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Cherenkov radiation is pretty common in nuclear engineering, and occurs naturally in a number of contexts. It’s not some forebear of doom. Otherwise, a great a

Cherenkov radiation is pretty common in nuclear engineering, and occurs naturally in a number of contexts. It’s not some forebear of doom. Otherwise, a great article!

wincy 4y ago
I got to see Cherenkov radiation once on a high school class trip with only water between me and the blue glow! Being a teenager I asked “what would happen if I jumped into the reactor?” The researcher (this was a medical and research reactor) laughs and says “well, if you just jump into the water and splashed around we’d have hell to pay with filling out an incident report to <something important sounding, I forget>, but physically you’d be fine since the water shields you from the radiation. If you did a swan dive down toward the glow your skin would all melt off before you got to the reactor” maybe he was just saying this for effect but it’s always stuck in my head that water is a really, really good insulator against radiation.
- krisoft 4y ago
  > water is a really, really good insulator against radiation. Absolutely. There is this[1] horror story about a diver who was doing maintenance in a transfer pool next to two spent fuel pools. After he was done with the work he found an unidentified object at the bottom of the pool and was instructed to put it in his tool basket. The object was a broken piece of irradiated reactor component. They realised that something is very wrong when the diver was lifting the basket out of the water and the area radiation monitors started to alarm, so they lowered the basket back into the water. On the 10th slide of the document there is a diagram showing the water's shielding as a function of distance. At 1.4 meters there is no dose they can measure while they measure extremely high doses at centimeter distances. 1: https://isoe-network.net/publications/pub-proceedings/symposia/north-american-tc-symposia/fort-lauderdale-usa-january-2011/slides-14/session-iv-1/1756-ritter2011-ppt/file.html https://isoe-network.net/publications/pub-proceedings/sympos...
- ceejayoz 4y ago
  Relevant XKCD: https://what-if.xkcd.com/29/ https://what-if.xkcd.com/29/
  - asah 4y ago
    """ So, as far as swimming safety goes, the bottom line is that you’d probably be ok, as long as you didn’t dive to the bottom or pick up anything strange. But just to be sure, I got in touch with a friend of mine who works at a research reactor, and asked him what he thought would happen to you if you tried to swim in their radiation containment pool. “In our reactor?” He thought about it for a moment. “You’d die pretty quickly, before reaching the water, from gunshot wounds.” """ Actually, at a depth of 3-5 feet the bullets wouldn't hurt you: https://www.google.com/search?q=bullets+in+water https://www.google.com/search?q=bullets+in+water
- willis936 4y ago
  I think you need power densities much higher than the shielding of an MPRR you saw to melt skin away. You'd probably get some bad radiation sickness and maybe even die instantly within a short radius, but not have the Hollywood skin melt.
m4rtink 4y ago
All is fine until you see it in the air. ;-)

Cherenkov radiation is pretty common in nuclear engineering, and occurs naturally in a number of contexts. It’s not some forebear of doom. Otherwise, a great article!

wincy 4y ago

I got to see Cherenkov radiation once on a high school class trip with only water between me and the blue glow! Being a teenager I asked “what would happen if I jumped into the reactor?” The researcher (this was a medical and research reactor) laughs and says “well, if you just jump into the water and splashed around we’d have hell to pay with filling out an incident report to <something important sounding, I forget>, but physically you’d be fine since the water shields you from the radiation. If you did a swan dive down toward the glow your skin would all melt off before you got to the reactor” maybe he was just saying this for effect but it’s always stuck in my head that water is a really, really good insulator against radiation.

krisoft 4y ago
> water is a really, really good insulator against radiation. Absolutely. There is this[1] horror story about a diver who was doing maintenance in a transfer pool next to two spent fuel pools. After he was done with the work he found an unidentified object at the bottom of the pool and was instructed to put it in his tool basket. The object was a broken piece of irradiated reactor component. They realised that something is very wrong when the diver was lifting the basket out of the water and the area radiation monitors started to alarm, so they lowered the basket back into the water. On the 10th slide of the document there is a diagram showing the water's shielding as a function of distance. At 1.4 meters there is no dose they can measure while they measure extremely high doses at centimeter distances. 1: https://isoe-network.net/publications/pub-proceedings/symposia/north-american-tc-symposia/fort-lauderdale-usa-january-2011/slides-14/session-iv-1/1756-ritter2011-ppt/file.html https://isoe-network.net/publications/pub-proceedings/sympos...
ceejayoz 4y ago
Relevant XKCD: https://what-if.xkcd.com/29/ https://what-if.xkcd.com/29/
- asah 4y ago
  """ So, as far as swimming safety goes, the bottom line is that you’d probably be ok, as long as you didn’t dive to the bottom or pick up anything strange. But just to be sure, I got in touch with a friend of mine who works at a research reactor, and asked him what he thought would happen to you if you tried to swim in their radiation containment pool. “In our reactor?” He thought about it for a moment. “You’d die pretty quickly, before reaching the water, from gunshot wounds.” """ Actually, at a depth of 3-5 feet the bullets wouldn't hurt you: https://www.google.com/search?q=bullets+in+water https://www.google.com/search?q=bullets+in+water
willis936 4y ago
I think you need power densities much higher than the shielding of an MPRR you saw to melt skin away. You'd probably get some bad radiation sickness and maybe even die instantly within a short radius, but not have the Hollywood skin melt.

m4rtink 4y ago

All is fine until you see it in the air. ;-)