I WANT to build a nuclear reactor.

[Morbius]

I don't know if this has been stated before. Check the rules. Some don't allow certain temperatures to be attained. I remember reading about a high school student doing this. His name was Brian something I believe. Google Brian nuclear reactor and I'm willing to bet you'll get his page.

Moose,

I believe one of the issues is the radiation field. One can get a fairly high radiation field
without a high temperature. After all, the little electron accellerator that produces X-rays
for your dentist doesn't get very hot.

There have been many students that have undertaken projects like this - without the proper
supervision, and without knowing what they are doing; and have created problems for
themselves and others.

I don't think building something like a "fusor" is especially worthy in the type of training
one would hope a student would get from a science project. If all the student does is get
the plans for some apparatus off the Internet, and builds it; I don't think that is particularly
instructive.

The purpose of a science project, in my view; is to give the student a chance to
"problem solve". That's the key skill that they need to practice and become adept at
for a career in science.

I would much more like to see the student try to build something of their own design.
That way, they'll bump into all the problems that one does when designing something
new - and the student will have to figure out the solution to those problems.

I believe that's infinitely more rewarding and valuable an experience for the student than
putting together some device that someone else has already designed. When one merely
puts together an apparatus that someone else has designed, the student doesn't really
get an appreciation for why the device was designed the way it was, as opposed to some
other way. Yes - I do realize that the student may make modifications to the given
design - but nothing beats designing something from a clean sheet of paper.

Reminds me of the old adage: "The person that knows HOW to do something will always
have a job - working FOR the person that knows WHY!"

Dr. Gregory Greenman
Physicist

 

[sunday]

What about a fusor? Those can produce neutrons and plenty of x-rays and I don't think they are illiegal...

The construction of a farnsworth fusor wouldn't be absurd and can achieve nuclear fusion (even better than fission!). A hand full of amateurs have successfully built working (fusing) fusors in this country, including some very young people (well, not 6 year-olds). This would be an ambitious, but doable project IMHO.

You could also built a fusor demonstrator, a far less dangerous and costly version of the real thing, that would none-the-less show the principles behind electrostatic confinement. Basically you need a vacuum chamber and vacuum pump, a high voltage power supply, some stainless steel wire to make your anode and cathodes, and the knowledge to put it together.

What do the rest of you think?

-Alan

Yep.

See:

http://www2.ljworld.com/news/2006/nov/19/teen_creates_nuclear_fusion_basement/

http://www.fusor.net

 

[sunday]

Nate,

In the 'nuclear" field - a "reactor" is self-sustaining.

(...)

Dr. Gregory Greenman
Physicist

Morbius,

I'm only a dull engineer but by your definition, all the tokamaks, ICF facilities, etc., built up to date aren't reactors, as they are not self-sustaining. And then the R on ITER should not be granted until it demonstrates that could do break-even AND extracts enough energy to sustain itself without external power inputs. I find this kind of disturbing.

Best regards.

Jose

 

[Morbius]

I'm only a dull engineer but by your definition, all the tokamaks, ICF facilities, etc., built up to date aren't reactors, as they are not self-sustaining. And then the R on ITER should not be granted until it demonstrates that could do break-even AND extracts enough energy to sustain itself without external power inputs. I find this kind of disturbing.

Jose,

I don't consider the tokamaks, ICF facilities to be "reactors".

They are "experiments" - in spite of what the builders of these devices call them.

If someone today says, "nuclear reactor" - then it's clear that the meaning is that
the device is a "nuclear fission reactor".

In the future, when we have power plants based on fusion energy, then the term
"nuclear reactor" will become ambiguous - there will be the need to qualify whether
the device is based on fission or fusion.

However, until that day, "nuclear reactor" means a "self-sustaining, critical, nuclear
fission reactor" in my parlance, and that of most scientists.

Dr. Gregory Greenman
Physicist

 

[sunday]

Dr. Greenman,

Thanks for the clarification.

Jose

 

[mheslep]

- it gives them the
impression that it is an energy source via nuclear fusion. It isn't - it's a dead end.

I've gotten questions like this from friends and neighbors that read this and ask,
"Why are you spending all this money for a big facility like the National Ignition
Facility; when a teenager can do the same thing in his garage?"

The point is - the teenager CAN'T do the same thing in his garage. The "fusor" will
NOT reach thermonuclear ignition.

