Magnox pond decommissioning innovations

30 Jun 2008

Sealing and deployment trials have been completed off site in preparation for work on the sludge and effluent lines that connect the Magnox storage pond to the effluent tank at the plant.

Sellafield Ltd. commissioned Corus Process Engineering (CPE) to provide a sealing solution for its two sludge and effluent (RESPS) lines.  The potential risk of a hydraulic 'link' between the two plants meant that a technique was required to reliably isolate the lines and eliminate any potential fault scenarios.  It also allows the early start of the sludge and effluent removal from the Magnox Storage pond.

These lines are located seven metres underwater inside the Effluent Tank Sludge Sump and four metres underwater in the Effluent Tank Inlet Chamber creating a real challenge.  However Sellafield Ltd and CPE were able to use knowledge gained from a previous collaboration on the Magnox Pond RESPS project in early 2006 when they developed new sealing techniques for a number of other RESPS pipelines.  After numerous trials, recommendations were made for the use of a special technique sourced from Steve Vicks International.  This technique has now been adopted as the basis for the sealing of the RESPS lines into the Effluent Tank.

Testing time
The project teams were located at CPE's Workington test facility enabling all the new trialling work and safety case documentation to be completed within the established timescale.  Due to this, costs were contained and it was possible to get immediate feedback on trialling and test data.

Stuart Pegler, Project Engineer at CPE, said that the new sealing and deployment technique potentially has many other plant applications at Sellafield and may offer opportunities as a technical solution in the remediation and decommissioning of facilities across the site.

"The project was very successful and represents a major risk reduction exercise for the Sellafield site" Chris Cunningham, Project Manager at Sellafield Ltd.