# Kid builds reactor

#### Greg Bernhardt

Related Nuclear Engineering News on Phys.org

#### Mr. Robin Parsons

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#### MathematicalPhysicist

Gold Member
are there any notes (preferablely his) about how did he build the reactor?

#### Claude Bile

If that kid came second, I wonder who came first?!

#### Zantra

Just goes to show if you're intelligent enough, and you've got access to the internet, you can build just about anything.

#### Phantomas

Zantra said:
Just goes to show if you're intelligent enough, and you've got access to the internet, you can build just about anything.
Makes you think huh :uhh:

P.

#### NateTG

Homework Helper
loop quantum gravity said:
are there any notes (preferablely his) about how did he build the reactor?
http://www.fusor.net/
is probably the best source around. This is a pretty old story.

#### theCandyman

Incredible, I'm motivated to build one myself seeing that it can be done.

#### Tom McCurdy

It makes me want to go work on my mentorship project---- its only automating a light spectromter but its pretty cool... I will post pics when we start actual construction

#### Morbius

Dearly Missed
Greg Bernhardt said:
Greg,

I wouldn't call that a reactor.

There's no way that device achieves fusion ignition.

I'm sorry - physics says no.

It would have to be at a temperature of million of degrees to
achieve fusion ignition.

That's why fusion is called "thermonuclear" fusion.

Dr. Gregory Greenman
Physicist LLNL

#### theCandyman

article said:
The ball is, literally, a small sun, where an electric field forces deuteron ions (a form of hydrogen) to gather, bang together and occasionally fuse, spitting out a neutron each time fusion occurs.
Morbius, isn't this what fusion is?

#### NateTG

Homework Helper
Morbius said:
There's no way that device achieves fusion ignition.

I'm sorry - physics says no.
What makes you think that the device does not or would not work? How do you explain the neutron emissions? I understand that the device is not suitable for energy production (there's a really nice paper at MIT about that) but that doesn't mean that there isn't fusion.

http://en.wikipedia.org/wiki/Farnsworth-Hirsch_Fusor

The reactor is almost certainly a fusor (inertial electrostatic confinement), and others have also succesfully had fusion reactions (or at least neutron emission) from similar set ups starting, as far as I am aware, in the 60's.

Putting out nuclear fire confusions with gasoline

NateTG said:
Morbius said:
There's no way that device achieves fusion ignition.

I'm sorry - physics says no.
What makes you think that the device does not or would not work?
Morbius did not say the device could not work. He said it could not achieve fusion ignition.

The sun is on nuclear fire. It has achieved fusion ignition, and it is still ignited. The device in question does not achieve ignition of nuclear fire, and the article is therefore wrong in describing it as containing a ball that is "literally, a small sun." The device merely achieves a singe fusion ~four times a minute.

If a device were demonstrated that achieved a gasoline molecule oxidation ~four times per minute, would you call sum of those reactions inside the device a gasoline fire?

#### theCandyman

Ah, I see. Thanks for clearing that up hitssquad.

#### Janitor

I spent a night in Logan this summer. The next morning Utah State University was on my left as I drove toward nearby Logan Canyon and on to Bear Lake.

#### Morbius

Dearly Missed
NateTG said:
What makes you think that the device does not or would not work? How do you explain the neutron emissions? I understand that the device is not suitable for energy production (there's a really nice paper at MIT about that) but that doesn't mean that there isn't fusion.

http://en.wikipedia.org/wiki/Farnsworth-Hirsch_Fusor

The reactor is almost certainly a fusor (inertial electrostatic confinement), and others have also succesfully had fusion reactions (or at least neutron emission) from similar set ups starting, as far as I am aware, in the 60's.
Nate,

Because I work in the field of thermonuclear fusion for Lawrence Livermore
National Laboratory - after receiving my doctorate from M.I.T.

As for the neutrons - there are stray neutrons all over the place.