Morbius -
Sorry to come in late on this. I'm familiar w/ the various criticisms (Rider, Nevins) of IEC fusion approaches that stand demand answers from anyone proceeding down that road, but I don't consider those criticisms proof that all IEC is a 'dead end'. What do you have in mind when making that statement? If its purely a manner of daunting engineering practicalities, then one might say the same about huge neutron flux producing Tokamaks. Lidsky certainly did.

mheslep

 

[Morbius]

What do you have in mind when making that statement? If its purely a manner of daunting engineering practicalities, then one might say the same about huge neutron flux producing Tokamaks. Lidsky certainly did.

mheslep,

I'm just saying that no-body sees a way that IEC is ever going to lead to a self-sustaining
reaction and net power production.

We can induce fusion by accelerating deuterons in a cyclotron and throwing them at a
target. You get fusion - but there's no way that such a configuration is going to give you
fusion "ignition". IEC is in this same boat.

Contrast this with a technology like inertial confinement fusion, or "laser fusion". It is
believed that we CAN get fusion ignition in such a configuration - as long as the imploded
pellet can trap the alphas produced in the reaction. That means we have to implode a
big enough pellet; but havent't had the laser energy to do it.

That has changed with the building of the megajoule-class lasers of the National Ignition
Facility, or NIF. The reason it is called NIF, is that it is expected to achieve "ignition":

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

Dr. Gregory Greenman
Physicist

 

[mheslep]

...I'm just saying that no-body sees a way that IEC is ever going to lead to a self-sustaining reaction and net power production.

We can induce fusion by accelerating deuterons in a cyclotron and throwing them at a target. You get fusion - but there's no way that such a configuration is going to give you fusion "ignition". IEC is in this same boat.

I'm not so sure. First people working on IEC for energy purposes don't fire at solid targets, they are instead beam-beam focus designs and they are well aware of maxwellian 'collisions' hurdles thanks to Rider et al. There some renewed effort to address them, c.f. http://forum.nasaspaceflight.com/forums/get-attachment.asp?attachmentid=25188" 2003

Contrast this with a technology like inertial confinement fusion, or "laser fusion". It is believed that we CAN get fusion ignition in such a configuration - as long as the imploded pellet can trap the alphas produced in the reaction. That means we have to implode a big enough pellet; but haven't had the laser energy to do it.

That has changed with the building of the megajoule-class lasers of the National IgnitionFacility, or NIF. The reason it is called NIF, is that it is expected to achieve "ignition"

As I understand the issues w/ implosion, the technical ability the build higher power lasers was never in question. Issues that are in question:
-Drive efficiency of the laser: high enough to ever enable net power?
-Symmetry of energy delivery. Yes there have been order of magnitude improvements here but I'm unaware that anyone has demonstrated the physics & engineering necessary for net power.
-Protection of the illumination devices. How does one have a clear illumination path to the fusion target and at the same time protect it from GW neutron fluxes?

mheslep

 

[Morbius]

-Symmetry of energy delivery. Yes there have been order of magnitude improvements here but I'm unaware that anyone has demonstrated the physics & engineering necessary for net power.

mheslep,

The only devices that produce net energy productions from fusion work quite well in that
regard; the symmetry of energy delivery is pretty much solved.

Dr. Gregory Greenman
Physicist

 

[mheslep]

the symmetry of energy delivery is pretty much solved.

Oh? Is that via direct or indirect drive, or both? Could you suggest any references?

 

[Morbius]

Oh? Is that via direct or indirect drive, or both? Could you suggest any references?

mheslep,

Most of the designs I've seen are for indirect drive.

http://www.llnl.gov/str/Haan.html

For the present, Livermore target designers are focusing on both the indirect-drive
capsules and the hohlraums enclosing them.

http://www.llnl.gov/str/September02/September50th.html

http://www.llnl.gov/str/JulAug05/VanArsdall.html

http://www.llnl.gov/str/September05/Hill.html

Dr. Gregory Greenman
Physicist

 

[rewebster]

amberb617 --do you happen to live in Iran?

 

[HallsofIvy]

I am reminded of the time it got into the newpapers that a boy in New York City had built an atomic bomb as a high school project! It even was made into an episode of the "Barney Miller"- with the bomb being brought into the police station and everyone being terrified of it.

The boy had indeed built an atomic bomb- he just didn't have any fissionable material for it...

