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I WANT to build a nuclear reactor.

by amberb617
Tags: build, nuclear, reactor
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Supercooled
#55
Jul23-07, 07:55 PM
P: 2
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
#56
Sep21-07, 10:26 PM
P: 64
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 cant 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
#57
Sep21-07, 11:43 PM
P: 395
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
#58
Sep22-07, 12:25 AM
Emeritus
Sci Advisor
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P: 6,236
Quote Quote by lilrex View Post
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
(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
#59
Sep22-07, 03:27 PM
Sci Advisor
P: 2,340
Quote Quote by amberb617 View Post
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
#60
Sep22-07, 03:44 PM
Sci Advisor
P: 1,152
Quote Quote by Chris Hillman View Post
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
#61
Sep22-07, 11:30 PM
Emeritus
Sci Advisor
PF Gold
P: 6,236
Quote Quote by Morbius View Post
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 ?


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