8 ms·
Building a Reactor
- amelius 2y ago> The reactor itself, the nuclear core, is not a complicated mechanical contraption. The core has no moving parts or complex mechanisms. It's just an arrangement of special materials, that permits nuclear reactions to occur. There are moving parts to transfer the heat and control the reactions, but it's basically a pile of bricks. I could say roughly the same thing about a smartphone.
- willis936 2y agoYes, but a smartphone has billions of microswitches and articulated features. The smallest feature of a fission core is about the same size as a smartphone. The level of sophistication of the tooling needed is miles apart. If we were to start from scratch we could make a fission core long before we could make a smartphone.
- numpad0 2y agoNuclear reactors are definitely simpler. The simplest reactor is just a pure enough and large enough blob of a fissile material. A Turing machine is more complex.
- acidburnNSA 2y agoArguably, the complexity of getting the blob of fissile material should count as complexity. I'd argue that the simplest reactor therefore is the kind you can make with natural material, so a beryllium, heavy water, or graphite moderated natural uranium reactor like CP-1. Even then there was much complexity in getting pure enough graphite.
- grecy 2y agoThe article even mentions there were naturally occurring nuclear reactors on earth a while ago. So it's possible to for a blob of fissile material to just form naturally.
- acidburnNSA 2y agoWell, that was 2 billion years ago. Since U-235 has a shorter half-life than U-238, the natural uranium enrichment was far higher back then. And indeed that was a water-moderated reactor. [1] Some people have postulated that the moon itself was formed in a nuclear fission excursion [2], and/or that there is or was a nuclear reactor in the center of Earth [3]. These are both not commonly believed. [1] https://en.wikipedia.org/wiki/Natural_nuclear_fission_reactor https://en.wikipedia.org/wiki/Natural_nuclear_fission_reacto... [2] https://phys.org/news/2010-01-moon-nuclear-explosion.html https://phys.org/news/2010-01-moon-nuclear-explosion.html [3] https://arxiv.org/abs/1308.5934 https://arxiv.org/abs/1308.5934
- tekla 2y agoThe Chicago pile was demonstrated in 1942. Transistors weren't even invented yet. You are incredibly off on complexity
- simmerup 2y agoNot to pile on but there have been natural reactors in nature, but zero natural smartphones
- krallja 2y ago> pile I see what you did there
- bobthepanda 2y agoI mean our brains are basically meatsack computers.
- barfbagginus 2y agoYep you definitely need Unix Theory to build and run a nuclear reactor. I'm saying you're right!
- 12_throw_away 2y agoNot sure how any this description could apply to even the simplest microprocessor-containing device. Seems like fabs are sufficiently advanced tech so as to be indistinguishable from magic ... so much so that we forget how amazingly, absurdly, not-simple they are?
- preisschild 2y agoSomewhat related, a random nuclear reactor generator :) https://whatisnuclear.com/random.html https://whatisnuclear.com/random.html
- dtgriscom 2y agoRats. I thought the "Start Company" button would draw up custom incorporation papers for a company building my random nuclear reactor.
- dtgriscom 2y ago> To split atoms and release nuclear binding energy, we need to launch neutrons at the fuel atoms. ... 1 kg of natural Uranium generates just 10 such neutrons per second. Not saying that's wrong, but my seat-of-the-pants guess would have been ten orders of magnitude higher than this. (Citation?)
- credit_guy 2y agohttps://en.wikipedia.org/wiki/Isotopes_of_uranium https://en.wikipedia.org/wiki/Isotopes_of_uranium Natural uranium is a mix of 0.7% U-235 and 99.3% U-238. U-235 has a half-life of 700 million years and a spontaneous fission (SF) probability of 7e-11. U-238 has a half-life of 4.5 billion years and a SF probability of 5.4e-7. So on average it takes 6 times longer for a U-238 to decay than U-235, but when it does it has a probability to do it by spontaneous fission that is 7000 times higher. Add to that that U-238 is 141 times more plentiful in natural uranium, and you get that you can completely ignore U-235 when it comes to spontaneous fission. 1 kg of Uranium is about 4.2 moles. Each has 6e23 atoms (Avogadro's number), that's a total of about 25e23 atoms. Every year about 1 in 4.5 billion of those will decay one way or another. That's 5.5e14 decay events. The probability of spontaneous fission is 5.4e-7, so basically 10 million of these decay events are SF. There are 32 million seconds in a year, so I am getting about 0.3 SF events per second. On average a fission event generates about 2.5 neutrons, so that's close to 1 neutron per second. They are getting 10 per second. They are nuclear engineers and I'm just a guy who knows how to multiply and how to read wikipedia. Most likely their number is correct.
- ffhhj 2y agoInteresting. How much Uranium do we have on Earth?
- archgoon 2y agoDepends on what you mean. If you mean "how much is commercially viable" versus "how many kilograms of the stuff are there" you get very, very different answers. For just "how much stuff is there", we can look at the concentration in the earths crust, and we get about 10^17 kilograms of the stuff (10^15 if you want U-235). If you just say "Sure, but we can't get most of that, how much can reasonably get extracted at current prices and technology" then you go down to about 10^9 kilograms.
- lven 2y agoI worked on this and host it on my site as well where it's not parceled up into bits and pieces. Have to thank Bartosz Ciechanowski. Learned a lot from his code and approach. https://lvenneri.com/nuclear_reactor_explainer https://lvenneri.com/nuclear_reactor_explainer
- algo_trader 2y agoGreat looking widgets and graphs. What tool is used for these ?
- lven 2y agoWebgl + js. same approach as https://ciechanow.ski/ https://ciechanow.ski/