[zapkitty]

(Major edit … no biggie, what’s a wrong answer 19.7 times smaller than the actual answer between friends?)

The discussion seems to be overlooking the matter of scale. It’s the amount of He per FF unit that matters most.

The cooling bottleneck is in the confined volume of the anode, specifically the part of the anode nearest the focus point. Thus the advantage of helium for that purpose. But that helium loop needs only to be long enough to reach from the anode tip to the anode base.

Once the heat is out of the anode then standard cooling techniques can take over without strain.

And the pB11 unit would requiire a much smaller anode than even what LPP is currently working with.

So from dimensions LPP gave previously for a production FF unit we’re talking about something less than a hundred or so cubic centimeters.

Estimates for helium as reactor coolant quote from 2-7 megapascals… for now I’ll guess at 2 MPa for something like a DPF…

edit: forgot to multiply from atmospheric to MPa… lets try that again..

So say 150 cubic centimeters of He @ 2 MPa x 462,280,000,000 FF units for current global electrical generation

He is 0.0001786 grams per cc at 101325 Pa… at 2 MPa thats 0.0035253 g per cc… times 150 cc per dpf core that’s 0.52879349 g per dpf… times
462280000000 units gives 244450650000 grams He for global FF power or ~244451 tons…

So, even though that’s 19.7 times my original estimate, that is still feasible given that it will take years to build up to that point and that this He used for dpf coolant would still be recycled.

But Earthside supply limitations will have to be considered along the way, what with our wise and benevolent elites deliberately shaping a helium shortage to further entrench their fossil-derived power (and further enrich themselves, natch).

… and re lunar He: we’d only have to mine ~729 sq km of regolith at a 4 meter depth to cover the current projection of global FF helium needs…

[zapkitty]

Breakable wrote: I am sorry that Linux incompatibility has not come to my attention earlier, before making a decision on the means of communications.

Well, this came up in emails dated as far back as 21 Jun 2012… so when you announced that we’d be doing the annual meeting the same way I assumed you’d decided that was the choice we had to go with.

I just wanted to give a heads up to the general membership via the forum and was surprised it had not been mentioned here. I’d just assumed it already had been. But perhaps this could be tied in to greater membership attendance at meetings.

[zapkitty]

Apparently no posted reminder for the upcoming members meeting?

… and from what I can gather from the emails I received it’s a webinar that’s going to require either windows or a mac running proprietary software in order to attend?

If so, well, I’m running linux here…

[zapkitty]

benf wrote: Yeah, I wouldn’t want to see the moon with a sad face >:(

On average helium-4 is 28 ppm of lunar regolith. 3He is from 1 to 50 ppb and is not considered further here.

About 1.07 billion metric tons of regolith would need to be processed to yield the 30,000 tons of helium mined on Earth annually.

Earthside mining handles vastly more material than than that annually and that’s in a fragile ecosystem… unfortunately.

“The smallest lunar features we can distinguish with the naked eye are about 200 km across.”

And regolith is about 3 tons per cubic meter. A reasonable depth for mining would be about 4 meters. So a trench 1000 meters wide and 1000 meters long and 4 meters deep would yield 4,000,000 cubic meters or 12,000,000 tons of material which in turn yields ~336 tons of 4He.

A trench a kilometer wide and about 90 kilometers long processed and refilled for each year?

… and the lunar surface area is 37.8 million square km.

The folks on Earth looking up will notice lunar space stations and perhaps lights from the surface installations of lunar cities and not much else.

[zapkitty]

delt0r wrote: The moom has helium in the parts per *billion* range.

Nope, that’s helium -3.

In lunar regolith helium-4 is measured in ppm. Depending on the figures you use there might be over 450 million tons of helium available for mining on the moon.

Aneutronic fusion would enable us to do just that.

That would solve our (deliberately engineered) helium shortage for about forever. And with pB11 aneutronic fusion we wouldn’t care about how much of the total bulk of He was helium-3… although I’m quite sure that sundry labs and industries would happily pay to separate some of that 3He out for various purposes.

