I catch the London Underground (the Tube) to and from work each day; about 10 miles each way. Takes me about 25 mins each way, thats a decent amount of reading time. I easily get through a book a week!

Still with the terrar its made it less enjoyable

Since when? I suppose in the long run everything is unsustainable, the sun will die, the universe will continue expanding and die... But lets keep this to the next few thousand years for the sake of argument.
http://en.wikipedia.org/wiki/Breeder_reactor

Here's a discussion of why nukes are unsustainable:

http://www.greatchange.org/bb-thermoche ... y_rev.html

This is laughable given that we've illustrated by the numbers how unsustainable nukes are to Montequest. If we ran all of civilization at ten times our current power consumption there is still enough nuclear fuel for hundreds of millions of years; Monte's response was 'well, we cant afford them then. We have no money.' or some such ignorant nonsense.

I guess everything is eventually unsustainable as you approach the heat death of the universe and timelike infinity. I assume he just meant he doesn't like them.

Did you read that? Their discussion of breeder reactors involves no discussion at all! All they state is that fast breeding programs have turned out to be failures... Contrary to what the wikipedia article states. There haven't been many applications because we don't need them. We have plenty of fuel given the number of reactors we have, if the number changes I garauntee we'll see more emphasis on breeders.

In fact, it seems as if they haven't thought much about the CO2 issue at all. It's glaringly obvious that the more electrical energy we produce, the more we'll use for construction of the same power plants (especially if we factor in the decline of oil/NG). Naturally the first few plants will require substantial production of CO2 via ff's. But as we turn to electricity (aka hydrogen) more, we'll see less ff powered equipment and the amount of CO2 released in building these will decline monotonically.

Here's something else to chew on from another Phd.
http://www.nationalcenter.org/NPA378.html
etc...
http://www.nuc.berkeley.edu/designs/ifr/
http://www.anlw.anl.gov/anlw_history/reactors/ifr.html
If the article is correct, then IFR's are the safest, cheapest example of nuclear power to date.

Ludi is posting a link that primarily cites the Storm van bullshit report that was thouroughly dissected as utter garbage a month ago... the one that inflates decomissioning costs, selectively uses the most energy intensitve mining techniques from half a century ago, and most telling, only assumes gasseous diffusion enrichment for light water reactors, something that no one does anymore because its so energy intensive.

And yes, breeder reactors are discounted with one or two sentances as being unviable in spite of decades of experience with them.

I've been over this before with Ludi and shown why nuclear fuel and nuclear power wont run out in any timeframe worth discussing. Uranium and thorium is everywhere.



Ah, lets have a sense of perspective here. The IFR was a testbed reactor for doing molten salt reprocessing of metallic fuels. The IFR certainly isn't cheap, less safe than a LWR and presents a significant proliferation risk compared with other reactors, even other breeders. The first problem the IFR faces is the sodium cooling system is a huge mass of chemical potential locked up just waiting to start sodium fires should there be any loss of coolant incident.

Second its a fast neutron reactor that primarily runs on Pu-239, so the delayed neutron component of the reactor (the beta) is very low... meaning the reactivity flux doesn't occur over minutes like in thermal and epithermal reactors but seconds to microseconds. A giant flux is a huge neutron flash incidient waiting to happen and possibly cause corresponding fuel melt.

Interesting work was done at ANL but its a mistake to look at the reactor there as any sort of next generation design. Indeed, all liquid metal breeder reactors are best for doing one thing: make weapons grade Pu239, with some incidental power production at over twice the price of a LWR.

Why do you suppose the superpheonix reactor was discontinued? HMM?

Public opinion. I kinda wonder what would happen to the automobile if the safety requirements were as rigorous as nuclear power?
http://en.wikipedia.org/wiki/Superph%C3%A9nix

Because its a costly reactor to maintain and France has enough Pu-239 to satisfy its nuclear weapons requirements. If you want to make a breeder reactor for producing electric power, Superfenix would not be it.

In fact, given how extraordinarily cheap uranium is today and likely to be for the next century, I'm not sure any breeder reactor is going to be worth any extra costs. If breeders come out competitive it will be because of benifits besides fuel efficiency; Smaller waste streams perhaps.

But to assume that breeder reactors are unworkable in principle is ignoring the decades of experience with them.

Since I don't know much about nuclear power, I'll post links to various parts of one of the articles I posted, with the hope that you'll be kind enough to provide insight.


It would seem to me that the reactor producing the most energy from some given amount of material is the cheapest in terms of the vague EROEI.













Don't the "inherent safety features" override other problems like this, in terms of the overall risk?





First off, can we moniter and head off a huge flux? And if it does occur, would the "fuel melt" result in something similar to this?





Now is this assuming the current stable price of fissable material? Or during the long run (lets say 10k years), are IFR's still more expensive than LWR's even though they make much better use of the energy potential of fissable materials and result in material that doesn't need to be stored as long?

