Energy From Thorium Discussion Forum

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 Post subject: Re: Economising Uranium
PostPosted: Jun 15, 2014 2:42 pm 
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Cthorm wrote:
I'm not sure I understand your premise. There is no "major rollout" of nuclear power in the West even planned, if anything the near term concern is keeping existing plants operating. Are you expecting a huge increase of Western orders for ESBWR and AP1000? I'd be very glad if that happened, but most wouldn't be operating in less than 10 years.

Kazakhstan and Australia are hardly the only uranium rich mining areas. Western Colorado & Eastern Utah had very productive mines that could be reopened if the demand is there. There are large deposits in Africa. I'd be surprised if there aren't similarly large deposits in the Andes. I don't think there is much basis for uranium supply constraints in a 50 year window.


Let's not forget Canada. MacArthur River - average ore grade 15.8% uranium oxide ... that is not a typo (the ore requires special handling because it is significantly radioactive). 250 million lbs proven reserves.

They just opened Cigar Lake, and there is a lot more exploring that can be done in the Athabasca basin. One geologist in Greenland said when they stick a shovel in the ground there, it comes up with uranium (OK that is a bit anecdotal).

Anyway, the only reason a lot more uranium isn't produced is no one needs it yet.


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 Post subject: Re: Economising Uranium
PostPosted: Jun 15, 2014 7:27 pm 
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Indians have not been able to buy any uranium from Australia or Canada yet. They have been buying from France, Russia and Kazakhstan. Unsurprisingly, they are still devoted to their three stage program, with a thorium breeder as the holy grail. Their three stage program is the most active uranium conservation program anywhere.
For those who can get uranium, a uranium fast breeder/IFR system is a good enough idea with no motivation for thorium.


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 Post subject: Re: Economising Uranium
PostPosted: Jun 16, 2014 2:00 pm 
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jagdish wrote:
Indians have not been able to buy any uranium from Australia or Canada yet. They have been buying from France, Russia and Kazakhstan. Unsurprisingly, they are still devoted to their three stage program, with a thorium breeder as the holy grail. Their three stage program is the most active uranium conservation program anywhere.
For those who can get uranium, a uranium fast breeder/IFR system is a good enough idea with no motivation for thorium.


That's over or about to be over:

http://www.stratpost.com/canada-to-supp ... m-to-india

http://www.business-standard.com/articl ... 691_1.html


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 Post subject: Re: Economising Uranium
PostPosted: Jun 16, 2014 7:15 pm 
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I am aware of these negotiations but the scars of decades of sanctions take long to go away. Even more uranium mining has been established in India. India will continue to try for a thorium breeder, AHWR is only a step along the way as it is not a breeder.


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 Post subject: Re: Economising Uranium
PostPosted: Jun 16, 2014 8:49 pm 
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Assuming, for example, a 100GWe reactor park made up of EC6 reactors utilising a simple 1.2% SEU fuel cycle - that would require something on order of ~9000t of natural uranium assuming the reactors are run flat out as much as possible (assume a summer demand for some industrial use taking advantage of the very low marginal cost?) with the aforementioned 0.1% tails fraction.

9000t of natural uranium costs, at ~$125/kg, some $1.125bn, roughly the price of ~10m barrels of Brent crude oil - which is roughly 50 days of crude oil imports.

Meanwhile using the OTT cycle the reactors will require something approaching 7670t of uranium, and 190t of thorium.
Assuming thorium oxide is roughly ~$30/kg at present prices that yields a fuel cost of $965m, a saving of some ~14.5% in raw materials costs.

The amount of enrichment expended will be roughly comparable so it seems that a OTT cycle might be able to reach total lower fuel costs depending on the costs of the demountable bundles and of the fuel manipulations required to make it work.

And as an aside it would appear that the reprocessing of 190t of thorium fuel could yield a saving of roughly ~750t of uranium and 170t of thorium by allowing the spent thorium bundles to be reconstituted into new bundles with the equilibrium quantity of 233U already contained.
Unfortunately at present prices ($1500+/kgHM) of reprocessing that would require a huge increase in the cost of uranium, driving it roughly ~$380/kg at least.
That is however remarkably lower than most other reprocessing options so might be worth it simply to gain experience in the reprocessing of thorium bundles, as it would only cost $255m/yr while saving something approaching ~$94m/yr in input uranium, for a net cost of only $161m, or something like $0.18/MWh which is essentially nothing.


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 Post subject: Re: Economising Uranium
PostPosted: Jun 16, 2014 10:47 pm 
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In addition to conserving uranium, using thorium in existing and near-future water cooled reactors could be a great way to make startup fuel for MSRs. However, more complicated fuel management including dismantling and rebuilding fuel bundles sounds like a headache that may not be worth the relatively modest gains in fuel efficiency. Is reorganizing fuel pins within the bundles really necessary? What about just putting the uranium in the central pins of the bundle where the thermal neutron flux is lower and the thorium on the edges where the thermal neutron flux is higher and keeping the bundles in the reactor until their contribution to the neutron balance becomes too negative?


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 Post subject: Re: Economising Uranium
PostPosted: Jun 17, 2014 4:45 am 
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uranium can be converted to volatile UCl4/UCl6 and separated by distillation. The Pu in rest of used fuel could be fluoridated to PuF6 and similarly sublimated.
PuF6 and UCl4 could be use as fuel in a fast MSR.
You could irradiate thorium in the blanket and use resultant 233UCl4 also as fissile.
These steps will increase availability of uranium fuel by 2 orders of magnitude. Chloride/fluoride volatility and fast MSR are the keys.


