4 ms·

A fusion powered 747 might be the result, but maybe not! Instead, let's see: With the CFR, we've got dirt cheap electric power. Okay, then we can also use

by graycat 12y ago

A fusion powered 747 might be the result, but maybe not! Instead, let's see: With the CFR, we've got dirt cheap electric power. Okay, then we can also use that power to make dirt cheap, very clean water. Then, yup, we can take that water, more of that power, and coal and make jet fuel. And maybe that is what the 747s would continue to use! Maybe!

rybosome 12y ago
If we get a working CFR as described, I'd be shocked if the cost of coal extraction and usage remained low enough for this to be a sound idea. In the face of extremely cheap, clean power, I'd sincerely hope that the government would incentivize its use. Coal and oil lobbies might be able to fight this to some extent, but once a safe and economically viable alternative is present, the days of fossil fuel reliance are numbered. This can't happen soon enough.
tonyplee 12y ago
According to "neutrons make other things radioactive", anything that carry by that fission 747 "might" be radioactive after a flight. True?
- graycat 12y ago
  From what I've read at just the level of Wikipedia, I'd guess yes. But nuclear physics just is not my field. I wanted my Ph.D. in mathematical physics, but all the physics courses I could find did the math in very sloppy ways, and my hope for any research progress in physics wanted to do the math with full care. I did get much of that math, but by then I was occupied with my money making work and didn't get back to physics. I'd like to, maybe, someday! Then maybe I'll be able to give you a solid answer. For now, some of the discussions claim that a lot of neutrons will make a metal brittle but don't go the next step and explain just why. Before I'd say anything about what neutrons do, if only as a check on the level of understanding, I'd want to know why.
  - maxerickson 12y ago
    This seems to explain much of it: http://en.wikipedia.org/wiki/Wigner_effect http://en.wikipedia.org/wiki/Wigner_effect Whatever production process partially relies on arranging the crystal structure of the metal to arrive at desirable properties, the neutrons disrupt it.
    - graycat 12y ago
      Okay, I'll accept that: What used to be the usual isotopes of iron, carbon, aluminum, etc. with some extra neutrons, after whatever gamma rays, alpha particles, etc. boil off, becomes some other isotope or element that doesn't fit in the crystal and, thus, makes the crystal brittle.
      - maxerickson 12y ago
        It can happen without neutron absorption, the neutrons simply knock the atoms out of alignment, and they bounce around a bit (so each neutron can cause more than 1 defect). (if it doesn't follow why that would matter, look into the heat treatment of steel)

by graycat 12y ago

rybosome 12y ago

If we get a working CFR as described, I'd be shocked if the cost of coal extraction and usage remained low enough for this to be a sound idea. In the face of extremely cheap, clean power, I'd sincerely hope that the government would incentivize its use. Coal and oil lobbies might be able to fight this to some extent, but once a safe and economically viable alternative is present, the days of fossil fuel reliance are numbered. This can't happen soon enough.

tonyplee 12y ago

According to "neutrons make other things radioactive", anything that carry by that fission 747 "might" be radioactive after a flight. True?

graycat 12y ago
From what I've read at just the level of Wikipedia, I'd guess yes. But nuclear physics just is not my field. I wanted my Ph.D. in mathematical physics, but all the physics courses I could find did the math in very sloppy ways, and my hope for any research progress in physics wanted to do the math with full care. I did get much of that math, but by then I was occupied with my money making work and didn't get back to physics. I'd like to, maybe, someday! Then maybe I'll be able to give you a solid answer. For now, some of the discussions claim that a lot of neutrons will make a metal brittle but don't go the next step and explain just why. Before I'd say anything about what neutrons do, if only as a check on the level of understanding, I'd want to know why.
- maxerickson 12y ago
  This seems to explain much of it: http://en.wikipedia.org/wiki/Wigner_effect http://en.wikipedia.org/wiki/Wigner_effect Whatever production process partially relies on arranging the crystal structure of the metal to arrive at desirable properties, the neutrons disrupt it.
  - graycat 12y ago
    Okay, I'll accept that: What used to be the usual isotopes of iron, carbon, aluminum, etc. with some extra neutrons, after whatever gamma rays, alpha particles, etc. boil off, becomes some other isotope or element that doesn't fit in the crystal and, thus, makes the crystal brittle.
    - maxerickson 12y ago
      It can happen without neutron absorption, the neutrons simply knock the atoms out of alignment, and they bounce around a bit (so each neutron can cause more than 1 defect). (if it doesn't follow why that would matter, look into the heat treatment of steel)