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The Pile Fuel Cladding Silo (PFCS) is the oldest legacy storage building on the Sellafield site, dating back to the 1950s. The 18 metre high ‘locked vault’, built to house aluminium pile fuel cladding waste, Magnox Swarf and other hazardous waste, was not constructed with emptying in mind.

The operation to get access to the waste and install the machinery to remove it consisted of a joint venture project, headed up by Cavendish Nuclear, to create a modular retrievals machine built on a concrete superstructure positioned next to the silo so that the waste could be removed through six newly cut containment doors.

Following successful completion of a control system for the doors, Servelec Controls was reengaged to design and build four linked control systems to facilitate the waste removal, as part of the Early Retrievals project. Thanks to a collaborative supply chain partnership, the project was completed significantly ahead of the agreed site schedule.

Integrated Control Systems

Servelec Controls created four systems that work together to move waste containers, within either an Environmental Box or a Sellafield Package, into and out of a waste retrievals area. Each system controls a different stage of the process but all four are intrinsically linked to ensure that each stage, including those undertaken by the facility’s other systems, has been safety completed before the next can begin.

4 integrated systems, digitally interlocked for safety

Client’s full programme completed 3 years ahead of schedule

Risk reduced through COTs technology

 

Servelec Controls worked via a third party with my Engineering Design Team, within our collaborative project environment, to deliver the required integrated solution ahead of time, cost and to the specified quality”

Dr Sebastian Proctor
BCNS Project Engineering Manager, Cavendish Nuclear

Safe, Coordinated Process

System 331: Import/export bogie

System 331 imports the box or package on a transfer bogie from an external loading position to an internal lid-lift position. Digital interlocks interface with the subsequent lid lift system to prevent operation before the box is safely in position.

System 351: Package lid removal

Once the box or package is in place, System 351 controls the Lid Lift Machine which removes the external lid. Digital interlocks prevent operation of a third-party hoist until the lid is safely removed.

System 260: Waste container transfer bogie

The third-party hoist lifts the waste container from within the package/box and onto another transfer bogie. System 260 then positions this bogie and the waste container onto the waste loading port (WLP).

System 250: Waste loading

Once the bogie and container are in place, digital interlocks allow System 250 to open the WLP’s hydraulic actuated lid and waste is passed through into the waiting waste container.

Process reversal for container removal

Once complete and the lid is sealed, the four systems are again able to work in unison to reverse the process so that the package, now containing a full, safely sealed waste container, can be removed from the Silo.

Training and Support

Servelec Controls also provided copies of Systems 250 and 260 to be used for training purposes off site at Rosyth, and will continue to support the project on site at Sellafield and Rosyth, as required.

Sellafield Pile Fuel Cladding Silo (PFCS) Early Retrievals Control Systems

Click here to download a pdf of the Sellafield PFCS Control Systems case study.