4 ms·

More details would be nice. As the article notes, tritium itself is almost innocuous (its decay is via a weak beta particle emission, about the only way it coul

by mpyne 13y ago

More details would be nice. As the article notes, tritium itself is almost innocuous (its decay is via a weak beta particle emission, about the only way it could hurt you is if you ingested a lot of it). Either way the problem with radioactive materials relates to the concentration in solution of radioactive materials more than the binary "radioactiveness" of the material. After all the human body itself is 'radioactive' if only from the K-40 and C-14 that are present. Without knowing the concentration of radioactive contaminants like Co-60 and radiocesium that might leak into the sea it's hard to know how much of an 'emergency' we'd be looking at. All we'd know for sure is that TEPCO is incompetent... but then what else is new?

ChuckMcM 13y ago
It would be hugely better to actually have details. Water, aka H2O, doesn't activate so it is not radioactive, it can however carry radioactive isotopes in solution. Is the groundwater flowing from the neighbouring area? (implied) then the it is carrying cesium from the environment away (good thing if you want to move back into the neighbourhood) is it picking up new contaminants from a broken reactor vessel? I wonder if anyone has a better source for data here.
- khuey 13y ago
  Water can be radioactive if some of those hydrogen atoms are really tritium.
- akiselev 13y ago
  > Water, aka H2O, doesn't activate so it is not radioactive, it can however carry radioactive isotopes in solution. What? Tritium is an unstable hydrogen isotope that is radioactive, no matter what molecule it is found in. Combine that with acid-base chemistry which revolves around the disassociation of hydrogen from water and that tritium can end up as a beta emitter anywhere in the body, including in actual strands of DNA [1]. What radioactive isotopes the water carries as a solute is irrelevant to the presence of tritium in the molecules. [1] http://www.ncbi.nlm.nih.gov/pubmed/11130944 http://www.ncbi.nlm.nih.gov/pubmed/11130944
  - ChuckMcM 13y ago
    Ah yes, there is that. And in fact a bit of searching turns up this is probably what Reuters was reporting [http://www.japantimes.co.jp/news/2013/08/03/national/huge-leak-of-tritium-feared-in-fukushima/#.Uf_p4Ndj3mE http://www.japantimes.co.jp/news/2013/08/03/national/huge-le...] I had originally dismissed Tritium as a candidate for the contamination because its nominally only in the reactor water and the Reuter's article talked about 'groundwater' (which is the name nominally given to water that accumulates in aquifers as a result of soil percolation). Apparently TEPCO is losing control of the reactor coolant water which is a different thing. That said, Tritium [1] isn't a particularly "bad" agent as it decays into Helium3 (great for fusion reactors if you've got one :-) and then floats away. [1] http://en.wikipedia.org/wiki/Tritium http://en.wikipedia.org/wiki/Tritium
- mpyne 13y ago
  Water can activate (much more so than you think in fact, though I can't discuss further maybe someone with a civilian background in nuclear physics can fill in). Certainly the long-term danger is more from what the water will carry in solution than from the water itself though.
  - ChuckMcM 13y ago
    It is too bad you can't say more about this, one of the fun things I got to do a couple of years ago was to stare into the pool of the Reed Research reactor running at power and look at the awesome Cerenkov radiation (that eerie blue glow, it looked exactly like this : http://en.wikipedia.org/wiki/File:Cerenkov_Effect.jpg http://en.wikipedia.org/wiki/File:Cerenkov_Effect.jpg [yes that is the actual reactor, no I didn't take this picture :-)])
  - VLM 13y ago
    "though I can't discuss further maybe someone with a civilian background in nuclear physics can fill in" Oh spare us the cloak and dagger. I don't think oxygen radioactivation has been classified for about 80 years now. There's even a pretty good wikipedia page at http://en.wikipedia.org/wiki/Isotopes_of_oxygen http://en.wikipedia.org/wiki/Isotopes_of_oxygen The "natural" stable isotope O-16 needs to get triple neutron activated before you get an unstable isotope O-19 and the half life of that is like a minute. So its about half a million minutes per year, and its been about two years, so thats about a million half lives later... I think all the O-19 is long gone. I do agree 100% that the "stuff" dissolved in the water is about a zillion times more important than the oxygen itself. Its so mainstream there's some interesting radio oxygen dating work done using the Dole Effect, which also has a wiki page. TLDR is photosynthesis preferentially concentrates certain O isotopes so you can make all kinds of assumptions about glaciation and where plants are growing (ocean or land) given some 16O:18O ratios. http://en.wikipedia.org/wiki/Dole_effect http://en.wikipedia.org/wiki/Dole_effect There's even a cool wikipedia article with a UTF-8 name. http://en.wikipedia.org/wiki/%CE%9418O http://en.wikipedia.org/wiki/%CE%9418O Which brings you to the greater topic of isotope geochemistry http://en.wikipedia.org/wiki/Isotope_geochemistry http://en.wikipedia.org/wiki/Isotope_geochemistry I'm sure there is at least some cloak and dagger stuff that can't be discussed but there's a simply huge amount of open literature about oxygen radioactivity. I would suspect there's more open lit stuff about isotopic geochemistry than cloak and dagger stuff.
