re: Glaze over canyons on Mars
Note that 1 bar of pressure is equivalent to the pressure at the base of a 10m column of water. Coincidentally, the Earth's atmosphere has a shielding effect equivalent to 10m of water (though the longer paths in the atmosphere have a better shielding effect from high energy cosmic rays).
10m of water is enough to have naked reactor fuel rods lying around glowing with Cerenokov radiation, and still safely look into the pool and say "Wow!"
You can also dope the glass (Lead glass is good for stopping radiation!)