I consider nukes unsustainable because they produce long lasting toxic waste. It's totally irrelevant to me whether we have infinite years of uranium and thorium supplies, that does not in itself make the technology sustainable.

There's just no way we can continue this way of life into the future anymore. The massive energy consumption way of life is over, period.

pilferage:


Well, breeder reactors in general sure are going to be more energy efficient than light water reactors. But the world runs on money efficient, which is related only obliquely to energy efficiency.

Of breeder reactors, sodium cooled metal fueld reactors are decidedly an inferior choice except for rapidly building up weapons material. For this purpose, IFR like facilities would be ideal save for the reprocessing regime.



This argument is misleading. Spent fuel doesnt just become useless after its finished in a light water reactor. You can chemically extract all the neutron poisons and fission products and burn the fertile and fissile fuel it in a variety of reactors. And if we only used the once through fuel cycle with our global power requirements, we might only have tens of thousands of years of fuel rather than hundreds of millions. It really isn't worth talking about conservation alone when discussing breeders because of fuel avaliability. Theres just too much of it.



This statement is misleading also. ALMR's might have some inherent saftey features that arent present in LWR's currently in use, but there are significant risks in fast neutron reactors that this little faq ignores entirely: very high prompt neutron ratios, positive void coefficients, sodium fires, and other issues are among the risks just not present in LWR's (or superior breeders such as molten salt breeder reactors)



Then they'd be able to do it much faster than if they had a LWR of the same power output. Liquid metal cooled reactors were designed for this sort of thing in mind.


One of the real reasons that weapons designers prefer 94%+ Pu239 in the isotopic mix is because of the lack of spontaneous fissions. It makes it easy and safe to handle and very predictable so you can make very calculated designs ideal for fusion triggers.

But spontaneous fissions from isotopically dirty reactor grade Pu just means that a country/organization running on the cheap doesnt have to put together a neutron trigger.



Uh, not true. Britain did, harvested from magnox reactors. North Korea claimed to.



Remind me what inherent safety features there are besides a higher than average negative temperature coefficient. There are reactors with inherant saftey features that prevent meltdowns and other accidents, but they aren't the IFR design.



Yes we can monitor this and mitigate it, in light water reactors. With fast reactors life just sucks... the prompt neutron ratio is so high that you might only have microseconds to scram the reactor rather than minutes. Now unless you engineer your plant to turn into a bomb, this isn't the end of the world, but a giant neutron flash criticality excursion is a bit dangerous and can damage the reactor.

And yes, this can cause the fuel to melt. The heat has to go somewhere.



Given that you can run LWR's on MOX fuel and how insensitive nuclear power is to fuel price, LWR's will probably still outperform IFR in 10k years, but that speculation holds technology standing still and pretends other reactors dont exist. IFR sucks not just because its a bad design compared to LWRs in the economics, saftey, and proliferation departments, but also because it compares poorly to other breeder reactor designs... certainly the molten-salt breeder reactor is far superior, as is the Pb-Bi metal cooled fast reactor, the pebble bed fast reactor, and so on.

I like the idea of doing on site reprocessing, I really do. I just think the MSBR does it much much better. True negative void coefficients, much higher delayed neutron ratio, no fuel fabrication, most strongly negative temperature reactivity, low vapor pressure, high efficiency. I'm not sure if uranium will ever be expensive enough to start building a bunch of them though.

Ludi:
Sorry I mischaracterized your position, but the report you cited was attacking nuclear power on a lack of fuel. I would argue that the waste stream eventually becomes harmless as it decays and that the relative amount of waste compared to any other industry is very small, but I suspect not small enough for your sensibilities.

Oh no. Not this old argument again.

I agree with deza, that at least technically, nuke power plants can provide all the
power we need for centuries, if not much longer. Economically I'm not as certain.

And I also feel the entire nuclear waste problem is waaay overblown. The stuff can
be dealt with. Yucca mountain is a start. Consider that your average coal fired power
plant emits pounds and pounds of radioactive elements everyday through its smokestack,
which fall out as a residue in the environment and end up in the food chain. During the
early days of nuclear testing the US (and other countries) disposed of tons
of nuclear waste by simply putting it in barrels and dumping these in the Ocean.
Sometimes the barrels were shot full of bullet holes to encourage them to sink. Nuke
waste is bad, but most of its reputation is hysteria.

Nuke power is really the only option we have if we want to continue an 'energy dense'
way of life.

That said, I'm with the people in the powerdown camp. It's the only sane solution.
(which is why it will never happen.) Ideally all power would be derived
from wind and solar, and the human population would be much less than it
currently is.

All the above just underscores that we are f*cked at this point.

Good day.

Have you guys heard of this design which has many advantages as has been run by the Germans ( Laboratory ) for 21 years? Pebble Bed