jlgreco 13y ago
> its decay is via a weak beta particle emission, about the only way it could hurt you is if you ingested a lot of it Well, it is water contamination they're talking about. People have the tendency to ingest large amounts of water. Of course, as you say, knowing the concentration is vital to understanding the risk posed. You could drink gallons of water laced with a gamma emitter if the concentration were low enough (well, not gallons. You'd get water intoxication ;).
- mpyne 13y ago
  Well I don't think people ingest large amounts of seawater. :) Perhaps fish and other seafood (assuming that the tritium concentrates in the seawater around Japan and doesn't get dispered into the wider Pacific). But then the tritium would be mostly "fixed" within the flesh of the fish and end up being mostly self-shielding. Perhaps the ATP w/ tritium and similar products get carried into cells but by that point we're talking about nothing worse than the day-to-day problems of life under the sun, eating bananas, breathing the sweet sweet scent of brick-induced radon, etc.
nknighthb 13y ago
I'm not sure that Reuters didn't misunderstand something. The tritium mention seems oddly out of place. A lot more than tritium has leaked from this plant, and I would be surprised if the water they're leaking now is contaminated solely with tritium. Also, I think with regard to tritium spilling into the sea, they're probably less concerned about a direct effect on people than on the fish swimming around in it.
mzs 13y ago
Back in '07 the Canadian Nuclear Safety Commission couldn't get a limit from Japan: http://nuclearsafety.gc.ca/eng/readingroom/healthstudies/tritium/ http://nuclearsafety.gc.ca/eng/readingroom/healthstudies/tri...
yk 13y ago
But Tritium can be quite ugly if it gets into the body, since it can replace hydrogen. (And can therefore accumulate in the body.) This depends on the molecules tritium is attached to. And on a further note, I believe that websites which need JS to scroll text are malicious.
- VLM 13y ago
  Ah its not so bad. If you have to take something radioactive, thats the one element I'd take because I'd pee most of it out in about a week. The phrase no one on HN has mentioned yet is "biological half life". There's a pretty decent wikipedia article at http://en.wikipedia.org/wiki/Biological_half-life http://en.wikipedia.org/wiki/Biological_half-life Whats important is the ratio of biological half life to radiological half life. Superficially it sounds like you're WAY better off with contaminated water, with a bio half life of about a week, than plutonium around 100 years, a difference of about 4 ords of magnitude. However the half life of 3H is in the 10s of years range and non-RTG Pu is about 20K years range or about 3 ords of magnitude lower activity. So the net effect is it hangs around 4 ords of magnitude longer, but specific activity is 3 ords of magnitude lower, so given X number of atoms, Pu is only about 10 times worse for you than 3H. All bets off for the Pu RTG isotope that is so short half life it self-melts pretty easy, or that one Pu isotope thats mostly harmless but its decay product is icky (I think 241pu to 241Am where the 241Pu if it wouldn't decay is mostly harmless but the 241Am is icky)
  - mpyne 13y ago
    Plus when we're talking about transuranics we have to account for the chemical toxicity which is normally much more dangerous than the radiation itself. Great point bringing up biological half-life by the way, especially as that helps explain why some isotopes are considered more dangerous than others for what may seem to be counterintuitive reasons.
  - yk 13y ago
    Well, the question is where is the tritium. If it comes in the form of heavy water, then the biological half life is indeed short. But tritium can substitute essentially any hydrogen, and so it can also come in the form of amino acids, which have a good chance to end up in the nucleus of a cell. So especially for tritium, it can essentially end up in anything where organic chemistry is involved, which is to say everywhere. However, the general problem I have with articles about the dangers of radioactivity is, that they almost never contain enough information to actually judge how dangerous it is. It is usually easy to get a factor of 100 or more variation in the dangers of radioactivity, based on the exact contamination scenario, the precise isotope abundances etc. So even Pu is not always very bad, since PuO is almost insoluble in water, which can be used for nice party tricks [1]: [...] to eat as much plutonium as any prominent nuclear critic will eat or drink caffeine. My offers were such as to give me a risk equivalent to that faced by an American soldier in World War II, according to my calculations of plutonium toxicity which followed all generally accepted procedures. [1] http://www.phyast.pitt.edu/~blc/book/chapter13.html http://www.phyast.pitt.edu/~blc/book/chapter13.html