However, if you are using only deuterium for the fusion fuel - then
the fusion reaction would be the D-D fusion reaction which produces
3.27 MeV of energy - of which 2.45 MeV goes into the neutron.

So - if this device were producing D-D fusion, one would not just see
neutrons - but neutrons of a particular energy 2.45 MeV.

If the fusion fuel were a mixture of deuterium and tritium - then one
would see the D - T fusion reaction which liberates 17.6 MeV of energy -
of which the neutron gets 14.1 MeV. So one would expect to see
a 14.1 MeV neutron.

In order for fusion to occur - one has to have both the requisite density
and temperature.

All this machine does is make a diffuse plasma. Nothing "special" there -
I have a "plasma globe" decorating my living room - no big deal.

I don't believe it's particularly helpful to popularize the "pseudo-fusion"
machines. It misinforms people about how truly difficult it is to
achieve fusion reactions.

Besides, there's plenty of progress on "real" fusion machines to talk about:

http://www.llnl.gov/nif/

Dr. Gregory Greenman
Physicist

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DaimlerChrysler Aerospace markets tabletop fusion device

• Appl Radiat Isot. 2000 Oct;53(4-5):779-83.

The IEC star-mode fusion neutron source for NAA--status and next-step designs

Miley GH, Sved J.

Fusion Studies Laboratory, University of Illinois, Urbana 61801, USA. g-miley@uiuc.edu

Based on research at the University of Illinois, a commercial neutron source has been developed by Daimler Chrysler Aerospace using a small grided-type Inertial Electrostatic Confinement (IEC) plasma device (Miley and Sved, 1997) This device employs a unique "Star-Mode" deuterium plasma discharge to create ion-beam driven fusion reactions in a plasma target (Miley et al., 1997a, 1997b, 1997c; Miley, 1999). As such, it represents the first commercial application of a confined fusing plasma. The Star-Mode discharge is an essential feature of this device since it minimizes ion-grid collisions and also allows tight beam focussing.

PMID: 11003520

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#### Morbius

Dearly Missed
• Appl Radiat Isot. 2000 Oct;53(4-5):779-83.

The IEC star-mode fusion neutron source for NAA--status and next-step designs

Miley GH, Sved J.

Fusion Studies Laboratory, University of Illinois, Urbana 61801, USA. g-miley@uiuc.edu

Based on research at the University of Illinois, a commercial neutron source has been developed by Daimler Chrysler Aerospace using a small grided-type Inertial Electrostatic Confinement (IEC) plasma device (Miley and Sved, 1997) This device employs a unique "Star-Mode" deuterium plasma discharge to create ion-beam driven fusion reactions in a plasma target (Miley et al., 1997a, 1997b, 1997c; Miley, 1999). As such, it represents the first commercial application of a confined fusing plasma. The Star-Mode discharge is an essential feature of this device since it minimizes ion-grid collisions and also allows tight beam focussing.

PMID: 11003520

Miley, et. al. have a neutron source.

They have a device for producing neutrons if that's what you want.

However, if you want energy - which is the goal of fusion research -
this device requires more energy to run it than you get out.

Because of the operating principles of the device - it will ALWAYS
require more energy to run than you get out of it.

Dr. Gregory Greenman
Physicist

#### CharlesP

It amazes me how fast junk science gets around and how hard it is to put out fires like this one.

#### NateTG

Homework Helper
CharlesP said:
It amazes me how fast junk science gets around and how hard it is to put out fires like this one.
How, precisely, are IEC fusion reactors junk science? As far as I can tell, fusor reactors, for example, are well documented and repeatable.

Unless the language has been changed recently, cold fusion notwithstanding, the problem is generally that people are apparently unable to distinguish the of fusion reactor and fusion power source. Of course, Hollywood isn't exactly helpful on that front.

