Description

The surface landform changes on a regional and local scale, i.e. the general configuration of the Earth’s surface, caused by large-scale geological changes. In turn, these can impact hydrological and ecological conditions which also affect landscape evolution. Examples of landforms directly resulting from geological changes are fold mountains, rift valleys and volcanoes.

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.

  • 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.

Geomorphological responses to geological changes, such as development of mountains, valleys, or volcanoes, could impact upon the performance and safety of a repository by:

  • impacting on the chemical and physical environment of the repository, its host rocks and rocks in the wider hydrogeological system within which the repository presently resides or may reside in future; and
  • the nature and spatial distribution of environmental receptors, including the biosphere, that might be impacted should radionuclides and/or other contaminants be transported from the repository.

Geomorphological responses to geological changes may cause the characteristics and spatial distributions of surface water bodies, rivers and coastlines to change. There would be consequent influences on the spatial distributions of groundwater recharge and discharge zones. These geomorphological responses will also impact upon the rates of groundwater recharge, for example by influencing atmospheric circulation, and hence rainfall. Therefore, geomorphological responses impact upon the fluxes and directions of groundwater flow through and around a repository and the potential distances over which radionuclides and / or other contaminants may be transported between a repository and the biosphere. There will be a corresponding influence on the chemical conditions in and around a repository since these are coupled to groundwater fluxes, flow directions and flow path lengths. For example, groundwater that flows from the recharge zone to a repository very slowly and over a great distance will be more likely to be reducing by the time it reaches the repository than groundwater that flows from the recharge zone to the repository rapidly over a short distance. The characteristics of the biosphere will be markedly impacted by changes in geomorphology. Flora and fauna will be affected by factors such as altitude and proximity to surface water bodies, rivers or coastlines.

2000 List

A reference to the related FEP(s) within the 2000 NEA IFEP List.

Not explicitly mentioned