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Old 2022-12-12, 10:18   #3037
LaurV
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ft site is behind a paywall
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Old 2022-12-12, 13:39   #3038
Dobri
 
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Quote:
Originally Posted by xilman View Post
Behind a paywall
Quote:
Originally Posted by LaurV View Post
ft site is behind a paywall
I was able to read the entire FT article with my Chromium browser for Raspberry Pi despite the paywall.
Here are some additional links which refer to the original FT article:
https://www.irishtimes.com/environme...-breakthrough/;
https://www.foxbusiness.com/energy/u...-energy-report; and
https://edition.cnn.com/2022/12/12/p...ate/index.html.
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Old 2022-12-12, 14:09   #3039
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We've known a way to produce electricity from fusion for ~4-5 decades. It involves an underground cavern, lots of water and nuclear bombs set off one by one, and a willingness to take certain environmental risks. It was not considered economically competitive however. https://physics.stackexchange.com/qu...tricity#363533 I remember reading an article describing that in the American Society of Mechanical Engineers magazine in the 1980s.
For the recent development, it's unclear whether they have achieved caloric breakeven, or potential electrical breakeven. I think from reading the various articles it was caloric breakeven. Operating the many lasers and other equipment takes a lot of electrical energy. If the fusion reaction produced 20% more heat than the electrical energy expended to trigger it, that's above caloric breakeven but falls well short of electrical breakeven, since practical Rankine cycles are ~50% efficient typically. Next step after achieving electrical breakeven is commercial breakeven, where the electricity produced is worth more than the inputs required (materials, manufacturing, operation costs, decommissioning, hot components disposal, etc. amortized per unit of electricity produced). After that is achieving cost competitiveness with other methods of generation.
A former coworker (a pretty bright guy) claims that after the first fusion reactor's components are made so radioactive by irradiation with neutrons, that the site requires armed guards for a century, that fusion will become a dead research area and never reach commercial implementation. He thinks exploitation of the existing fission reactor under us all via deep drilling geothermal anywhere is the way to go forward. https://spectrum.ieee.org/altarock-e...othermal-wells
An inherent constraint regardless of energy source is the planet's ability to radiate waste heat to space while keeping mean radiator temperature acceptable is finite. Standard of living is closely coupled to energy usage.

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Old 2022-12-12, 21:24   #3041
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Default Fusion power maybe...

Rumored net power from NIF test: Ars Techinca via FT
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Old 2022-12-12, 23:02   #3042
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Originally Posted by sdbardwick View Post
Rumored net power from NIF test: Ars Techinca via FT
I heard they aim to raise the temperature to 1bn oC in a picosecond

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Old 2022-12-12, 23:44   #3043
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Quote:
Originally Posted by kriesel View Post
<snip>
For the recent development, it's unclear whether they have achieved caloric breakeven, or potential electrical breakeven. I think from reading the various articles it was caloric breakeven.
<snip>
From a Washington Post article:
Quote:
<snip>
Scientists refer to the current breakthrough as "scientific net energy gain" - meaning that more energy has come out of the reaction than was inputted by the laser. That's a huge milestone that has never before been achieved.

But it's only a net energy gain at the micro level. The lasers used at the Livermore lab are only about 1 percent efficient, according to Troy Carter, a plasma physicist at the University of California, Los Angeles. That means that it takes about 100 times more energy to run the lasers than they are ultimately able to deliver to the hydrogen atoms.

So researchers will still have to reach "engineering net energy gain," or the point at which the entire process takes less energy than is outputted by the reaction. They will also have to figure out how to turn the outputted energy - currently in the form of kinetic energy from the helium nucleus and the neutron - into a form that is usable for electricity. They could do that by converting it to heat, then heating steam to turn a turbine and run a generator. That process also has efficiency limitations.

All that means that the energy gain will probably need to be pushed much, much higher for fusion to actually be commercially viable.
<snip>
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Old 2022-12-13, 00:50   #3044
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Quote:
Originally Posted by Dr Sardonicus View Post
From a Washington Post article:
So, worse than I imagined, by orders of magnitude.
100 arbs electrical input to lasers -> 1 of laser photons > 1.2 of fusion-produced heat > 0.6 of electrical output from a well designed heat engine. Unless you could run the lasers and their power supplies really hot, then you might get to ~51 out for 100 in. Not exactly V-E day, is it.
Oh, and they can only fuse 1 pellet per day, while commercial viability is likely to require repetition rate of ~ 0.1- 1 Hertz. That's a few more orders of magnitude to conquer.
I wonder what small yield fusion bombs would cost in large production quantity.

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Old 2023-01-12, 15:56   #3046
kriesel
 
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Earth size exoplanet in habitable zone https://abcnews.go.com/US/nasa-satel...ry?id=96343188

Webb exoplanet find https://exoplanets.nasa.gov/news/172...rst-exoplanet/

Last fiddled with by kriesel on 2023-01-12 at 15:57
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