Interim storage refers to the retention of radioactive waste in a facility or a location with the intention of retrieving the waste at some point in the future.
Storage therefore anticipates future actions, such as to provide further conditioning or packaging of the waste, to maintain the facility in which storage takes place or to construct new facilities for further storage and ultimately disposal.
At most of the NDA’s sites, the strategy is to place ILW in interim storage until a final disposal solution is available. For England and Wales, this will require the construction of a GDF, which is expected to be available from the 2050s. Interim storage can therefore last several decades.
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Case study
NRS Interim Storage Facilities
Parallel construction and replicating a common design were top of the agenda when constructing new interim storage facilities (ISF) at Chapelcross and Hinkley Point A sites. This joined up approach has enabled a reduction in design and build costs as well as shared learning and efficiencies. A shared design programme has previously been used at other sites, including the ISF build at Berkeley and Bradwell.
NRS Waste Manager said: “One specific example of shared learning and efficiencies was demonstrated with a change to how the roofing sheets were attached. Following some difficulties associated with the clips used to attach the panels at Chapelcross, the design was tweaked slightly ensuring we didn’t face the same issue at Hinkley Point A.
Another common denominator for the stores’ construction was the principal contractor, Interserve. This enhanced shared learning and co-operation between the sites.
The Harwell Intermediate Level Box Store (HIBS) does not replicate the design of these stores as the design was agreed before Harwell and Winfrith joined NRS.
The HIBS Project Manager explained: “Even though we didn’t follow the same design at Harwell, being part of the same programme has helped tremendously. Speaking to colleagues, particularly those involved with the engineering of the already-built stores at Bradwell and Berkeley, about specifics such as concrete pour sizes, crane faults, concrete finishes etc, was so beneficial.”
The stores will house higher activity waste which cannot be consolidated for storage in another site’s ISF. Their construction facilitates long-term storage on-site before final disposal at the geological disposal facility.
As of January 2024, the Chapelcross store is operational and receiving active packages. Both Hinkley Point A and Harwell HIBS have completed inactive commissioning but are yet to start placing active packages.
During the storage period a programme of inspections will be used, based on a common approach to ensure the integrity of the waste packages is maintained. These inspections will be performed remotely.
All stores hold a variety of different packages and will also house metal coupons and dummy packages to help measure corrosion, determine the condition of the packages and predict how they will perform in the future.