The final flask of used fuel from UK’s Wylfa Site has been dispatched for reprocessing at Sellafield in Cumbria, marking the end of defuelling operations at all 26 of UK’s first-generation nuclear reactors.
The Wylfa Site was the biggest and last Magnox reactor site to be built in the UK. Its two 490MWe reactors began commercial operation in 1971 and 1972. Wylfa unit 2 was permanently shut in 2012, and unit 1 in 2015. The site generated 232TWh of electricity during that time.
Completing defueling will enable Wylfa to move into its decommissioning phase, and allows Magnox and the Nuclear Decommissioning Authority (NDA), which owns the site, to progress with the cleanup of the UK’s civil nuclear legacy safely, securely and cost-effectively, according to a joint statement on 19 September from Magnox Ltd, NDA, and Sellafield Ltd. Some 87,890 fuel elements were removed from the twin-reactor site. “The elements, which measure 43 inches in length, would stretch for 17-and-a-half miles if placed end to end,” the statement said.
The final shipment means that more than 99% of the total radioactivity has now been removed from the site. Wylfa Site Director Stuart Law said it was not an easy task and the work at Wylfa is far from complete, but nevertheless a significant landmark had been reached in the site’s journey towards care and maintenance. “The defuelling process was hampered by ageing equipment for the first 18 months which brought challenges, but the dedication and problem-solving abilities of the Wylfa team and expertise drawn from across the nuclear industry led to what is, overall, an incredible performance in completing this task,” he noted.
Gwen Parry-Jones, Magnox CEO, added: “As the final Magnox site to defuel, this marks a significant landmark for Magnox as a whole in carrying out our mission to safely decommission our fleet and marks a new focus on the next phase for the whole company.” Wylfa will now refocus its team on decommissioning activities, including a mix of conventional and radiological projects to further reduce hazards on site.
The workforce at Wylfa that once stood at about 600 will be reduced to 175 by the end of November. Tim Dunham, head of nuclear operations for Magnox, which is now part of NDA said: "All of us are now looking for something else to do - and change is challenging." He added that the expertise of the engineering teams at Wylfa meant few would be out of work, but recognised that for some it remained a difficult time.
Decommissioning at Wylfa will now move to preparation for "care and maintenance", which will start in December, as the site is cleared. Buildings will be demolished and the turbine halls will be dismantled. This is expected to take up to seven years and would leave only the two reactor buildings and the empty dry fuel stores. Under current plans, those buildings will be monitored for a century - until about 2126 - when radiation will have decreased to manageable levels.
Last flask of fuel from the Wylfa reactor (Credit: Magnox)