Work has begun to tackle one of the the biggest challenges in the UK nuclear clean-up programme: the remote removal of spent nuclear fuel from the Magnox cooling ponds at Sellafield.
On instruction from the Nuclear Decommissioning Authority (NDA), owners of the Sellafield site and architects of the national cleanup programme, British Nuclear Group (BNG) prepared a plan to tackle the ponds, considered by the NDA to be the number one priority for the country in terms of hazard reduction.
The ponds and their associated decanning facility were commissioned in 1958 to process irradiated Magnox natural uranium fuel from the UK fleet of 26 units, Latina in Italy and Tokai Japco in Japan. In 1986 the original facilities were replaced by the Fuel Handling Plant (FHP) but some SNF remained unprocessed in the ponds, where it has stayed ever since for a number of reasons:
- The condition of the SNF made it difficult to handle.
- There was a very high throughput of fuel during the 1980s.
- Some of the stored SNF was inaccessible, some fragmented and some unsuitable for reprocessing.
In total, the ponds are thought to hold 1.3t of plutonium, about 400kg of which is in the form of sludge on the pond floors.
For many years, European Union (EU) inspectors working under the Euratom treaty have complained that accounting for the contents of the ponds is inadequate. Inspectors have said that visibility in the store is too low and radiation levels too high to assess the contents quickly and accurately enough for spot safeguards inspections.
But now a submersible remotely operated vehicle has completed a survey of the ponds, operating in the heavily alkaline and murky waters. The information gleaned allowed BNG engineers to develop a new procedure to retrieve the SNF and place it in containers for further inspection and possible reprocessing in the FHP. The first stage of the process was piloted in early November.
Tony Price, BNG’s director of clean-up said: “The success of this pilot represents a major step towards delivering one of the NDA’s primary objectives, which is to accelerate hazard reduction in Sellafield’s Magnox cooling ponds.”
Successes in key clean-up jobs such as this, which demonstrate the reality of nuclear clean-up and the efficacy of the new national organisational structure, are crucial to creating a positive climate for new nuclear build in the UK.
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