I’ve seen it from afar and it is indeed a bright blue.

Edit: I don’t think that is what we are see here though. It looks like the water itself might have something added to it. There are several elements that absorb neutrons. Such as boron but I’m unsure what color it would be dissolved in water. I inhaled boron gas when I was on the first crew into the containment building at a shutdown. Had to stay at decon until it was out of my lungs.

I saw the spent fuel pool at a nuke from over a hundred feet. It was low light and you could clearly see the blue glow from the spent fuel rods. We were just passing through so it was a quick look to the work site and back from it.

I’ve also seen a reactor shutdown with the fuel rods exposed in preparation for a fuel shuffle. There may have been a glow but all the lights were on so it would have been washed away.