We cannot drill our way out of this oil crisis. Since 2000, oil companies working in the U.S. have doubled the number of wells drilled per year.
Although increased drilling has added new oil to the nation's supply, it has not done so fast enough to offset the terminal decline of existing fields.
We are going to have to import more of our oil. Period.
Posted: Wed Feb 15, 2006 2:25 pm Post subject: Re: Fission FAQ v 1.5
Thank you for the explanation. I do know that there used to be a CANDU reactor in Karachi, Pakistan but I don't know if it's still operational. My impression always was that the extra cost for this style of reactor was more than made up for by the cheaper fuel, online fueling, etc. Some of Ontario Hydro's plants had uptimes of 99+% if I recall correctly, for years on end.
Posted: Thu Feb 16, 2006 12:37 pm Post subject: Re: Fission FAQ v 1.5
a layman's question on fast breeders.
Everywhere where I read about those breeders there are arguments being made that the reactors are unprofitable, unreliable and things. But as of now i did not find any document that would clearly say: "YES there are breeders running, that actually turned U238 into fissable fuel and thus actually generated more fissable fuel than consumed, however unprofitable and unreliable they might have been. Provided that they did not consume more energy than generated of course".
Can anybody of you proffessional guys say a definite YES or NO to that question? I am really puzzled, i even read that info about the russian BN-600 here http://eng.rosatom.ru/?razdel=160
a pretty nice description, but does not answer the question whether that thing can fastbreed.
Thanks in advance, I think this question should really be included into the FAQ, but it is my opinion.
Posted: Sat Feb 18, 2006 7:56 am Post subject: Re: Fission FAQ v 1.5
There have been functioning fast reactors that have generated electricity and produced more fissile fuel than they used.
E.g the Phenix reactor at Marcoule, France. This is a demonstration reactor, for testing of the FBR concept. It has operated as a breeder, with a proven breeding gain of 16% (for every 1 kg of plutonium burned, 1.16 kg are formed). It produced approx 20 TWh of electricity.
Posted: Sun Apr 02, 2006 1:46 pm Post subject: Re: Fission FAQ v 1.5
I'm trying to figure out how expensive natural uranium will get before enrichment facilities find it economical to go back and extract more u235 from their depleted uranium. For back-of-envelope calculation purposes, I assume 400 nuclear power plants each using 30 tons fuel annually for 25 years, with each ton of fuel burned leaving 7 tons of depleted uranium behind at the enrichment plant, with 2/10ths of a percent U235 still left in it. That would be 400 x 30 x 25 x 7 x .002, or 4200 tons U235 that once separated could be blended at a 24 to 1 ratio with U238 to make 105,000 tons of burnable fuel, or 105000/(400x30)=8.75 years supply, long enough to bring plenty of new production into the market. What I can't even guess at, is how much more marginally expensive it becomes to centrifuge out that last ounce of U235, when the decisions have already been made once that it's not worth it. Any ideas? When I tried to guess the price where power companies would find it cheaper to switch to natural gas, it came out around $500 a pound, so maybe it's a moot point if recovery from depleted U works out even higher.
Joined: Apr 28, 2005 Posts: 3277 Location: West shore Lake Eire, MI, USA
Posted: Sun Apr 02, 2006 7:32 pm Post subject: Re: Fission FAQ v 1.5
J_S_Bokchoy wrote:
I'm trying to figure out how expensive natural uranium will get before enrichment facilities find it economical to go back and extract more u235 from their depleted uranium. For back-of-envelope calculation purposes, I assume 400 nuclear power plants each using 30 tons fuel annually for 25 years, with each ton of fuel burned leaving 7 tons of depleted uranium behind at the enrichment plant, with 2/10ths of a percent U235 still left in it. That would be 400 x 30 x 25 x 7 x .002, or 4200 tons U235 that once separated could be blended at a 24 to 1 ratio with U238 to make 105,000 tons of burnable fuel, or 105000/(400x30)=8.75 years supply, long enough to bring plenty of new production into the market. What I can't even guess at, is how much more marginally expensive it becomes to centrifuge out that last ounce of U235, when the decisions have already been made once that it's not worth it. Any ideas? When I tried to guess the price where power companies would find it cheaper to switch to natural gas, it came out around $500 a pound, so maybe it's a moot point if recovery from depleted U works out even higher.