In comparison to the lunar regolith, Jupiter’s outer atmosphere would be a mother lode of helium if you can get to it and scoop ii out of the atmosphere… and we will definitely need fusion-powered ships for that 🙂

[zapkitty]

ikanreed wrote: Could a FoFu 1 generate enough power to reach escape velocity from Jupiter’s gravity well? I know conventional rockets wouldn’t be able to manage the lift.

It’d have to be “touch and go”… like an unsuccessful aerobraking maneuver.

That way you’d keep most of your orbital velocity and could use a high efficiency in-space drive.

The question is how deep would you have to dive into the mostly-hydrogen exosphere to be able to scoop up usable amounts of helium.

Be a wild trip to pilot…

The #1 reality show of 2105: “Jovescoop Drivers!”

[zapkitty]

Tweet from LPPX:

[em]”The power is back on @LPPX post-Sandy! No flooding, so we’ll hope next week is productive”[/em]

… no word as to whether the shark dropped off a resume.

[zapkitty]

asymmetric_implosion wrote: My question is how do they know that alternative concepts are economically competitive?

As always these are based on the starting assumption of “… if a particular method works.”

If it is assumed that a given aneutronic process works, such as Focus Fusion or Polywell, then the basic order of magnitude costs of those generators have already been gamed out. They work or they don’t. Others such as Tri-Alpha’s (whatever they’ll call it) still have insufficient public info as to base costs.

But the primary driver of baseload-class plant costs is not the power source. It’s the generators that turn that power into electricity.

So if one speaks of proton-Boron fusion as Hirsch does and as we do here, then one is perforce speaking of direct conversion of fusion energy to electricity. No turbines.

Direct conversion is not a mystery, we’ve just not had much use for it in power generation up till now. But there would be no turbines.

And that would, without a doubt, mean massive savings over the equivalent structures in any given fossil or fission power plant. Baseload electricity generation via turbines is [em]expensive[/em]. Massive arrays of costly moving parts constantly wearing themselves down.

So in order for the cost of a given aneutronic process to be [em]non[/em]-competitive it would not only have to exceed the cost of its fossil or fission equivalent power source but it would also have to exceed the cost of the associated generation gear.

Not going to happen. FF units, for example, would need to have their current estimated costs come in at over *50* times the current budget in order to… draw even with current power sources. Co-gen, using the waste FF heat as industrial process heat etc etc, more than doubles that margin.

*If* a given aneutronic process works it will be competitive… and then some 🙂

asymmetric_implosion wrote: This has been the bane of the mainline ICF and MCF programs for years. Claims of clean, cheap energy without a configuration that is capable of producing more energy than it takes in. Doesn’t it seem premature to assume the economics are known before the physics is demonstrated to work?

Nope. Not with the scale of savings that the basic concept of aneutronic fusion brings to the table.

asymmetric_implosion wrote: Doesn’t engineering the system need to be done to understand the components and people that are the real cost of fusion? This will provide the inputs to decide if carbon free energy from fusion is worth the investment.

Sorry, no. A working aneutronic fusion process has a completely different set of cost assessments associated with it than any other power source. It has neither the noxious chemical outputs of fossil or the radioactive waste output of fission. It can provide both baseload and on-demand power. It can be both centralized and distributed….

It won’t be perfect, nothing ever is, but it will be far closer to an ideal power source than anything currently in use or planned.

asymmetric_implosion wrote: It frustrates me to no end that national lab folks talk about clean, cheap energy as a way to keep pouring money into programs they know are not viable for producing energy.

And that’s why the aneutronic contenders struggle for funding to complete their research. Do you believe they are wrong for doing that research with the clearly stated goals of achieving aneutronic fusion power sources?

[zapkitty]

Joeviocoe wrote:
What would be the impact of 200+ lightning strikes per second?

FF beam pulse ≠ lightning.

