Development and Implementation of Technology for the Treatment and Encapsulation of Operational Intermediate Level Wastes

Since 1982, BNFL Research and Technology has run an extensive research, development and implementation programme to define suitable materials and processes for the long-term containment of a wide variety of Intermediate Level Waste (ILW) streams arising from nuclear operations. This has provided both the empirical and underpinning data required to allow regulatory approval for the construction, commissioning and operation of four waste stream specific, cement-based encapsulation plants at the Sellafield site. The research and development programme has also succeeding in producing a team of highly skilled and experienced specialist researchers and technical staff equipped with a detailed database of knowledge concerning encapsulation methods applicable for a wide variety of ILW streams of concern within the UK and abroad. The objectives of this paper are to: • review the systematic, phased approach taken to assess potential encapsulants and develop suitable wasteforms and processes for ILW treatment that lead to the selection of a cement-based matrix as the preferred option for current ILW arisings, • discuss the key issues associated with the development of successful waste treatment systems and wasteforms, which have been encountered and addressed, • introduce ongoing work to confirm the longer term properties of archived full scale cemented wasteforms and provide additional information on the fundamental mechanisms which dictate waste-encapsulant interactions and wasteform behaviour.