Transmutation of Nuclear Waste

[Dynamos]

Hi.

How viable/safe is the option of transmuting nuclear waste? Why don't we hear more about it? Is it still in the development stage (e.g. like fusion tech)?

Thanks

 

[russ_watters]

What exactly do you mean by "transmuting"?

 

[Dynamos]

What exactly do you mean by "transmuting"?

Changing the spent fuel into an isotope that is less radioactive, or that is radioactive for a fraction of the time it would have been otherwise.

http://en.wikipedia.org/wiki/Nuclear_transmutation

 

[russ_watters]

Well, as the wiki says, it's what's going on inside a nuclear reactor. So the best way would probably be to reprocess the spent fuel to remove the not-so-radioactive parts and put the still radioactive parts back into a reactor to fuel it for a while longer. Doing that, most of the eventual waste is much less radioactive than when it was dug out of the ground.
http://en.wikipedia.org/wiki/Nuclear_reprocessing

Unfortunately, reprocessing is banned in the US for political reasons.

 

[Thermalne]

Actually one of my professor's recently completed research projects was on trans mutating 243-Am. It came out very successful, just really really expensive to do it.

 

[Argentum Vulpes]

...
Unfortunately, reprocessing is banned in the US for political reasons.

It was banned in the USA starting with Gerald Ford in 1976, banning the commercial reprocessing/recycling of plutonium, then in 1977 with Jimmy Carter banning the reprocessing of nuclear fuel. Ronald Reagan lifted the banns in 1981, but the reprocessing industry in the USA had already been dealt a very large economic blow, coupled with the relative low cost of virgin uranium, and the political hot potato that the subject is, there has been no push to start back up the reprocessing industry in the USA.

 

[Dynamos]

Oh, thanks.
I knew about the reprocessing ban in the US. I guess I just saw different terms (trasmutation vs reprocessing) in different contexts/places, and didn't recognize that they were basically the same thing. My bad.

 

[Dynamos]

Actually one of my professor's recently completed research projects was on trans mutating 243-Am. It came out very successful, just really really expensive to do it.

This is also informative.

 

[russ_watters]

It was banned in the USA starting with Gerald Ford in 1976, banning the commercial reprocessing/recycling of plutonium, then in 1977 with Jimmy Carter banning the reprocessing of nuclear fuel. Ronald Reagan lifted the banns in 1981...

Hmm... That's not what I'd heard before and looking at the wiki (and the talk page) it appears there has been some debate about the issue relatively recently. People don't seem too sure of the history. I'll look into it some more...

 

[Dynamos]

Say, what do people here think about this report from a few years ago?

http://www.ucsusa.org/nuclear_power...ation_and_terrorism/nuclear-reprocessing.html

Thus far I have only come across the benefits of nuclear reprocessing. Also, it seems like a challenge that I might enjoy. I have never seen a counter argument until this one. I am just an undergrad, so I am not in a position to evaluate the article. I know that others here are.

Thnx.

 

[Bob S]

Transmutation of nuclear waste usually refers to the burning or transmutation of transuranic (TRU) waste in a subcritical nuclear reactor, driven by a proton-accelerator-driven neutron source. This is often referred to as ATW (or Accelerator for Transmutation of Waste). See

http://www.wipp.energy.gov/science/adtf/ATW.pdf

This article is a summary of a thorough study of the major required technology developments, the timescale, and the cost of an ATW. One concern might be that the U.S. could probably afford to build only one of these ($279 B, see page 7-3), so it means shipping all the TRU waste to a single site for processing.

Like reactors, the thermal energy (and electricity) output of the ATW is larger than the energy input, like for running the proton accelerator. Furthermore, because the ATW reactor itself is subcritical and can only become critical when the accelerator is on, there is no startup criticality problem with reactor "poisons" like xenon-135. See

http://en.wikipedia.org/wiki/Neutron_poison

Bob S

 

[Bob S]

Transmutation of nuclear waste usually refers to the burning or transmutation of transuranic (TRU) waste in a subcritical nuclear reactor, driven by a proton-accelerator-driven neutron source. This is often referred to as ATW (or Accelerator for Transmutation of Waste). See

http://www.wipp.energy.gov/science/adtf/ATW.pdf

This article is a summary of a thorough study of the major required technology developments, the timescale, and the cost of an ATW. One concern might be that the U.S. would probably only [STRIKE]one[/STRIKE] eight of these (life cycle cost $279 B, see page 7-3), so it means shipping all the TRU waste to [STRIKE]a[/STRIKE] [STRIKE]single[/STRIKE] few sites for processing.

Like reactors, the thermal energy (and electricity) output of the ATW is larger than the energy input, like for running the proton accelerator. Furthermore, because the ATW reactor itself is subcritical and can only become critical when the accelerator is on, there is no startup criticality problem with reactor "poisons" like xenon-135. See

http://en.wikipedia.org/wiki/Neutron_poison

Bob S

see edits above

Bob S

 

[Tyrannical]

If you have a use for nuclear waste, is it really still considered waste?
You can generate electricity directly from radioactive decay, so in theory highly radioactive waste has potential to generate electricity. Other radioactive waste materials may be transformed into more useful isotopes.

 

[gmax137]

Say, what do people here think about this report from a few years ago?

http://www.ucsusa.org/nuclear_power...ation_and_terrorism/nuclear-reprocessing.html

Thus far I have only come across the benefits of nuclear reprocessing. Also, it seems like a challenge that I might enjoy. I have never seen a counter argument until this one. I am just an undergrad, so I am not in a position to evaluate the article. I know that others here are.

Thnx.

I think it's simplistic and naive. It doesn't recognize that there are isotopes of plutonium, and that the different isotopes have different properties. The plutonium (239) produced during reactor operation becomes (by absorbing neutron) Pu240. Pu240 is no good for making weapons. This is why the DoE 'production' reactors run for short times between refuellings - so that they can harvest the Pu239 before it becomes too contaminated with the Pu240. Bottom line - power reactor spent fuel is not good for making bombs.

There are other people here far more knowledgeable on this subject than me, maybe they can chime in.

 

[Tobias Anhalt]

As far as I know Canada already burn french nuclear waste in their candu reactors.

But this don't solve the so called "waste" problem.