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What is spent fuel and what does ANSTO do with it?

Fuel elements that have been used to their limit are removed from the reactor and termed 'spent fuel'.  This is not waste, as it still holds material that can be extracted and used. 

The old ANSTO reactor (HIFAR), which was shutdown in January 2007, was powered by 25 fuel elements, with the reactor core being about the size of a washing machine.  Every four weeks, three to four spent fuel elements were removed from the reactor and stored in an adjacent storage block.  The heat and radioactivity decreased rapidly.  After about a year, the fuel was transferred to another pond, where the parts that did not contain uranium were removed.  A similar process will happen in the new OPAL reactor, with 16 fuel assemblies maintained in a similar way.  Fuel is removed when it has decreased its potential to maintain the fission process effectively (usually to around one quarter of the original element). 

The section containing the uranium is stored under water for another three to four years for further decay.  All fuel storage areas are subject to inspection by the IAEA (the International Atomic Energy Agency) and ASNO (the Australian Safeguards and Non-Proliferation Office) and regulated by ARPANSA.

In the mid-1990s, the Australian Government decided to send spent fuel overseas for reprocessing or storage.  Most of the HIFAR spent fuel has left Australia, and as more is used it too will be transported overseas. 

The intermediate-level waste resulting from the overseas reprocessing of HIFAR spent fuel is due to return to Australia by around 2015.  The spent fuel sent to the United States - both the remaining HIFAR fuel and the OPAL fuel from the first ten years of operation  - will be stored, with no waste returned to Australia.  Spent fuel from later years of operation of OPAL is likely to be reprocessed in France, with the return of a small quantity of resulting intermediate-level waste to Australia.