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I've been a bit of a nuclear nerd for a long time, and somehow the author still shares information that is new to me: I had no idea how quickly high-level waste

by aeonik 4y ago

I've been a bit of a nuclear nerd for a long time, and somehow the author still shares information that is new to me: I had no idea how quickly high-level waste dissipated, love the plots of the radioactive decay. > The decay of heat and radioactivity over time means that after only forty years, the radioactivity of used fuel has decreased to about one-thousandth of the level at the point when it was unloaded. Less than 1% is radioactive for 10,000 years. The portion that stays radioactive for longer is about as radioactive as some things found in nature and can be easily shielded to protect humans.

inglor_cz 4y ago
It is somewhat logical. Radiation isn't free and if something radiates a lot, it loses quite a lot of energy while radiating. Typically: intense radiation is caused by massive presence of isotopes with short half-life, which means that they go away quite quickly. Even the notorious Elephant's Foot in Chernobyl, made of molten core content, is now much safer than it used to be, to the degree that people are now willing to enter the room and make photos of it [0] https://en.wikipedia.org/wiki/Elephant%27s_Foot_(Chernobyl) https://en.wikipedia.org/wiki/Elephant%27s_Foot_(Chernobyl)
uoaei 4y ago
"About" and "less than" are lovely weasel words for the ideologically committed. According to this graph, the truth is more like 1% after 100 years, 0.1% after 10,000 years. https://en.wikipedia.org/wiki/Spent_nuclear_fuel?useskin=vector#/media/File:Activitytotal1.svg https://en.wikipedia.org/wiki/Spent_nuclear_fuel?useskin=vec...
nicoburns 4y ago
IMO that's quite misleading. It's true that the amount of radition will dramatically decline. But it does so unevenly, and certain isotopes last much much longer. That's not really a problem if the waste stays contained in one location, but if that waste somehow leaked into water sources or similar then it could have significant consequences. Even a very small amounts of these isotopes can be dangerous if inhaled or ingested.
zizee 4y ago
It's an often (deliberately?) overlooked aspect of nuclear waste discussions. People will loudly say "radioactive waste needs to be stored for thousands of years", and "you go near some radioactive waste, you will surely die from radiation exposure". This gets combined into something like "This highly dangerous stuff, that you cannot approach stays highly dangerous and unapproachable for 10k years". Then people say "how can we possibly hope to store this incredibly dangerous stuff for 10k years, it's such a hard problem to solve, better not create this stuff in the first place, no more nuclear!". But the stuff that lasts 10k years is a very different beast from the stuff that kills you quickly from just being near it. The supremely radioactive stuff tends to have a very short half-life. We can think about storage methods in very human time-frames, it's much more achievable. The other, long half life stuff needn't be stored with nearly the same extremly stringent standards, because it just isn't so extremely dangerous.
Schroedingersat 4y ago
So it goes from killing you if you're in the same room in seconds to merely bioaccumulating and poisoning the top levels of the food chain for thousands of square km in a few centuries. Very nice good faith representation.

by aeonik 4y ago

inglor_cz 4y ago

It is somewhat logical. Radiation isn't free and if something radiates a lot, it loses quite a lot of energy while radiating. Typically: intense radiation is caused by massive presence of isotopes with short half-life, which means that they go away quite quickly. Even the notorious Elephant's Foot in Chernobyl, made of molten core content, is now much safer than it used to be, to the degree that people are now willing to enter the room and make photos of it [0] https://en.wikipedia.org/wiki/Elephant%27s_Foot_(Chernobyl) https://en.wikipedia.org/wiki/Elephant%27s_Foot_(Chernobyl)

uoaei 4y ago

"About" and "less than" are lovely weasel words for the ideologically committed. According to this graph, the truth is more like 1% after 100 years, 0.1% after 10,000 years. https://en.wikipedia.org/wiki/Spent_nuclear_fuel?useskin=vector#/media/File:Activitytotal1.svg https://en.wikipedia.org/wiki/Spent_nuclear_fuel?useskin=vec...

nicoburns 4y ago

IMO that's quite misleading. It's true that the amount of radition will dramatically decline. But it does so unevenly, and certain isotopes last much much longer. That's not really a problem if the waste stays contained in one location, but if that waste somehow leaked into water sources or similar then it could have significant consequences. Even a very small amounts of these isotopes can be dangerous if inhaled or ingested.

zizee 4y ago

It's an often (deliberately?) overlooked aspect of nuclear waste discussions. People will loudly say "radioactive waste needs to be stored for thousands of years", and "you go near some radioactive waste, you will surely die from radiation exposure". This gets combined into something like "This highly dangerous stuff, that you cannot approach stays highly dangerous and unapproachable for 10k years". Then people say "how can we possibly hope to store this incredibly dangerous stuff for 10k years, it's such a hard problem to solve, better not create this stuff in the first place, no more nuclear!". But the stuff that lasts 10k years is a very different beast from the stuff that kills you quickly from just being near it. The supremely radioactive stuff tends to have a very short half-life. We can think about storage methods in very human time-frames, it's much more achievable. The other, long half life stuff needn't be stored with nearly the same extremly stringent standards, because it just isn't so extremely dangerous.

Schroedingersat 4y ago

So it goes from killing you if you're in the same room in seconds to merely bioaccumulating and poisoning the top levels of the food chain for thousands of square km in a few centuries. Very nice good faith representation.