by mpyne 13y ago

ChuckMcM 13y ago

It would be hugely better to actually have details. Water, aka H2O, doesn't activate so it is not radioactive, it can however carry radioactive isotopes in solution. Is the groundwater flowing from the neighbouring area? (implied) then the it is carrying cesium from the environment away (good thing if you want to move back into the neighbourhood) is it picking up new contaminants from a broken reactor vessel? I wonder if anyone has a better source for data here.

khuey 13y ago
Water can be radioactive if some of those hydrogen atoms are really tritium.
akiselev 13y ago
> Water, aka H2O, doesn't activate so it is not radioactive, it can however carry radioactive isotopes in solution. What? Tritium is an unstable hydrogen isotope that is radioactive, no matter what molecule it is found in. Combine that with acid-base chemistry which revolves around the disassociation of hydrogen from water and that tritium can end up as a beta emitter anywhere in the body, including in actual strands of DNA [1]. What radioactive isotopes the water carries as a solute is irrelevant to the presence of tritium in the molecules. [1] http://www.ncbi.nlm.nih.gov/pubmed/11130944 http://www.ncbi.nlm.nih.gov/pubmed/11130944
- ChuckMcM 13y ago
  Ah yes, there is that. And in fact a bit of searching turns up this is probably what Reuters was reporting [http://www.japantimes.co.jp/news/2013/08/03/national/huge-leak-of-tritium-feared-in-fukushima/#.Uf_p4Ndj3mE http://www.japantimes.co.jp/news/2013/08/03/national/huge-le...] I had originally dismissed Tritium as a candidate for the contamination because its nominally only in the reactor water and the Reuter's article talked about 'groundwater' (which is the name nominally given to water that accumulates in aquifers as a result of soil percolation). Apparently TEPCO is losing control of the reactor coolant water which is a different thing. That said, Tritium [1] isn't a particularly "bad" agent as it decays into Helium3 (great for fusion reactors if you've got one :-) and then floats away. [1] http://en.wikipedia.org/wiki/Tritium http://en.wikipedia.org/wiki/Tritium
mpyne 13y ago
Water can activate (much more so than you think in fact, though I can't discuss further maybe someone with a civilian background in nuclear physics can fill in). Certainly the long-term danger is more from what the water will carry in solution than from the water itself though.
- ChuckMcM 13y ago
  It is too bad you can't say more about this, one of the fun things I got to do a couple of years ago was to stare into the pool of the Reed Research reactor running at power and look at the awesome Cerenkov radiation (that eerie blue glow, it looked exactly like this : http://en.wikipedia.org/wiki/File:Cerenkov_Effect.jpg http://en.wikipedia.org/wiki/File:Cerenkov_Effect.jpg [yes that is the actual reactor, no I didn't take this picture :-)])
- VLM 13y ago
  "though I can't discuss further maybe someone with a civilian background in nuclear physics can fill in" Oh spare us the cloak and dagger. I don't think oxygen radioactivation has been classified for about 80 years now. There's even a pretty good wikipedia page at http://en.wikipedia.org/wiki/Isotopes_of_oxygen http://en.wikipedia.org/wiki/Isotopes_of_oxygen The "natural" stable isotope O-16 needs to get triple neutron activated before you get an unstable isotope O-19 and the half life of that is like a minute. So its about half a million minutes per year, and its been about two years, so thats about a million half lives later... I think all the O-19 is long gone. I do agree 100% that the "stuff" dissolved in the water is about a zillion times more important than the oxygen itself. Its so mainstream there's some interesting radio oxygen dating work done using the Dole Effect, which also has a wiki page. TLDR is photosynthesis preferentially concentrates certain O isotopes so you can make all kinds of assumptions about glaciation and where plants are growing (ocean or land) given some 16O:18O ratios. http://en.wikipedia.org/wiki/Dole_effect http://en.wikipedia.org/wiki/Dole_effect There's even a cool wikipedia article with a UTF-8 name. http://en.wikipedia.org/wiki/%CE%9418O http://en.wikipedia.org/wiki/%CE%9418O Which brings you to the greater topic of isotope geochemistry http://en.wikipedia.org/wiki/Isotope_geochemistry http://en.wikipedia.org/wiki/Isotope_geochemistry I'm sure there is at least some cloak and dagger stuff that can't be discussed but there's a simply huge amount of open literature about oxygen radioactivity. I would suspect there's more open lit stuff about isotopic geochemistry than cloak and dagger stuff.

