• Zagorath@aussie.zone
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    22 hours ago

    The amount is genuinely much less, because far more of the fuel goes through e=mc². It can’t be radioactive waste if it’s been converted into energy.

    I’m not sure this makes sense. The conclusion might be right, but I don’t think the explanation is. Matter isn’t being annihilated in nuclear fission. The number of protons and neutrons at the start is the same as at the end. The reduced mass is a result of increased binding energy.

    At least, that’s how I remember it from highschool physics. I find this stuff fascinating so I’d love to hear an explanation of how it’s wrong or overly simplified, if so.

    • Badabinski@kbin.earth
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      21 hours ago

      AFAIK, the number of protons and neutrons is the same, but the overall mass is reduced because the binding energy holding the nucleus together counts towards the mass. I do not understand why the binding energy acts as mass (I dropped out of physics after moving past classical mechanics), but that’s what’s I’ve heard over the years.

      So basically, you have it right, and my explanation is overly simplified because I am not very competent and forgot how this shit worked lol. I remembered that the overall mass of the waste is lower than what was put in, but I fucked up when explaining why that happens. Breeder reactors can’t do much with the fission products themselves, but the worst part of nuclear waste from a long-term storage perspective is the transuranics that get created inside of a reactor. FBRs make a lot of neutrons that can transmute those transuranics into fissile materials and then burn them up, extracting the binding energy from them and reducing the overall mass. Eventually you’re just left with fission products which are generally very short lived.

      EDIT: I accidentally hit post way too soon, so I wrote most of this as an edit. Apologies for that.