[dennisp]

So he’s expecting a fusion gain over 5 sometime around 2017, when they convert to D-T: https://s3-us-west-2.amazonaws.com/pnwmsnw/NIAC_PhaseII_FDR.pdf

That should help funding efforts, if nobody else achieves it before then.

And then a full-scale ground demo in 2020, a space mission a couple years later with a 40x gain, and 2030 for a manned Mars mission with a 200x gain.

[dennisp]

There’s not just one group of environmentalists. Some are deeply motivated by non-environmental concerns, others just want to fix climate change and ecosystem destruction, and are quite happy with technical solutions including fission reactors. James Hansen, James Lovelock, Stewart Brand, and many others are in the latter group.

This particular group sounds closer to the former. For people in that crowd, I would emphasize the decentralization inherent in focus fusion’s small reactors, along with LLP’s determination to liberally license the technology. Also of course the lack of neutron radiation and nuclear waste.

Of course I’m a little late with my comment. How’d it go?

[dennisp]

Nice: “There are several external energy source or ‘driver’ technologies under development: lasers, particle beams, and pulsed magnetic fields… the committee concluded that a range of driver technologies should continue to be pursued, rather than choosing a single technology at this time.”

[dennisp]

Protactinium separation is well-known to the engineers working on thorium reactor designs (though overlooked by much of the public.) Some designs make it easier than others.

The main advantage of the thorium fuel cycle is that you’ve got non-fissiles shipped to and from the reactor, so you at least don’t have to worry about theft by terrorists (other than for dirty bombs). So if a state already has nuclear weapons, thorium reactors don’t add much risk. Since the biggest carbon emitters are all nuclear powers already, thorium still seems like a good idea to me.

For other states, if they had reactors without protactinium separation and they didn’t make their own fissile startup fuel, we still might be in reasonably good shape. The breeding ratio of thorium is near breakeven, so if they removed much fissile the reactor would stop and they’d have to ask for more startup fuel. We’d definitely want to think through what they could get away with though.

Of course if aneutronic fusion works out, thorium reactors will as obsolete as everything else, and proliferation will be much less of a concern.

[dennisp]

I think it’s more that it’s just not working out that well.

Something else that could be a good reason, though I haven’t seen anyone mention it, is that fast laser ignition is looking a lot more promising: http://en.wikipedia.org/wiki/Inertial_confinement_fusion#Fast_ignition

Some recent papers even claim that it makes boron fusion feasible, once the lasers get a bit bigger.

[dennisp]

They are running a lot of shots on their research reactor, and with $90 million in venture capital they probably have some spare bandwidth. NIF’s been doing the same thing with their LIFE design. Heck, General Fusion pretty much started with a production-scale reactor design.

In any case, I’m pretty much rooting for everybody and it’s nice to see Tri-Alpha talking for a change.

[dennisp]

Wow. Didn’t know there was so much IEC work going on outside the Navy project.

[dennisp]

Personally I’m just thrilled to see the NYTimes writing about tokamak economics, polywell, and boron fusion. Maybe the word is starting to get out, and a little big-fusion money can be pried loose for alternative approaches.

I know nothing about the engineering and economics of switches, and I’d like to see other people’s views on that. I think if FF simply demonstrates scientific feasibility, it’ll go a long way towards raising funds both for switch development and for other aneutronic designs.

[dennisp]

The cost could be even lower using this new water desalination technique presented at Google’s Solve for X:
http://www.youtube.com/watch?v=R63zYZZuRvQ

Less energy required, and no high-pressure systems to build.

And with focus fusion getting rid of our coal plants and so on at the same time, we’d end up actually reducing our CO2 level pretty significantly.

[dennisp]

I think the basic flaw in Murphy’s argument is that a society with such an enormous amount of energy available would find it very cheap by comparison to expand into space. If exponential energy growth continues that far, it won’t be on this planet.

(Murphy has another post skeptical of space colonization, but in that one doesn’t assume vastly larger energy resources.)

[dennisp]

The timeline for replacing all the world’s power plants would be quite long *if* you assume the new plants have a similar cost. Then people are pretty much going to wait until end-of-life before replacing each plant.

However, at half a million bucks for a 20MW reactor, focus fusion reactors could replace a coal plant for less than the cost of one year of fuel. Any coal plant operator would come out way ahead by replacing his plant as quickly as possible, even if the plant is new. Since he could do it 20MW at a time, he could even buy the FF reactors with revenue, instead of needing a loan, and each new reactor will increase his profits more. With each reactor so small, capital requirements are so minimal that even a reasonably well-heeled individual could build a reactor and run a nice little business selling power to the grid.

And with a steady output and high capacity factor, we wouldn’t need a super-advanced smart grid either.

Focus fusion is the one technology I know of that would replace our infrastructure extremely quickly. Focus fusion plants would be installed as quickly as they could be rolled out of the factories.

[dennisp]

I was going to ask you about your previous post mentioning momentum…if there’s a simple explanation, why does that force the nucleus to split? Why couldn’t the proton just stick to the boron and give it a push, like a bullet hitting a block of clay?

I understand there will be energy that has to go somewhere…the clay heats, but the carbon could, as you say, emit a gamma.

(As I’m sure you can tell, my physics training only extends to a couple semesters.)

[dennisp]

Yes, carbon 12 is stable. It’s the same isotope as most of the carbon in your body. You wouldn’t say a brick is unstable because you blows up when you pack it with C4 and detonate it.

Fusing a proton with Boron-11 is equivalent to detonating C4 in a brick. It’s not the breaking of the brick that causes the energy release. The energy release causes the breakage.

Energy releases when you fuse nuclei lighter than iron, or when you fission nuclei heavier than iron.

Therefore I’ll vote “fusion.”

[dennisp]

Sometimes you have to just do the smart thing and never mind what the idiots think about it.

[dennisp]

Joeviocoe wrote: could think that this facility contains that much energy at any given time.. and a simple accident (like the beam not shutting off for 1/8th of a second) could vaporize the city

Ok that’s a good point.

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