 

[Astronuc]

The boy had indeed built an atomic bomb- he just didn't have any fissionable material for it...

Nor high explosives.

 

[Morbius]

The boy had indeed built an atomic bomb- he just didn't have any fissionable material for it...

HallsofIvy,

No boy has built an atomic bomb!

The design of an atomic bomb took some of the brightest physicists of the world several
years to design - Oppenheimer, Bethe, Teller, Fermi, Von Neuman, Feynmann, ...

You aren't going to tell me that a little kid in New York did what Nobel Prize caliber physicists
took years to do! It still takes whole teams of scientists the better part of a year or more
to design nuclear weapons; even using the world's most powerful computers and
software that has been honed for decades.

Add to that the boy had neither the fissile material [ not fissionable - U-235 is "fissile"
U-238 is "fissionable" which means fission is a threshold reaction; but you can't build
a bomb out of U-238 ], and neither did the boy have chemical explosives.

It makes a "cute" story to think that a high schooler could build a nuclear weapon;
but it's pure fantasy!

Dr. Gregory Greenman
Physicist

 

[stoorssarg]

I don't know about you guys, but I built a nuclear bomb for my science fair project. ( But I was also questioned by the FBI for 5 straight hours after that)

 

[Morbius]

Wow, that is really an extreme statement. "No boy has built an atomic bomb." Am I to assume that the author knows every boy, just like Santa Clause? Is that also to imply that no boy will ever build an atomic bomb?

HDcandela,

NO - but I DO KNOW how incredibly complex the design of a nuclear weapon is.

It took the work of several Nobel-prize winning Physicists - people like Hans Bethe,
Richard Feynmann, Enrico Fermi...

It took the work of several of the BEST minds in Physics of the 20th Century -
Nobel-prize winners - to design these weapons.

These Nobel-prize caliber physicists needed to design experiments that were
carried out by a whole army of technicians in order to determine the physical
and nuclear properties of the materials involved. Even Nobel-prize winning
physicists can't design a nuclear weapon ab inititio - from "first principles"
only. They need to know the mechanical and nuclear properties of the materials.

If one had read one of the many histories of the Manhattan Project, one would
know the extensive experimental facilities that were required to get this data.
Where did the high school student get his data? How does this high school
student know how many neutrons come out of a fission of U-235 at 1.0 MeV?

That type of information is necessary to the design process. The student can't
just "derive" this without measurement! It is beyond our capabilities even
today to calculate the nuclear properties needed without input from experiments.

Because the high schooler could not have done these experiments - he doesn't
have the financial means to fund them, nor the cadre of trained technicians at
his disposal - he can't get the data he needs to do his design.

To think that a boy that had yet to study Physics at the University level would match
the intellectual horsepower of several Nobel-prize winners, as well as to match the
experimental capabilities of a small army of technicians is LAUGHABLE

Dr.GG the Physicist also plays the psychological games of "expert" and "rank & file." Doc, are you feeling threatened?

Threatened? NOT AT ALL! [ Why do people always contend that one must be
"threatened" in order to point out how ridiculous the claimed situation is ].

Designing nuclear weapons takes the skills of MANY, MANY scientists in a vast
number of fields; from hydrodynamics, solid-state physics. transport theory, nuclear
data...

I wouldn't believe that a single high school student could design a nuclear weapon any
more than I would believe that a high school student could SINGLE-HANDEDLY design
a Boeing 777 or the Space Shuttle!

A dirty bomb is easy.

Yes - a "dirty bomb" or RDD - radiological dispersal device is easy.

But a "dirty bomb" is NOT a nuclear weapon.

Dr. Gregory Greenman
Physicist

 

[Morbius]

For that matter, in the process of building and running a pile reactor in the back yard, what if the teen uses graphite or some other ""dangerous when burning"" material to make rods?

HDcandela,

You do NOT make the "rods" out of graphite.

Not knowing what materials the teen may find or make to fuel the reactor (among other things) I can not tell you what temperature or levels of radioactivity could be reached. HOWEVER, you do not know either.

There are a very limited number of materials that can be used - you can count them
on the fingers of one hand.

Perhaps someday we will see (not quite all the way down to China).

"China Syndrome", even in a power reactor is a nonsense term used for scaring children.
[ It belongs more to Grimm's Fairy Tales than the nuclear technology lexicon.]

