Description
The sediments formed by the deposition of particulates from surface water and the processes affecting their potential evolution.
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.
- Feature
- Process
Comments
The “Comments” field, when present, contains any additional explanation of the IFEP, beyond that implicit in the FEP's description and provided in the “Relevance to Performance and Safety” field. This additional explanation may include, where appropriate, the IFEPs characteristics, the circumstances under which it might be relevant and its relationship to other (especially similar) IFEPs.
Aquatic sediments are found at the bottom of surface water bodies and are generally composed of fine-grained sand, clays, gravel and organic material. They can be differentiated into upper sediments which can have higher biological activity and lower sediments that are covered by the upper sediments and are more compact. The former are subject to wave action and currents and can be eroded and reformed relatively easily. Sediments may eventually form surface soil when, for instance, a river changes its course or a lake dries up. They can be dredged for use as soil conditioners.
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.
Contaminants that might have migrated from the repository may become bound to aquatic sediments. Physical and chemical processes which affect the mobility of sediments, and their ability to retain contaminants, will influence the potential for exposure of aquatic biota and humans to contaminants bound to the sediments and contained in the water body overlying those sediments.
2000 List
A reference to the related FEP(s) within the 2000 NEA IFEP List.