6 m3 Concrete Box Studies

Conrad Izatt - Arup
Darryl Smith - Magnox Ltd.
Phillip Ashton - Magnox Ltd.
File Attachment
Magnox Ltd. is intending to use 6 m3 Concrete Boxes (CBs) for the packaging and disposal of Intermediate Level radioactive Waste (ILW) at a number of sites. Current plans include their use at Berkeley, Chapelcross, Harwell, Hinkley Point A and Winfrith. The 6 m3 CB is constructed of reinforced concrete and has a cast in-situ reinforced concrete lid, placed after the waste has been loaded and encapsulated with grout. The 6 m3 CB must exhibit long-term durability for surface storage of ILW, meet transport requirements as IP-2 transport packages and satisfy RWM requirements for impact accidents in the Geological Disposal Facility (GDF). Magnox plans to entomb some wastes, but the impact performance of 6 m3 CBs with entombed wastes is yet to be substantiated. A number of entombment concepts have been considered and development of waste packaging proposals at Magnox led to the adoption of waste immobilisation in “Sacrificial Bins”. This Sacrificial Bin concept was then developed and is the preferred option for the majority of Magnox wastes in 6 m3 CBs. This paper will describe the finite element analysis work carried out to evaluate the Sacrificial Bin entombment concept for the transport normal condition scenario (0.3 m base down drop) and GDF impact accident scenarios.