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Comment by zbobet2012 | Hacker News Reader

zbobet2012

https://en.wikipedia.org/wiki/Inertial_confinement_fusion#As...

That's utterly incorrect:

"Fast ignition and similar approaches changed the situation. In this approach gains of 100 are predicted in the first experimental device, HiPER. Given a gain of about 100 and a laser efficiency of about 1%, HiPER produces about the same amount of fusion energy as electrical energy was needed to create it (and thus will require more gain to produce electricity after considering losses). It also appears that an order of magnitude improvement in laser efficiency may be possible through the use of newer designs that replace flash lamps with laser diodes that are tuned to produce most of their energy in a frequency range that is strongly absorbed. Initial experimental devices offer efficiencies of about 10%, and it is suggested that 20% is possible."

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This is irrelevant - each shot also requires a highly precision engineered piece of metal called a hohlraum to be destroyed.

With current technology, running an ICF plant would cost literally hundreds of millions of dollars per hour in hohlraums, since a single one costs millions, and you need to shoot several times per minute to produce energy.

That's why ICF is not even close to being a plausible electricity generation technology, so it is only being researched by nuclear weapons research labs like LLNL.

hohlraums are not expensive because of base materials, but because today we generally produce them as one offs and the process is incredibly man hour intensive. The DOE "roundtable" on the announcement today addressed this.

For an actual look at the challenge of ICF i'd say look here: https://www-pub.iaea.org/MTCD/Publications/PDF/TE_1704_web.p...

and also consider that it might be used in combination with MCF for example: https://medium.com/fusion-energy-league/the-fundamental-para...

They are one-offs, but even if they were to be mass-produced, they require extraordinary precision. I very much doubt claims that one can be built in the range of a few dollars that each shot is worth in terms of generated electricity.

The reports you quote actually mention the target costs very clearly. The IAEA one talks about needing 500,000 targets per day, and sets a target of 0.30$ per target. At the time it was written, it says that a target costs 1000$, which is probably before NIF found put just how much more stringent the requirements for the shape of the target were (since the numbers I saw last time NIF achieved ignition were closer to hundreds of thousands of dollars per target, though maybe I am misrembering).

It's also worth noting that that report was expecting NIF to achieve the current milestone within 3-6 years, and it actually took 13. So I feel their numbers can well be considered optimistic.

I thought Fast Ignition had been abandoned because it was found it didn't work.

HiPER is also dead, I think.

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