Depleted Uranium Munitions

[Moontanman]

Originally Posted by CraigD

Moontanman, do you have any support for this claim?

The only nuclear fuel of which I’m aware that uses depleted uranium is MOX. This fuel requires weapon-grade plutonium, however – without the plutonium, the spent uranium is valueless.

Adding depleted uranium to Thorium FBR fuel has been proposed as a way to “spoil” the spent fuel for weapon use (see Fast breeder reactor - Wikipedia, the free encyclopedia). The depleted uranium in this application is simply an additive, not a fuel.

In neither case is depleted uranium alone worth very much. Since it’s an inexpensive waste product of conventional fission power plants, I doubt you (or an enemy) could profit much by gathering depleted uranium projectiles.

http://www.nuc.berkeley.edu/thyd/ne1.../project5.html

[freeztar]

Originally Posted by Moontanman

http://www.nuc.berkeley.edu/thyd/ne1.../project5.html

That article states:

In conclusion, since Liquid Metal Fast Breeder Reactor use U(238)

As MB mentioned above, there is some fissile U-235 remaining, but it was implied that no U-238 remained.

[Moontanman]

Originally Posted by freeztar

That article states:



As MB mentioned above, there is some fissile U-235 remaining, but it was implied that no U-238 remained.

did you bother to actually read trhe artical? Here is the introduction.

Introduction
Nuclear energy, though presently being debated and publicly discussed, contributes significantly to the electricity production in industrialized countries, often to more than 30%. Because the world's reserves of U(235) are not adequate to support indefinitely the needs of a growing nuclear power industry based only on burner or converter reactors, the breeder reactors become more and more popular today. With the introduction of breeder reactors, the fuel base switches from U(235) to U(238) or thorium, both of which are considerably more plentiful than U(235). Furthermore, all of the depleted uranium--that is, the residual uranium, mostly U(238), remaining after the isotope enrichment process--can be utilized as breeder fuel. Breeder Reactors are capable of satisfying the electrical energy needs of the world for thousands of years.

Background

[Mercedes Benzene]

Can a breeder reactor function on U-238 alone?
It seems like you would need a whole lot of it for that to be possible. I will admit I don't know much about breeder reactors.

[CraigD]

Originally Posted by Moontanman

http://www.nuc.berkeley.edu/thyd/ne1.../project5.html

From the linked-to article:

The LMFBR operates on the uranium-plutonium fuel cycle or thorium-U(233) fuel cycle. The reactor is fueled with bred isotopes of plutonium in the core, and the blanket is natural or depleted uranium.

and 2 paragraphs earlier

Furthermore, all of the depleted uranium--that is, the residual uranium, mostly U(238), remaining after the isotope enrichment process--can be utilized as breeder fuel

Fast breeder reactors can use the depleted uranium (U-238) produced as a by-product of producing enriched uranium (U-235), but their primary energy source is PU-238, which is produced in U-235 reactors, taken from dismantled nuclear bombs, or from U-238 that has been transformed (“bred”) by the FBR.

U-238 in a FBR isn’t fuel, in the usual sense, but is transformed into fuel by its plutonium core, making a system of FBRs and reprocessing plants very efficient.

A FBR won’t work (nor will any reactor) if fueled by depleted uranium alone – it must have enriched plutonium. Depleted uranium is cheap and plentiful, while enriched plutonium is rare, expensive, and available only to a few nations. So I just can’t see how the original claim

Originally Posted by Moontanman

Depleted urnium is the fuel of teh future. It wil be in demand for fast breeder reactors and other moder n reactors. Shooting it an enemy is like shooting oil at them.

can be true. Anybody with the plutonium they need to fuel a FBR will already have more depleted uranium than they need, and won’t be interested in buying it from people who have had their fields littered with it by a passing military, unless through some coincidence of lack of foresight and shooting a lot of depleted uranium projectiles, a nuclear state uses up all its depleted uranium making projectiles. Even if this were to happen, it could make more by enriching uranium for a conventional fission reactor, which it has constant need to do to supply its conventional fission (U-235) reactors.

