INTERNATIONAL COST EFFECTIVE TRANSPORT OF REPROCESSED UO3

Sellafield Limited provides a storage service to its customers for uranium products in the form of UO3; this service is not indefinite so at some point the UO3 belonging to overseas customers requires exporting. The UO3 to be exported has a range of (U-235) enrichments, some of which meet the IAEA Fissile Excepted Package criteria and some that are marginally outside this criterion, therefore this implies that two package types will be required; a Fissile Excepted package and a Fissile package, the latter will require multilateral approval. The challenge is to minimise the number of shipments by optimising a single package design and the loading arrangement of this design to enable the safe transportation of large volumes of the fissile UO3 material. To accommodate the higher enriched material the use of an Industrial Fissile (IF) Package is proposed. IF Packages are typically IP-2 qualified packages supported by a criticality safety case. This safety case demonstrates an adequate sub-critical safety margin, without claiming any integrity for the packaging, under accident conditions of transport. This option provides the potential for significant cost savings, particularly with respect to package testing, as the safety of the package need only be demonstrated for normal conditions of transport. For this specific application research was carried out to establish an acceptable method for: • maximising payload within the package by mixed loading of UO3 at all enrichments • maximising the number of packages on the trains; and • maximising the number of packages on the vessels to minimise shipments. The approach adopted is somewhat complex requiring both an IAEA Shipment Approval and IAEA Radiological Protection Programme (RPP) for Special Use Vessels. There has been a great deal of constructive interaction between the plants involved, criticality specialists, project engineers and the UK Competent Authority during the development of this approach. A systematic set of controls has been developed to ensure compliance with IAEA regulations during loading operations and transport which will minimise shipments without compromising safety.