Nuclear powerRecycling nuclear fuel offers plentiful, clean energy
Currently, only about 5 percent of the uranium in a fuel rod gets fissioned for energy in a nuclear reactor; after that, the spent rods, still containing about 95 percent uranium fuel, are taken out of the reactor and put into permanent storage; researchers say that recycling used nuclear fuel could produce hundreds of years of energy from just the uranium that has already been mined, all of it carbon-free
Assemblies cooling at a French nuclear recycling facility // Source: jimdo.com
Imagine what would people think if we mined one ton of coal, burned 5 percent of it for energy, and then threw away the rest.
This is what happens today with uranium for nuclear fuel. Currently, only about 5 percent of the uranium in a fuel rod gets fissioned for energy; after that, the rods are taken out of the reactor and put into permanent storage.
There is a way, however, to use almost all of the uranium in a fuel rod. Recycling used nuclear fuel could produce hundreds of years of energy from just the uranium that has already been mined, all of it carbon-free. Problems with older technology caused recycling used nuclear fuel in the United States to be halted, but an Argonne National Laboratory release reports that new techniques developed by scientists at the U.S. Department of Energy’s (DOE) Argonne Lab address many of those issues.
One of the reasons why so little uranium is used is that almost every commercial reactor today is a type called a light-water reactor, or LWR. LWRs are good at many things, but they are not designed to wring every last watt of energy out of fuel.
LWRs are not the only type of reactor. Another class, called fast reactors, have the ability to “recycle” used fuel to get much more energy out of it.
The main difference between the types of reactors is what cools the core. LWRs use ordinary water. Fast reactors use a different coolant, such as sodium or lead. This coolant does not slow the neutrons as much, and consequently, the reactor can fission a host of different isotopes. This means that fast reactors can get electricity out of many kinds of fuel, including all of that leftover used fuel from LWRs (LWRs can burn recycled fuel too, with some modification, but they are not as good at it).
If fast reactors are built, it would be entirely possible to take all of the used fuel that has been generated over the past sixty years, currently stored at reactor sites, and feed it back into fast reactors. Some of it would still need to be permanently stored, but far less; recycling all of the uranium and other actinides would reduce the volume of waste that needs to be store permanently by 80 percent.
To get used fuel ready to put back into a reactor, however, it needs some processing. This has been done
