TBerk wrote:

Here's a question along those lines:

What happens to a large body of say a Colonies Drinking Water if its
used as Radiation Shielding?

Very little provided that it is reasonably pure. You just need enough of
it to provide adequate shielding.

Sodium in sea or brackish water might be a bit of a problem (neutron
activation makes it into a nasty radioisotope). Drinking water would be
OK, deionised would be better.

For example (and please excuse the OT nature of this thread) if a below
the surface habitat had a cavern overhead filled with a large amout of
water and it had a dual use as drinking/agricultural supply as well as
a mass to aid with blocking unwanted radiation- what would happen to
the water itself when exposed to said radiation?

Would elecrolysis be the the main problem? Perhaps ionization or the
formation of 'Heavy Water"? (And would that be a problem?)

You would see a faint ghostly blue glow from Cherenkov radiation -
particles passing through the water travelling faster than the speed of
light in the medium shed energy in the electromagnetic equivalent of a
sonic boom. Not much else would happen. Astronauts have even seen such
flashes in their eyes as cosmic rays pass through them.

Regards,
Martin Brown