Energy From Thorium Discussion Forum

It is currently Oct 19, 2018 1:54 am

All times are UTC - 6 hours [ DST ]




Post new topic Reply to topic  [ 93 posts ]  Go to page Previous  1, 2, 3, 4, 5, 6, 7  Next
Author Message
PostPosted: Nov 24, 2009 12:36 pm 
Offline

Joined: Dec 20, 2006 7:50 pm
Posts: 280
jagdish wrote:
For various reasons given by different members, thermal cycle will lead to peak uranium.


You simply are ignoring all the evidence out there. Rossing speaks very loudly.

http://nuclearinfo.net/Nuclearpower/Web ... lear_Power

Quote:
Another Uranium source for Forsmark is the Rossing Mine in Namibia. A description of the operations of the mine is available here. The Rossing mine produced 3037 tonnes of Uranium in 2004, which is sufficient for 15 GigaWatt-years of electricity with current reactors. The energy used to mine and mill this Uranium was about 3% of a GigaWatt-year. Thus the energy produced is about 500 times more than the energy required to operate the mine.


http://nuclearinfo.net/Nuclearpower/Ura ... stribution

Quote:
The total abundance of Uranium in the Earth's crust is estimated to be approximately 40 trillian tonnes. The Rossing mine in Nambia mines Uranium at an Ore concentration of 300 ppm at an energy cost 500 times less than the energy it delivers with current thermal-spectrum reactors. If the energy cost increases in inverse proportion to the Ore concentration, shales and phosphates, with a Uranium abundance of 10 - 20 ppm, could be mined with an energy gain of 16 - 32. The total amount of Uranium in these rocks is estimated to be 8000 times greater than the deposits currently being exploited.


Breeders need to offer more than fuel utilization to be attractive. Fortunately LFTRs do offer far more. But make no mistake, there is no resource constraint for uranium production. Its literally everywhere.


Top
 Profile  
 
PostPosted: Nov 24, 2009 2:52 pm 
Offline
User avatar

Joined: Nov 30, 2006 9:18 pm
Posts: 1946
Location: Montreal
A bit of perspective on the Rossing mine:
Quote:
The pit at Rossing is approximately 330 metres deep, 1.5 kilometres wide and 3.5 kilometres long. It is deep enough to accommodate the Eiffel tower and is presently one of the deepest open-pit uranium operations on Earth.


Image

Presumably, if you mine at a Uranium abundance of 10 - 20 ppm instead of 300 ppm, you will need 20 of these enormous holes.....

The resulting landscape will resemble West Virginia's coal mining areas.

Is that what we want ?


Top
 Profile  
 
PostPosted: Nov 24, 2009 7:35 pm 
Offline

Joined: Jul 01, 2009 1:13 am
Posts: 241
jaro wrote:
A bit of perspective on the Rossing mine:
Quote:
The pit at Rossing is approximately 330 metres deep, 1.5 kilometres wide and 3.5 kilometres long. It is deep enough to accommodate the Eiffel tower and is presently one of the deepest open-pit uranium operations on Earth.


Image

Presumably, if you mine at a Uranium abundance of 10 - 20 ppm instead of 300 ppm, you will need 20 of these enormous holes.....

The resulting landscape will resemble West Virginia's coal mining areas.

Is that what we want ?


The limiting case is seawater. Speaking only for myself, I take the Japanese aldoxime resin work quite seriously. Ironically the driving force for the thermodynamics of separation in this case is solar energy, although one can get a certain thermodynamic kick back from intake cooling pipes on ocean water.

Seen from this perspective, given that the ocean is continuously saturated with respect to uranium, one might argue - given the low solubility (by comparison) of thorium - that uranium is a renewable resource and thorium is not, since crustal rocks are continuously leaching uranium - at least in the case where rivers are actually allowed to flow into oceans, not a good bet these days.

Please understand that the last statement is, in part, dry humor, or wet humor as the case might be.


Top
 Profile  
 
PostPosted: Nov 24, 2009 8:09 pm 
Offline

Joined: Dec 20, 2006 7:50 pm
Posts: 280
jaro wrote:
Presumably, if you mine at a Uranium abundance of 10 - 20 ppm instead of 300 ppm, you will need 20 of these enormous holes.....

The resulting landscape will resemble West Virginia's coal mining areas.

Is that what we want ?

Want has nothing to do with it. Its inevitable, no matter what path we take on energy. Resource utilization is on the rise and will continue, with massive open pit mines for all sorts of resources, not just uranium.

However, by the time we need 10-20ppm uranium, there certainly will be different mining techniques such as in situ leech mining that are allready used today. And one might reasonably imagine by the time we're reduced to harvesting such poor ore grades we'll be using different fuel cycles for reasons other than fuel efficiency. Either we'll be using LFTR's because they're simply more economic to build and operate or we'll be doing something really wild. This is centuries in the future after all.


