The Hinkley Point 'A' Nuclear Power Station was shut down in May 2000. The Intermediate Level Waste (ILW) store will contain intermediate level waste arising from the operation and decommissioning of the station.
The building comprises a heavily shielded concrete vault where the waste will be stored in stainless steel containers, a service area which will house the package handling machine (crane) used during vault filling and emptying, and an import/export facility comprising of an airlock and package inspection facility. The reinforced concrete structure is fully enclosed within aluminium cladding to provide an aesthetic finish, additional protection from normal environmental effects and to maintain the internal environment of the vault within specified temperature and humidity limits.
Halcrow has been providing civil/structural and building services consultancy services as part of an Alliance formed by Magnox South (formerly British Nuclear Group), Halcrow, Babcock Nuclear Services (BNS) (Formerly Weir Strachan & Henshaw) and Nuttall to deliver the new facility. The design has been led by its safety functional requirements, particularly seismic design requirements, thermal loading and seismic secondary response spectra for design of mechanical components.
The Pre-Construction Safety Report (PCSR), supported by Halcrow's Design Substantiation Reports was accepted by the Nuclear Installations Directorate, prior to start of construction. Completion was originally planned for early 2008 but was subsequently suspended during construction because of altered funding priorities. A detailed internal environment study using building simulation techniques was completed during the early stages of the project. This analysis was used to assess temperature variations for structural design and condensation risk within the vault during the 100 years life of the facility.
The Hinkley Point store is very similar to the store at Hunterston and the experience gained at Hunterston has been of significant benefit to the project. Through a value engineering exercise, promoted in conjunction with our client, the Hinkley facility has been significantly streamlined in certain areas to allow substantial cost reductions to be gained whilst still maintaining the full integrity and intent of the facility. Analysis and design techniques have also been enhanced by developing graphical interfaces to manipulate analysis and design output into a graphical format to facilitate reinforcement detailing. This has increased efficiency in design and delivered substantial savings in construction cost and time.
Halcrow has also been responsible for the building services design incorporating: mains power supplies, fire alarm systems, vault monitoring and vault and service area ventilation systems. Design co-ordination, across the design teams was based in three Halcrow offices and with the Crane designer, Weir Strachan and Henshaw, (now BNS) and has been very successfully met during the design period. Significant interfacing with the civil contractor, Nuttall, has also been incorporated during the design development ensuring high levels of buildability and a cost effective design.
On successfully achieving the INSA approval of the PCSR, Magnox ILWS Alliance project manager Neil Lock complimented the team stating that to accomplish this milestone "effectively ahead of programme, is a fantastic achievement".