Take a look at Enrichment and play with the numbers a bit. Keep in mind that most reactors are now using an enrichment level around 4.4% U-235 (which is the grade the FSU sells us downblended weapons Uranium) because it allows the plant to burn the fuel for 8-12 months longer, saving costly refueling down time periods. With a tails assay of .3% (which has been common with cheap Uranium availible) and a product assay of 4.4% you need 300 tons of natural Uranium feed to get 30 tons of enriched fuel. If you store that 270 tons of depleted tails, which is what they do now, you can later re-enrich those tails, but the energy cost is substantially higher. To enrich your 30 tons of fuel the first time you used about 182000 SWU (Seperative work units). A couple of point on this, the calculator is old and assumes you are using Gaseous Diffusion instead of Centerfuge enrichment, if you centerfuge you save a heck of a lot of SWU energy.
Quote:
The specific energy consumption is 2300-3000 kWh/SWU for Gaseous Diffusion, versus 100-300 kWh/SWU for gas centrifuge. The number of stages required to produce LEU is about 30 times larger in the diffusion plant than in the centrifuge plant. The corresponding equilibrium time is significantly longer in diffusion plants (months) as compared to centrifuge plants (hours). This effect, more intensive when the diffusion plant processes Uranium with higher enrichments, makes difficult and time consuming any significant change of the modus operandi of a gaseous diffusion plant. The large in-process inventory in the diffusion plant (a few tons in a small-scale diffusion plant) indicates the importance of closing the Uranium balance in this facility. On the other hand, for centrifuge plants, the small equilibrium time, small in-process inventory and the flexibility to change the cascade design (parallel to series) determine the importance of verifying that the plant is operating as declared.
Note that for worst case numbers a gas centerfuge is one tenth the cost per SWU in energy terms which needless to say substantially reduces the cost of enrichment. Because of this fact that 270 tons of .3% tails stored from a years worth of fuel production can go back through enrichment again, either retaining a moderate depletion level and making just a little more fuel, or being depleted to .12% which is the lowest level recorded for regular enrichment and which was done the last time Uranium prices were high. Depleting the tails from .3% to .25% only gains you 3.25tons of fuel enriched to 4.4%, depleting the tails all the way to .12% gains you 11.35 tons of fuel at 4.4%, or another third of a year worth of fuel from stored tails, without the cost of mining, milling and refining the metal which are sunk costs for the tails. To do this costs almost 209000 SWU, but when the cost has been reduced by 90% due to advances in the technology it is cheaper in economic terms than the orriginal enrichment preformed decades earlier with the old gas diffusion plants.
Another kink is that the spent fuel reprocessed in France and other countries seperates out the Uranium portion and stores it. This 'spent fuel' Uranium is about .84% U-235 and about .42% U-236 and can be sent back through enrichment to be reused, however it contains trace quantities of U-232 which is a gamma emmiter and requires much more stringent safety protocols during re-enrichment than does fresh natural Uranium or tails being upgraded. Currently this 'spent' Uranium is being stored because the price of natural Uranium was too low to make it worth the extra precautions needed, but as the price goes up re-enrichment becomes more attractive.
BTW all of this is covered in more detail on page 1 of this FAQ. _________________ Oxygen: - An intensely habit-forming accumulative toxic substance. As little
as one breath is known to produce a life-long addiction to the gas, which addiction invariably ends in death.--Isaac Asimov
Posted: Sun Apr 02, 2006 11:24 pm Post subject: Re: Fission FAQ v 1.5
So choosing a midpoint of 200 kwhr per SWU times 209000 @ 7 cents/kwhr would cost about 8 million for a third of a year's fuel. If the choice is between making fuel out of natural U or re-enrichment of stored tails, let the breakeven price equal B and solve for B as follows: $24 million = 10 (natural to fuel ratio) X 30 (tons a year) X 2000 lbs per ton X B, so B= $40 a pound. That's where it's at now, so I guess they might as well just leave their ore in the ground for 8 years until the million or so tons of tails worldwide get used up! At least it seems like that could inhibit the price from going much higher. But then if the value chosen for kwhr per SWU is 300, then B goes to $60. What other constraints could hold prices down, besides another TMI?
Posted: Tue Apr 04, 2006 12:12 am Post subject: Re: Fission FAQ v 1.5
AND please disregard preceeding inquiry, I forgot to include power expense on the right hand side. After that my hypothetical breakeven point was only $20 so the question must be pointless if the price is double that already. Maybe hedge fund speculation, panic inventory building or even the limited enrichment capacity now in operation washes out mere cost accounting.