Top
 Profile  
 
PostPosted: Nov 24, 2009 8:12 pm 
Offline

Joined: Apr 19, 2008 1:06 am
Posts: 2246
Wow! What an illustration of peak uranium. Russians and Indians are really wise to stick with breeders. Once Manmohan Singh's mission of agreement of US for reprocessing irradiated fuel is achieved, he should expedite the (Nuclear) waste to wealth project. All ideas including Molten Salt Coolant, Molten Salt Breeder Reactor, Eutectic metal fueled Reactor and LFTR are welcome.
Anyone for cap and trade in SNF?


Top
 Profile  
 
PostPosted: Nov 25, 2009 12:30 pm 
Offline

Joined: Mar 07, 2007 11:02 am
Posts: 911
Location: Ottawa
Quote:
Presumably, if you mine at a Uranium abundance of 10 - 20 ppm instead of 300 ppm, you will need 20 of these enormous holes.....

The resulting landscape will resemble West Virginia's coal mining areas.

Is that what we want ?


Jaro, for a little perspective, a single open pit copper mine in Utah is 4 km wide, 1.2 km deep and processes about 150 million tonnes of ore per year (Bingham Canyon). Even if that was only pulling out 20 ppm uranium such a single pit could supply 3000 tonnes U per year or enough for about 100 GWe liquid fluoride converter reactors producing about 40 billion$ worth of electricity at 5 cents/kwh (i.e. DMSRs). As mentioned though, we`d likely never need to get down to such poor grade ores.

World annual copper production alone mines 2300 million tons of ore per year to get 14 million tonnes copper (at an average 0.6% copper, down to 0.1% profitably).

Coal is 7000 million tonnes (which is coal only, not the rock needed to move, anyone know the average overburden ratio?)

Iron is 1700 million tonnes of iron ore alone (again, not sure how much actual rock moved that means)

Uranium mining is about 44 thousand tonnes uranium per year, likely averaging about 0.5% ore (because of Canada`s high grade deposits). Even if world supply came from only 20 ppm we`d still be less than copper mining alone! Yes, I know some supply comes from old weapons right now but today`s world usage of uranium could supply close to 3000 GWe of liquid fluoride converter reactors (which need about 30 tons of uranium per GWe year or about 1/7th that of a PWR).

World reserves of copper in 1970 were supposed to mean we`d run out by the 1990s. The price just goes up, you explore more and you have more reserves. Uranium world reserves went up 15% in just two years following the price spike a few years back. It is not like fossil fuels which were biologically produced and truly limited (and whose exploration budget is perhaps a 100 to a 1000 times that of uranium).

I still want to learn a lot more about just how "dirty" uranium mining is but I am expecting it is mostly hype and based on the early horrible mining practices in the U.S. early in the cold war. Yes, if you don`t properly ventilate a mine (almost any mine) you are going to expose miners to way to much radon. Once it is flushed into the open air though it quickly dilutes to have almost no effect on background radiation levels (again I`m still learning, anyone with good numbers speak up).

I know thorium is wonderful and is an easy selling point to the public but I`m not ready to give up on uranium. To me it has always been the reactor itself (molten salt, aka liquid fluoride) that has been the amazing thing due to its great safety, low potential cost and reduction of long term wastes. These properties are just as good while relying on uranium, not just thorium. That said, I again fully understand how simple and useful it is to promote the advantages of thorium so it is indeed a bit confusing on how to proceed in terms of promotion.

David LeBlanc


Top
 Profile  
 
PostPosted: Nov 25, 2009 1:00 pm 
Offline

Joined: Dec 05, 2008 8:50 am
Posts: 336
David wrote:

I still want to learn a lot more about just how "dirty" uranium mining is but I am expecting it is mostly hype and based on the early horrible mining practices in the U.S. early in the cold war. Yes, if you don`t properly ventilate a mine (almost any mine) you are going to expose miners to way to much radon.


I also suspect it was perfectly the same for other minning operations (iron, copper, etc..)


Top
 Profile  
 
PostPosted: Nov 25, 2009 1:14 pm 
Offline

Joined: Mar 07, 2007 11:02 am
Posts: 911
Location: Ottawa
Lars wrote:
David,
I'm wondering about the converter reactor.
Over the life of the reactor, for each isotope (232Th, 235U, 238U), how much do we supply and how much is left at the end?


For the unmodified DMSR study of 1980 you would start with 110 tonnes of thorium and never add anymore. There would be 93 tonnes left in the salt at the end of 30 years. This is for 1000 MWe

For LEU (20%) you would start with 17.5 tonnes (which has 3.5 tonnes U235) which came from about 670 tonnes of U metal (788 tonnes U3O8). Over 30 years you would need to add less than 1 tonne 20% per year which meant close to 900 tonnes total U metal needed over 30 years. At the end you`d have about 35 tonnes of U in the salt with about 3 tonnes fissile (U233+U235). If you recycle that, the lifetime U metal requirement drops down to about 800 tonnes U metal.

