351
lemmy.net.au
57 readers0 users here now
This instance is hosted in Sydney, Australia and Maintained by Australian administrators.
- Sign-ups are Application at present
- Email Verification is not required
- Downvotes are enabled
- Community creation is open
- Federation is enabled
- Our status page is coming soon
Feel free to create and/or Join communities for any topics that interest you!
Rules are very simple
- don't be a cunt
- no racism
- no activities that might the laws of Australia
- all bot accounts must be clearly marked as bot accounts
- bots may not vote on any posts or any comments
- bots must state their purpose on profile
- no community may be run by bots
- bots must not primarily responsible for the content in any community
Mobile apps
What is Lemmy?
Lemmy is a selfhosted social link aggregation and discussion platform. It is completely free and open, and not controlled by any company. This means that there is no advertising, tracking, or secret algorithms. Content is organized into communities, so it is easy to subscribe to topics that you are interested in, and ignore others. Voting is used to bring the most interesting items to the top.
Think of it as an opensource alternative to reddit!
founded 1 year ago
ADMINS
353
354
355
356
358
359
360
So i'm doing a bit of reading about the basics of nuclear fission these days, just to understand what's actually happening there.
Here are some interesting things that i think that i learned so far:³
- nuclear engineering is all about the neutron economy. If you had an easily-available cheap source of neutrons, we wouldn't need big nuclear power plants because energy could be easily generated by hitting Hydrogen-1 (protium) with neutrons to make H-2 (deuterium) out of it. According to this diagram, this releases around 2 MeV of energy per collision (resulting nucleus has 2 nucleons), which is a lot of energy.
-
the problem is that we don't have a cheap source of neutrons, and that's about where the whole trouble with nuclear energy begins. we're smashing U-235 specifically because it's fissile and can sustain a chain reaction: It emits more neutrons per collision than it absorbs, so we get a net gain of neutrons out of it.
-
the sun sources its neutrons from weak interaction between protons and electrons¹. Basically this fuses a proton and an electron together to make a neutron. This is the rate-limiting factor in the sun's fusion and determines the sun's lifetime before it burns through its fuel. The average time for a particle to undergo weak interaction is about 10¹⁰ years in the sun's interior which is about the sun's lifetime. If the sun had more neutrons, it would burn faster.²
[1]: well, sorta. this is kinda simplified and more precisely described in the proton-proton chain which is the same thing but with extra frills.
[2]: Also note that while the weak interaction is the rate-limiting factor of the fusion process, it barely releases any energy. Almost all of the energy is released due to the strong interaction which glues protons and neutrons together really tightly and that way releases a lot of energy.
[3]: if you know better, please do correct me.
362
363
364
366
367
368
1
Google Opposes Site Blocking in Europe as U.S. Piracy Blocking Plans Gain Momentum
(torrentfreak.com)
369
370
371
372
373
374
375