Description
The origin and development of soils, with reference to the factors responsible for the formation of soil from parent material, including hydrological, atmospheric and biological processes. Pedogenesis depends upon climatic conditions and their impact on weathering processes, as well as on rock type, mineral composition, topography and biological processes.
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.
Pedogenesis may influence repository performance and safety primarily by:
- affecting the behaviour of any radionuclides or other contaminants that are transported from the repository to the ground surface during the post-closure period; and
- by affecting the nature of the biosphere that might be impacted by these radionuclides and contaminants.
Pedogenesis will control the physical and chemical characteristics of soils which in turn will control the partitioning of any radionuclides and other contaminants present among solid organic and inorganic phases, groundwater, gas and organisms present in the soil. These processes will control the concentration, mobility and bioavailability of any radionuclides or other contaminants. The nature of the biosphere that might be impacted reflects the kinds of fauna and flora that might develop within a soil. These fauna and flora depend in turn upon the characteristics of pedogenesis. Climatic and other environmental factors, such as human actions, may affect pedogenesis. Consequently, the soils generated are likely to vary throughout the timescale considered by a performance assessment (often c. 1 Ma). Pedogenesis is of primary concern to environments at and very near the Earth’s surface. However, ‘fossil’ soils (palaeosols) produced by ancient surface exposure could conceivably occur at some depth within certain sedimentary rock sequences that might occur near a repository. Ancient pedogenesis would have influenced the radionuclide/contaminant transport and retention properties of such palaeosols.
2000 List
A reference to the related FEP(s) within the 2000 NEA IFEP List.
Related References
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Metcalfe R and Watson SP (), Technical Issues Associated with Deep Repositories for Radioactive Waste in Different Geological Environments, Environment Agency Science Report SC060054/SR1, Environment Agency, Rio House, Waterside Drive, Aztec West, Almondsbury, Bristol, BS32 4UD, 213, http://www.gov.uk/government/uploads/system/uploads/attachment_data/file/291763/scho0809bqvu-e-e.pdf