Description
The effects of warm tropical and desert climates, including seasonal, meteorological and geomorphological effects specific to these climates within the region/locality of the repository. These effects may include extreme weather patterns (e.g. monsoons, hurricanes under tropical climates, infrequent heavy rainfall events in desert climates) that could result in flooding, storm surges and high winds with implications for erosion. These effects also include desertification, which could lead to deforestation and loss of grassland.
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
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.
Warm climate effects may influence repository performance and safety by: 1) influencing the groundwater flow regime in and/or around the repository; 2) influencing the chemistry of groundwater in and/or around the repository; 3) influencing the separation of the repository from the biosphere; and 4) influencing the natures and spatial distributions of receptors that could be impacted by any radionuclides or contaminants that are transported from the repository. Warm climate effects may be sudden and of short duration (e.g. typhoons) or more prolonged (e.g. desertification). Sudden warm climate effects that could affect the environment of a repository include floods and landslips. Warm climate effects that would influence recharge of groundwater include variations in rainfall, evapotranspiration and influences on nature of soils. Under tropical climate conditions there will be high levels of evapotranspiration compared to desert regions. In desert regions, total rainfall, erosion and recharge may be dominated by infrequent storm events. Warm climate effects could exert a profound control on the depth of the water table. In tropical regions the water table may be near the ground surface, but in arid regions the water table could be at a considerable depth (maybe hundreds of metres). A lowered water table would affect natural biota, and might also lead to the use of deep water-supply wells to support local agriculture (or to use of distant water supplies). Warm climate controls on recharge would influence groundwater fluxes. Weathering and erosion could be influenced strongly by warm climate effects. Tropical weathering could potentially extend much deeper than desert weathering. Similarly, transport and sedimentation of material removed by erosion could be influenced strongly by warm climate effects. In turn, weathering and erosion or sedimentation could affect the thickness of overburden above a repository. Weathering processes would also influence the chemistry of the groundwater system. In tropical climates weathering would be important to greater depth than in arid regions. In arid climates evaporation of surface water bodies (which may be ephemeral) could generate hypersaline and potentially hyperalkaline lakes, which could influence the chemistry of underlying groundwater. Desertification caused by extended drought could lead to deforestation and loss of grassland; dust storms might become a common feature causing soil erosion; alkali flats might form causing the accumulation of salts and contaminants at the soil surface.
2000 List
A reference to the related FEP(s) within the 2000 NEA IFEP List.
Related References
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IAEA (), Environmental Change in Post-closure Safety Assessment of Solid Radioactive Waste Repositories, Working Group 3 Reference Models for Waste Disposal of EMRAS II Topical Heading Reference Approaches for Human Dose Assessment. Environmental Modelling for Radiation Safety (EMRAS II) Programme, International Atomic Energy Agency, Vienna, IAEA-TECDOC-1799, http://www-pub.iaea.org/MTCD/Publications/PDF/TE1799web.pdf