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Comment by clarionbell | Hacker News Reader

Richmod may be an expert in his field. But even he couldn't point to anything that could actually happen.

His report, and that of his colleagues, is intentionally vague, with no predictions and lot of FUD. Seriously, there is not a single thing they point to and say: "This could happen!"

It's almost as if tritium wasn't that problematic and they were trying to get people who payed them for the study at least something for their troubles.

Tritium has half-life of 12 years, into helium. It isn't something that would persist for generations in considerable levels.

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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.

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.

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]

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?

> 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.

Biological half life is the more important figure here, by the way, and it’s very short (less than a month)

> 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.”

https://pubmed.ncbi.nlm.nih.gov/22863967/

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.

"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"

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.

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.

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.

> 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.

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).

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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