[freeztar]

No, I didn't, just skimmed it.
I also had it backwards as U-238 is depleted uranium.

The wiki article on breeder reactors does indeed mention using U-238:

Production of fissile material in a reactor occurs by neutron irradiation of fertile material, particularly Uranium-238 and Thorium-232.

So the U-238 is processed and turned into P-239 (?) from the neutrons streaming out, presumably from the plutonium.

In many FBR designs, the reactor core is surrounded in a blanket of tubes containing non-fissile uranium-238 which, by capturing fast neutrons from the reaction in the core, is partially converted to fissile plutonium 239 (as is some of the uranium in the core), which can then be reprocessed for use as nuclear fuel. Other FBR designs rely on the geometry of the fuel itself (which also contains uranium-238) to attain sufficient fast neutron capture.

Fast breeder reactor - Wikipedia, the free encyclopedia

So it appears that without enriched plutonium, you can't do anything with the depleted U in FBR technology. But the last sentence in the quote above does not make that clear.

[freeztar]

You beat me to it Craig.

Originally Posted by CraigD

From the linked-to article:and 2 paragraphs earlierFast breeder reactors can use the depleted uranium (U-238) produced as a by-product of producing enriched uranium (U-235), but their primary energy source is PU-238, which is produced in U-235 reactors, taken from dismantled nuclear bombs, or from U-238 that has been transformed (“bred”) by the FBR.

In the wiki article I linked to in my last post, it says that the U-238 is converted into Plutonium-239. Is that a typo?

[Mercedes Benzene]

Originally Posted by freeztar

You beat me to it Craig.



In the wiki article I linked to in my last post, it says that the U-238 is converted into Plutonium-239. Is that a typo?

I don't think that's a typo. It's very possible to transmute U-238 to Pu-239, and reading up on breeder reactors, it seems that is exactly what happens.

[freeztar]

So what about the U-235 Craig brought up?
Perhaps it's in one of the links, but to be honest I did not read them all, just skimmed. I'm trying to get as much Hypo time in as possible before the fiancee shows up and demands all my attention, so I've been comparably light on the reading/researching tonight.

[Moontanman]

Originally Posted by CraigD

From the linked-to article:and 2 paragraphs earlierFast breeder reactors can use the depleted uranium (U-238) produced as a by-product of producing enriched uranium (U-235), but their primary energy source is PU-238, which is produced in U-235 reactors, taken from dismantled nuclear bombs, or from U-238 that has been transformed (“bred”) by the FBR.

U-238 in a FBR isn’t fuel, in the usual sense, but is transformed into fuel by its plutonium core, making a system of FBRs and reprocessing plants very efficient.

A FBR won’t work (nor will any reactor) if fueled by depleted uranium alone – it must have enriched plutonium. Depleted uranium is cheap and plentiful, while enriched plutonium is rare, expensive, and available only to a few nations. So I just can’t see how the original claimcan be true. Anybody with the plutonium they need to fuel a FBR will already have more depleted uranium than they need, and won’t be interested in buying it from people who have had their fields littered with it by a passing military, unless through some coincidence of lack of foresight and shooting a lot of depleted uranium projectiles, a nuclear state uses up all its depleted uranium making projectiles. Even if this were to happen, it could make more by enriching uranium for a conventional fission reactor, which it has constant need to do to supply its conventional fission (U-235) reactors.

the reaction can also be started by thorium isotopes but the main this that once you get the reation started it breeds more and more plutonium to star more reactions. Using like that the supply of plutonium, which by the way when the thorium cycle is it cannot be used for nuclear bombs. Some people think that thorium is the way to go and avoid the whole uranium scare thing. the only reson we now uranium is that this 1950's tecnology and change come slowly to some tecnologies.