= 27d567bc2d48d9f40e9ccc20ea370b15)
gwern comments on A cynical explanation for why rationalists worry about FAI - Less Wrong
You are viewing a comment permalink. View the original post to see all comments and the full post content.
= 783df68a0f980790206b9ea87794c5b6)
Loading…= b715d02e85f7b3b4ae65ca3d3e450868)
Subscribe to RSS Feed
Powered by Reddit
= f037147d6e6c911a85753b9abdedda8d)
You are viewing a comment permalink. View the original post to see all comments and the full post content.
Comments (179)
Exploring many unusual and controversial ideas? Certainly we get criticized for focusing on things like FAI often enough, it should at least be true!
Saying that you save the world by exploring many unusual and controversial ideas is like saying you save the world by eating ice cream and playing video games.
Isn't "exploring many unusual and controversial ideas" what scientists usually do? (Ok, maybe sometimes good scientist do it...) Don't you think that science could contribute to saving the world?
What I am saying is "exploring unusual and controversial ideas" is the fun part of science (along with a whole lot of drudgery). You don't get points for doing fun things you would rather be doing anyways.
Actually, I think you get points for doing things that work, whether they are fun or not.
Some of the potentially useful soft sciences research is controversial. But essentially no hard sciences research is both (a) controversial and (b) likely to contribute massive improvement in human well-being.
Even something like researching the next generation of nuclear power plants is controversial only in the sense that all funding of basic research is "controversial."
Nuclear science is controversial for the same reason that equal-access marriage is controversial: Because there are people who have some opinions that cannot be changed by rational argument.
<moar cynicism>If the real reason people want nuclear power plants were their benefits compared to other ways of generating power, they'd use thorium not uranium.</moar cynicism> http://en.wikipedia.org/wiki/User:RaptorHunter/FunFacts#Thorium_reactor
[citation needed]
No, a user's talk page won't do.
Over-hyped BS. There are regular reactors, and there are breeder reactors (fast neutron reactors), both can use uranium but only the latter type can use thorium. The latter type, also, incidentally, uses a lot less uranium than the former, and can use depleted uranium. The cost of fuel is of no consequence and all the safety issues are virtually identical for fast neutron reactors using thorium and using uranium (and for both, are expected to be significantly more severe than for regular water moderated reactors) There's a lot of depleted uranium laying around costing negative $ . Not thorium, though.
I thought that depleted uranium wrapped in paper was pretty much as safe as lead?
It's uranium hexafluoride actually, that's laying around.
Ah, so it's about as safe as elemental mercury or many mercury compounds then.
Really? As in... I can sleep with a cubic metre of the stuff under my bed and not expect to get cancer within a decade or two?
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)
(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.
For fun: read the parent as implying that wedrifid has slept on top of a cubic meter of lead for decades.
There's some ambiguity in your use of the word "science." Nuclear engineering is controversial (i.e. building and running nuclear plants is politically controversial).
But the post I was responding to was about research. In terms of political controversy, I suspect that nuclear researchers receive essentially no hate mail, especially compared to sociologists researching child-rearing outcomes among opposite-sex and same-sex couples.
Nuclear researchers run reactors. It's pretty much the only commercially viable way to test the effects of neutron bombardment on materials. They typically aren't power plants, because steam turbines are a lot more work to operate and research reactors are typically intermittent and low power (in terms of the electrical grid)