on Thursday April 28, 2022 @05:48AM (#31190578)
Then why not use it as a valuable source of the very expensive and non renewable Helium?

It seems that they are trowing money to the sea after paying yet for storing it for the last 11 years.

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Re:Japan’s plan to dump nuclear waste into the pacific ocean... by ben_w on Thursday April 28, 2022 @06:43AM (#31190939)
> Then why not use it as a valuable source of the very expensive and non renewable Helium?

Same reason we don’t use nuclear reactors to turn lead into gold, even though we can: it’s far more expensive than it’s worth.

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Re:Japan’s plan to dump nuclear waste into the pacific ocean... by perihelions on Thursday April 28, 2022 @07:46AM (#31191368)
That's actually what we do, in this case: nuclear reactor-derived tritium is the *sole* source of helium-3.

https://en.wikipedia.org/wiki/Helium-3#Human_production

It's *ten* times more expensive than gold!

(If I remember correctly, medical ³He MRI's are done on a closed rebreather -- they literally want to recycle your lung air, it's that valuable).

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Re:Japan’s plan to dump nuclear waste into the pacific ocean... by ben_w on Thursday April 28, 2022 @09:16AM (#31192078)
Indeed. I was assuming that the comment I was replying to was referring to helium in general because they were not more specific, and the normal form is ⁴He — we’re not filling party balloons with it.
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Re:Japan’s plan to dump nuclear waste into the pacific ocean... by ramchip on Thursday April 28, 2022 @06:39AM (#31190914)
It's 15 grams of tritium in total, so it won't generate much helium.

Source: https://www.meti.go.jp/english/earthquake/nuclear/decommissi... [Q6]

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Re:Japan’s plan to dump nuclear waste into the pacific ocean... by pvaldes on Thursday April 28, 2022 @06:53AM (#31191003)
Very interesting, thanks.

Another silly question. As is known that Tritium is bioaccumulative to the point of probably acting as a persistent organic pollutant, why they don't use biology to concentrate and eventually remove it from the tanks?. Or to keep it safely trapped in the tanks?

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Re:Japan’s plan to dump nuclear waste into the pacific ocean... by adhesive_wombat on Thursday April 28, 2022 @07:32AM (#31191261)
Tritiated water isn't particularly bioaccumulative: chemically, it's water and acts like it. The body doesn't preferentially retain tritium compared to normally hydrogen, so it doesn't concentrate in tissues like, say, dioxins or mercury. It can be incorporated into tissue, but not preferentially to normal hydrogen.

Making dioxins with tritium atoms in place of hydrogen would probably be a bad idea, though.

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Re:Japan’s plan to dump nuclear waste into the pacific ocean... by ceejayoz on Thursday April 28, 2022 @07:25AM (#31191204)
> As is known that Tritium is bioaccumulative…

What? https://en.wikipedia.org/wiki/Tritium#Health_risks

“HTO has a short biological half-life in the human body of 7 to 14 days, which both reduces the total effects of single-incident ingestion and precludes long-term bioaccumulation of HTO from the environment.”

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Re:Japan’s plan to dump nuclear waste into the pacific ocean... by pvaldes on Thursday April 28, 2022 @09:38AM (#31192277)
https://pubmed.ncbi.nlm.nih.gov/22863967/
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Re:Japan’s plan to dump nuclear waste into the pacific ocean... by ceejayoz on Thursday April 28, 2022 @10:05AM (#31192600)
https://academic.oup.com/jrr/article/62/4/557/6256015

> Because some people are concerned about biological accumulation of OBT in the environment, we briefly summarize the behavior of OBT in the ecosystem. Scientific data about the environmental behavior of OBT are still limited, however, it is clear that biological accumulation is not the case for tritium including OBT.

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Re:Japan’s plan to dump nuclear waste into the pacific ocean... by pvaldes on Thursday April 28, 2022 @11:55AM (#31194113)
"A factory worker ingested tritium over 7.4 years. His exposure dose was estimated at 3–6 Sv. He developed isochromic anemia, and subsequently died of pancytopenia"
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Re:Japan’s plan to dump nuclear waste into the pacific ocean... by ceejayoz on Thursday April 28, 2022 @12:37PM (#31194720)
Eating tritium straight from the factory for years at a time seems like a special case, yes?

Yes, you can beat the biological half-life if you eat whopping doses of the stuff. That's... not a common situation.

If you ate said factory worker, you'd be back to normal in a couple weeks, as long as you didn't keep eating factory workers.

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Re:Japan’s plan to dump nuclear waste into the pacific ocean... by adhesive_wombat on Thursday April 28, 2022 @06:24PM (#31198971)
At a dose factor of 0.000018 mSv/kBq for tritiated water, you would get a 3 Sv dose from "only" 1/5000 of the water.

Drinking (or inhaling) 50,000 gallons of the (undiluted, so best case in terms of volume) water from storage tanks would probably get you with kidney failure somewhat before the tritium does.

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Re:Japan’s plan to dump nuclear waste into the pacific ocean... by jhugo on Thursday April 28, 2022 @07:14AM (#31191134)
> As is known that Tritium is bioaccumulative to the point of probably acting as a persistent organic pollutant

Huh? It has a half-life of 12 years.

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Re:Japan’s plan to dump nuclear waste into the pacific ocean... by jayparth on Thursday April 28, 2022 @08:28AM (#31191667)
Biological half life is the more important figure here, by the way, and it’s very short (less than a month)
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Re:Japan’s plan to dump nuclear waste into the pacific ocean... by boomboomsubban on Thursday April 28, 2022 @06:35AM (#31190887)
I know very little, but the amount of tritium involved likely decays into a trivial amount of helium. A quick look at Wikipedia suggests that there is 2.1 g of Tritium in 860,000 cubic meters of water.
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