A New Type of Fusion Reactor or Just a Scam?

CrazyEgg

Hi
A friend of mine is doing an assignment on alternative sources of energy when he came across this site and sent the link to me:
http://www.crossfirefusor.com
From reading a couple of pages it seems deceptively simple and I'm told that the guy expects to get a net gain of a couple MW of electricity from his prototype.
I told him to hold off on submitting the paper, he's not in university or anything, he's 17 so the assignment is not scrutinised for science but it at least has to be right.

So what do you guys think?

Thanks

phyzguy

I wish it would work, but I wouldn't get your hopes up. The calculations on this web site seem focused on showing that the fusion energy is available assuming that the nuclei fuse. This has never been the issue - we know fusion works, just go look at the sun if you don't believe it. The problem has been confining the energetic plasma long enough at high enough density so that the rate of energy production exceeds the rate of energy loss. This web site seems to assume that if I accelerate these ions at each other, they will collide and fuse. In fact, the impact parameter of most collisions is such that they will "miss" and simply be deflected. It takes a near head-on collision to result in fusion, and these are rare, so you need to confine the plasma long enough so that there are enough of these rare collisions. I don't see anything to indicate that this approach will confine the plasma any better than the hundreds of other configurations that have already been tried. However, I hope I'm wrong and this approach works - we need clean energy badly. It's certainly correct that these "aneutronic" reactions are preferred, since they generate vastly less radioactive waste. However, the problem has been that the reaction rates for these reactions is orders of magnitude less than the D-T reaction, which is why the D-T reaction has been preferred up until now.

russ_watters

For a school paper on nuclear power, I would not use a source that is not a nuclear scientist/engineer. Though the idea may end up having merrit, he doesn't have the credentials to be worthy of considering the claim since it hasn't been peer reviewed.

Strat-O

Wow, the proposed spaceship that's powered by the proposed fusion engine has a greater mass than a fully loaded 747!

No sense in developing small proof-of-concept models when you know in your gut that this baby's gonna work!

CrazyEgg

Well he's not going to be writing about it anymore especially after I sent him a link where the inventor says that the proposed spaceship will reach alpha centauri in 35 months with a maximum velocity of 3 times the speed of light.

Honestly a part of me actually wishes that it would work and I'm told that the inventor is getting the design verified by a plasma physicist so who knows.

What's your opinion on the design russ (or anyone else for that matter)?
I ask because I'm just curious.

Astronuc

The calculations page at crossfire fusor are missing the critical/vital equations related to the reaction rate. One has to look at the scattering and fusion rates to see if it's feasible. Without those calculations, there's no credibility.

There might be some p+¹¹B fusions, but not p+p. The claim about "the rest of 4 x ¹H" is implausible.

Cosmos2001

I’m not an expert, but it seems to have the acceleration and confinement system more feasible than the tokamak, and as far as I can understand, the calculations are made to predict the minimum requirements for the acceleration and confinement. I think the acceleration system can trigger fusion rates; and the confinement system can reduce a little bit the scattering problem.

Astronuc

There is no basis for this.

The crossfirefusor author needs to produce the fusion reaction rate = n_p n_B <σv>, n_p = proton density, n_B = boride density, and <σv> reaction rate parameter for the particular reaction. Then he needs to do an energy/power balance for the heating and fuel transfer, fusion reaction, and losses. Those calculations are not on the calculations page. I'd want to see the proton beam spectrum and profile.

mheslep

The bit on direct energy conversion is crackpottery. While direct conversion has been frequently discussed in the literature, this description is nonsense:

There are no million volt switch mode power supplies.

Cosmos2001

Maybe with a custom cascade mega-volt power supply, million volts can be possible.
This picture is an exemplification showing only two modules connected to an electrical transformer:

mheslep

No, a theoretical first stage can not be isolated sufficiently at that voltage. Discussion of semiconductor switching power supplies in this context is nonsense.

Cosmos2001

I think this schematic is to have several stages with their output connected in series.
But, there is another solution. If it is needed 1MV, and an IGBT cannot withstand no more than 2kV, then connect 500 IGBT in series to withstand 1MV, controlling them using optical fiber to get high electric insulation protecting control system from electromagnetic interferences.

mheslep

This is nonsense.

Cosmos2001

Sorry, I'm not good with words to explain things.
I mean with HVDC technology, few mega-volts can be possible.

I think "nonsense" is a question of point of view.
For me, nonsense is to waste billions of dollars on NIF and ITER behemoths, while cheaper and more well-conceived alternative fusion concepts are left aside.

Mu naught

I don't know where you guys are seeing all these wacky claims on that website, but I think the design concept is pretty cool. If you can get beam currents and collision rates high enough, I think the design concept is perfectly plausible.

mheslep

It may be the NIF and ITER are ill conceived, but there's nothing articulated here that shows this scheme as being well conceived. And no it's not possible to serially connect 500 IBGT's across a megavolt.

Cosmos2001

In this case, someone should advise HVDC engineers to stop connecting IBGT and other semiconductors in series across a megavolt.
http://www.ptd.siemens.de/HVDC_Solut...09-07_V_1b.pdf
http://web.archive.org/web/200804080...Technology.pdf


Oops, diodes connected in series, some guys are using multiplier circuits to withstand 3.4 MV, is it a nonsense?
http://www.hst.tu-darmstadt.de/filea...03b.pdf#page=4