Pretty much, yeah. The hexafloride is somewhat harder to contain, though. And expect long-term brain damage from the block of lead. (The decay chain of U-238 is mostly alpha and beta, which are completely absorbed by paper wrapping. There is some gamma radiation in some of the decay steps, but not significantly more than background for any reasonable amount. 18,500 metric tons of the stuff might have a total activity somewhat higher (=2.74e15 Bq), or one mole of helium produced every 70 years from direct decay alone, and a few mA's worth of electron emissions once the decay products reach equilibrium. It looks like the half-thickness for 'uranium' is about 7mm for Co-60 gamma emissions.
Doing the calculus, the total unshielded activity at the surface of the block would be equal to the integral of (total activity per unit thickness {14.8 Bq/mg; DU has a density of 18.5 G/cc}*percentage unshielded at that depth)
*{(}1/2)}%5E{(1000x/7cM)}dx)
(1000cM^2 is the cross sectional area, 1000mG/G is a conversion factor, making the first term the total activity per thickness; second term is the percentage unshielded calculated by raising 1/2 to the power of the number of half thicknesses of uranium above the layer in question. X is in cM.)
Overall though, the stochastic effects of ionizing radiation exposure are close enough to zero that studies of the effects of occupational exposure do not find conclusive correlations of long term low-level exposure to disease.
And expect long-term brain damage from the block of lead.
I don't believe you.
It's wrapped in paper (your stipulation) and under the bed (my stipulation). Are you asserting that the wrapped, undisturbed block of counterfactual lead under my bed is a significant airborne pollution threat?
Overall though, the stochastic effects of ionizing radiation exposure are close enough to zero that studies of the effects of occupational exposure do not find conclusive correlations of long term low-level exposure to disease.
Fascinating, thankyou.
My friend, hearing me recount tales of LessWrong, recently asked me if I thought it was simply a coincidence that so many LessWrong rationality nerds cared so much about creating Friendly AI. "If Eliezer had simply been obsessed by saving the world from asteroids, would they all be focused on that?"
Obviously one possibility (the inside view) is simply that rationality compels you to focus on FAI. But if we take the outside view for a second, it does seem like FAI has a special attraction for armchair rationalists: it's the rare heroic act that can be accomplished without ever confronting reality.
After all, if you want to save the planet from an asteroid, you have to do a lot of work! You have to build stuff and test it and just generally solve a lot of gritty engineering problems. But if you want to save the planet from AI, you can conveniently do the whole thing without getting out of bed.
Indeed, as the Tool AI debate as shown, SIAI types have withdrawn from reality even further. There are a lot of AI researchers who spend a lot of time building models, analyzing data, and generally solving a lot of gritty engineering problems all day. But the SIAI view conveniently says this is all very dangerous and that one shouldn't even begin to try implementing anything like an AI until one has perfectly solved all of the theoretical problems first.
Obviously this isn't any sort of proof that working on FAI is irrational, but it does seem awfully suspicious that people who really like to spend their time thinking about ideas have managed to persuade themselves that they can save the entire species from certain doom just by thinking about ideas.