'Ingenuity is required' – managing setbacks at Europe's most complex nuclear clean-up

Recently, engineers working on decommissioning the Dounreay nuclear power plant in Scotland encountered a big problem.

There was an issue with a polar crane, which picks up objects from a bridge rotating on a circular rail. 

Operators were forced to suspend work with the crane, which transfers a shielded flask containing radioactive ‘breeder’ elements from the site’s defunct fast reactor, after a fault developed. 

Tests revealed that the head of the rail had separated from the upright ‘web’ section. Repairs, which involved replacing the rail and repairing rail supports over several months, stopped work on the vital element of the decommissioning project. The issue was a reminder of the work’s reliance on ageing machines. 

“One of the major challenges we face is ensuring that we can continue to operate with some of the ageing assets we have on our site,” says Jennifer Gilmour, senior mechanical engineer at Dounreay Site Restoration. 

“I know this challenge is faced by all across the board and as such there is a great opportunity for us to pool our collective knowledge and resources to overcome these challenges. Ultimately we need to ensure the safety, security and reliability of our personnel, our plant and the environment.”

Decommissioning is a growing industry in the UK – a recent report by the Nuclear Decommissioning Authority estimated it will take 120 years and £121bn to “clean up” 17 of the earliest nuclear sites. 

Balancing ageing and poorly-maintained equipment with financial constraints, environmental conditions and challenging timescales is “very difficult”, says Gilmour. 

“It is not impossible, but a level of ingenuity is required, which only comes from a mixture of qualifications, experience and technical understanding. Getting the right mix can take time.” 

Engineers also have to stay abreast of change in the sector. “The industry is constantly evolving and technology is advancing at a phenomenal rate – software which has recently been installed can be out of date within months, if not days, trying to get hold of spare parts for older equipment is becoming increasingly difficult, and ensuring knowledge retention is captured are some of the daily challenges,” she says.  

Despite the breakneck speed of progress, Gilmour says she looks forward to more advanced technology being adopted. Virtual technology for design, drones for maintenance and inspection and new materials are all possibilities, she says.

Jennifer Gilmour will speak at the seminar on Nuclear Materials: Avoiding Structural Integrity Failures in Manchester tomorrow (3 October). Find out more at imeche.org/events.