http://en.wikipedia.org/wiki/Integral_Fast_Reactor

I’m actually coming around to believing this type of nuke plant might be worth pursuing. If I can believe the many accounts about it, the sodium cooled integral fast reactor could be the best bet to deal with spent fuel and will produce CO2-free energy while doing it.

I was a little apprehensive about the liquid sodium coolant thing but they practically won’t work w/o it. The history of sodium cooled reactors is a checkered one. Numerous lengthy plant closures - permanently in some cases - have resulted from water somehow mixing with sodium in the heat exchanger.

But the more I look at that, the more manageable the sodium thing seems. One possible solution is to use CO2 or even helium at high pressure as the expansive medium in the turbine. Just take water out of the picture.

A laudatory article about IFRs appeared in the Huffington Post:

http://www.huffingtonpost.com/steve-kirsch/climate-bill-ignores-our_b_221796.html

I wouldn't be so inclined to favor these things if not for the terminally intractable problem with nuke waste disposal. We can’t promise to safely store the stuff for 50,000 years. IFRs reportedly will ‘burn’ spent fuel such that the resultant waste is much reduced in volume, and rendering it much safer, with radioactive half lives in the hundreds of years instead of the hundreds of thousands of years.

It sounds great but I don’t want to naively fall for self-promoting hype.

Amory Lovins wrote this piece disputing born again nuke booster Stewart Brands proposals:

Stewart Brand’s nuclear enthusiasm falls short on facts and logic 

He didn't mention the issue of IFRs processing existing spent fuel into safer components.

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"I was a little apprehensive about the liquid sodium coolant thing but they practically won’t work w/o it."

I dont know why people get up tight about sodium. If you have a turbo diesel MB (or some other engines like jags), you have valves cooled with the stuff !! If the design is right, its not a problem.

I'll bite =)

Given that you need 2 loops of heat exchange medium, and that I've never seen an industrial process that routinely pumps liquid metal (I'm sure they exist...) I can understand why the research/engineering minds aren't jumping on this.
I would welcome a proliferation of 300MWe steam turbines - much easier to handle than 800MW steam turbines. (cheaper when they break too =)

I get the impression that the difficulty (environmental permits, building permits, state licenses, local bribes =)....) with building a new generation site is equal whether you are making 300MWe or 3000MWe (ESPECIALLY if they are nuclear...)
Modular construction lets you skirt some of those permits (maybe?), but it still isnt easy. Now you have to prove that 3 little reactors are easier/cheaper to operate/maintain than 1 big one- if you can do that, THEN the big players might give you money to build some...

i agree that it looks like a good idea, just trying to highlight why I think these arent going to catch on quickly

-John

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Wave soldering machines have been around as long as printed circuit boards. Just don't turn on the pump before the solder is melted.
I have no idea how the sodium is initially melted in a reactor, but it's done.
We can vitrify nuke waste and send it out to the sun in containers that will withstand re-entry.

Such containers exist? That would have to be hugely expensive.

I don't think IFRs will catch on either, just yet anyway. A few more decades of rising prices and dicey supply of other forms might raise interest. I'm not inclined to favor nuclear power but I agree with Stewart Brand that coal is just so bleedin' bad that we have to consider lesser evils.

Supposedly the physics of the setups for IFRs and pebble bed reactors don't allow runaway reactions, meltdowns, etc, in the event of loss of coolant.

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I believe such containers would be a bargain compared to the cost of storing and securing nuke waste. A Soviet reactor survived re-entry years ago.

Actually, back in the 80's before they closed the site down, there was a helium cooled prototype test reactor out at Hanford in WA state. Difference was , from what I understand, was that helium was the coolant in the PRIMARY loop - what was actually circulated thru the reactor - and they still used water on the secondary side to run steam turbines. Back in '88, an old Navy Nuke friend was living in Benson City and had gotten a job there with a waste disposal company, gave me something of a mini-tour and described some of what was going on at the site, including the helium cooled test unit. One of the problems he mentioned was that they were having a deuce of a time designing pump and valve seals that wouldn't continually leak a small amount of helium.

