511
US scientists achieve net energy gain for second time in a fusion reaction
(www.theguardian.com)
this post was submitted on 06 Aug 2023
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Where do you get those numbers from? They don't seem to match the figures in this article or the article it links to. I get that you're saying they leave out some important facts about the total energy used in the experiment, but I'm curious about exactly what's not documented here.
Wikipedia's figures for the last time they made this claim. The exact figures might be a bit different this time round, but I doubt they've found 99% efficiency gains. Livermore sends out this sort of press release pretty regularly and it always comes down to the same creative accounting
Basically, there's a whole load of input energy that they just don't count. Heat? Doesn't count. UV? Doesn't count. Plasma? Doesn't count. this diagram from the wiki might be instructive. There may be decent justifications for counting it like this - I don't know, I'm not a nuclear physicist. But I think the way they continue to report it to the media is simply dishonest.
The logic is that they don't count ignition costs because they only have to be paid once. So it's producing more than it consumes, and would eventually start netting a surplus.
Except it's not and it won't. It's just a fraction of a second pop and done. There's no sustained reaction because inertial confinement by it's nature is extremely temporary, and there's no way to introduce new fuel. If they do some monster fuel pellet that outshines the laser then sure - they can claim a net surplus. If they find some contrivance to keep a reaction going after it's started then fantastic, well done, the day is saved. But they're not likely to do that at the NIF because, shhh! NIF is not really about generating energy.