Joined: Apr 28, 2005 Posts: 3277 Location: West shore Lake Eire, MI, USA
Posted: Tue Apr 04, 2006 4:31 am Post subject: Re: Fission FAQ v 1.5
J_S_Bokchoy wrote:
AND please disregard preceeding inquiry, I forgot to include power expense on the right hand side. After that my hypothetical breakeven point was only $20 so the question must be pointless if the price is double that already. Maybe hedge fund speculation, panic inventory building or even the limited enrichment capacity now in operation washes out mere cost accounting.
You are forgetting a couple key ingredients in the whole deal, so to speak. One factor is time and inertia, most Uranium is bought on long term contracts with the mines, not on the spot market because none of the power companies is going to risk sitting around with an expensive to build power plant and no fuel on hand. As those long term contracts expire new contracts are written based on more current market conditions, this raises the contract price more slowly than the spot market price, but the rise is less subject to short term uncertainty. As the long term price goes up the producers are incentivized to invest in greater production which will most likely exceed short term demand and drive the price back down.
For going on 15 years now the price of Uranium has been very depressed because back in the 1970's a lot of power companies signed very long term contracts or stockpiled large quantities of natural Uranium and stored it when prices were lower. Then on top of those factors the demand side was less than projected because TMI sensationalism badly hurt the nuclear industry in the USA and new plant construction ground to a halt. This left a few large companies with stockpiles for plants that were no longer being built and many companies with stockpiles for several plants but only one plant completed. If you buy a contract to fuel a set of 3 plants for 10 years and then end up with only 1 plant you have a potential 30 year fuel stock for that plant. Then add in the fact that the USA and USSR/Russia arms reduction treaties added even more Uranium to the market, so much that the price crashed and the treaty had to be renegotiated to reassure producers that well under half of any years supply would be reclaimed weapon material. On top of all that France aggressivley pursued reprocessing and MOX use that even further reduces demand for fresh Uranium.
Of course once the price crashed a new balance on the enrichment side was reached, especially in the USA where everything was still done with cold war designed gasseous diffusion plants and SWU is expensive. To save money cheap natural Uranium was only depleted to .3% instead of .15%, which leaves a bit more depleted Uranium but saves big bucks on enrichment costs, it cost about twice as much to deplete the tails to .15%. Halving the tails assay changes about 4% of the total feed from Tails into Fuel, how much does the feed have to cost and how cheap does your SWU have to be to make doing that a good idea economically? It is my understanding that in France they even reduced tails depletion to .35% or for a time .4%, but I don't have any documentation to confirm or deny that this happenned. _________________ Oxygen: - An intensely habit-forming accumulative toxic substance. As little
as one breath is known to produce a life-long addiction to the gas, which addiction invariably ends in death.--Isaac Asimov
Posted: Wed Apr 05, 2006 12:17 pm Post subject: Re: Fission FAQ v 1.5
sch_peakoiler wrote:
a layman's question on fast breeders.
Everywhere where I read about those breeders there are arguments being made that the reactors are unprofitable, unreliable and things.
I think (anybody who disagrees feel free to step in) MOST breeder reactors were not built with the primary intention of supplying energy.
Since breeders can "produce" Plutonium it has definite military applications. Modern nuclear bombs are fusion and not fission bombs. Therefore they do not recieve their power from plutonium per say. Instead the PU is used to create a fission reaction which produces massive amounts of heat. The heat "triggers" the fusion reaction. Basically every fusion bomb is actually 2 bombs in one. A fission reaction is necessary to create a fusion reaction.
Because of its significant military applications I would assume all breeder reactors must be government owned. That would explain their unprofitable history.
Joined: Apr 28, 2005 Posts: 3277 Location: West shore Lake Eire, MI, USA
Posted: Wed Apr 05, 2006 6:36 pm Post subject: Re: Fission FAQ v 1.5
cube wrote:
sch_peakoiler wrote:
a layman's question on fast breeders.
Everywhere where I read about those breeders there are arguments being made that the reactors are unprofitable, unreliable and things.
I think (anybody who disagrees feel free to step in) MOST breeder reactors were not built with the primary intention of supplying energy.
Since breeders can "produce" Plutonium it has definite military applications. Modern nuclear bombs are fusion and not fission bombs. Therefore they do not recieve their power from plutonium per say. Instead the PU is used to create a fission reaction which produces massive amounts of heat. The heat "triggers" the fusion reaction. Basically every fusion bomb is actually 2 bombs in one. A fission reaction is necessary to create a fusion reaction.
