Nuclear Power and the Clean Energy Transition
Shrinking nuclear waste and increasing efficiency for a sustainable energy future By Jeffrey Donovan
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ast neutron reactors can increase efficiency of nuclear energy and shrink the environmental footprint of radioactive waste. Several countries are looking to these innovative reactors to help ensure a sustainable energy future. Fast reactors use neutrons that are not slowed down by a moderator, such as water, to sustain the fission chain reaction. While only a fraction of natural uranium is used as fuel in existing thermal reactors, fast reactors can use almost all uranium contained in the fuel to extract up to 70 times more energy, reducing the need for new uranium resources. Fast reactors also operate in what is known as a closed nuclear fuel cycle. A closed fuel cycle is when spent fuel — nuclear fuel after it has been irradiated — is recycled and reused. Such an energy system could potentially be sustainable for thousands of years. This contrasts with an open fuel cycle, where nuclear fuel is used once and the spent fuel is declared as waste for eventual underground disposal in geological repositories. Fast reactors can also produce or ‘breed’ more fuel than they consume and burn off some of the waste contained in spent fuel, such as minor actinides, which thermal reactors cannot do efficiently. Burning them off significantly reduces the volume, toxicity and lifespan of the longest-living radioactive waste.
14 | IAEA Bulletin, September 2020
“The environmental footprint of an energy source, such as its waste, is a big question for many countries as they look for sustainable ways to deliver clean energy,” said Amparo Espartero Gonzalez, Technical Lead for the Nuclear Fuel Cycle at the IAEA. “The ability to shrink that footprint, while also getting more out of nuclear fuel is a big part of the growing appeal of fast reactors for many countries and what is driving their technological development.”
Making a comeback Fast reactors were among the first technologies deployed during the early days of nuclear power, when uranium resources were perceived to be scarce. But as technical and materials challenges hampered development, and new uranium deposits were identified, light water reactors (LWRs) eventually became the industry standard. Five fast reactors are now in operation: two operating reactors (BN-600 and BN-800) and one test reactor (BOR-60) in Russia, India’s Fast Breeder Test Reactor (FBTR) and the China Experimental Fast Reactor (CEFR). New concepts, technologies and advances in materials research, combined with a long-term vision of nuclear power as part of sustainable energy, are now reviving the fast reactor option. These advances generally feature innovative upgrades, such