Dr. Gregory Greenman
Physicist

 

[Morbius]

Stoorsrarg, If they questioned you for 5 hours without arresting and/or charging you... it would have been quite "reasonable" to state: that your time is of worth; that you are going into the consulting business effective imediately (business license not required); that you shall be charging & invoicing them by the day; that what you just informed them of this on tape & it has been witnessed by those sworn to uphold the law; and that any other related questions they ask of you would be understood as the retention of your consulting services for hire at the verbally specified rate you have just anounced. Then, ask them for: their supervisor's name; their identification particulars; their office address & phone number; and what specific part of the code that they are enforcing (in writing) so that you can understand they are "reasonable?" All of that is your Right.

HDcandela,

One wouldn't consider "invoicing" your local police when they are investigating a crime;
why would anybody think that one could do that to the FBI.

As far as what law is being enforced; that is simple - the Atomic Energy Act of 1954.

The Atomic Energy Act of 1954 has the concept of "born secret". Any covered nuclear
activity is forbidden whether you have had access to classified data or not. There is no
need to sign a non-disclosure agreement - or anything of that sort.

The Atomic Energy Act of 1954 applies to ALL citizens within the jurisdiction of the USA.

Dr. Gregory Greenman
Physicist

 

[Supercooled]

Morbius,

On the topic of fusors, what are your thoughts regarding the recent frenzy surrounding the claims associated with Robert Bussard and his fusor work (i.e. his Google talk and requests for millions of dollars for more work)? He hasn't published anything and it has the unmistakable odor of pseudoscience. Amazingly, the general public seems to eat this stuff up -- will someone actually try to fund this? Every time I read about Bussard I think of an analogy to Hafnium isomer triggering and that debacle as documented in "Imaginary Weapons" by Weinberger.

I'm a mere condensed matter physicist and would appreciate your take on this.

 

[lilrex]

Dr. Greenman,
I don’t mean to be disrespectful of your years of training and work that may have left you with many large and difficult problems to get around but the thoughts on absolutism have me unable to keep my mouth shut. A reader of most of the material concerning fission will say without a doubt that anyone with the material resources can construct a fission device. All that is required is the pilling of U235 in one place and in enough quantity and fission will ensue (you can't stop it with a high school diploma). One can calculate the cross-section required and ba-dah-bing a working device. The reason that it took so many scientists to do this is that it was a race, and the stakes were high. They had to get it right the first time and every time after that (safely) I do not understate their work they had allot to do and the pioneering act alone was impressive. However the construction of a device capable of fission is not absurd in the sense that it can be done by the inexperienced. I just wouldn’t be reckless enough to attempt it myself.

Like I said I don’t disrespect you I just think your views on this matter are misled (it happens to the best of us), if a kid came up to me excited about science and said "I am going to make an X-ray machine" I would do my best to help the bright young mind along, pointing him to the right supervision and providing him all the support he needs. Otherwise he will end up doing it anyway without the proper supervision (it would probably work too), or become disinterested in the sciences because we are a bunch of crabby aristocrats, and there goes a potential Livermore, abusing himself on videogames and TV instead.

I would say, to the subject of the thread: go find a cheerful physicist, do the work on paper, come up with all the calculations and dimensions, explain why you think the device would work, elaborate on the things you discovered while on your paper project, and look at their face, if impressed you did good, if they take you under their wing you did excellent and that would be almost as satisfying as getting thrown in prison for making a working reactor! Plus you may live through it.

 

[theCandyman]

It's been said already that building such a device would be against the law. I doubt any scientist or engineer would encourage a student to presue illegal (and dangerous) activities. And building a bomb is much different from a fission device - you even get spontaneous fission from some isotopes such as Pu-240, if you have access to it. For comparison, it's like hooking up a light bulb to a battery in a simple circuit then claiming you could build something as complicated as a computer.

 

[vanesch]

if a kid came up to me excited about science and said "I am going to make an X-ray machine" I would do my best to help the bright young mind along, pointing him to the right supervision and providing him all the support he needs. Otherwise he will end up doing it anyway without the proper supervision (it would probably work too), or become disinterested in the sciences because we are a bunch of crabby aristocrats, and there goes a potential Livermore, abusing himself on videogames and TV instead.

