Description
The damage caused to the repository materials surrounding the waste package by radiation. Radiation damage may result from radiation emitted by the waste packages, or by radioactive decay of radionuclides within the materials of the EBS. These latter include radionuclides that have been released by waste packages (assuming that radionuclide release from the waste packages is possible), radionuclides that occur within the repository materials, or radionuclides that have been transported into the EBS from the surrounding geosphere. Radiation damage could affect the macro-scale properties of the EBS materials, or alternatively only be relevant to the micro-scale.
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.
Radiation damage may affect the mass transport properties and/or mechanical properties of components of the EBS and / or the adjacent geosphere. Potentially, radiation damage may contribute to producing pathways through components of the EBS and/or adjacent geosphere, via which radionuclides and other contaminants that originate in the waste might be transported, should they be released by a waste package.
Radiation damage may mechanically weaken barrier components and/or structural components, thereby allowing them to deform more readily than in the absence of radiation damage. This deformation might impact upon the effectiveness of the barriers. For example, deformation might produce pathways through the barriers, through which radionuclides and other contaminants might migrate.
Radiation damage might affect the partitioning of radionuclides and other contaminants among immobile solid phases and potentially mobile fluid phases (such as liquid water, non-aqueous liquids and gases). Radionuclides and other contaminants may sorb onto new solid surfaces created by the effects of radiation. Conversely, radiation may cause structural damage to solid phases that contain radionuclides or other contaminants, thereby causing enhanced leaching of the radionuclides or other contaminants by flowing water.
2000 List
A reference to the related FEP(s) within the 2000 NEA IFEP List.