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Is A Nuclear Reactor A.....

by Mistic
Tags: nuclear, reactor
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Mistic
#1
Jul13-04, 11:02 AM
P: 10
I am not sure if this is the right forum or not, I figure its about space stuff so it might be.

My question is, could one safely use a nuclear reactor on a large-scale space station. Of course there is the issue of shielding, but since space stations have to be shielded against virtually all forms of radiation anyhow, adapting the shielding for a nuclear reactor would not be hard.

My question is, would it work, and is it viable.
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Clausius2
#2
Jul13-04, 12:02 PM
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I'm going to give you my opinion. Some day I read a newspaper article that talked about mars permanent ground station. This was a part of a sciencist thesis. It could be read how this station would keep on living on mars surface, with the help of a nuclear reactor and vehicles, and an oxygen generator. Well, now this sciencist (spanish by the way) is working at NASA.
But to my surprise, the article (I don't know if the thesis as well) does not talk about HOW can human beings transport a nuclear reactor inside of a spaceship. I think it's too heavy for trying it with newadays technology. It is not only the reactor core, but heat exchangers, pupms, turbines, refrigeration systems, pipes, in order to produce some power there.

I don't know exactly what is the shuttle thrust at liftoff, but surely that Soyuz rocket is not capable for transport it.
Entropy
#3
Jul13-04, 12:15 PM
P: 609
I know nuclear thermoelectric generators have already been used on probes so I would think you could put it on other spacecraft. Its just that its dangerous having radioactive materials orbiting so close to Earth. If it fell into the atmosphere it could be devistating.

Njorl
#4
Jul13-04, 01:48 PM
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P: 875
Is A Nuclear Reactor A.....

It is a huge engineering undertaking to have a useful and operational fission reactor in space. The energy is released as high speed neutrons. They are not an immediately useful form of energy. They are captured by water, which becomes steam and is used to make turbines rotate. We are not talking about just some uranium and a little machinery. We are talking about something that outweighs every bit of man-made stuff put into orbit combined I would bet - probably by more than an order of magnitude.

Even so, it is more of an engineering challenge than a science challenge, and more of an economic challenge than an engineering challenge.
Njorl
Yggdrasil
#5
Jul13-04, 02:21 PM
P: 14
Yes one could. In fact, NASA is building another part for the ISS with TWO nuclear reactors in it. It can supply energy for 160 years or more.
LURCH
#6
Jul13-04, 02:55 PM
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P: 2,510
Quote Quote by Entropy
I know nuclear thermoelectric generators have already been used on probes so I would think you could put it on other spacecraft. Its just that its dangerous having radioactive materials orbiting so close to Earth. If it fell into the atmosphere it could be devistating.
Yea, I keep thinking about Skylab. If it had a reactor onboard, we'd have had some real trouble! Before we do any such thing, I think we need to remind ourselves that what goes up must eventually come down.
Mistic
#7
Jul13-04, 08:14 PM
P: 10
First off, I want to thank you all for you input, and any others that fallow this post.

Most of you point out that while you could, the big problems would be getting it there, and what happens if it falls out of orbit.

I don't have an answer for the getting it there part, but as for falling, most sattilites are in low, unstable orbits, the station I am talking about would be in a very high, and stable orbit.

Check this site out, its the results of a Space Settlement Contest by Nasa, this is a previous winner, look at chapter 2.

http://www.belmont.k12.ca.us/ralston...nner/leda.html
Njorl
#8
Jul14-04, 09:53 AM
Sci Advisor
P: 875
Quote Quote by Yggdrasil
Yes one could. In fact, NASA is building another part for the ISS with TWO nuclear reactors in it. It can supply energy for 160 years or more.
Fission devices of all kinds are still banned from orbit by international treaty, I believe. Those reactors are almost certainly of the type that utilize radioactive decay, not fission.

Njorl
Entropy
#9
Jul14-04, 10:10 AM
P: 609
Those reactors are almost certainly of the type that utilize radioactive decay, not fission.
Radioactive decay is fission.
Mistic
#10
Jul14-04, 10:23 AM
P: 10
I don't know about international treaty, but I do know that the U.S. has satallites in space that have nuclear reactors on them with weapons grade material on them. As well as russia and china are also supposed to have satillites with nuclear reactors on them....
Lord Flasheart
#11
Jul14-04, 08:35 PM
P: 94
Quote Quote by Njorl
Fission devices of all kinds are still banned from orbit by international treaty, I believe. Those reactors are almost certainly of the type that utilize radioactive decay, not fission.

