In November 2018 we will shear the final batch of commercial fuel in our Thermal Oxide Reprocessing Plant (or, as we like to call it, Thorp). By the end of 2020 our Magnox reprocessing plant will also have finished its nationally important mission.
The end of reprocessing is one of the most important events in Sellafield's history. After the closure of Calder Hall, it's the biggest change to our site in the 21st century.
But what is reprocessing?
Recycling. Nuclear style.
Like all forms of electricity production, nuclear reactors need fuel. The difference with nuclear reactors is that after 5 years the fuel becomes less efficient. So it is taken out and replaced with new fuel. We call the used fuel ‘spent fuel’.
Reprocessing is how we take the spent fuel and break it down into its component parts; uranium, plutonium and waste.
This approach to taking a used product and seeking to get maximum use from its component parts is not unique to the nuclear industry. It isn’t unique to any industry. You do it every time you recycle household waste. Glass and tin is collected, sorted, separated and either stored or recycled into new products and containers.
What is different, of course, is the presence of nuclear materials and so our processes take more time and more layers of protection than your standard recycling facility.
In Sellafield’s earliest days this was done so that the plutonium could be used in atomic weapons as part of the national defence programme.
How do you reprocess nuclear fuel?
Once the nuclear fuel has been taken out of a reactor it is stored in a pond at the reactor site for 200 days to allow the short lived radiation to die away and for the fuel to cool.
It is then transported to Sellafield where it is placed into other storage ponds to cool further.
When ready, the fuel is taken to either our Magnox Reprocessing Plant or Thorp, depending on the type of fuel.
The fuel is then chopped up and dissolved in nitric acid before solvents are added to separate the uranium, plutonium and waste.
The waste is evaporated to dry it out and to reduce its volume before it is mixed with molten glass to form a stable solid block of waste. The nuclear materials are stored in high integrity stores.
Why is reprocessing ending?
Since Thorp went on-line more than a quarter of a century ago, it has brought in more than £9billion to the UK from around the world by reprocessing 9,000 tons of fuel.
But the plant was designed to operate for 25 years and has now reached the end of its design life.
In the 1980s, building and running Thorp made economic sense – because it was built using money paid upfront by customers, it didn’t cost the country anything, yet it has brought £9billion into the UK during its lifetime.
Back then, nuclear operators around the world were legally obliged to reprocess their spent fuel – which is why our customers were willing to pay the £1.4billion needed to get Thorp up and running.
But the world has changed. Operators can store their spent fuel now, and so the customer demand that built and ran Thorp just isn’t there anymore.
The Nuclear Decommissioning Authority has a mission to clean up the UK’s earliest nuclear sites, and we are part of that. The closure of Thorp will reduce our authorised discharges and eventually reduce the hazard posed by the Sellafield site.