Fusion, even 'exothermic' fusion, has been possible for more that 50 years now -- a 15megaton hydrogen bomb (Bravo Shot) was set off on Feb 25, 1954. People have been trying to harness fusion power in a less destructive fashion since before then.

The fusion power problem isn't just achieving fusion, but achieving contained and exothermic fusion.

#### Morbius

Dearly Missed
NateTG said:
Fusion, even 'exothermic' fusion, has been possible for more that 50 years now -- a 15megaton hydrogen bomb (Bravo Shot) was set off on Feb 25, 1954. People have been trying to harness fusion power in a less destructive fashion since before then.

The fusion power problem isn't just achieving fusion, but achieving contained and exothermic fusion.
Nate,

When discussing power by nuclear fusion - it pretty much goes unsaid, and
is taken as a given; that the reaction has to be exothermic [ the whole idea
is to get useful power ], and controlled [ H-bombs don't count as a power
source].

Dr. Gregory Greenman
Physicist

#### dream_reaper

IEC vs. "REAL" fusion

To quote Dr. Greenman: "In order for fusion to occur - one has to have both the requisite density and temperature."

Please correct me if I'm wrong - but I was of the understanding that in order for 'Fusion to Occur' you need to overcome the Coulomb Barrier - Essentially, you need to push two Ions close enough together so that the Strong nuclear force, slightly more powerful but acting over shorter distances than the Electromagnetic force acting to repel the like-charged particles), is able to exert its influence and bind the two nuclei together? In the case of D - T fusion, you've got a pair of alpha particles that result from this fusion... the odd-man-out Neutron with it's 14.1 MeV of kinetic energy, and the Helium-4 nucleus with it's 3.5 MeV (? I don't remember if that's correct or not on the H4 nucleus).

Granted, the approach followed by those inelegant toroidal behemoths is to overcome this barrier with the 'Requisite density and temperature'. The procces, as I understand it (and again simplified), is to increase the pressure of the plasma in the reactor, and thus decrease the total temperature required to overcome the Coulomb Barrier. The total energy is the same as if you were to collide a Deuterium nucleus with a Tritium nucleus with a combined energy of ~100 KeV, rather than heating up and containing a plasma, as in the Tokamak approach. The ultimate goal is of course 'Ignition'; the point at which the fusion reaction becomes self-sustaining and the excess energy from the reaction exceeds the energy required to sustain it.

IEC fusors, however, seem to follow a different approach. Rather than using a form of 'heating' to add energy to a contained plasma, the IEC method adds the requisite energy <i>directly </i> to the hydrogen ions, rather than <i>indirectly</i> as in the Tokamak approach. The basic design is simplistic, and is capable of producing fusion (as evidenced by the neutron production - and to counter your previous argument, I doubt this student had the ability to measure the specific kinetic energies of the neutrons he was detecting, but I'd wager he was smart enough to see a spike in the neutron count that would statistically deviate from the ambient 'background noise'). However, a major drawback is, of course, the fact that the spherical electrodes are designed to attract the positively charged ions, and as a result, a large amount of energy is wasted in particle-grid collisions. Alternatively, 'Leakage' of unruly neutrons from the superheated plasma in the Tokamak approach seems to provide folks with Dr. Greenman's occupation headaches as well.

It seems to me that the IEC approach is considered too simplistic for 'real' scientists to bother considering it as a 'real' player in the research field. Hey, why build a Fusor for \$100k when you can drop millions more on a Tokamak, right? Granted, the fusor has its problems - Quite possibly insurmountable obstacles. It seems, however, that the Tokamak may as well.

Of course, the Tokamak research is invaluable, and I AM confident that eventually the engineering obstacles will be overcome -- But does this make IEC fusion research any less 'real'? What, exactly, is 'real' fusion, and why exactly is so little attention paid to a system which was producing hydrogen controllable hydrogen fusion years before any Tokamak? Why should we avoid considering alternative solutions, when researching other methods in addition to the only apparent 'Real' methods will yield invaluable insight (if even definitive proof that the system is non-workable)?

