Description
The effects of radiation emitted from the waste in the waste packages on the seals and other repository engineered features, and the overall radiogenic evolution of the repository.
Category
Categorisation as a Feature, Event and/or Process.
Features
are physical components of the disposal system and environment being assessed. Examples include waste packaging, backfill, surface soils. Features typically interact with one another via processes and in some cases events.Events
are dynamic interactions among features that occur over time periods that are short compared to the safety assessment timeframe such as a gas explosion or meteorite impact.- "Processes" are issues or dynamic interactions among features that generally occur over a significant proportion of the safety assessment timeframe and may occur over the whole of this timeframe. Events and processes may be coupled to one another (i.e. may influence one another).
The classification of a FEP as an event or process depends upon the assessment context, because the classification is undertaken with reference to an assessment timeframe. In this generic IFEP List, many IFEPs are classified as both Events and Processes; users will need to decide which of these classifications is relevant to their context and its timeframes.
- Event
- Process
Relevance to Performance and Safety
The “Relevance to Performance and Safety” field contains an explanation of how the IFEP might influence the performance and safety of the disposal system under consideration through its impact on the evolution of the repository system and on the release, migration and/or uptake of repository-derived contaminants.
Radiological processes may potentially affect the physical, chemical and biological characteristics of the EBS and adjacent geosphere. These processes may influence the performance of the barriers.
Potentially, radiological processes could contribute to the development or enhancement of pathways through the engineered and natural barriers, via which radionuclides and other contaminants originating in the wastes might be transported, if they are released by a waste package. The physical and chemical forms of these radionuclides and other contaminants might be influenced by radiological processes (e.g. whether in gaseous form or in aqueous solution). Radiological properties could affect the partitioning of radionuclides and other contaminants between immobile solid phases and potentially mobile fluid phases (such as water, non-aqueous liquids and gases).
Radiological processes may affect the nature of the fluid phase present (e.g. nature and quantities of gas) and the complexation of dissolved chemical components. For example, radiolysis might generate gas and/or contribute to the breakdown of non-aqueous organic liquids. Radiolysis may influence the redox conditions, which would impact upon the chemical speciation of certain chemical components.
Radiological processes may also influence forces driving the movement of these radionuclides and other contaminants, for example by affecting gas pressures, which might influence advection, or chemical gradients, which might influence diffusion.
Radiological processes such as decay and ingrowth may cause temporal variations in the quantities and natures of radionuclides that are present within the barrier system.
2000 List
A reference to the related FEP(s) within the 2000 NEA IFEP List.
Related References
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UNSCEAR (), Source and Effects of Ionizing Radiation, United Nations Scientific Committee on the Effects of Atomic Radiation (UNSCEAR) Report to the General Assembly with Scientific Annexes, United Nations, New York, ISBN 978-92-1-142274-0, http://www.unscear.org/docs/reports/2008/09-86753_Report_2008_Annex_B.pdf
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Dzaugis ME, Spivack AJ, D’Hondt S (), A quantitative model of water radiolysis and chemical production rates near radionuclide-containing solids, Radiation Physics and Chemistry, Elsevier, 115, 127-134, http://www.sciencedirect.com/science/article/pii/S0969806X1500239X