long hand of casey newton (by proxy) outputs a weird hit piece on ed zitron in wired https://archive.is/chsCw so far bluesky in shambles with no other effects
so on top of that 1%-ish gallium (which stabilizes delta phase, the least dense one, that collapses under pressure to alpha, the most dense one, which allows slightly less compression to be used, and this means more compact weapons), which would need to be separated before that plutonium gets turned into MOX, i understand that most of american plutonium stockpiles are somewhere around 94% 239Pu, and some are 97%+. i guess they're selling the worst stuff, which would make little difference for reactors, and if there's anything that american military is good at, it's logistics. on production side, the very shortened story is that we start with uranium and irradiate it, which gives
238U (n,gamma) 239U (beta) 239Np (beta) 239Pu
and that's it. but it really is a bit more complicated, because first, nothing stops that just made plutonium from reacting further, so some of it will fission which means that it can't be recovered, but it also means more neutrons, which will also make some plutonium, so it's not all bad. but not all plutonium will fission, and so there's entire series of reactions:
at this point reaction stops because 243Pu is very short-lived, and it decays into 243Am. at the same time, if neutrons react without leaving fuel pin, they won't be slowed down much, which means another reaction is possible (but much less likely):
of these, 238Pu and 240Pu have unacceptably high neutron emission rate, which means that if there's too much of these nuclear weapon is likely to predetonate. because the most important use of plutonium in modern advanced thermonuclear weapons is in primary, this means that it could be so that entire weapon fails to function if there's too much of these contaminants (low-kt or even sub-kt yield instead of, say, 350kt). of these, 238Pu and 241Pu have short halflives, which means that plutonium containing these will heat up with considerable power. this can damage explosives bonded to it. 240Pu is additionally a radiation hazard because of neutrons emitted, but it's only really relevant for submarine crews. this is why these weapons use the better 97%+ grade plutonium, and additionally some of that 97% grade was made in order to blend with some older, worse quality stocks
there's remarkably few parameters that can be used in order to steer these reactions in the way we want. about the only relevant one here would be neutron temperature, which is really chosen at reactor design stage and increasing it means that neutron capture is less likely. this makes fission more likely, more neutrons are present and more plutonium can be formed. this also turns reactor into fast reactor which are notoriously hard to build and iirc only russia and india operate large fast reactors today. short of that, about the only way to prevent 239Pu from reacting further is to take it out of there, which means low burnup and only tiny amounts can be recovered per run. from what i understand, the choice of 94%-ish 239Pu content is end effect of massive optimization problem focused on how to make a pit at the lowest price. this includes all the (expensive, slightly dangerous) labour it takes in reprocessing fuel and how required pit mass increases with lower quality plutonium
little of that matters when running a powerplant. some isotopes being neutron emitters are actually an advantage because it makes startup smoother. the longer fuel stays in reactor the less fissile plutonium there is as a result, and the more advanced reactors allowing higher burnups make plutonium recovery less attractive, or, in other words, most of benefit of recovering plutonium in order to put it in new fuel can be realized just by leaving fuel in reactor for longer time in the first place. in regular light water reactor, steady state develops where plutonium is formed as fast as it is consumed, and it accounts for about third of energy released when that steady state sets in. this also means that about third of fissile uranium can be replaced by fissile plutonium with no modifications to reactor
on top of weapons use, some countries do reprocessing anyway as a matter of policy as a hedge against future shortages of uranium. some of these schemes require fast reactors which can burn these isotopes useless in regular reactor and make fresh, weapons grade almost pure 239Pu, which limits countries that can make it work, by diplomatic means, only to already established nuclear powers, and labour costs needed for its operation limit it to currently only india and russia, and formerly france. this is because at any burnup, in best case plutonium can be only separated once from light water reactor fuel and used in light water reactor. after that, plutonium quality is too low to be useful this way
