Comment by bitumen | Hacker News Reader

Comment by bitumen | Hacker News Reader

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As you can see from some here, people just want to believe. Fusion is the power source of sci-fi, and they’re scared of fission. As with self-driving cars, people just imagine what it could be like and that’s enough for them. Never mind that decades of R&D on fission has yielded breakthroughs in safety and efficiency, and by the time a workable fusion design is possible far more advanced fission will be possible. People want the future to be now, so they believe their way into it. Scientists want funding for research, so they sex it up for the media and mass consumption.

The truth is that politics aside, we could be using fission today to solve the problems people want fusion to solve decades from now. Granted, if aneutronic fusion becomes possible (no time soon, even experimentally with a surplus of energy) that will be a miracle. DT fusion though, is only useful for research purposes.

Most people, including most people here don’t have a working understanding of nuclear physics or the requisite engineering of a power plant. When you don’t understand the hurdles, fusion seems kind of magical. If you’re desperate for advanced space flight, fusion seems kind of magical. Even more, no one has any negative experiences with fusion, while we’ve been literally burned by fission.

It’s hard to argue against a fantasy, and hoping for fusion also let’s people ignore the hard work of using fission. The politics feel intractable in the US, the waste is manageable, but scary. Fusion isn’t real yet in that sense, so like an online romance people can project a fantasy onto it.

"Granted, if aneutronic fusion becomes possible (no time soon, even experimentally with a surplus of energy) that will be a miracle."

A group at Princeton has a concept for a FRC-based reactor burning D-3He that, through a combination of quite interesting tricks, reduces the fraction of power output in neutrons to as little as 0.5%. The design is also very small, with a power output of 1 MW. At this level of neutron output the reactor structure are lifetime components, with no replacement needed due to neutron damage. Power density is still a struggle, although the small size of the reactor helps there.

The downside (assuming the aggressive plasma physics doesn't disappoint) is where do you get the 3He.

At this point, my default vision of the future is neither fission nor fusion, but rather renewables and storage. The engineering and economic issues of these appear much more tractable. Simply extrapolating solar down its demonstrated experience curve puts the cost of PV electricity at $0.01/kWh or less when fully scaled out.

I was only aware of Helion doing D-3He, and they're in Washington. Do you have a link for the Princeton group?

Sam Cohen’s Rotating Magnetic Field experiments have shown higher temperature and reasonably long-lived FRCs. His vision is steady operating, 3He systems, atleast at first targeting propulsion. As you dial up the Helium percentages, the neutron output goes down, though the required ion temperature goes up. Princeton Satellite Systems has several NASA programs looking at the propulsion applications.

"required ion temperature"

The scheme involves significantly non-maxwellian ion distributions, so "temperature" isn't really appropriate. In particular, 3He ions get pumped to higher energy than D ions, which helps suppress DD fusion. They claim the scheme is consistent with Rider's limits on energy circulation in non-maxwellian plasmas.

https://en.wikipedia.org/wiki/Princeton_field-reversed_confi...

The small company proposing using this for a notional Pluto orbiter:

http://www.psatellite.com/

Primary patent for the reactor:

http://www.freepatentsonline.com/9767925.html

To be fair some reponsabilites also come from poor performances of fission industrie leaders. In France the next generation fission power plant EPR was so much delayed that a lot of people are getting skeptical about this tech if not totally opposed for environmental reasons (trues or romanticized).

This is a shame as I globally agree with you that fission might have a transitional role to play in the mix needed to reduce our global warming impact. Consuming less non-renewables ressources being the first line of action anyway.

Before you judge their efforts, I would watch this video:

https://youtu.be/KkpqA8yG9T4

Sounds like the only thing standing in the way is prototype funding.

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