Modelling the Radiological Impact of Release of Radionuclides into the Biosphere from Solid Waste Disposal Facilities

Abstract

This paper describes the approach being adopted to improve confidence in biosphere modelling for the assessment of the post-disposal radiological impact of disposal of low and intermediate solid radioactive waste at alternative sites proposed by UK Nirex Ltd.

Release from a disposal facility may be precipitated by a number of mechanisms and ultimately result in release of activity into the surface environment, or biosphere. The range of potential receiving environments in the biosphere is discussed, and preliminary results for the consequences of unit release of relevant radionuclides are used to identify the most significant factors which lead to uncertainty or lack of confidence in results for biosphere modelling. The paper then goes on to consider the steps which might be taken to improve confidence in the predictions based on understanding of the relevant processes and mechanisms. These steps include the setting up of appropriate field and laboratory experiments and use of appropriate natural and other analogues to provide the best practicably obtainable database against which the biosphere model may be tested. The scope for such methods is discussed, noting the extended periods over which releases might occur, and the likely delays before they start.

This work is funded by UK Nirex Ltd.