The Chapelcross site, which ceased operation in 2004, has hit the target defueling date four months ahead of schedule, the UK Nuclear Decommissioning Authority announced, 26 February.

Formal permission to start defueling was received from the Office for Nuclear Regulation (ONR) in July 2008, and the first flask of fuel left the site in April 2009. Since then, a total of 38,075 fuel elements have been shipped to Sellafield. The NDA said that 30 flasks were dispatched in 2009/10, with 51 in 2010/11 and 73 in 2011/12. The remaining 103 flasks were sent to Sellafield in 2012/13.

The NDA attributed the improving performance year-on-year to an "innovative approach – based on the ‘Marginal Gains Concept’" which it said was implemented across the site’s defueling operations.

"The Marginal Gains Concept involves improving every step within a process by at least 1%, which will get you significant improvement overall when you add the steps together," John Grierson, Chapelcross Site Director explained.

Once fuel free status is verified in the next few months, Chapelcross will move to a new post-defueling structure, scheduled for September 2013. Work will continue on various decommissioning projects until the site prepares to enter into interim care and maintenance in 2017.