Radionuclide migration through marine (deep sea) sediment -a review

This report reviews the general research require to provide the scientific basis for assessing the capacity of the sediment barrier to retard activity around canisters of HLW buried in deep ocean sediments. The natures of the physical and chemical systems that will be involved in the migration of waste through a sedimentary barrier are described. Certain items considered fundamental to the research are then reviewed so that the particular research projects that constitute the national research programme may be assessed on the basis that they fulfil both the overall research objectives and the scientific requirements for research. The interaction between the sediment and the canister is next reviewed, in terms of the sediment response to each stage of the disposal programme. The review considers both near and far fields as the suitability of the far field to provide a barrier will depend in part upon the chemical form of the nuclides leaving the near field and hence the influence of the near field upon them. Those subjects where essential research is required are identified; of these, special attention should be given to the nature of adsorption and the mobility of pore water. (author)