We can do better than that with some simple modifications or going the other way we can make the reactor even simpler at the expense of a little more lifetime uranium (such as a cheaper, non tritium producing carrier salt).

David L.


Top
 Profile  
 
PostPosted: Nov 25, 2009 1:17 pm 
Offline

Joined: Apr 19, 2008 1:06 am
Posts: 2246
The world is much more crowded than it was a century ago. Any change in land use bothers some people. All uranium except some of Canadian mines is below 1000ppm (!kg per ton of ore) so it covers more area. It is time to burn U238 and thorium. Use any uranium and SNF basically as a source of fissile "Kindling" and for creation of more of it.


Top
 Profile  
 
PostPosted: Nov 25, 2009 1:39 pm 
Offline

Joined: Jan 24, 2007 2:24 pm
Posts: 436
Location: Montreal, Quebec CANADA
like every other commodity that is mined, the driving force will be economics. The reality is that fuel prices are not a very big factor in the cost of producing nuclear energy and could conceivably increase by two orders of magnitude. This can be ether due to the exhaustion of high-grade deposits, or because of more restrictive regulations. At that price-point low grade deposits become economically viable or there is an impetus to develop more efficient techniques for extraction, like the work being done with seawater production, or re-enrichment of depleted uranium stocks and leaching of mine tailings. All of these have been considered seriously enough to have warranted proof-of-concept projects, at one time or another.

Therefore the choice of breeding over mining will be made by a simple formula: which way is cheaper, and little else.


Top
 Profile  
 
PostPosted: Nov 25, 2009 2:48 pm 
Offline

Joined: Dec 20, 2006 7:50 pm
Posts: 280
jagdish wrote:
Wow! What an illustration of peak uranium. Russians and Indians are really wise to stick with breeders.


You haven't made any argument at all for that ridiculous assertion, and I've posted numerous citations that point to the contrary, that uranium supply is assured for millinia.


Top
 Profile  
 
PostPosted: Nov 25, 2009 5:08 pm 
Offline

Joined: Jul 14, 2008 3:12 pm
Posts: 5045
dezakin wrote:
DV82XL wrote:
Therefore the choice of breeding over mining will be made by a simple formula: which way is cheaper, and little else.

I believe that LFTR concepts will be chosen simply because they are cheaper to build and operate, having nothing to do with fuel consumption whatsoever.


In the short to medium term, there may be issues with mining capacity bottlenecks.

Your suggestion that ore grade is the determining variable considering uranium resources is too simplistic. There are many other important geochemical and geophysical variables such as solubility and permeability in case of leeching, which also needs two impermeable layers by the way, not to mention not be in contact with groundwater etc, then there's hardness of the rock, depth, then there's above ground factors such as politics and geographic location etc.

One of the main reasons why phosphates are so interesting is that they are very soluble, and in fact that this is used for fertilizer production already. So solvent extraction can readily be used.

You're probably right that a hell of a lot more uranium is recoverable but a lot of other variables have to be considered that do restrict the economic-geologic hypothesis.


Last edited by Cyril R on Nov 25, 2009 5:21 pm, edited 1 time in total.

Top
 Profile  
 
PostPosted: Dec 14, 2009 9:57 pm 
Offline
User avatar

Joined: Nov 30, 2006 3:30 pm
Posts: 3819
Location: Alabama
SL Tribune: Stop uranium train

Quote:
Depleted uranium is a bomb with a very long fuse.


The hyperbole and fear-mongering in order to sell newspapers continues...


Top
 Profile  
 
PostPosted: Dec 18, 2009 10:29 pm 
Offline
User avatar

Joined: Nov 30, 2006 3:30 pm
Posts: 3819
Location: Alabama
SL Tribune: Is Utah disposal site safe for depleted uranium?

Quote:
State regulators begin taking comments next month on how to contain DU effectively for 10,000 years or more.


Uh, will they be taking comments on how to "contain" the billions of tonnes of natural uranium in the state of Utah that will be more radioactive than DU for the next 5 billion years? I didn't think so...


Top
 Profile  
 
PostPosted: Dec 19, 2009 4:51 am 
Offline

Joined: Jul 14, 2008 3:12 pm
Posts: 5045
There are also dry cask storage methods being developed that use depleted uranium as radiation shielding material. The idea is to use it as major additive to the concrete casks. It seems like much of the depleted uranium could be effectively (and usefully) 'disposed' this way, while actually making the dry casks leak less radiation.


Top
 Profile  
 
Display posts from previous:  Sort by  
Post new topic Reply to topic  [ 93 posts ]  Go to page Previous  1, 2, 3, 4, 5, 6, 7  Next

All times are UTC - 6 hours [ DST ]


Who is online

Users browsing this forum: No registered users and 1 guest


You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum
You cannot post attachments in this forum

Search for:
Jump to:  
Powered by phpBB® Forum Software © phpBB Group