Above: Hunterston B nuclear power plant


THE UK’S HUNTERSTON B NUCLEAR power station performs maintenance outages on a periodic schedule basis to comply with licence conditions. The activities include fuel route maintenance, for which Cavendish Nuclear is the primary contractor.

The charge machine is a key part of the fuel route and it has to operate in two modes. It must be able to load fuel assemblies and fuel plug units (FPUs) into the reactor and, critically, have the correct corresponding protection systems active. To deliver this, existing protection systems had to be modified and new modules developed, re-wiring had to be completed and a new interface panel installed, identified as the Logicon Bridge 3 Panel.

The new Logicon Bridge 3 Panel is the interface between several existing Logicon panels and plant-based switches and signals. The panel consisted of fourteen relays, 10 indication LEDs and associated interface wiring. The space available for the new panel was constrained and proved challenging when arranging the components and safety features within the panel.

There was a challenging timescale for producing engineering drawings, a test specification and approval from the start of the project in early February. But soon afterwards our supplier had to face a new challenge in sourcing components as factories in mainland Europe closed down due to COVID-19. Additionally, the UK lockdown meant that all Cavendish Nuclear office-based staff had to change to working remotely from home in less than one week. Verification of documents and drawings became challenging, but we were still able to meet deadlines by finding new ways of communicating, verifying and formally approving documentation.


Above: A new Logicon Bridge 3 Panel was delivered during the COVID-19 crisis


Delivering differently through remote testing

Despite the restrictions of lockdown, our supplier EDM, based in Leicester, was able to adapt to new ways of working to manage the new risks and comply with social distancing and protection measures. EDM worked with Cavendish Nuclear to progress production of the panel through to factory acceptance test. In a novel approach, the witnessed FAT was conducted remotely, instead of in person with the customer present. This was achieved using a number of cameras that provided a live feed from the factory floor to the customer’s engineers in Scotland.

The remote testing was a great success. Engineers were able to witness the testing and interact with the supplier during the process. It was also possible to move the cameras to suit requirements as testing progressed. There were some initial connection problems at the start, but these were soon overcome and the work was successfully delivered from the comfort of a remote home office or work space.

An additional benefit was the removal of long journeys, risk, overnight stays and associated expenses. Recognising these benefits, discussions are now underway for the remote witness testing of another, larger and more complex panel at Cavendish Nuclear’s own works.

Through careful management of the new risks and work constraints, Cavendish Nuclear and its suppliers were able to proceed with the build, test and delivery ahead of the contract milestone date and on-budget, as part of the outage programme at EDF’s Hunterston B power station.

David Queen, EDF investment delivery project manager said, “I would like to thank Cavendish Nuclear and their supplier for working through the technical challenges of undertaking the successful FAT. Please convey our thanks to the Cavendish Nuclear team and their supplier for their hard work in building the panel and undertaking the FAT in challenging times and with a successful outcome.”