4 ms·

You got something terribly wrong, U-238 is more stable than U-234, by a factor of a thousand or so. You don't get to anything more stable in the U-238 decay ch

You got something terribly wrong, U-238 is more stable than U-234, by a factor of a thousand or so. You don't get to anything more stable in the U-238 decay chain until you reach Pb-206, which is stable.

godelski 2y ago
I literally copied these numbers from the provided link. Because I never remember this stuff off the top of my head, even when I was working in nuclear. But sanity checking, we find the same chart on the EPA's website[0] as well as the IAEA's site, which you can then calculate the chain yourself pretty easily (down 2 + left 2 (alpha), diag up left (beta-), diag up left (beta-)). Maybe you're thinking of U-235, which has a half-life of 7e8yrs? Or U-233 with 1.6e5yrs? These aren't considered stable btw. [0] https://www.epa.gov/radiation/radioactive-decay https://www.epa.gov/radiation/radioactive-decay [1] https://www-nds.iaea.org/relnsd/vcharthtml/VChartHTML.html https://www-nds.iaea.org/relnsd/vcharthtml/VChartHTML.html
- jojobas 2y ago
  From the provided link: U-238 4.468×10^9 a U-234 2.45×10^5 a
  - godelski 2y ago
    >>>> godelski: >>>> how Uranium-238 decays into Thorium-234, in 4.4e9 years, >>>> Uranium-234, which has a long half-life of 2.45e5 years >>> jojobas: >>> You got something terribly wrong > jojobas: > From the provided link: > U-238 4.468×10^9 a > U-234 2.45×10^5 a I've been checking for a typo, so that's why I quoted, but I'm not seeing it. Can you clarity? It looks like you used the same numbers as I did. Is the confusion "a"? It stands for annum. Which in the decay chart on the EPA site (at the bottom) there's a nifty legend that specifies "half-life units: a - years". But the IAEA site specifically uses "y", stating "4.468 x 10^9 y" and "2.455 x 10^5 y". Are you mad at the rounding? I'm really trying to understand what you're saying I've said is in error. If I made an error I'd like to fix it.
    - hairycrab 2y ago
      I think the correspondent takes issue with the 4th paragraph in your post describing alpha and beta decay; specifically your calling U-234 "much more stable" than U-238. I don't know if "more stable"/"less radioactive" denotes a slower rate of decay, less energy released, or is based on some other metric, but the perceived error seems to hinge on the half-life of U-234 precluding it from being considered "more stable" than the much longer-lived U-238. As I don't know if that's what a degree of stability in an isotope would refer to I don't take a position, but simply offer a hopefully less confused reading of the exchange y'all are having. I enjoyed reading your posts and found them very approachable.
      - godelski 2y ago
        Oofff, yeah, that was a mistake. Thank you for clarifying. I really wasn't getting what the other user was trying to communicate, but it does make sense now. I was having a hard time seeing it because I was like "yes, that's correct?" not seeing where the actual blunder on my part was lol. Yes, U-238 is more stable than U-234. I incorrectly wrote the reverse before. Degree of stability would refer to the rate of decay, which generally is going to strongly correspond to the half-life. (I think the error happened in an edit, where I was previously still talking about Pa. Either way, I messed up)
        jojobas 2y ago
        [flagged]
        godelski 2y ago
        There's no need to be rude. We just misunderstood one each other. I admitted I was wrong. At this point you're just antagonizing for no reason. If I need to touch grass, why don't you join me, because clearly I'm not alone.

godelski 2y ago

I literally copied these numbers from the provided link. Because I never remember this stuff off the top of my head, even when I was working in nuclear. But sanity checking, we find the same chart on the EPA's website[0] as well as the IAEA's site, which you can then calculate the chain yourself pretty easily (down 2 + left 2 (alpha), diag up left (beta-), diag up left (beta-)). Maybe you're thinking of U-235, which has a half-life of 7e8yrs? Or U-233 with 1.6e5yrs? These aren't considered stable btw. [0] https://www.epa.gov/radiation/radioactive-decay https://www.epa.gov/radiation/radioactive-decay [1] https://www-nds.iaea.org/relnsd/vcharthtml/VChartHTML.html https://www-nds.iaea.org/relnsd/vcharthtml/VChartHTML.html

jojobas 2y ago
From the provided link: U-238 4.468×10^9 a U-234 2.45×10^5 a
- godelski 2y ago
  >>>> godelski: >>>> how Uranium-238 decays into Thorium-234, in 4.4e9 years, >>>> Uranium-234, which has a long half-life of 2.45e5 years >>> jojobas: >>> You got something terribly wrong > jojobas: > From the provided link: > U-238 4.468×10^9 a > U-234 2.45×10^5 a I've been checking for a typo, so that's why I quoted, but I'm not seeing it. Can you clarity? It looks like you used the same numbers as I did. Is the confusion "a"? It stands for annum. Which in the decay chart on the EPA site (at the bottom) there's a nifty legend that specifies "half-life units: a - years". But the IAEA site specifically uses "y", stating "4.468 x 10^9 y" and "2.455 x 10^5 y". Are you mad at the rounding? I'm really trying to understand what you're saying I've said is in error. If I made an error I'd like to fix it.
  - hairycrab 2y ago
    I think the correspondent takes issue with the 4th paragraph in your post describing alpha and beta decay; specifically your calling U-234 "much more stable" than U-238. I don't know if "more stable"/"less radioactive" denotes a slower rate of decay, less energy released, or is based on some other metric, but the perceived error seems to hinge on the half-life of U-234 precluding it from being considered "more stable" than the much longer-lived U-238. As I don't know if that's what a degree of stability in an isotope would refer to I don't take a position, but simply offer a hopefully less confused reading of the exchange y'all are having. I enjoyed reading your posts and found them very approachable.
    - godelski 2y ago
      Oofff, yeah, that was a mistake. Thank you for clarifying. I really wasn't getting what the other user was trying to communicate, but it does make sense now. I was having a hard time seeing it because I was like "yes, that's correct?" not seeing where the actual blunder on my part was lol. Yes, U-238 is more stable than U-234. I incorrectly wrote the reverse before. Degree of stability would refer to the rate of decay, which generally is going to strongly correspond to the half-life. (I think the error happened in an edit, where I was previously still talking about Pa. Either way, I messed up)
      - jojobas 2y ago
        [flagged]
        godelski 2y ago
        There's no need to be rude. We just misunderstood one each other. I admitted I was wrong. At this point you're just antagonizing for no reason. If I need to touch grass, why don't you join me, because clearly I'm not alone.