Strictly speaking, building a reactor or an X-ray machine or whatever is not really "doing science", but rather "doing engineering". A very important part in engineering is safety considerations, and doing dangerous things because of lack of knowledge and experience, even if they are exciting at first sight, is bad engineering. So it would be a good lesson in engineering NOT to do so.

However, as long as it is paper design and simulation, I would also encourage that person, but I would seriously object to building a dangerous system.

You are right that building a (bad and dangerous) nuclear reactor is easy if you have the materials at hand: pile up enough uranium and graphite in the right proportions, and you'll have a reactor, that will be uncontrollable, irradiate all people in the neighbourhood and maybe have your own little mini Chernobyl in your backyard. Even better, just find enough enriched uranium oxide. If you can find 20% enriched uranium, that's perfect. Ask your local grocery store. You need some 50 kg of it. Now go and dissolve this in concentrated nitric acid (be careful, it's dangerous if you get it in your eyes... ), and pour all this in a big, round bottle. You'll see a nice blue flashing light :rofl:
(oh, yes, first go and tell the neighbors to go and have a walk). It might be that you feel a bit bad in your stomac after half an hour or so...

Happily, it is not so simple to get enough of the right material. The whole art of building a reactor is to make a SAFE one. Doing these things, or even trying to do these things, is playing an apprentice sorcerer. And it is - for very good reason - against the law.

 

[Chris Hillman]

Mention some past cases

Ok so I know that this seems like an absolutely absurd and almost impossible idea but I want to build a nuclear reactor to enter in the state science fair next year.

I know that it takes time, wit and money but I'm completely prepared to take on the challenge.

Lemee see, I think we helpful PF science advisors have some enriched uranium lying around here somewhere...

But seriously, amber, although I happen to suspect you were merely trolling, one never knows, so let me say that I agree with all the others: this project would not be a good idea!

You might try to find a New Yorker profile which appeared some years ago of a high school student who did exactly what you are proposing (using commerically available radioactive material) and who got in a lot of trouble--- including medical trouble: he didn't know what he was doing in terms of safety and created a dangerous mess, his family lost their home, and their health was seriously imperiled. Another New Yorker article told the tragic story of a village in Mexico which was seriously contaminated when children playing in a dump found and broke open a container containing radioactive material (later traced to a device which had been used by an American hospital to provide radiation therapy to cancer patients and which had been improperly discarded when it became outdated). And many years ago yet another New Yorker profile told the story of a high school student who managed to draw up blueprints for a crude but feasible atom bomb--- he got in quite a bit of trouble too, although at least he didn't physically harm anyone, unlike the first two cases.

(All this according to the New Yorker, which has suffered its share of fakes over the years. I believe that at least one of these tales has been verified by other journalists, however.)

(EDIT: after reading the entire thread, I see that Morbius already mentioned the first episode I cited. The "bomb" brought to a police station is a different event from the third episode I cited. Amber, assuming you were not trolling [in which case I guess you are chortling at our handwringing], it would be nice if you posted to say that you've been convinced to choose another project.)

 

[Morbius]

And many years ago yet another New Yorker profile told the story of a high school student who managed to draw up blueprints for a crude but feasible atom bomb--- he got in quite a bit of trouble too, ...

Chris,

I don't think anyone can say that his device was "feasible".

ANYONE who knows what is or is not feasible is PRECLUDED from saying if the device
is feasible or NOT.

Anyone who has any expertise in nuclear weapons design, when confronted with a potential
design by high school student, or anyone; has exactly one response - "No Comment".

Many in the media have taken that "no comment" as a confirmation of the device's authenticity.

However, scientists who are asked this question HAVE TO respond no comment - even if the
supposed bomb is a bunch of utter nonsense.

So nobody can say that the high schooler's bomb was feasible or not.

However, one can say that the original bomb designs created at Los Alamos and the Manhattan
Project took years for a very respectable group of physicists to design; including a number of
Nobel Laureates; like Feynman, Fermi, Rabi, Lawrence, Wigner, Bethe,...

It's NOT the type of project that a high school student would have the expertise to achieve.

Dr. Gregory Greenman
Physicist

 

[vanesch]

However, scientists who are asked this question HAVE TO respond no comment - even if the
supposed bomb is a bunch of utter nonsense.

All right, let's test your integrity in this domain then
Say that I compress a spherical ball of 150 kg of peanut butter with a pressure of 10 KBar during 10 milliseconds. Will I get a nuke or not ? :tongue: