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PostPosted: Feb 09, 2015 12:08 am 
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Alex,
Start with roughly 1kW/person as a typical first world usage including industry.
Forecast the world population at 12 billion before it finally stablizes.
So far you have 12TWe.

Now, whether we have hit peak oil or not may be debatable but lets be generous and assume that we aggressive exploration we are able to continue to pump today's volume of oil far into the future. But as the worlds economies grow there will be ten times as many people wanting to use that oil. Imagine trying to get by on a ration at 10% your current oil usage - that includes 10% of the plastics and 10% of the air travel. Don't think that will fly. We will need to convert whatever oil usage we can to electricity. This will easily double the electricity usage to 24TWe and could require very much more.

Now consider fresh water. We've been pumping ground water pretty seriously and again as economies improve there will be more pumping. It seems very likely that desalination will become a big application.

So 30TWe seems like a reasonable mid-term estimate but probably low in the longer term.


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PostPosted: Feb 09, 2015 2:02 am 
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alexterrell wrote:
KitemanSA wrote:
darryl siemer wrote:
I've decided that I could make a good case for building the equivalent of "10,000 to 30,000" full-sized (not modular), one GWe, reactors ASAP...and did.
I suspect 30,000 will be a bit low. I arrived at 70,000 myself. Of course, a bit of it was for water.


Sorry to go back a bit, but .... hard to see a need for 30TWe - without high velocity space applicatoins.



My guess about how much nuclear power we'll need is based upon the fact that "rich" countries like the USA now use about 100 exajoules/year/300 million people which is equivalent to the total (thermal) energy output of about 1000 1 GWe nuclear reactors. Assuming that the world's population eventually plateaus out at 9 billion (in my opinion about 2x too high) & they all deserve to be as rich as we are now, they'll need to build about 30,000 (9 billion/300 million*1000) full-sized reactors.

It would be impossible to generate that much power with reactors fueled (primarily) with 235U.

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PostPosted: Feb 09, 2015 6:06 am 
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Of course, need and demand are different things.

If MSRs can churn out electricity at 2c/KWh, then "Demand" could well surpass 30TW.

But at the moment, the UK uses around 700W per person - and this is falling as LEDs and low energy devices more than make up for the proliferation of gadgets. Heat pumps and electric vehicles could push this to 1.5KW. Of course, if you heat uninsulated buildings with resistance heaters, and take electric Humvees to the Mall, then it'll go higher - but that's a question of demand, not need.

Anyway - what's really relevant:

Quote:
I've decided that I could make a good case for building the equivalent of "10,000 to 30,000" full-sized (not modular), one GWe, reactors ASAP...and did.


Is the case stronger for building 5,000 or 30,000?

1. Here's a reactor that replace all the current fossil fuel generation and heating and most transport. We'll need 5,000 - 10,000 of them.
2. Here's a reactor that will produce unlimited amounts of clean energy. We'll need 10,000 - 70,000 of them.

I'd suggest (1) is a better sales pitch. For a start, you'll get fewer annoying people :) questioning you're first paragraph and detracting from the more important messages.


Last edited by alexterrell on Feb 10, 2015 4:19 pm, edited 1 time in total.

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PostPosted: Feb 09, 2015 8:03 am 
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If electricity drops to <2 cents/kWh (or you go with power purchase rather than energy purchase) demand can be expected to skyrocket.

Electric Patio heaters, desalination, Resistance heaters (as they will have lower life cycle cost than pumps) for hot water and possibly even space heating... the list goes on.

Having more energy available is always a good thing.

Also lets say we have DMSRs with ~21GWd(e)/t of natural uranium (as the numbers work out) - that means that 30TWe would only require something like five hundred thousand tonnes of uranium per year - a rate only ten times that of today - which while high is not so enormous as to be totally absurd, especially since at that very very high uranium utilisation seawater extraction would certainly be economic.
(Even 0.5 US cent/kWh would put the price of uranium at $2520/kg)


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PostPosted: Feb 09, 2015 3:28 pm 
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E Ireland wrote:
If electricity drops to <2 cents/kWh (or you go with power purchase rather than energy purchase) demand can be expected to skyrocket.

Electric Patio heaters, desalination, Resistance heaters (as they will have lower life cycle cost than pumps) for hot water and possibly even space heating... the list goes on.

Having more energy available is always a good thing.

Also lets say we have DMSRs with...


I totally agree - if clean power were to become cheap enough, we'd have no problem coming up with lots of novel/constructive "apps" for it.

Footnote 27 of my article's* footnotes summarizes my opinion of DMSRs. I know that they would be probably be "better" than today's reactors but also that they would still not be "sustainable", would certainly generate more & tougher-to-manage radwastes, and are likely to be more expensive to both build & operate than isobreeding MSFRs. There certainly would be niche markets for modular DMSRs (e.g., ship engines) but to address humanity's big problems, we'd have to use something that's not so compromised performance-wise.

The main problem with stopgap schemes is that socioeconomic forces tend to lock them into place - that's how the nuclear power industry fell into the "Rickover trap" (see last chapter of James Mahaffey's "Atomic Accidents").



* Wiley's just notified me that it's been published - see http://onlinelibrary.wiley.com/doi/10.1002/ese3.59/pdf

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PostPosted: Feb 09, 2015 3:57 pm 
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I would love to live in a world locked-into DMSRs. It'll power civilisation cleanly, reliably and cheaply, and do so forever with seawater uranium alone - in so doing putting all the "uranium will run out" naysayers to bed with their 1965 resource antics.


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PostPosted: Feb 09, 2015 7:47 pm 
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Cyril R wrote:
I would love to live in a world locked-into DMSRs. It'll power civilisation cleanly, reliably and cheaply, and do so forever with seawater uranium alone - in so doing putting all the "uranium will run out" naysayers to bed with their 1965 resource antics.


It'd be a fine place but not quite so prosperous or energy-secure as would one powered with MSFRs. Here's why:

If we assume that the earth's oceans average 2 miles deep, cover 70% of its surface, & contain 2.7 ppb U by weight, the amount of U in them would be about 3.2E+9 tonnes.

Your basis 21 GWe*d/t U DMSR would require about 17 tonnes of U per year to generate a gigawatt's worth of electrical power. That translates to having to quantitatively recover the U in about 1.5 quadrillion gallons of seawater per year per reactor. If our descendants need 30,000 of them to power their clean, green DMSR-powered world, they'd run out of "gas" in about 6000 years after having to run all of water in all the oceans through their magic separators many, many times. While that scenario makes more sense than trying to implement a nuclear renaissance with LWRs (163 tonnes U/GWe*year), it's still pretty inefficient relative to the system I'm advocating (initially 4-5 tonnes of "fresh" Th/GWe-year, less later after the FP in waste forms decays & Th recycle begins).

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PostPosted: Feb 09, 2015 7:56 pm 
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21GWd(e)/t is sufficiently high to boost uranium production prices to unbelievable levels without causing serious problems for power prices.
That means that ridiculous quantities of terrestrial ores will become available.
What is that rule of thumb? Double the price and the resource increases by an order of magnitude?
We can double the price three or four times.

And six thousand years from now we will likely have proton-boron fusion or something absurd like that.
Remember that seawater uranium is being recharged at something like 32,000t/yr and it could be expected that the uranium in seawater is in equilibrium with the seabed - therefore uranium will dissolve into the ocean if its concentration decreases.

EDIT:

Also a question on scaling laws - lets say I take the Reference 30-year once through DMSR design.
If I wanted to make a "60 year once through design" would I get a reasonable estimate by simply doubling the volume of the fuel salt inventory and graphite?
That would cut the fluence/yr of the Graphite in half and thus allow graphite life to extend and it would also dilute the fission products to allow the reactor to remain critical?
So the initial fissile load would double but the annual makeup charge would remain the same (as the amount of fissions remains the same in both cases).
I believe this would be conservative as it would not account for the reduced 233Pa losses due to the reduced neutron flux, but I just want to know if this gives a reasonable order of magnitude result.


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PostPosted: Feb 09, 2015 11:18 pm 
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LWR served some purpose. It put nuclear energy in use as one of the options. It can now be opposed but not wished away with Russia, China and India in the ring. It also created the reality of mountainous quantities of used fuel.
DMSR if implemented as looks somewhat likely, will exhibit the reality of MSR. It could go down under the reality of discarded graphite moderator. While the used fuel of LWR can be recycled in the DMSR or the fast reactors, the graphite is forever.
The holy grail of energy is the fast reactors and reprocessing leaving only fission products as waste. Use could be found for a part of it. The fast reactors could be the solid fuelled ones as being pursued by Russia, India and China, or the MSFR.