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 Post subject: Re: Economising Uranium
PostPosted: Jun 17, 2014 9:43 am 
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Titanium48 wrote:
In addition to conserving uranium, using thorium in existing and near-future water cooled reactors could be a great way to make startup fuel for MSRs. However, more complicated fuel management including dismantling and rebuilding fuel bundles sounds like a headache that may not be worth the relatively modest gains in fuel efficiency. Is reorganizing fuel pins within the bundles really necessary? What about just putting the uranium in the central pins of the bundle where the thermal neutron flux is lower and the thorium on the edges where the thermal neutron flux is higher and keeping the bundles in the reactor until their contribution to the neutron balance becomes too negative?


The proposed design has the thoria in the central 8 pins and the standard UOx driver fuel in the outside.
Once the fuel is through the reactor once the UOx elements are dismounted and new ones attached before the fuel is returned to the reactor.

The problem with just attempting a once through burn is that the thorium is unable to contribute large amounts of fissile material before the burnup cycle is complete and the fuel has to be removed from the reactor as the driver elements are worn out.


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 Post subject: Re: Economising Uranium
PostPosted: Jun 17, 2014 11:27 pm 
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E Ireland wrote:
The problem with just attempting a once through burn is that the thorium is unable to contribute large amounts of fissile material before the burnup cycle is complete and the fuel has to be removed from the reactor as the driver elements are worn out.

What levels of burnup would you speculate the Thor/Halden test will be able to achieve ?
As far as the Xenon issue go, is it mostly a matter of having enough volume to take in the Xenon ?
What about long term neutron losses from Xenon buildup ?
My limited knowledge suggests the neutron poisons would prevent achieving anything like even 5% burnup, even on a heavy water reactor.

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 Post subject: Re: Economising Uranium
PostPosted: Jun 18, 2014 12:12 am 
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Indian AWHR fuel assumes 60/64MWd/t of burn up against 7.8 of natural uranium fuel in the PHWR. Nearly 40% 0f power is contributed by thorium burnt in situ after irradiation. Similar burn up can be obtained by changing to thorium based fuel.
http://dae.nic.in/writereaddata/.pdf_38
http://dae.nic.in/writereaddata/.pdf_31


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 Post subject: Re: Economising Uranium
PostPosted: Jun 18, 2014 2:15 am 
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Jagdish: those documents you list show that in terms of uranium enrichment that fuel is drastically inferior compared even to the SEU CANDU - let alone this cycle.
Beating the LWR baseline case is not a major achievement for a Heavy Water Reactor.
It apparently gets only ~7.8GWd/t

I will attempt to run the numbers they give for fuel using my enrichment assumptions but it doesn't look very good.
macpacheco wrote:
What levels of burnup would you speculate the Thor/Halden test will be able to achieve ?
As far as the Xenon issue go, is it mostly a matter of having enough volume to take in the Xenon ?
What about long term neutron losses from Xenon buildup ?
My limited knowledge suggests the neutron poisons would prevent achieving anything like even 5% burnup, even on a heavy water reactor.

Xenon buildup will not normally occur because the isotope with a very very very large neutron capture cross-section has such a short half life that it is gone within a matter of a days, preventing it from building up.

As I said, studies seem to indicate that the Thorium fuel elements would last to ~9.5atm% burnup, which is enough to reduce the price of the thorium to essentially zero.
I'm afraid I don't know enough about the Halden test to comment but I believe it is primarily a materials test rather than an attmept to run the fuel productively to high burnup so they might just use the normal fuel of the reactor to 'drive' the elements to artificially high burnups to see what happens in terms of internal chemistry and grain structure and so on.

EDIT:

My own figures conclude a similar effective Natural Uranium burnup to the figures provided in the second PDF Jagdish linked - they are drastically inferior to the cycle I am proposing even making the same enrichment assumptions I have made (roughly 9.38GWd/t).


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 Post subject: Re: Economising Uranium
PostPosted: Jun 18, 2014 7:23 pm 
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The lower figure is for natural uranium fuel. The consumption of uranium for same power falls if thorium is irradiated and burnt in situ. This amounts to partial use of thorium as fuel. Increasing power production from mined uranium is the aim of the (paper) exercise. It has not been implemented yet.


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 Post subject: Re: Economising Uranium
PostPosted: Jun 18, 2014 8:16 pm 
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No, if you read the numbers provided that is the equivalent NU burnup for the ~64GWd/t fuel they propose, that has the 19.75% enriched uranium in the fuel elements. (Its starting overall enrichment was over 4%.....)

Remember just because it produces a large part of its energy from thorium, it does not neccesarily mean that it has a high burnup per unit uranium.
IN this case the thorium is just substituting for plutonium that would have been bred anyway.

The reactor appears to be proposed as a first phase thorium fuel system to suppress plutonium production and to prove the use of thorium recycling technologies - it does not really conserve uranium at all, as would be expected from a reactor with considerably worse neutron economy than an EC6 (light water coolant crushes neutron economy as the ACR discovers).


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 Post subject: Re: Economising Uranium
PostPosted: Aug 04, 2014 1:52 am 
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E Ireland wrote:
Seawater extraction of uranium will require uranium prices well over $500/kg to even approach viability at the present time, and while such prices would not be crippling in terms of the price of produced electricity it would undoubtedly alter the economics of reactor operation in tways that would benefit efficiency in uranium use.


The technology for removing uranium from seawater isn't static, current developments would significantly lower the cost making it competitive with mining.

http://www.technologyreview.com/news/51 ... -seawater/

http://phys.org/news/2013-11-sorbents-e ... water.html


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 Post subject: Re: Economising Uranium
PostPosted: Aug 04, 2014 5:21 am 
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I know, I have been following it since 2008 when I first went to university and gained access to academic papers.

The price has dropped by an order of magnitude since then.
But I was attempting to be conservative.


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