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Nuclear Safeguards Education Portal

Definition of Spent Fuel

Spent nuclear fuel pool
Spent nuclear fuel pool 

The NRC defines spent nuclear fuel (SNF) as fuel elements that have been used at commercial nuclear reactors, but that are no longer capable of economically sustaining a nuclear reaction.  The term spent nuclear fuel is commonly used to refer to any fuel that has been irradiated in a nuclear reactor (usually at a nuclear power plant) and subsequently removed. Spent nuclear fuel is also referred to as "used nuclear fuel."

Spent fuel can have many different elemental and isotopic compositions, as well as different physical/chemical forms.  These differences will depend both on the type of reactor and the amount of time that the fuel was used in the reactor. 

The quantity of spent nuclear fuel is also changing with the growth of nuclear power in many countries.  Currently, U.S. nuclear power plants generate around 2000 metric tons of spent fuel annually, with the entire global industry producing approximately 74000 metric tons over the past 40 years (the size of a football field 8 yards deep if the fuel was stacked).  For a majority of countries, a plan for long-term storage of spent fuel (typically a geologic waste repository) has not been developed.  Consequently, interim storage will continue to be employed as the primary location for spent fuel in the near future.

Interim storage is, by definition, temporary.  Due to the potential valuable and movable nature of the spent fuel in interim storage, safeguards need to be in place at these sites.  Nuclear spent fuel safeguard measures provide assurances that the state is not diverting the material from peaceful purposes.  The following module describes in detail both the different types of spent fuel / storage facilities and the different safeguards systems in place at these sites.

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