in comparison to reactor grade plutonium, weapons grade plutonium would allow to make more fuel per kg of this material, but also it would be astronomically expensive compared to regular stuff, which is already unprofitable for power generation in countries with western labour costs, unless it's a fire sale. the second problem is that if more than this 1/3 of fissile isotopes in fresh fuel is plutonium, then generally reactors would need recertification or maybe completely new design, because plutonium gives less delayed neutrons which are critical for smooth control of reactor power. this is, mind you, in context of country that practically stopped building new nuclear powerplants. if small reactors are on the table, then these naturally need higher amount of fissile isotopes, like 20-30%, and something tells me people involved would like to try this
another thing to note here is that there's an old american policy in place that forbids (domestic) plutonium recovery for alleged (international) nonproliferation reasons. i don't believe this is the case, it makes zero sense, and instead i think that nuclear industry wanted a way out of that money pit without state backing, because plutonium recovery and reuse for power generation is more expensive than just buying more uranium, sustainability of this energy source and volume needed for nuclear waste be damned. they could get away with this because military weapons grade plutonium stockpiles were assessed as sufficient. now they're pawning heirloom nukes to monorail salesmen instead
every batch of plutonium is made mostly out of Pu-239 that's just how plutonium works. it can't be separated into isotopes in any meaningful amounts so any batch of plutonium is also a mix of a couple of isotopes. reactor grade might be something like 55% Pu-239 plus say 12% also fissile Pu-241 with the rest being nonfissile Pu-240, Pu-242 and Pu-238 in that order. the newer reactor and fuel pin design, the higher burnup and the less fissile isotopes will be present at the end of the cycle. even in purely uranium fueled reactor about third of energy at the end of the fuel cycle comes from plutonium bred in the same fuel pin. i can elaborate on that if you want to
i don't think so, it's like megatons to megawatts but stupider, instead of using up uranium from adversary they want to use up their own plutonium, while also having policies against spent fuel reprocessing (for alleged nonproliferation reasons, which is patently bullshit, power generation was straight up cheaper this way because new uranium is cheaper than reprocessing and use of mox. some other countries (at minimum ru, fr, in, pk, jp, cn, il) do reprocessing as a matter of national security/energy independence/hedge against future shortages of uranium). also this requires recertification of reactors for mox use, which won't always work or else only part of uranium can be replaced, and if it's for smr, then there's gonna be a lot of plutonium in there, and it all starts with handing plutonium to motherfucking sam altman, for only a slight chance of any positive results
i see it more as current administration ripping copper wiring from walls than anything else tbh
in my country it used to be like this for 50 years, you get flat rate per day, counted up to fractions of day, separately for accomodation and food + everything else. you only have to keep transportation tickets
there's zero reason to make chart like this, it's both barely comprehensible and touching surface level stuff only (where are palladium couplings for one)
ahem. h5n1 for ferrets was probably made because ferrets turn out to have immune systems similar enough to humans, in that they do get (common strains of) flu and transmit it by sneezing, that is ferrets are good model organisms for flu vaccine development. so if regular ferrets don't catch h5n1, then you have to modify either virus or ferret because otherwise it won't work. it's not some random virologist deciding to wage biological war against fuzzy noodle critters
if only, maupin spoke on a conference in teheran next to dugin and publishes his books. the layer of red paint on brown couldn't be possibly thinner. see also: jackson hinkle, maga-communism. i wish everyone involved nice tuberculosis infection in damp ukrainian prison
It’s funny (read: farcical) to see a person posing as leftist say they are “pro-AI” but “anti-AI industry”.
not looking to start instance war or anything btw
iirc one of db0 admins is of this opinion which boils down to, in their case, that they're pro-ai but only if self-hosted (ie "yes, i'm pro-ai, just not pro-the kind of ai that is actually used in 99.9% ai output"). they join it with pro-piracy and anarchist positions and it's part of the reason why ai content is allowed on that instance. iirc it's not even consensus among their other admins
you can just put a flywheel on synchronous machine and it also works, especially where you have infra left over after coal plant shutdown or something similar
they might have done it this way because hydro, nuclear (or any steam turbine based) or gas (or any gas turbine based) generation is rotating generation, which helps to stabilize grid in a way that solar or (some of) wind power doesn't. on top of that, many of solar installations won't output energy without mains (grid-followers). getting rid of that would be a is a complex problem that would require infrastructure buildout and policy changes
https://xcancel.com/dril/status/549425182767861760#m