this post was submitted on 27 Oct 2024
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water does not expand upon irradiation, what the fuck are you talking about. you can't reflect high energy protons (what would be important in radiation in interplanetary travel) you can only either absorb them or let them pass, there's no third option, same for anything above uv and electrons
to a first approximation (rather good one at that) (for gammas) absorption is proportional to how much mass per area unit is used as a barrier. 1 g/cm^2 of water is just as good barrier as 1 g/cm^2 of lead or steel. this means that you can absolutely use completely normal, regular potable water as a radiation shield
i'm not even sure what it's supposed to mean, unless your understanding of ionizing radiation is uncut nonsense
chemically speaking, it's completely fine to irradiate water because whatever is formed as a result of radiolysis would just most of the time form water back, with the rest becoming very weak solution of hydrogen peroxide. this is big part of the reason why water is used as a coolant in nuclear reactors
there are also specific nuances to stopping anything that is not gammas, like secondary x-rays, gammas from neutron absorption etc and this actually favours light element shields, like water or liquid hydrogen, for this kind of radiation shielding
Okay, so where do the neutrons go in your head? Gotta go somewhere.
Re: your point about water in its purest form. It means zero contamination. We aren't even capable of doing that, and the purest we can make would kill humans pretty quickly for the similar amount we ingest.
what neutrons? we're talking about shielding of spacecraft moving out of earth's magnetosphere, not a spacecraft travelling through core of active nuclear reactor
the kind of radiation that is relevant are high energy protons (and alphas and electrons, with a sprinkle of heavier nuclei) from sun, mostly. there's no relevant source of neutrons
(and incidentally water is pretty good at absorbing neutrons too)
I think you are confused about how radiants work on Earth vs Space.
Again, the OP is about water "absorbing" radiation, and then being drinking water. It's not possible once past a certain amount. This is not possible.