200 hz lightning would be the equivalent of about 7,500,000 FF cores going full tilt (using LPP’s figure of 80 kJ gross ion beam output per pulse)…

Exactly what kind of ship were you trying to power with 7.5 million FF cores? 🙂

From another calculation I did elsewhere that would be enough FFs to keep about 17 and a half supercarriers airborne…

[zapkitty]

BSFusion wrote: Please cast a vote.

The energy released in the pB11 process comes from fusion: the fusion of a hydrogen nucleus (a proton) with a boron-11 nucleus into a stable and quite non-radioactive carbon 12 nucleus.

But the C12 nucleus can’t contain the energy that resulted from its creation and it flies apart… but the [em]cause[/em] of breakup is not an unstable heavy nucleus decaying, as happens in fission.

The cause is instead an external energy input into the nucleus… even though that input came from the event that actually created the nucleus.

And thus even though it results in the C12 breaking apart and ending up with 3 helium nuclei (alpha particles)… the energy released in the pB11 process comes strictly from fusion.

[zapkitty]

Francisl wrote: This article indicates that a particular tungsten copper alloy may have the longest electrode life.

… but copper and tungsten are not particularly transparent to x-rays and beryllium is. It’s a heating problem.

I’m sure that LPP would be glad if it turns out they can get by with just copper electrodes for the production units but it seems they are planning on having to use beryllium.

[zapkitty]

Henning wrote: This needs special handling on the launch site, when maintenace crew needs to service the craft.

Nope. You’ve confused the FF unit with a fission reactor.

A fission unit is a neutron source whether it’s on or off.

An FF unit is just a pile of machinery when it’s turned off. When even an unshielded FF unit is not operating there won’t be a neutron problem for the maintenance crew to worry about.

And be advised that attempts at describing “near-term” FF-powered launchers are an interesting mental exercise but should not even be considered in a real-world context of near-term FF power plants and then ships etc etc.

[zapkitty]

Joeviocoe wrote:
Thanks James for the clarification. Mobile operations will indeed be difficult if heavy gamma shielding is needed. But submarines and ships can handle it since they already deal with heavy shielding for their fission reactors.

When considering mobile uses for FF units one must take into consideration the mass and volume not only of the power system being replaced but also the mass and volume of the fuel (usually fossil) that is no longer needed. The mass and volume of fossil fuel storage is a surprisingly large portion of all current Earthside transport methods.

The most common near-term mobile uses considered for commercial FF units (given that the parameters proposed by LPP hold up) are for:

cars – too heavy

trucks – semi-sized [em]could[/em] be made to work

trains – a good fit

large watercraft – also a good match. The Navies of the world will love you forever.

large hovercraft – well… [em]I[/em] considered them 🙂 Some interesting possibilities, I think.

aircraft – high subsonic cargo transports, which is the bulk of commercial aviation, should work well if you can deal with the C11 in a crash scenario

spaceborne applications – good for surface bases and large space stations but FF launch vehicles and FF-propelled spacecraft will require a scale of vehicles and infrastructure not yet under consideration… or a very [em]interesting[/em] lack of shielding 🙂

… but you could plant crewed lunar research stations wheresoever they suited you.

[zapkitty]

asymmetric_implosion wrote: A Q>1 PF could be filled with D2 or DT and produce a large burst of neutrons coupled with a 200 Hz drive.

… and what happens to the DPF structure in that 200 Hz neutronic environment?

There were earnest questions asked in the forums about the possible effects on the DPF structure from the occasional neutron produced by aneutronic reactions.

So if there were structural worries about aneutronic reactions, where the neutrons carry only .2% of the total reaction energy, then how much more so with neutronic reactions where the neutrons carry 400 times that?

And of course there’s the little problem of the DPF core melting long before you get to that level to begin with…

[zapkitty]

ikanreed wrote: I didn’t seriously think it was that risky a thing. The only non-sarcastic concern I had was that there would be serious legal repercussions I hope there aren’t. If Iran got a working fusion reactor, they’d lose all pretense for their existing fission program. It couldn’t possibly be portrayed as a peaceful energy endeavor anymore.

… and that would apply to all nations on this planet.

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