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Post by davidm on Jul 22, 2012 3:06:53 GMT 9.5
I can see partly from this blog of Barry Brook why the IFR exercises such a magical hold on folks. In theory it appears it is a closed loop in house operation that never has to truck with fossil fuel or uranium mining or long term waste management again and contributes no ghg in the post fossil fuel world while as a system powering eternally and being continually expandable. It has something of the feel of a perpetual motion machine that grows. Now all it has to do is work. bravenewclimate.com/2010/03/08/tcase8/
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Post by David B. Benson on Jul 22, 2012 8:42:07 GMT 9.5
The EBR-II ran for 30 years without a hitch. Essentially that design is commercialized by GE-Hitachi as the PRISM although currently without the pyroprocessor.
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Post by davidm on Jul 22, 2012 9:42:52 GMT 9.5
The EBR-II ran for 30 years without a hitch. Essentially that design is commercialized by GE-Hitachi as the PRISM although currently without the pyroprocessor. Yeah I read an interview from a link on this site with an expert on the PRISM and he seemed confident it was ready to go, pyroprocessor and all if that was ordered. Still you have to wonder with all these different outfits working on 4th generation nuclear reactors why there isn't a working model up and ready to go. This guy is an IFR enthusiast and even he has at least cost problems. Perhaps it is once again one of those deals where short term economics trumps the greater good long term. As long as we are on the subject of the IFR I'd like to include this link which takes you to an extensive wikipedia analysis of the subject.
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Post by Scott on Aug 7, 2012 2:39:17 GMT 9.5
Why does EROI even matter?
So if you have a 10:1 EROI then 90% of the energy used provides useful work.
So you have a 100:1 EROI then 99% of the energy used useful work.
9% difference. If the useful work provided by the first source is cheaper and more reliable, then go for it. And if the energy input is distributed over the lifetime of the plant, as it is for nuclear plants, then it can be created by the nuclear plant itself.
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Post by anonposter on Aug 7, 2012 3:04:28 GMT 9.5
Why does EROI even matter? Well if it's less than one then you don't have any energy source (although no one seems to be seriously proposing such a thing for electricity production) though even if the EROI is less than one it might still be useful for energy storage or as portable energy (synthetic hydrocarbons come to mind). Other than that high EROI sources would be expected to be more economical, but it'd probably only be a relatively weak correlation.
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Post by davidm on Aug 7, 2012 3:38:28 GMT 9.5
Why does EROI even matter?
So if you have a 10:1 EROI then 90% of the energy used provides useful work.
So you have a 100:1 EROI then 99% of the energy used useful work. Let's make sure we are on the same page. 10:1 EROI means 10 units of energy output for one unit of energy input. 100:1 EROI means 100 units of energy output for one unit of energy input. As long as the principal input is fossil fuel which it would be for a while even after the IFR is brought on line then the below EROI example would reduce the carbon gas contribution by 10 times as compared to the upper example over the long term.
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Post by David B. Benson on Aug 10, 2012 12:03:02 GMT 9.5
David M --- As best as I can determine there has been no rush to commercial IFRs since the actual LCOE is not yet known, only estimated, and estimated to be slightly higher than for a Gen 3 LWR. This will continue to be true, probably, as long as there are ample uranium ores.
What has changed sufficiently for GE-Hitachi to proceed with the PRISM is the intent of at least the USA, UK and Russia to dispose of a significant quantity of excess plutonium. While conversion to MOX can be done, France's LaHavre MOX plant continues to have (minor) problems and the UK has given up attempting to build a working MOX plant (after a serious attempt). The USA continues to work on a MOX plant (which is already projected to be 150% over budget). I don't know the exact status of the Japanese MOX plant but suspect it doesn't work yet. Worse, NPP operators appear to accept MOX rather than just plan old uranium oxide for the actinide pins with considerable reluctance.
But the PRISM can be used as an anti-breeder to consume the plutonium. If equipped with a pyroprocessor all the plutonium is eventually consumed, at least in principle. [It hasn't been demonstrated in practice yet.] SO it seems to UK is given serious consideration to the GE-Hitachi proposal to use two PRISM reactors to rid the UK of its excess plutonium.
In the US I believe plans are afoot to build a demonstration PRISM at a DoE site; no electricity to the grid will be generated and NRC hasn't approved the type yet and won't for quite a few more years.
China has a research scale IFR. My understanding is that a Russian/Chinese consortium is designing a commercial sized version. [I'll add that an IFR is considerably easier to design to the same degree of nuclear safety than a Gen 3 NPR.]
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Post by trag on Aug 16, 2012 7:28:35 GMT 9.5
i found the short cut equation near the end of the article confusing, but ultimately supported after I did some equation doodling. I thought it might be helpful to share it here.
