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Cake day: March 31st, 2025

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  • also unless you’re dissipating much more heat out at lower temperature, it won’t even work as a heatsink because otherwise it goes pretty directly against second law of thermodynamics

    if i’m looking at this right, for copper alpha capture is actually still exothermic (by 3.7MeV and 4.4MeV for 63Cu and 65Cu respectively). it’s different from alpha process, because in alpha process whatever comes after calcium is two or more beta plus decays away from stable, that is there’s already too many protons and next alpha capture only makes it worse, and it all happens too fast for these decays to happen. it’s equilibrium process anyway at that point, but barriers are so large it probably doesn’t matter








  • slight clarification here

    so i looked it up again and this plutonium was already declared surplus, and was slated for disposal for 25 years now. it’s a part of 34 tons of plutonium that both russia and us each were supposed to dispose of, as agreed in a treaty. that disposal consists of using plutonium as fuel, because irradiating it in reactor for a long time makes it useless for weapons use. russians did their part, in part because they were using plutonium in their own power reactors for a long time, so they could just use existing infrastructure. americans didn’t, and they wanted to contaminate it with something and store underground, but some people wanted to burn it in reactors as it should be, so they instead did nothing and they still have some of that plutonium in there. that contamination can be probably reversed so russians objected to it, and didn’t like that americans did nothing either. this is why russians suspended this treaty in 2016 and formally withdrew this monday. therefore it was a fire sale then and it is a fire sale today

    and the reason for why americans don’t have infrastructure or expertise to use plutonium as fuel is at least partially another fire sale, which used up russian ex-weapons uranium for fuel in american powerplants and started five years prior (russia was flat broke in 2000). rosatom became significant fraction of nuclear fuel supply worldwide (until that ex-weapons uranium ran out), that pushed nuclear fuel prices down and guided management decisions against plutonium-based fuel in infinite wisdom that uranium will stay cheap forever (plutonium remains more expensive now, but it doesn’t have to be the case forever). another big one was american policy against reprocessing spent fuel. couple of other countries have national energy utilities that have different priorities and do recycle their fuel in way that would be useful for the program above, weren’t part of this program and continued to use plutonium for multiple reasons. americans could ask for technical assistance from french or japanese or other allied countries, or perhaps even pawn plutonium to them, but i guess that not-invented-here syndrome won

    i don’t know what kind of diplomatic win are they trying to get there, if any, considering that russians don’t care about this treaty anymore and had more surplus plutonium anyway