The fast-reactor system with pyroprocessing is remarkably versatile. It could be a net consumer or net producer of plutonium, or it could be run in a break-even mode. Operated as a net producer, the system could provide start-up materials for other fast-reactor power plants. As a net consumer, it could use up excess plutonium and weapons materials. If a break-even mode were chosen, the only additional fuel a nuclear plant would need would be a periodic infusion of depleted uranium (uranium from which most of the fissile uranium 235 has been removed) to replace the heavy-metal atoms that have undergone fission.
Business studies have indicated that this technology could be economically competitive with existing nuclear power technologies. Certainly pyrometallurgical recycling will be dramatically less expensive than PUREX reprocessing, but in truth, the economic viability of the system cannot be known until it is demonstrated. The overall economics of any energy source depend not only on direct costs but also on what economists call “externalities,” the hard-to-quantify costs of outside effects resulting from using the technology. When we burn coal or oil to make electricity, for example, our society accepts the detrimental health effects and the environmental costs they entail. Thus, external costs in effect subsidize fossil-fuel power generation, either directly or via indirect effects on the society as a whole. Even though they are difficult to reckon, economic comparisons that do not take externalities into account are unrealistic and misleading.
Coupling Reactor Types
If advanced fast reactors come into use, they will at first burn spent thermal-reactor fuel that has been recycled using pyroprocessing. That waste, which is now “temporarily” stored on site, would be transported to plants that could process it into three output streams. The first, highly radioactive, stream would contain most of the fission products, along with unavoidable traces of transuranic elements. It would be transformed into a physically stable form—perhaps a glasslike substance— and then shipped to Yucca Mountain or some other permanent disposal site.
The second stream would capture virtually all the transuranics, together with some uranium and fission products. It would be converted to a metallic fast-reactor fuel and then transferred to ALMR-type reactors.
The third stream, amounting to about 92 percent of the spent thermalreactor fuel, would contain the bulk of the uranium, now in a depleted state. It could be stashed away for future use as fast-reactor fuel.
Such a scenario cannot be realized overnight, of course. If we were to begin today, the first of the fast reactors might come online in about 15 years. Notably, that schedule is reasonably compatible with the planned timetable for shipment of spent thermal-reactor fuel to Yucca Mountain. It could instead be sent for recycling into fast-reactor fuel.
As today’s thermal reactors reach the end of their lifetimes, they could be replaced by fast reactors. Should that occur, there would be no need to mine any more uranium ore for centuries and no further requirement, ever, for uranium enrichment. For the very long term, recycling the fuel of fast reactors would be so efficient that currently available uranium supplies could last indefinitely.
Both India and China have recently announced that they plan to extend their energy resources by deploying fast reactors. We understand that their first fast reactors will use oxide or carbide fuel rather than metal—a less than optimum path, chosen presumably because the PUREX reprocessing technology is mature, whereas pyroprocessing has not yet been commercially demonstrated.
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7 Comments
Add CommentPerhaps the "smartest" thing that we could do is to stop calling it nuclear "waste".
Reply | Report Abuse | Link to thisAs this article makes clear, the byproducts of nuclear fission are potentially valuable in and of themselves. Instead of elaborate schemes to bury this stuff for thousands of years, we should "mine" its possible uses.
Treat it like garbage and it's a problem - treat it like gold and it won't end up dumped in a stream.
In retrospect it’s too bad our environmental friends gave the “man made global warming” treatment to nuclear power in the 60’s by using superstition and scare tactics to intimidate people with bad information. I’m sure they thought they we’re justified in their views at the time but now we realize the extreme damage of their ignorance. If we had gone nuclear 40 years ago we could have averted spewing gigatons of tons of carbon into our atmosphere and averted the “tipping” point we find our climate in today. Not to mention we could have spent the last 40 years making nuclear power safer and more efficient and the United States less reliant on fossil fuels. This is just one example of how environmentalist can do incalculable damage to our nation and to our climate when they start screaming before they know what they’re talking about.
Reply | Report Abuse | Link to thisNuclear power's problems were and are primarily financial; the plants are simply not cost effective relative to the alternatives. We can build a 750 mW(e) combined-cycle plant for around $750 million or a 1200 mW(e) nuclear unit for 6 or 7 billion dollars.
Reply | Report Abuse | Link to thisThe fast reactor concept, while technically intriguing, is likely to be even more of an economic problem.
http://en.wikipedia.org/wiki/Generation_IV_reactors
Reply | Report Abuse | Link to thisLiquid Metal Fast Reactors (LMFRs), of which the authors are touting, have a terrible operational record. The USA has built 3, of which 2 have had unintentional core melts. In 1996, the Japanese Monju LMFR leaked 5 tons of its highly radioactive liquid sodium coolant which caught fire, and has been shut down for 10 years. The French Super Phoenix had power oscillations which caused them to shut it down too.
Reply | Report Abuse | Link to thisIn 1972, President Nixon fired ORNL's Director, Dr. Weinberg for advocating the meltdown proof Molten Salt Reactor (MSR) because the GOP had selected the LMFRs instead. MSRs can and have operated on all 3 fissiles (U235, U233, & Pu239) and can best utilize thorium. Why not restart this Generation IV reactor instead?
REFs: http://en.wikipedia.org/wiki/Alvin_M._Weinberg
http://en.wikipedia.org/wiki/Molten_salt_reactor
http://en.wikipedia.org/wiki/Generation_IV_reactors
The leak at Monju was not radioactive.
Reply | Report Abuse | Link to thisChap, you are correct, the sodium leak was not radioactive as it was in Monju's Secondary Coolant circuit. I apologize for the mistake I posted above.
Reply | Report Abuse | Link to thisHowever, had the leak been in the Primary Coolant circuit while the reactor was operating, the leak would have been highly radioactive due to the 15 hr halflife of Na-24, which emits energetic 1.4 MeV & 2.8 MeV gamma rays. Large amounts of Na-24 are created by neutron absorption within the LMFR's core.
Furthermore, sodium fires, even without complicating radioactivity, are difficult to contain because hot sodium reacts with air, water, carbon dioxide (CO2), and even concrete! It's ash is sodium oxide (Na2O), which will combine with any water to make highly caustic sodium hydroxide (NaOH), which is lye, or Draino (drain cleaner)!
Molten Salt Reactors (MSRs), coolant and fuel is melted LiF-BeF2 into which sufficient fissile (U-235, U233, &/or Pu-239) are dissolved. Molten salts do not react with air or water and freeze below 500 C, thereby encapsulating the radioactive materials (e.g., Fission Products). Furthermore, they do not require pressure vessels as they operate at atmospheric pressure. The USA has built and successfully operated 2 MSRs at Oak Ridge National Laboratory: ARE (1954) & the MSRE (1960s).
REFs:
http://www.gen-4.org/Technology/systems/msr.htm
http://nuclear.inl.gov/deliverables/docs/msr_deliverable_doe-global_07_paper.pdf
http://www.ornl.gov/~webworks/cppr/y2001/pres/119930.pdf