Proliferation?

[Brian H]

The one weapons possibility I see is the use of the X-ray beam version; a bright X-ray beam could be used to seriously mess up soldiers, electronics, missiles, etc.

[Brian H]

Transmute wrote: I’m not talking about the alpha beam, I’m talking about the very high energy neutrons produced by T+D fusion (or the moderately high energy neutrons produced in D+D fusion) the “alpha beam” or beam of non-neutron (charged) nuclei produced by the DPF would in a Fusion Driven Sub-critical Reactor (as opposed to an ADSR) would best be spent hitting a splatation target making more neutrons. Destroy nuclear waste in such a manner would produce huge amounts of heat, in an economy where cheap B11+P DPF reactor have not yet taken over adding steam turbines to the nuclear waste destroyer would add profit to a previously unprofitable task.
look up subcritical reactors.

I grew up cheek-by-jowl with a fission reactor research site; I’m quite familiar with subcritical reactors. But in fusion the X-ray cooling problem makes even break-even difficult. This was EL’s major breakthrough with p+B11, IMO. Reducing that cooling to the point that the beta beam retained enough energy to reheat the plasma and the alpha enough energy to refill the capacitors for another shot. With the residual 40% energy as X-rays manageable and managed and exploited.

The T+D and D+D DPF reactors instead require external power for the plasma and the cathode pulse. It is possible that the heat-engine waste destruction would be able to provide it, but it would likely be a near thing.

Exploiting the neutron shower would also be quite a trick, I think The neutrons are undirected and undirectable, so the apparatus gets rather massive and multi-layered. I also wonder what metals would stand up to that kind of bombardment. Pressure piping and container degradation are already serious issues with ordinary fission processes. This sounds even hairier. But maybe not.

[Transmute]

Brian H,

You don’t need break even at the fusion level with energy multiplication from the induced fission. Even with particle accelerators in conventional subcritical designs the multiplication factor is 60to1, to 60 times more energy comes out then put in, a D+D or D+T focus fusion driven reactor could possibly achieve even higher energy multiplying factors.

Subcritical reactor designs are usually very large, but replacing a giant particle accelerator with a much smaller focus fusion device helps.

The point is we have huge stockpiles of nuclear waste and not much we can do with it, but that could change if we achieve even limited D+D or D+T fusion using focus fusion.

[Brian H]

Hm. How ’bout we wait a few years till FF is available, use it to help build a Space Fountain, and use that to sling the waste into a parking orbit around the sun or onto a designated Dump Crater on the Moon? 😉 Who knows, maybe some future generation would have some interest in using all those exotic isotopes!

[Transmute]

Brian H wrote: Hm. How ’bout we wait a few years till FF is available, use it to help build a Space Fountain, and use that to sling the waste into a parking orbit around the sun or onto a designated Dump Crater on the Moon? 😉 Who knows, maybe some future generation would have some interest in using all those exotic isotopes!

aah why waste it like that, when you can covert it into power and non-radioactive isotopes. It’s not “some future generation” sub-critical reactors are technically feasible NOW!.

[digh]

I’m coming late to the proliferation issue and FF but now that we move forward I think we should consider our response to this concern. When we develope a garage sized device that could be distributed world wide this will come up! Of the two reactions DD and DT that could be used to produce a stream of neutrons I wonder how energetic DD is. Already DD has been used to produce the first pinch and I haven”t heard of anyone glowing in the dark nor has the FF “FO” been declared a hazardous site. The DT reaction might be much more active but you already need nuclear technology to produce Tritium. Then again, would FO really stand up to DT neutrons or flame out. Actually I’m not terribly worried about some rogue group refining nuclear fuel and constructing a nuclear device. The principles are well understood but the engineering is a nightmare (North Korea’s attempt was a dud). The greater concern is enriching deplet U238 to a sizable percentage of U235 that could blanket a dirty bomb. Hey! no one wants to rain on this parade least of all me but again we should consider our response.

[Phil’s Dad]

Digh, am I missing something here? %-P

Surely our response is “aneutronic”.

What is there in pB11 to proliferate (apart from vast amounts of cheap energy)?

[digh]

Yes Phil’s Dad when you use PB11 it is. also if you used H3. But other fuels DD (which has already been used in FO to create the first pinch- albeit minimally) and DT would definately not be aneutronic and could produce neutrons.

[Phil’s Dad]

Of course you are right but I was only really considering the end game.

[YordanGeorgiev]

According to this document
http://www.thorea.org/publications/ThoreaReportFinal.pdf
a reliable and cheap source of neutrons would be needed …. Even if Focus Fusion is price competitive the business oportunity from the disposal of nuclear waste should not be underestimated …

The thread here is the eyebrows raising of the established business … although one also argue that this is more oportunity than a thread …

[Breakable]

As far as I see, Eric is specifically trying to workaround producing a neutron source. There are concerns of nuclear proliferation once you produce a cheap neutron source.

[zapkitty]

Breakable wrote: As far as I see, Eric is specifically trying to workaround producing a neutron source. There are concerns of nuclear proliferation once you produce a cheap neutron source.

As I understand it the FF concept does not favor a neutron-steam-turbine setup. One reason is that the small size of the unit is not suited for the thermal output needed to drive efficient turbines. It’s going to be a chore to get 7-8 megawatts of heat out of the core of a 5 MWe pB11 FF unit but that should be doable…

… getting ~15 MWt out of the core of a 5 MWe D-T FF unit is going to be [em]extremely[/em] difficult.

Another showstopper for a neutronic FF unit is neutron activation and embrittlement. People speculate here in the forum as to the extent of the problems that may result from having occasional neutrons that carry only .2% of the pB11 reaction’s fusion energy….

… in D-T fusion the neutrons carry [em]80%[/em] of the reaction energy.

As far as I can tell an FF setup is not suitable for sustained neutronic power production… or even sustained neutron production.

[delt0r]

In order for a neutron source to be a proliferation risk, it also has to be a power source. At least if you want to transmute enough stuff under a few 100 years anyway.

We can run some basic numbers. Lets assume DD fusion with full T ash burn and no He3 burn. Thus we have

DD->T +p, DD->3He +n, DT->4He+n

total reaction is

5D->3He+4He+2n+p 24.9MeV (16.5 MeV in neutrons)

So if we want to get 7kgs of Pu from 238U we need about 30 moles of neutrons assuming 100% efficiency. To do this in one year you need a average power of 1.1MW. Definitely not just a neutron generator.

EDIT: i forgot the not unsubstantial power from the transmutation itself.

[Breakable]

delt0r,
Average coal power plant in US is about 330MW (if I got the comma right), so its certainly not an issue to run a 1.1 MW non-break-even fusion reactor.

[zapkitty]

Breakable wrote: delt0r,
Average coal power plant in US is about 330MW (if I got the comma right), so its certainly not an issue to run a 1.1 MW non-break-even fusion reactor.

… which brings us back to the fact that anyone with access to electrical power can produce neutrons even without using fusion tech.

And the advent of cheaper accelerators and subcritical reactor tech isn’t going to lessen such proliferation risks…

[Author]

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