Magnox ILW Interim Storage Facility, Berkeley

Entered by Virtual Construction Ltd

Built to last

The Intermediate Level Waste (ILW) Interim Storage Facility (ISF) at the site of the former Berkeley Nuclear Power Station is one of six new highly-engineered industrial grade Magnox facilities to provide protection for ductile cast iron ILW containers until the eventual Geological Disposal Facility is available for permanent disposal. The purpose of the ISF's is to keep the ILW containers in a secure and controlled environment for up to 150 years. Storage of ILW through ISFs is part of a new and innovative Magnox approach whereby ILW is stored in robust self-shielding transportable containers, minimizing the need for shielding within the building structure, and thus significantly reducing decommissioning costs and timeframes.

The design

The six ISF's are of varying size, and a scale-able design has been developed to accommodate the varying number of ILW containers and stacking arrangements at each site. The design aims to minimise maintenance and maximise low-energy passive measures to provide the required storage environment, while also including active environmental monitoring and control measure.

Selection of design features:

  • A long-life, galvanised steel frame and insulated aluminium standing seam roofing and cladding system.
  • A curved overhanging eaves and no rainwater gutters reduce maintenance and potential sources of leaks.
  • An electric overhead crane used to move the containers.
  • Prefabricated reinforcement edge beams, wall panels and roll out mats used to speed up the construction of the 400 tonnes of reinforcement.

Interoperability with Revit model

On this project the structural engineers model was imported using the industry standard open IFC format (Industry Foundation Class) into Tekla Structures and used this as a base to produce the cast in-situ reinforced concrete details. The reinforcement model was then exported into Tekla BIMsight to overlay with the engineers model and issued to Arup for checking and problem solving alongside the drawings and schedules provided.

Avoiding clashes with existing piled foundations

The framing contractor, Cara Construction, requested detailed pre-fabricated cages where possible which could be manufactured off site and significantly speed up the construction process. This would generally be a relatively straightforward task but on Berkeley was made more complicated by the reuse of existing piled foundations which had been installed in some cases up to 300mm off a regular grid. The Arup model containing the surveyed pilecap positions was referenced into our Tekla model and we were able to accurately detail around these to ensure there would be no clashes once the cages reached site. A new colour coded drawing system was utilised to help with the fabrication of the reinforcement cages and placement of rebar.

Project participants

Project owner: Magnox Ltd
General contractor: Interserve Construction Ltd
Concrete and groundwork subcontractor: Cara Construction
Architect: Arup
Structural design: Arup
Mechanical and electrical engineering: Arup
Other structural detailing: Arup
Steel detailing: Caunton Engineering Ltd
CIP/reinforcement detailing: Virtual Construction Ltd