7 Jun (NucNet): The UK Nuclear Decommissioning Authority (NDA) confirmed today that it intends to close the Thermal Oxide Reprocessing Plant (Thorp) at Sellafield towards the end of 2018, upon completion of existing foreign and domestic reprocessing contracts.
In a statement the NDA said a strategic review had confirmed its position that completing the reprocessing contracts at Thorp remains “a viable and cost-effective strategy”. Any remaining advanced gas-cooled reactor fuel, including any future arisings, will be placed into interim storage pending a decision to dispose of it in a geological disposal facility. There are seven AGRs in the UK.
The statement said this will result in the reprocessing contracts being complete by 2018, at which time Thorp would “cease reprocessing activities and enter a post-closure and clean-out phase” before decommissioning.
After the NDA was formed in 2004 it inherited a range of contracts covering reprocessing and storage of oxide spent fuels in the Thorp facilities. The NDA was directed by the Energy Act 2004 to operate Thorp to complete the reprocessing contracts for both overseas and domestic customers.
At the time Thorp was expected to complete the reprocessing contracts by 2010. However, due to operational difficulties both in Thorp and in downstream support plants, this was not possible. Thorp is now expected to complete the reprocessing contracts in 2018.
One of the operational difficulties was a three-year shutdown that began in April 2005 following an incident which led to 83 cubic metres of dissolver liquor (fuel dissolved in nitric acid) leaking from a fractured primary containment pipe into the secondary containment of the feed clarification cell.
The NDA said Sellafield Ltd has undertaken options studies and technical assessments to choose the best interim storage method to manage AGR spent fuel following the closure of Thorp. The company has concluded that wet storage in the Thorp pond is the best available technique from both a technical and environmental standpoint.
AGR spent fuel is currently buffer stored in ponds at Sellafield and will typically spend less than 10 years in storage prior to reprocessing, the NDA said.
The NDA’s position paper on Thorp is online:
www.nda.gov.uk/documents/upload/Oxide-Fuels-Preferred-Options-June-2012.pdf