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PostPosted: Feb 10, 2015 12:18 am 
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jagdish wrote:
...DMSR if implemented as looks somewhat likely, will exhibit the reality of MSR. It could go down under the reality of discarded graphite moderator. While the used fuel of LWR can be recycled in the DMSR or the fast reactors, the graphite is forever.
The holy grail of energy is the fast reactors and reprocessing leaving only fission products as waste. Use could be found for a part of it. The fast reactors could be the solid fuelled ones as being pursued by Russia, India and China, or the MSFR.


Right on Jagdish!

Now pretend that you are a utility CEO & ask yourself if you would rather buy breeders that would let you simply discard a few liters of cheap salt per GWe/day or ones that would force you to, first, pay for fabulously expensive solid fuel assemblies & then shuffle, remove, dissolve, reprocess, refabricate, reinstall, etc them many times in order to run your new reactors?

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PostPosted: Feb 10, 2015 4:16 am 
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darryl siemer wrote:
jagdish wrote:
...DMSR if implemented as looks somewhat likely, will exhibit the reality of MSR. It could go down under the reality of discarded graphite moderator. While the used fuel of LWR can be recycled in the DMSR or the fast reactors, the graphite is forever.
The holy grail of energy is the fast reactors and reprocessing leaving only fission products as waste. Use could be found for a part of it. The fast reactors could be the solid fuelled ones as being pursued by Russia, India and China, or the MSFR.


Right on Jagdish!

Now pretend that you are a utility CEO & ask yourself if you would rather buy breeders that would let you simply discard a few liters of cheap salt per GWe/day or ones that would force you to, first, pay for fabulously expensive solid fuel assemblies & then shuffle, remove, dissolve, reprocess, refabricate, reinstall, etc them many times in order to run your new reactors?


The fuel costs less than $1/MWh to fabricate, judging by recent contracts.


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PostPosted: Feb 10, 2015 11:53 am 
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Cyril R wrote:
The fuel costs less than $1/MWh to fabricate, judging by recent contracts.


LMFBR-type fuel? In any case, the issue isn't just initial fuel fabrication cost - it's the cost of having to go through the entire solid fuel reprocessing/refabrication etc. loop multiple times to achieve IFR-like performance. The ref. noted in footnote 26 of my paper points out that the pyroprocessing-type "management" of EBR II's fuel just once would cost $88,000/kg.

Over the years there's been several LMFBRs made/operated but, as far as I know none of them have been run in a way that rendered them genuinely sustainable. Dittmar's review/critique of Nuclear energy including Gen IV "The Future of Nuclear Energy: Facts and Fiction ( http://europe.theoildrum.com/node/5929#Ref_20 ) has lots of good refs & questions:- Part IV deals with : Energy from Breeder Reactors and from Fusion?"

Here's a quote:
"In summary, the IAEA data base for fast reactors does not present any evidence that a positive breeding gain has been obtained with past and present FBR reactors. On the contrary, the presented data indicate at best that a more efficient nuclear fuel use than in standard PWR reactors can be achieved during normal running conditions. However, once the short and inefficient running times of FBR's, in comparison with large scale PWR's, are taken into account, even this better fuel use has not been demonstrated. In fact, the required initial fuel load in FBR's contains at least twice as much natural uranium equivalent and with a fissile material enrichment that is roughly 5 times larger than that in a comparable PWR. A fair comparison of the fuel efficiency should include the efficiency to recycle fissile material from used nuclear fuel in both reactor types."

Here's another:
"... those in favor of developing a thorium breeder re­actor should start taking a strong position against the current nuclear energy establishment. They should point out that (i) the current use of nuclear energy has no perspective because of the limited amount of available uranium resources, (ii) the Th232 breeder cycle is by orders of magnitude better than the ideas about U238 breeder cycles with FBR's, and (iii) nuclear fusion is at least 50-100 years away."

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Last edited by darryl siemer on Feb 10, 2015 12:52 pm, edited 1 time in total.

