Case Study // Dungeness Power Station – Magnox Ltd

History

Dungeness A Site occupied about a quarter of a 91 hectare civil nuclear site on the Kent coast, in an area of Special Scientific Interest.
Dungeness A ceased generation at the end of 2006 after 40 years of safely supplying electricity to the national grid. As part of the decommissioning process, both Magnox reactors have been de-fuelled with the spent fuel dispatched to Sellafield in Cumbria for
reprocessing.
At the end of decommissioning the area is due to be left as a brownfield site in keeping with the world-renowned shingle peninsula of Dungeness. Erith Contractors & Magnox Limited Ltd are working on behalf of the Nuclear Decommissioning Authority to manage the asbestos removal, deplant and demolition of the South Side of Site Structures including the Turbine Hall.

Scope

Dungeness Power Station was the rest project awarded under the ten year Magnox framework to include: de-plant demolition and asbestos removal of the former power station. Erith adopted the role of principal contractor under an NEC3 Option C target cost;
working in close collaboration with Magnox throughout.
The first phase of the works saw the strip out, asbestos removal and demolition to a series of outbuildings situated adjacent to the main turbine hall. Right from the off, the site wasn’t without its constraints, as Erith had to undertake work adjacent to the licensed operational Dungeness B site; as well as being confined within a Site of Special Scientific Interest.

Following on from this, Erith began the bulk asbestos removal of the turbine hall. One of the key challenges of this project was the mechanical isolation of the turbine’s steam tunnels – ensuring that the risks from any stored energy were managed safely. Overall, the site delivery team successfully completed the compliant removal of approximately 120 tonnes of asbestos waste; racking up an impressive 50,000 man hours without any health & safety incidents or lost time accidents.

As part of the de-plant phase of the turbine hall, the existing gantry crane became a focal point of operations. It became a requirement to ensure that the cranes could cope with the planned de-plant activities and as a consequence, Erith’s site team meticulously executed four proof loading tests to each crane. Utilising on our past power station experience, the cranes were tested to their SWL plus 10%. The final crane required the use of 5 nr 35te water bags, which proof loaded the main crane hook to 165.00te.

Main Demolition

The final phase of the works incorporated the main demolition of the turbine hall. A high risk exclusion zone was set up around the portal bay steel framed structure, which was demolished at all levels utilising a 360° 67 tonne high reach excavator. Operatives were on hand in support of the demolition, utilising hand tools and hot cutting techniques to process sections of the structure as necessary for demolition and on-site processing.

Health & Safety

Health and Safety was at the forefront of our operations for the duration of the project. A full check of each work zone was carried out by the Site Manager at the end of every shift, in addition to the daily pre/post job briefings given to each Operative on site. Erith were able to complete the project with zero reportable health and
safety incidents.