New paper describes method for cleaning up nuclear waste

Mar 20, 2012

While the costs associated with storing nuclear waste and the possibility of it leaching into the environment remain legitimate concerns, they may no longer be obstacles on the road to cleaner energy.

A new paper by researchers at the University of Notre Dame, led by Thomas E. Albrecht-Schmitt, professor of civil engineering and geological sciences and concurrent professor of chemistry and biochemistry, showcases Notre Dame Thorium Borate-1 (NDTB-1) as a crystalline compound which can be tailored to safely absorb radioactive ions from nuclear waste streams. Once captured the radioactive ions can then be exchanged for higher charged species of a similar size, recycling the material for re-use.

If one considers that the radionuclide technetium (99Tc) is present in the nuclear waste at most storage sites around the world, the math becomes simple. There are more than 436 operating in 30 countries; that is a lot of nuclear waste. In fact, approximately 305 metric tons of 99Tc was generated from nuclear reactors and weapons testing from 1943 through 2010. Its safe storage has been an issue for decades.

"The framework of the NDTB-1 is key," says Albrecht-Schmitt. "Each crystal contains a framework of channels and cages featuring billions of tiny pores, which allow for the interchange of anions with a variety of , especially those used in the nuclear industry, such as chromate and pertechnetate."

Albrecht-Schmitt's team has concluded successful laboratory studies using the NDTB-1 crystals, during which they removed approximately 96 percent of 99Tc. Additional field tests conducted at the National Laboratory in Aiken, S.C., and discussed in the paper have shown that the Notre Dame compound successfully removes 99Tc from nuclear waste and also exhibits positive exchange selectivity for greater efficiency.

The paper appears in the journal .

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Eikka
3 / 5 (2) Mar 21, 2012
In fact, approximately 305 metric tons of 99Tc was generated from nuclear reactors and weapons testing from 1943 through 2010. Its safe storage has been an issue for decades.


All the coal burned in the United States produces about 3800 tonnes of uranium and thorium concentrated in the fly ashes and blown up the smokestacks. They end up either spread around the countryside or buried in landfills.

Every year.

I'd say that is a more acute problem than a couple hundred tons of nuclear waste in 70 years. At least the nuclear waste from reactors is contained instead of just being dumped everywhere.

Incidentally, there's more energy available in the uranium and thorium that is being thrown away than there is in the coal that is being burned.
antialias_physorg
not rated yet Mar 21, 2012
I'd say that is a more acute problem than a couple hundred tons of nuclear waste in 70 years

Yes. I have the numbers here for germany (formerly 19 reactors in operation - currently 9). Average amount of highly radioctive waste produced: 600 tonnes per year.

The interchange of anions method doesn't do away with the radioactive material. The stuff must still be stored somewhere. Currently no real good methods exist for this. Dumping it into the oceans (the way Russia and the UK have been doing) isn't really a long term option, either.
Eikka
5 / 5 (1) Mar 21, 2012
Yes. I have the numbers here for germany (formerly 19 reactors in operation - currently 9). Average amount of highly radioctive waste produced: 600 tonnes per year.


That however includes all of the spent fuel. An amount that could be greatly reduced by re-processing and re-using the fuel.
antialias_physorg
not rated yet Mar 21, 2012
We're already reprocessing fuel (or to be more precise: letting the french do it for us). 600 tons is what is left per year.

And the amount of low level radioactive waste is MUCH more. Asse II ALONE contains over 100k barrels of low radioactive waste and 1.2k barrels of medium radioactive waste in a salt mine.

(Did I mention that these oh-so-stable salt mines which have been selected after umpteen rounds and from dozens of candidates have already sprung leaks? The stuff - at least that part which can even be handled - is now being carted through the country - again - to the next salt mine...yay!)

http://en.wikiped..._Asse_II
Eikka
not rated yet Mar 21, 2012
We're already reprocessing fuel (or to be more precise: letting the french do it for us). 600 tons is what is left per year.


Does that amount contain the spent fuel from the decommissioned reactors now being emptied, or just the amount produced by the active reactors?

I wasn't able to find a good answer by a quick googling, but it seems that a single 1 GWe reactor uses roughly 25 tonnes of fuel per 1-2 years. Apparently Germany still has about 12 GWe, which means there should be 150-300 tonnes of spent fuel produced every year, and much less actual waste after reprocessing since most of the spent fuel can be recycled.

All in all, I don't think I believe the figures you quoted are representative of nuclear power in general.
Eikka
5 / 5 (1) Mar 21, 2012
And the amount of low level radioactive waste is MUCH more. Asse II ALONE contains over 100k barrels of low radioactive waste and 1.2k barrels of medium radioactive waste in a salt mine.