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PostPosted: Feb 10, 2015 12:28 pm 
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The $1/MWh is for BWR fuel. Based on long term contract of a medium sized BWR.

Reprocessing solid fuel, especially non metal fuel, is more expensive than that, but still not prohibitive.

uranium-is-going-to-run-out is silly. Totally 1965 you know, when a bunch of silly journalist confused resource-production ratio with total resource availability. That mistake has never been corrected, oddly, even though it is a total lie and profoundly silly. The stuff is abundant. If nothing else, the ocean could power 10x today's fleet of uranium guzzlers forever.


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PostPosted: Feb 10, 2015 3:11 pm 
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Cyril R wrote:
...uranium-is-going-to-run-out is silly. Totally 1965 you know, when a bunch of silly journalist confused resource-production ratio with total resource availability. That mistake has never been corrected, oddly, even though it is a total lie and profoundly silly. The stuff is abundant. If nothing else, the ocean could power 10x today's fleet of uranium guzzlers forever.


This will be my last response to critics of my decision to dredge up the uranium availability issue.


1. My background in both fuel reprocessing & radwaste management has made me appreciate what it costs to separate small amounts of U & Pu plus some key fission products from huge amounts of dross. While doing so can always be "demonstrated", it's inevitably terribly expensive, "dirty", & therefore shouldn't be done if you don't have to do it. That's why MOX doesn't make much sense & Hanford still hasn't solved its tank waste management problem. This conclusion would apply to trying to implement a nuclear renaissance with 2.7 parts-per-billion U water containing 30,000 ppm misc. salts plus suspended mud particles & tiny lifeforms (seawater).

2. The U availability figures I've used to bolster my case for switching to thorium (both "total identified at reasonable cost" & "undiscovered") were taken from the U industry's 2012 Redbook - they're not guesses or hopeful extrapolations.

3. Future uranium cost is unknown & would likely radically escalate from the current figure if the world were to try to implement a nuclear renaissance with converter-type reactors. The early 70's "U Cartel" scandal demonstrates how that business behaves when demand suddenly rises. More recently, in the heady run up to the Western World's most recent faith-based (i.e., in the "Greed is Good" principle) economic crash, the price of uranium spiked again, see the plot of U prices during the last 3 decades years at http://www.world-nuclear.org/WNA/Public ... naissance/

Do you have any helpful suggestions about how to go about making a "maintainable" MSFR?





.

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PostPosted: Feb 10, 2015 4:12 pm 
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1. The Seawater separation system has one major advantage over the other processes you mention - the source material is not toxic in any significant way.
It can be expected that the price will drop below current break-even estimates and will eventually reach something like $200-300/kg, which is easily low enough to ensure uranium prices never get high enough to prevent the DMSR from being economically viable. Indeed even the current price projections of $660/kg are sufficiently low to put a cap on DMSR electricity of less a cent more than it would cost with today's uranium prices.
Nuclear reprocessing experience is a very very long way from that process - this is a lot more like attempts to use metal organic frameworks to bring about remediation of contaminated materials (contaminated with low concentrations of various nasties)
Also don't almost all breeders have to do way more fuel handling than a DMSR does? The ORNL basis design has you touching one salt load every 30 years, and you only need the uranium, you can dump the rest straight to vitrification. (I favour a larger, 60 year life core to reduce plutonium in the vitrified material).

2. Reasonable cost will be reasonable cost for an LWR/PHWR, this means little when your uranium utilisation has dropped by an order of magnitude.

3. It doesn't really matter if the price of uranium trebles or quadruples even, this will simply lead to vertical integration of uranium production and reactor operation, probably based on seawater uranium. The cost of the uranium in a DMSR bill-of-materials is so low as to be nearly an irrelevance. And if it rises sufficiently high any cartel will simply collapse as the vertical integration I mentioned occurs. Low grade uranium deposits that are still concentrated enough to make a DMSR useful are too widely spread for a cartel to survive in the face of states simply developing resources to break it's hold on the market. Even the UK has deposits that are marginal at current prices (Orkneys and similar) - at $500/kg they are all viable, and still only add ~$1/MWh to the price of the produced electricity (at 21GWd(e)/tU).

4. You are going to have huge problems sourcing anywhere near the amount of fissiles required to start one of these reactors without adopting something that is essentially a DMSR. Breeders always get killed by the doubling time.


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