Water Supply Diversion, Calder Hall Decommissioning Project, Sellafield, Cumbria


Altrad Babcock




April 2023

The Project

This project involved the diversion of a critical water supply at the Sellafield nuclear site in Cumbria. The water supply diversion was required to allow additional isolation points and water supply feeds to be installed to facilitate ongoing decommissioning of the Calder Hall nuclear power station. The project included several months of planning and stakeholder engagement prior to site access to ensure water supplies to existing operational facilities were not interrupted. Our scope of work included:

  • Extensive stakeholder engagement, planning and work pack development.

  • Excavation to 2.2m depth to access the water supply pipework.

  • Installation of temporary sheet piling, and trench supports.

  • Removal of existing pipework.

  • Installation of new pipework and divertor valves.

  • Pressure testing.

  • Removal of temporary works.

  • Backfill and resurfacing.

Extensive stakeholder engagement and planning resulted in a successful project delivered on time.

Challenges and Successes

The project had to be completed without interrupting the water supplies to the operational facilities at Sellafield. This required us to plan the work 8 months in advance, engage with several dozen stakeholder groups including the Sellafield Utilities department, and carry out the pipework removal, reinstallation, and testing during the weekend.

The pipework modification was carried out in a Confined Space which necessitated the use of air powered tools rather than internal combustion engine to eliminate the risks associated with carbon monoxide.

Client Benefits

The successful completion of this project enabled our client and the site owner to continue with the Calder Hall decommissioning programme at Sellafield.


“I want to take this opportunity to thank DSD Construction for a fantastic job diverting the domestic water line. We appointed DSD as our Excavation Supervisor, and you helped us manage the process from conception to completion. The DSD team worked tirelessly and professionally excavating tarmac and soil immediately adjacent Street 92 without affecting the busy traffic and pedestrians.”

Des Graves, Decommissioning Manager, Altrad Babcock

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