Here's the problem with that issue:

Decommissioning experts are increasingly concerned about double standards developing in Europe which allow 30 times the dose rate from non-nuclear recycled materials than from those out of the nuclear industry. Norway and Holland are the only countries with consistent standards. Elsewhere, 0.3 to 1.0 mSv/yr individual dose constraint is applied to oil and gas recyclables, and 0.01 mSv/yr for release of materials with the same kind of radiation from the nuclear industry.


http://www.world-...f30.html

In other words, what counts as non-radioactive waste in other industries, counts as radioactive waste when it comes from nuclear power. It's like they're tinning old hazmat suits worn by nuclear plant workers as radioactive waste.
antialias_physorg
not rated yet Mar 21, 2012
Does that amount contain the spent fuel from the decommissioned reactors now being emptied, or just the amount produced by the active reactors?

No fuel has been moved from the reactors that have been shut down, yet.

The owners are still hoping that Merkel can be 'persuaded' to reverse the...erm...reversal of her reversal of the BINDING LAW that mandated a stop to nuclear power in germany by 2022.). They tried to sit out the law by betting that the conservatives would ditch it come the next election. They did. Fukushima happened 2 months later. If that hadn't happened we'd be sitting on those time bombs forever.

All in all, I don't think I believe the figures you quoted are representative of nuclear power in general.

There are also a number of research reactors which produce wastes.
Eikka
not rated yet Mar 21, 2012
And for comparison, the average yearly background radiation dose in Germany is around 2-3 mSv/yr which means that even stuff that emits 1/300th the naturally occurring radiation gets sent to the salt mines to be buried as radioactive material.

Eikka
not rated yet Mar 21, 2012
No fuel has been moved from the reactors that have been shut down, yet.


From the 8 reactors that were shut down recently, yes, but what about the ones that were decommissioned earlier? Their impact on the waste stream is visible years after decommissioning, because they're left to sit and cool down. A single decommissioned reactor leaves roughly three times the waste compared to a normal refueling cycle, because all the fuel is taken out at once.

A spent fuel rod cannot be sent to reprocessing hot out of the reactor, so they're stockpiled.
Eikka
5 / 5 (1) Mar 21, 2012
http://www.eea.eu...oduction

From the graph we can see that the quoted 600 tonnes for Germany actually includes the spent fuel and the reprocessing waste.

Unless Germany has started to produce massively more spent fuel since 2005, the amount of reprocessing waste cannot be 600 tonnes a year as Antialias claims.

On the same paper we see that the actual waste that contains 99% of the radioactivity is 10% of the spent fuel, which means that out of 600 tonnes of spent fuel, roughly 60 tonnes should be left after reprocessing.

antialias_physorg
not rated yet Mar 21, 2012
but what about the ones that were decommissioned earlier?

There are no reactors that were decomissioned earlier which still hold (highly) radioactive material (i.e. fuel rods) to be moved to storage. Though there are two which are considere 'safely' sealed (i.e. the stuff was just sealed up inside and the building will never be dismantled)

Twelve reactors are currently being deconstructed. This is scheduled to last till 2020. One notable exception will take until 2075. A lot of mid level and low level radioactive material will still come off those.

3 reactors have been completely deconstructed already.

Seeing as we have nowhere safe to put this gunk and no plan on finding anywhere safe, either, I'm pretty glad we won't be producing (much) more for long.
antialias_physorg
not rated yet Mar 21, 2012
Oh...and last year alone we exported 600k (not 600 but 600k!) tonnes of low level radioactive stuff to South Africa.

..but who's counting.
Eikka
not rated yet Mar 21, 2012
Seeing as we have nowhere safe to put this gunk and no plan on finding anywhere safe, either, I'm pretty glad we won't be producing (much) more for long.


Well, we could argue about the safety of the final disposal for the rest of the night and still reach no conclusion, so we'll just have to agree to disagree on that point.
Eikka
not rated yet Mar 21, 2012
Oh...and last year alone we exported 600k (not 600 but 600k!) tonnes of low level radioactive stuff to South Africa.

..but who's counting.


Is that the same low level waste that may have radiation levels of less than a percent of natural background radiation? Look at my previous post for that issue.

What counts as regular waste in other industries can be 30 times as radioactive as the minimum level coming from the nuclear industry.
Callippo
1 / 5 (2) Mar 21, 2012
Nuclear technology produces a way more waste, than just radioactive one, for example uranium fluoride, which explodes in contact with water. Many other agents and solvents used for nuclear fuel treatment are karcinogenic and explosive too. Of course, the best way is not to produce any waste with cold fusion technology, in which the waste forms an expensive copper metal, which is already under critical deficit. We are losing so incredible amount of money with ignorance of mainstream physicists, we could compare it to the war reparations. You can downvote me, but you cannot change these facts.
antialias_physorg
not rated yet Mar 21, 2012
It's mostly radioactive wastewater which cannot be fed back into the waterways (it's illegal in germany to dispose of toxic wastes by simply dumping it in a lake and claiming "it's diluted enough, now")

However, I suspect that is exactly what they're doing in South Africa (or they're simply dumping it into old uranium mines). Ican't really see them putting that stuff somewhere safe. Hope I'm wrong on that score.

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