The “relatively small” quantities of remaining overseas origin nuclear fuel in the UK should be managed by means of interim storage pending disposal, with the Nuclear Decommissioning Authority (NDA) “taking ownership” of the fuel where necessary, a government consultation document says.
The document, ‘Consultation on the management of overseas origin nuclear fuels held in the UK’, says the interim storage option would be used where the option of reprocessing is no longer available, practical or economic to deploy.
To ensure that the UK does not become a net importer of nuclear waste as a consequence of the interim storage policy, the NDA is proposing to use a policy of “virtual reprocessing”. This would mean that a radiologically equivalent amount of waste will be allocated and then returned to the customer as if the fuel has been reprocessed. Additionally, an equivalent amount of nuclear material will be allocated to the customer and stored pending agreement on their future management.
This approach would permit the NDA to close out the remaining overseas contracts, providing more certainty over the future plans for the Thermal Oxide Reprocessing Plant (Thorp) at Sellafield and for the future decommissioning of the Dounreay site, the document says.
The overseas origin nuclear fuel was sent to the UK for reprocessing at Thorp, or for processing at Dounreay, under commercial contracts, with either British Nuclear Fuels Limited (BNFL), which has been broken up, or the United Kingdom Atomic Energy Authority (UKAEA).
All of the original contracts date back to the 1970s and 1980s, when the provision of these spent fuel services to overseas customers was a profitable export market for the UK and received strong government backing.
But since these contracts were signed, the international nuclear landscape has “changed considerably” and the required facilities have either closed or, without significant infrastructure investment, will soon reach the end of their useable life.
Thorp has completed nearly 95 percent of its overseas order book with only about 300 tonnes of overseas origin fuel remaining to be managed before the facility is expected to close in late 2018.
The NDA said it expects to be able to reprocess most of the remaining 300 tonnes of overseas origin nuclear fuel as originally intended. However, a residual 30 tonnes of this fuel is made up of small amounts of prototype fuels, experimental fuels, mixed-oxide fuels and some materials left over from research programmes.
This would be challenging to deal with through reprocessing before the planned closure of Thorp, the document says.
The 30 tonnes of residual fuel also includes roughly two tonnes of overseas origin fuel held at Dounreay, which will be transferred to Sellafield for future management.