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by DennisP 1280 days ago
"Getting more than you put in to maintain it" is the whole point for all these net power discussions.

In this particular case, it's a quick laser pulse and an exploding fuel pellet, so there's no lengthy runtime possible.

2 comments

The next step is rep-rate, which a lot of the field has neglected, while some people (tooting my horn, my lab) were amongst the few pushing it. The thing is people couldn't even achieve the result with one shot, but now that it seems feasible now, hopefully scientists (and more importantly funders) will start to care about increasing rep-rate.
Yes, although they need to still leverage this ignition/scientific-breakeven achievement to get the higher energy gains needed for a practical power plant. Not just 1.5x but 25-50x. With ignition now being repeatable, that should be a doable proposition.
So, one of the things that I probably shouldn't say is the NIF design is not really optimized for fusion specifically (I won't say too much but you can guess why). There are schemes out there that can be more efficient, for example, not even bothering to convert to UV and then x-rays (start at UV in fact, or crank up the intensity of light, the light in NIF is very intense but modern high intensity systems are orders of magnitude more intense, they are however dramatically lower in pulse energy). That plus using modern laser tech when you realize NIF was designed in the 80s, we can definitely make it much more efficient eventually.
Don’t need to be too coy about the fact that NIF was built to recreate the processes inside an H-bomb after underground nuclear testing was banned. They literally use the same concept of a “Hohlraum” (here in miniature) where heat and light (from a fission trigger in the case on an H-bomb, lasers in the case of NIF) convert to x-rays on the outer casing and evenly illuminate the fuel pellet casing which ablates a bit to drive implosion which triggers the actual compression heating of the fuel pellet. Heck, some previous tests even used a uranium tamper (because in part, uranium has high inertia due its density thus prolonging the period of high pressure), just like a real H-bomb.
I don't see why not. Requirements are to inject the fuel (in pellet form) and ignite it with a laser pulse. Right now I believe the pellet is contained in an hohlraum that is held in place in order to perform the test but you could drop (or shoot) that assembly into the chamber and time the laser pulse to hit it when it's in the right location. That doesn't sound like it's beyond the realm of physical possibility.