Njorl
As far as I know, controlled fission reactors are completely legal in space. The Partial and Outer Space Test Ban Treaties stated that no nuclear weapons or explosions were permitted from the upper atmosphere and the heavens themselves.

It sickens me to see so many "treaties" hampering human expansion. A trip with a system that utilizes small nuclear charges for propulsion could get a ship from the ground to anywhere in only a few weeks. Instead, the NASA plan involves making space stations and lunar bases and martian expeditions for hundreds of billions of dollars! With a so-called Orion nuclear pulse rocket, you could get to wherever you want in the solar system with a single ship. No three-stage titanic chemical rockets that require strict launch windows are needed, no huge sums of cash are required.

Is a device you can activate and stop at will controlled? If so, Orion should not be limited by some pathetic little law blathered by buero-twits.

Cheerio.
Njorl
#12
Jul15-04, 09:50 AM
Sci Advisor
P: 875
I was wrong

It is only explosives that are banned. Several reactors have been put into orbit, including one by the US (now defunct).

http://www.uic.com.au/nip82.htm

They seem to be incredibly low power, for a nuclear reactor. I did not know you could make them work at such low powers.

Njorl
TALewis
#13
Jul15-04, 10:11 AM
P: 199
Quote Quote by Entropy
Radioactive decay is fission.
I don't think that's correct. Read this link:

http://en.wikipedia.org/wiki/RITEG-beacon

Scroll to the bottom and read the section titled "Safety." From the link:

RTGs use a very different technique from that used by nuclear power stations. Nuclear power stations generate power by a nuclear chain reaction in which the nuclear fission of an atom releases neutrons which cause other atoms to undergo fission.

...

Chain reactions do not occur inside RTGs, so that such a nuclear runaway scenario is impossible. In fact, fission itself does not normally occur inside an RTG; forms of radioactive decay which cannot trigger other radioactive decays are used instead.
Also, this PDF from NASA about the Cassini mission underscores the fact that RTGs aren't nuclear reactors:

http://saturn.jpl.nasa.gov/spacecraft/safety/power.pdf

RTGs are not nuclear reactors and have no moving parts. They use neither fission nor fusion processes to produce energy. Instead, they provide power through the natural radioactive decay of plutonium (mostly Pu-238, a non-weapons-grade isotope).
In short, the natural radioactive decay used in RTGs is not the same as the nuclear fission caused by chain reactions in a nuclear reactor.
Entropy
#14
Jul15-04, 01:32 PM
P: 609
I don't think that's correct. Read this link:

http://en.wikipedia.org/wiki/RITEG-beacon
Okay... That doesn't disprove what I said at all. Look here: http://dictionary.reference.com/search?q=fission

Quote Quote by http://dictionary.reference.com/search?q=fission
A nuclear reaction in which an atomic nucleus, especially a heavy nucleus such as an isotope of uranium, splits into fragments, usually two fragments of comparable mass, releasing from 100 million to several hundred million electron volts of energy.
"Splitting into framents" sounds a lot like "decaying." Wheather or not its emitting just a neutron, alpha particle, or into two equal new nuclei.

Anyways its not really important.
Lord Flasheart
#15
Jul15-04, 03:21 PM
P: 94
Fission reactions work by the process of neutrons stimulating atomic nuclei. An RTG gives power by "dying" isotopes, which are already unstable. The isotopes' short lives generate a low amount of power, which is good for passive space probes in areas of low solar intensity. In either type of atomic power, radioactive decay is important: A neutron source is needed to split the atom.

Cheerio.
KrazyIBKid
#16
Jul26-04, 11:07 PM
P: 25
Quote Quote by LURCH
Yea, I keep thinking about Skylab. If it had a reactor onboard, we'd have had some real trouble! Before we do any such thing, I think we need to remind ourselves that what goes up must eventually come down.
This is true but u must also keep in mind 'down' is relative with gravity.. down to me is up to the chinese and down for us may be sideways for ppl on Mars.. Down is the direction in which gravity is acting....


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