The author figures an EROEI, then divides that into the expected lifetime of the power plant and declares that the resulting time is the payback period for the energy investment in the power plant. It works out, but it's confusing on first (and for me, second and third) glance.
The LCA of the energy type (in this case) is the expected Kg of CO2 produced per MWHr of electricity generated.
So, for example, if we wanted to know the total CO2 produced over the lifetime of the plant, the equation would be:
LCAn * E/year * Lifetime = Total Lifetime Kg CO2.
Where E/year is the MWHr of electricity produced per year and the Lifetime is the lifetime of the power plant in years. The LCAn indicates that this is the LCA for nuclear electricity generation. We'll need to distinguish it from the LCA for fossil fuels in a bit.
So the last two elements give us the total energy generated by the power plant during it's lifetime. Multiplying that by the LCAn gives us all the CO2 generated in support of the power plant in its lifetime.
Now, all that CO2 was generated by burning fossil fuels. If we want to know how much fossil fuel energy the plant consumed in its lifetime, we divide the Total Lifetime CO2 by the LCA for fossil fuels:
Lifetime FF Energy Used = Total Lifetime Kg CO2 / LCAff
Remember that LCAff is the Kg CO2/MWHr.. So from a units point of view, the Kg-CO2 cancel out and we're left with MWHr. The energy used by the power plant during its lifetime.
Now that we have the energy used or the energy cost, we just divide that by the energy produced per year to get the years to payback:
Year to Payback = Lifetime FF Energy Used / (E/Year)
Where again, the E/year is the MWHr of electricity generated in a year by the power plant.
So using substitution, the full equation for Years to Payback is:
Years to Payback = ((LCAn * E/Year * Lifetime) / LCAff) / (E/Year)
The two E/Year terms cancel out, which is handy since they're unknowns for us, giving:
Years to Payback = LCAn * Lifetime / LCAff
Rearranging a bit yields:
Year to Payback = Lifetime * LCAn / LCAff = Lifetime / (LCAff/LCAn)
And that is the equation that the author used for years to payback.
Perhaps that was obvious to everyone but me.
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Post by Scott on Aug 17, 2012 13:57:05 GMT 9.5
A large amount of the energy input is distributed over the life time of most energy sources, including nuclear. Therefore the "pay back" period is misleading because you cannot pay back what energy has not been used yet. In other words, I don't pay back a loan before I've taken out the loan.
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Post by Scott on Aug 17, 2012 13:59:50 GMT 9.5
The energy required to operate a nuclear plant can be considered an input. The energy it puts out is considered an output. Therefore, just take some of the output and plug it back into the input. This exactly the same as the difference between the gross and net output of any existing power plant.
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Post by davidm on Aug 17, 2012 16:59:32 GMT 9.5
The energy required to operate a nuclear plant can be considered an input. The energy it puts out is considered an output. Therefore, just take some of the output and plug it back into the input. This exactly the same as the difference between the gross and net output of any existing power plant. Well things like mining, power plant construction and transportation are the major part of that input. Until you can make them nuclear power driven, directly or indirectly, then you can't have your contemplated perfect cycle. Of course the breeder plant approach presumes that mining will eventually be taken out of the picture and instead fuel will be self-generated.
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Post by David B. Benson on Apr 13, 2013 15:07:41 GMT 9.5
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Post by edireland on Apr 13, 2013 19:34:39 GMT 9.5
I have access to that through my University Library.... I will read it and crunch it.
EDIT:
The prices are all in 1991 values and represent the BN-800 projections at the time of the collapse of the USSR.
This information has already entered the general IAEA literature on fast reactors.
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Post by Graham Palmer on Apr 13, 2013 21:07:42 GMT 9.5
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Post by David B. Benson on Apr 14, 2013 11:04:16 GMT 9.5
Capital cost for NPPs with FRs generally accounts for 70-80% of the total nuclear electricity generation cost, compared to 40-55% for LWR plants. The reason for the higher cost of equipment for fast reactors, as is shown in this report, is their wider range and higher per installed kilowatt metal content. from p. 692 of STATUS OF FAST REACTOR RESEARCH AND TECHNOLOGY DEVELOPMENT IAEA-TECDOC-1691 www-pub.iaea.org/books/iaeabooks/8667/Status-of-Fast-Reactor-Research-and-Technology-Development
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Post by David B. Benson on Apr 14, 2013 12:45:25 GMT 9.5
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Post by jagdish on Apr 14, 2013 14:13:51 GMT 9.5
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Post by Edmond Overbey on Mar 29, 2015 4:33:16 GMT 9.5
Surprising that no one is discussing ITER or the Princeton Tokamak. When these projects are successful, it seems they will achieve a very favorable EROI.
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Post by jimbaerg on Apr 14, 2015 6:34:56 GMT 9.5
Edmond: Why do you say 'when' rather than 'if'?
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