If they could finally figure out a way to make it work, a Colliding Beam Reactor (CBR) using aneutronic fission (fission without neutrons) would be almost ideal from the standpoint of essentially no radiation or spent fuel/waste/radioactive byproducts. The idea is to cross over multiple particle streams of lithium, such that at the point of intersection the particle density is so high that particle collisions and fission of the lithium nuclei occur. Result is charged particles that can be converted to electricity, and little if any radiation.

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It's sorta fun to think about - generally I'm opposed to nuclear power but the science is interesting. It seems that most all the plants in the world are of a flawed design, compared to some of what's been discovered since.

What worries me though, is that boosters of the stuff get so invested in the idea working, they overlook simple things like metal fatigue, and problems with seals and pumps, like you mention.

On the sodium cooled IFR, holy crap, liquid sodium at around 800 F? That stuff is seriously reactive at room temp. I gather that a large percentage of sodium cooled reactors have had serious grief with sodium fires.

None of this stuff is ever going to be a problem . . . until it is.

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I liked that idea when I first heard it years ago but I'm wondering what the total weight of existing spent fuel, and the additional weight of the vessel would be. Would it require 10s or 100s of launches?

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I dunno how much waste is lurking about, or how much can be packed into close quarters in a container. A re-entry proof container is no big deal. And if one considers the process of re-entry, it's basically the result of a successfull launch.
To me, storing and securing nuke waste is a monumental, and so far a monumentally expensive, task.
Power generated by burning fossil fuels is an hourly evironmental disaster.

We have very anti nuclear sentiments in this country because of green nuts, ignorant politicians, and NIMBYs.

Anything related to radiation/nuclear/uranium/ sends warning bells off in these fools heads.

What they fail to realize is coal, fossil fuels, and other conventional energy sources release incredible amounts of pollution into the air. Green energy sources aren't ready to be able to run our energy grid at the same consistency that nuclear, coal,etc will run it. When the wind and sun disappear we're cold and powerless.

All of the nuclear reactors we have in this country are designed to process weapons grade fuel. Highly radioactive waste can still be used as fuel!

Nuclear is our answer to solve our energy solutions now. Unfortunately, industry interests and pure ignorance leave us with solutions that are far less safe.

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I've long been a nuclear power skeptic, but I'm starting to reconsider. Best I can tell, the fail safe physics of IFRs, pebble beds, and thorium molten salt cooled reactors are vastly superior to what's in place now.

I read though, that current plants are enormously profitable as they've been pretty much paid for. The owners/operators of such plants are going to want to keep them running come hell or high water (look, me make funny).

The cost of scuttling those and building IFRs at seismically stable sites would be huge. OTOH, if the hype is accurate, IFRs not only virtually eliminate existing waste, they will also provide around 100 years worth of electricity w/o any new U mining. Does sound too good to be true in some ways.

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I hate to take your quote out of context, but it is inconsistent with what I've read up until now - can you cite a page/source that tells me more?

-John

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The wiki article in the OP explains that somewhat. It's a different process going on in an IFR. The sodium coolant allows the neutron speed to be faster than does a water coolant - apparently neutrons collide differently with the hydrogen in water than with sodium, and conventional designs are set up with that in mind. As a result (if I get this right) the fuel is 'burnt' more thoroughly.

The sodium coolant thing seems like a huge problem at first glance but there are advantages with it also.

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Of course! A lot of people are unaware that our current "nuclear waste" problem was the cause of our bomb making activities during the cold war.

www.fas.org/sgp/crs/nuke/RS21988.pdf

http://www.ehso.com/NuclearWeaponsWaste.htm

http://www.forbes.com/2009/07/21/nuclear-waste-energy-technology-breakthroughs-nuclear.html

The last link deals with my claim that if it is still radioactive it can be reused as fuel. Like all processes however it isn't perfect.

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