jlgreco 13y ago

> its decay is via a weak beta particle emission, about the only way it could hurt you is if you ingested a lot of it Well, it is water contamination they're talking about. People have the tendency to ingest large amounts of water. Of course, as you say, knowing the concentration is vital to understanding the risk posed. You could drink gallons of water laced with a gamma emitter if the concentration were low enough (well, not gallons. You'd get water intoxication ;).

mpyne 13y ago
Well I don't think people ingest large amounts of seawater. :) Perhaps fish and other seafood (assuming that the tritium concentrates in the seawater around Japan and doesn't get dispered into the wider Pacific). But then the tritium would be mostly "fixed" within the flesh of the fish and end up being mostly self-shielding. Perhaps the ATP w/ tritium and similar products get carried into cells but by that point we're talking about nothing worse than the day-to-day problems of life under the sun, eating bananas, breathing the sweet sweet scent of brick-induced radon, etc.

nknighthb 13y ago

I'm not sure that Reuters didn't misunderstand something. The tritium mention seems oddly out of place. A lot more than tritium has leaked from this plant, and I would be surprised if the water they're leaking now is contaminated solely with tritium. Also, I think with regard to tritium spilling into the sea, they're probably less concerned about a direct effect on people than on the fish swimming around in it.

mzs 13y ago

Back in '07 the Canadian Nuclear Safety Commission couldn't get a limit from Japan: http://nuclearsafety.gc.ca/eng/readingroom/healthstudies/tritium/ http://nuclearsafety.gc.ca/eng/readingroom/healthstudies/tri...

yk 13y ago

But Tritium can be quite ugly if it gets into the body, since it can replace hydrogen. (And can therefore accumulate in the body.) This depends on the molecules tritium is attached to. And on a further note, I believe that websites which need JS to scroll text are malicious.

VLM 13y ago
Ah its not so bad. If you have to take something radioactive, thats the one element I'd take because I'd pee most of it out in about a week. The phrase no one on HN has mentioned yet is "biological half life". There's a pretty decent wikipedia article at http://en.wikipedia.org/wiki/Biological_half-life http://en.wikipedia.org/wiki/Biological_half-life Whats important is the ratio of biological half life to radiological half life. Superficially it sounds like you're WAY better off with contaminated water, with a bio half life of about a week, than plutonium around 100 years, a difference of about 4 ords of magnitude. However the half life of 3H is in the 10s of years range and non-RTG Pu is about 20K years range or about 3 ords of magnitude lower activity. So the net effect is it hangs around 4 ords of magnitude longer, but specific activity is 3 ords of magnitude lower, so given X number of atoms, Pu is only about 10 times worse for you than 3H. All bets off for the Pu RTG isotope that is so short half life it self-melts pretty easy, or that one Pu isotope thats mostly harmless but its decay product is icky (I think 241pu to 241Am where the 241Pu if it wouldn't decay is mostly harmless but the 241Am is icky)
- mpyne 13y ago
  Plus when we're talking about transuranics we have to account for the chemical toxicity which is normally much more dangerous than the radiation itself. Great point bringing up biological half-life by the way, especially as that helps explain why some isotopes are considered more dangerous than others for what may seem to be counterintuitive reasons.
- yk 13y ago
  Well, the question is where is the tritium. If it comes in the form of heavy water, then the biological half life is indeed short. But tritium can substitute essentially any hydrogen, and so it can also come in the form of amino acids, which have a good chance to end up in the nucleus of a cell. So especially for tritium, it can essentially end up in anything where organic chemistry is involved, which is to say everywhere. However, the general problem I have with articles about the dangers of radioactivity is, that they almost never contain enough information to actually judge how dangerous it is. It is usually easy to get a factor of 100 or more variation in the dangers of radioactivity, based on the exact contamination scenario, the precise isotope abundances etc. So even Pu is not always very bad, since PuO is almost insoluble in water, which can be used for nice party tricks [1]: [...] to eat as much plutonium as any prominent nuclear critic will eat or drink caffeine. My offers were such as to give me a risk equivalent to that faced by an American soldier in World War II, according to my calculations of plutonium toxicity which followed all generally accepted procedures. [1] http://www.phyast.pitt.edu/~blc/book/chapter13.html http://www.phyast.pitt.edu/~blc/book/chapter13.html