Successful collaboration led by Cerberus Nuclear delivers leak-detection demo

A prototype designed to map and identify cracks in concrete containment has been successfully demonstrated at Jacob’s Birchwood facility. Using a sensor package from Cerberus Nuclear contained inside a track and winch-style robot created by Jacobs Clean Energy, it is hoped that Sellafield will be able to locate any existing and potential leaks in the Magnox Swarf Storage Silos (MSSS).

The Magnox Swarf Storage Silos (MSSS) at Sellafield contain magnesium cladding or ‘swarf’ that was stripped from Magnox fuel prior to reprocessing. The construction of the original building silo is a reinforced concrete structure, with thick external walls as primary containment, obscured by free-standing shield walls standing around 6 metres high. The ageing concrete structure is known to have leaked in the past and may have some cracks that are difficult to identify and locate by current methods. It is valuable to know where such cracks are, in order to inform leak mitigation proposals, ongoing structural monitoring and safety management.

The slim-form robot from Jacobs has been designed to fit in the 100mm gap between the exterior and shield walls, moving across all X and Y coordinates. This allows the camera and radiometric sensor positioned inside the robot to map large surface areas, acquiring images and radiometric data which are later processed using the machine learning data analysis method developed by Cerberus Nuclear. By repeating these scans over a period of time, Sellafield will be able to monitor how the exterior wall is evolving and use the information to inform best practice for maintaining the MSSS.

The inactive demonstration, part of the Game Changers-funded proof of concept project, featured the robot performing a limited wall raster scan and a presentation of existing stitched wall images with graphically overlaid radiometric data.

Barrie Greenhalgh, Principal Consultant at Cerberus Nuclear, said: “This genuinely innovative technology will give Sellafield access to data they have not had before - actionable information that will help inform their strategy for looking after the MSSS facility.”

Helen Wild, Civil, Structural and Architectural Engineer at Sellafield Ltd, said: “The potential for MSSS is that we’re going to be able to instil more confidence about the condition of the concrete and the primary containment walls of the original building, particularly as we progress through our retrievals programme.”

Planning for further inactive testing followed by active demonstration of the technology on the Sellafield site is now underway.