Alas, ‘fast breeder’ reactors don’t solve the nuclear waste problem

Ultimately, however, the core problem may be that such new reactors don’t eliminate the nuclear waste that has piled up

Can Fast Reactors Speedily Solve Plutonium Problems? The U.K. is grappling with how to get rid of weapons-grade plutonium and may employ a novel reactor design to consume it , Scientific American, By David Biello | March 21, 2012 The U.K. has nearly 100 metric tons of plutonium—dubbed “the element from hell” by some—that it doesn’t know what to do with.

The island nation does not need the potent powder to construct more nuclear weapons, and spends billions of British pounds to ensure that others don’t steal it for that purpose. The unstable element, which will remain radioactive for millennia, is the residue of ill-fated efforts to recycle used nuclear fuel.

One solution under consideration is to recycle the plutonium yet further—by using it as fuel in a pair of new, so-called “fast” reactors. Such nuclear reactors can actually “consume” plutonium via fission (transforming it into other forms of nuclear waste that are not as useful for weapons). …..

The trouble with fast reactors has largely been related to what’s used to cool them—liquid sodium in the case of GE’s PRISM and many others. The better half of table salt, this element cools a fast reactor nicely and also ensures there is no perpetual chain reaction. And, thanks to a more than 800-degree Celsius boiling point, it can operate at low pressures, unlike conventional reactors. But sodium also reacts explosively with either air or water, necessitating elaborate safety controls in places where it must get close to water in order to create steam to turn a turbine to make electricity, such as steam generators. As a result of numerous fires from leaking systems, operating sodium-cooled fast reactors to date have been shut down more than they have run. “You can’t take the top off and look down in the reactor and correct any problems,” Cochran notes. “You have heroic maintenance issues any time you need to go into the reactor.”…

. The U.K. has a poor record in the past with its own experimental fast reactor designs—the Dounreay Fast Reactor and the Prototype Fast Reactor—including multiple sodium leaks. Dounreay also suffered an explosion at its dumping ground for used sodium coolant that may have contributed to radioactive particles from spent fuel turning up on nearby beaches. The Dounreay and Prototype cleanup and decommissioning continue today, despite both having been shut down for decades….. Ultimately, however, the core problem may be that such new reactors don’t eliminate the nuclear waste that has piled up so much as transmute it. Even with a fleet of such fast reactors, nations would nonetheless require an ultimate home for radioactive waste, one reason that a 2010 M.I.T. report on spent nuclear fuel dismissed such fast reactors. Or, as Cochran puts it: “If you want to get rid of milk, don’t feed it to cows.” http://www.scientificamerican.com/article.cfm?id=fast-reactors-to-consume-plutonium-and-nuclear-waste