Because of its significant military applications I would assume all breeder reactors must be government owned. That would explain their unprofitable history.
I guess it is better to be half right than all wrong
The problem starts with the premesis, a breeder reactor has one primary design goal, which is to produce more fuel than it consumes. They were not designed primarily ofr energy production, but rather for fissile fuel production. So long as Uranium remains cheap and abundant they are rather like the F-T Coal-to-liquid process, yes they work and yes they produce a usable fuel, but the natural abundant fuel is cheaper and easier to handle so why go to the extra expense and difficulty?
Commercial breeder reactors are all designed to produce elecricity to help offset the expense of running them, do a web search on Fermi I at Lagoona Point in Monroe, MI. It was the first commercial breeder and provided a lot of lessons to the electric utilities on just what was needed to make a commercial breeder work. It was not an economic success, but it was a technical success, the reactor produced more fuel than it consumed along with some electric power which was sold over the grid. In order to be a commercial success a breeder has to either be so efficient that it overcomes the cost difference in fuel manufacturing and reprocessing. In the past with aqueous 'chop-leach' reprocessing that was a very high hurdle, the new pyrometalurgical process however is vastly cheaper and produces a lot less secondary waste and may provide an economic incentive to build commercial breeders.
Weapons material reactors are hugely different from commercial breeders, they require frequent or constant refueling to keep the bred material from degrading in quality, and frequent reprocessing to recover the bred material. For the military with their bottomless budgets for nuclear weapons this was not a handicap, but for the electric utilities it is the road to financial ruin. _________________ Oxygen: - An intensely habit-forming accumulative toxic substance. As little
as one breath is known to produce a life-long addiction to the gas, which addiction invariably ends in death.--Isaac Asimov
Tons of information, including facts debunking the outrageous claims of low EROEI and negligible GHG benefits, graphs showing how the most radioactive materials decay very rapidly (in decades), while the waste that remains "for 1000s of years" is not nearly as radioactive and indeed can be rendered into a form less radioactive than the original ore.
Most interesting was the description of the French experience. I especially liked the part about how the waste of producing 20 years of electricity for a family of 4 is a glass cylinder the size of a cigarette lighter. The FAQs are also interesting. Confirms that we really need to breed plutonium for the nuclear option to make sense long-term. Also debunks the assertion that plutonium is the most toxic substance on earth.
Joined: Sep 13, 2004 Posts: 142 Location: New Zealand
Posted: Thu Jun 15, 2006 9:19 pm Post subject: Re: Fission FAQ v 1.5
UIC - that's like asking GM if an SUV is the right vehicle for you
Gentle hint - it's aka propaganda.
The PBS one has more interesting links. Thanks. _________________ Let's hope the next generation have a sense of humour ... our generation will need it.
Joined: Jun 20, 2004 Posts: 250 Location: California
Posted: Fri Jun 16, 2006 9:53 am Post subject: Re: Fission FAQ v 1.5
fastbike wrote:
UIC - that's like asking GM if an SUV is the right vehicle for you
Gentle hint - it's aka propaganda.
The PBS one has more interesting links. Thanks.
I'll take facts from any source. I'll take 'em from UIC or Greenpeace in equal measure. Everyone has biases.
UIC's site has a lot of factual information. Obviously any source may present only facts supporting it's position while omitting ones that do not, but, well, facts are facts. You just have to separate them from opinions. I always consider the source when reading anything. The only page I've found on UIC (so far) that is questionable is the one dealing with fuel availability. There is a mix of facts (like proven resources of 3.1 million tonnes, the value of reprocessing, expanding fuel by 60x with breeders) and unsupported assertions (reserves could be doubled if exploration was resumed, we could get Uranium from seawater at $1000/kg). Even there, at least they don't pretend there isn't a possible fuel issue. I contrast this with most anti-nuclear writings that contain lots of rhetoric and little useful information.
Posted: Sun May 13, 2007 8:39 pm Post subject: Once-through total-use nuclear cycle possible?
So, breeders convert more fertile material into fuel than the fuel it consumes, but the reprocessing is expensive. Why is it that the fuel has to be taken out for reprocessing at all? Why can't the newly produced fuel be used directly?
Is it possible to design a reactor where fuel rods only have to be put in and taken out once--where the reactor continuously produces fuel from the fertile material and uses it up, until all the fertile material has been converted and all the fuel used up--and the spent fuel rod would be worthless and can be taken directly to disposal without reprocessing?
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