Further Developments in High-Level Waste Transport Technology

Abstract

British Nuclear Fuels plc, with the assistance of Nuclear Transport Limited as contractor, are developing and designing a new transport flask in order to be ready for the return of vitrified high level waste to customers when the Windscale Vitrification Plant and Vitrified Product Store come on stream early in the 1990s.

The development and operation of the vitrification plant and store are described briefly. The nature of the vitrified residue is discussed, with particular reference to how it is affected by the different reactor types from which irradiated fuel is reprocessed at Sellafield, and the properties of the resulting residue packages or filled containers in relation to transport are described.

The requirements and constraints for transport are discussed and the reasons given for designing a new flask rather than adapting an existing irradiated fuel flask. The design concept for a flask which maximizes the payload is described, paying special attention to the novel arrangement of the internal support structure, and the handling arrangements, which will allow the flask to be transported using existing rail wagons and ships, are outlined. Harmonization of design features with the equivalent French flask, to enable both types to be unloaded at the same facilities, is discussed.

The factors considered in the preparation of the concept design are listed and a series of development tests is described which have proved the basic design concept of the internal arrangements and demonstrated its ability to meet the requirements for heat transfer and handling of the waste containers and internal support structure.

Other aspects of detail design are mentioned and an indicataion is given of the time schedule for proving the impact resistance and leaktightness of the package, preparing the Design Safety Report and obtaining competent authority approval as a Type B(U) Package Design, and construction of the flasks ready for the commissioning of the despatch facility at the Windscale Vitrified Product Store.