Well. I haven't yet had the god-like status that holding a doctorate must entitle a person bestowed upon me, so obviously my ideas aren't quite as 'real' as they could be, and obviously a kid building a IEC grid for a science fair project hasn't got any hope of ever understanding or learning anything from this 'pseudo-fusion' project.

Or maybe I'm just bitter.

#### Astronuc

Staff Emeritus
The D-T reaction is as follows:

$$\large D + T \rightarrow \alpha (He^4) + n + Q(17.6 MeV)$$

with only one He particle per fusion reaction and one neutron.

The objective in a fusion reactor is to generate much more energy than is put into the reactor, otherwise it makes no sense to build an expensive reactor.

The temperature (which is actually the kinetic energy of the particles (+ ions and - electrons)) is high so that kinetic energy of the particles overcome the coloumb barrier. Tokamaks use pulsed current to ohmically heat the plasma. The pressure (which increases with temperature) is high so as to increase the density of the plasma in order to assure that enough reactions take place, i.e. maintain a sufficient yield. Magnetic fields are used to confine the plasma (100 keV x 11605 K/ev = 1.16E9 K) which would otherwise contact the metal structure and rapidly cool.

It seems to me that the IEC approach is considered too simplistic for 'real' scientists to bother considering it as a 'real' player in the research field.
No actually - some fusion reactor concepts use neutral beam injectors to selectively put energy into the D ions such that the energy per ion is higher than the target plasma. This helps to reduce the energy losses from the plasma, which is relatively cooler. And there are other heating methods, such as RF (bascially microwaves) heating, as well.

D-T neutron generators (fusors) have been around for four decades so they are nothing new. My understanding is that the yields are very low. The question then becomes, are they scalable, i.e. can they produce excess power and be scaled to 100 MW or 1000 MW systems.

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#### Morbius

Dearly Missed
dream_reaper said:
To quote Dr. Greenman: "In order for fusion to occur - one has to have both the requisite density and temperature."

Please correct me if I'm wrong - but I was of the understanding that in order for 'Fusion to Occur' you need to overcome the Coulomb Barrier - Essentially, you need to push two Ions close enough together so that the Strong nuclear force, slightly more powerful but acting over shorter distances than the Electromagnetic force acting to repel the like-charged particles), is able to exert its influence and bind the two nuclei together? In the case of D - T fusion, you've got a pair of alpha particles that result from this fusion... the odd-man-out Neutron with it's 14.1 MeV of kinetic energy, and the Helium-4 nucleus with it's 3.5 MeV (? I don't remember if that's correct or not on the H4 nucleus).
dream_reaper,

In D-T fusion you have D + T --> He4 + n + 17.6 MeV

That He4 IS the alpha particle - and you get one - not two as you state
above. The "n" is a neutron. The neutron gets 14.1 MeV of energy and
the alpha gets 3.5 MeV of energy.

In order to get fusion - one needs to overcome the Coulomb barrier -
and the way that is done is with the requisite combination of density,
temperature and time. Check out something called the "Lawson
criteria" - which is the criterion which tells you if you will get
net energy from the fusion reactions.

For example, in magnetic fusion - the density is fairly low - but the
confinement time is relatively large; about a second or so. On the
other hand, inertial confinement fusion has very short confinement
times - but the densities are correspondingly larger.

Also, the Strong Nuclear Force is "slightly more powerful" than the
Coulomb Force - it's a MILLION times more powerful. Potential
energies due to the Coulomb Force are measured in eV [ electron Volts ].
Potential energies of the Strong Nuclear Force are in MeV.

That's why nuclear reactions give you - pound for pound - a MILLION
times the energy as a chemical reaction which is based on the
Coulomb Force.

Dr. Gregory Greenman
Physicist

#### slider527

its amazing....u can call him sort of a macguyver of physics hehehehe

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