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NASA Chief Scientist Jim Greene asks:

Can we go (to the Moon) and drink the water?

The source of the water in this case would be ice deposits to be found in permanently shaded areas on the Moon.

Is there any speculation on how radioactive water on the Moon might be? There are cosmic rays and energetic particles from the Sun and probably some flux of neutrons as well. These can induce reactions that can result in the production of radioactive isotopes of hydrogen and oxygen, and there may even be radioactive or heavy isotopes from the solar wind as well.

Screenshot from NASA's Gravity Assist Podcast Goes to the Moon

enter image description here

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    $\begingroup$ To be drinkable, water should not contain toxic minerals and salts. $\endgroup$ – Uwe May 26 at 15:08
  • $\begingroup$ @Uwe I'm just asking about the H2O itself. Water is easy to distill, so impurities won't be a problem. $\endgroup$ – uhoh May 26 at 15:37
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    $\begingroup$ You're seriously asking how much HTO is there in it? This is like last concern imaginable. $\endgroup$ – Mithoron May 28 at 17:18
  • $\begingroup$ @Mithoron what does concern have to do with interest? It's not like I'm planning a camping trip on the Moon. If I were I'd ask in The Great Outdoors SE! $\endgroup$ – uhoh May 28 at 23:35
  • $\begingroup$ @uhoh This is "Space Exploration SE", isn't it? So it does seem to be natural context... Otherwise Astronomy.SE could be better choice. $\endgroup$ – Mithoron May 29 at 20:41
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I lived on a nuclear submarine. Water was used to shield against the nuclear power plant radiation. Pure H2O cannot be radioactive. However, contaminants in H2O can be radioactive. One of the nuclear engineers on the submarine would drink the water that came out of the primary coolant loop for 20 bucks. The primary coolant loop water was as pure water that could be made and it flowed directly over the radioactive source.

--add I have no idea about high energy particles (protons) nor free flowing neutrons. My answer is stricly limited to Alpha, Beta and Gamma radiation.

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    $\begingroup$ As pointed out in the question, hydrogen and oxygen can certainly be radioactive. Neutrons from your reactor would certainly have produced a lot of extra tritium, an isotope of hydrogen with a half-life of 12.3 years, and it emits beta particles. I think that one of the nuclear engineers decided that the elevated tritium in his body could be purged with about 20 bucks worth of beer ;-) $\endgroup$ – uhoh May 25 at 15:54
  • $\begingroup$ "Pure H2O cannot be radioactive" isn't true. Besides the radioactive hydrogen isotope tritium, oxygen has plenty of radioactive isotopes. However they are all short-lived. $\endgroup$ – uhoh May 25 at 15:55
  • $\begingroup$ Tritium is only produced in heavy water, which you wouldn't be drinking anyway. The longest lived unstable isotope of oxygen has a half life of two minutes, and so won't accumulate in any great concentration and will almost entirely decay in a short time. $\endgroup$ – Christopher James Huff May 26 at 12:32
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    $\begingroup$ Natural water contains a little heavy water, so tritium may be produced not only in concentrated heavy water. $\endgroup$ – Uwe May 26 at 15:05
  • $\begingroup$ @ChristopherJamesHuff as pointed out water naturally contains some deuterium, though it's possible that the reactors used deuterium-depleted or "light water". Fast neutrons from the reactors can potentially produce other elements from oxygen via (n, p) and (n, α), so it takes some careful analysis to build a complete picture of what happens when sailors drink reactor water. $\endgroup$ – uhoh May 26 at 21:25

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