Description
The effects of glaciers and ice sheets within the region/locality of the repository, e.g. changes in the geomorphology, erosion, meltwater, mechanical and hydraulic effects.
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.
Glacial and ice sheet 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 around the repository; 3) influencing the stresses on the repository system and surrounding rocks; 5) reducing the thickness of the geological barrier; 6) if sufficient erosion occurs, impacting on the physical integrity of the EBS and 7) influencing the natures and spatial distributions of receptors that could be impacted by any radionuclides or contaminants that are transported from the repository. The presence or absence of ice will influence the water recharge to groundwater beneath the glacier or ice sheet. Beneath so-called “cold-bottomed” glaciers or ice sheets water recharge may be prevented. Permafrost may occur beneath a glacier / ice sheet, with similar effects as those described for FEP 1.3.4. Conversely, beneath so-called “warm-bottomed” glaciers or ice sheets water recharge may be enhanced by the weight of overlying ice that leads to high groundwater heads. Head gradients may develop beneath the glacier or ice sheet due to heterogeneous ice loading and heterogeneous distribution of recharge. Such gradients will tend to be greatest near the margins of the glacier or ice sheet. Ice sheets will also influence the geothermal gradient in the rocks beneath them, owing to the thermal insulating effect of the ice. Loading/unloading of the repository and surrounding rock during glaciation/deglaciation may change the characteristics of potential groundwater flow pathways (e.g. fracture dilation during unloading, fracture contraction during loading). The weight of large ice sheets may lead to isostatic depression of the land surface. The depressed surface will rebound following retreat of the ice sheet. These isostatic effects can result in changes in local sea level in the vicinity of a repository. Water recharged beneath a glacier or ice sheet will be fresh and oxidising. Such water could be detrimental with respect to certain engineered barriers should it reach the repository (e.g. bentonite buffer erosion being promoted by low salinity) and or with respect to transport of radionuclides or other contaminants (e.g. U being transported in an oxidised form). The advance and retreat of glaciers and ice sheets will influence erosion and sedimentation and have a major effect on topography. Erosional processes (abrasion, over-deepening) associated with glacial action, especially advancing glaciers and ice sheets, and with glacial meltwaters beneath the ice mass and at the margins, can lead to morphological changes in the environment e.g. U-shaped valleys, hanging valleys, fjords and drumlins. Depositional features associated with glaciers and ice sheets include moraines and eskers. These erosional and depositional processes could, in the long-term, influence the thickness of overburden above a repository.
2000 List
A reference to the related FEP(s) within the 2000 NEA IFEP List.
Related References
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Thorne M, Walke R and Kelly M (), Representation of Climate Change and Landscape Development in Post-closure Radiological Impact Assessments, QRS-1667A-1, AMEC/200041/001, RWMD/03/033, https://rwm.nda.gov.uk/publication/representation-of-climate-change-and-landscape-development-in-post-closure-radiological-impact-assessments-qrs1667a1/
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Claesson Liljedahl L, Kontula A, Harper J, Näslund J-O, Selroos J-O, Pitkänen P, Puigdomenech I, Hobbs M, Follin S, Hirschorn S, Jansson P, Kennell L, Marcos N, Ruskeeniemi T, Tullborg E-L and Vidstrand P (), The Greenland Analogue Project: Final Report, SKB Technical Report TR-14-13, http://www.skb.com/publication/2484498/TR-14-13.pdf
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Harper J, Hubbard A, Ruskeeniemi T, Claesson Liljedahl L, Kontula A, Hobbs M, Brown J, Dirkson A, Dow C, Doyle S, Drake H, Engström J, Fitzpatrick A, Follin S, Frape S, Graly J, Hansson K, Harrington J, Henkemans E, Hirschorn S, Humphrey N, Jansson P, Johnson J, Jones G, Kinnbom P, Kennell L, Klint K E, Liimatainen J, Lindbäck K, Meierbachtol T, Pere T, Pettersson R, Tullborg E-L and van As D (), The Greenland Analogue Project: Data and Processes, SKB Report R-14-13, http://www.skb.com/publication/2484511/R-14-13.pdf
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Fischer UH, Bebiolka A, Brandefelt J, Cohen D, Harper J, Hirschorn S, Jensen M, Kennell L, Liakka J, Näslund JO, Normani S (), Radioactive waste under conditions of future ice ages., Snow and Ice-Related Hazards, Risks, and Disasters, Elsevier, 323-375, https://doi.org/10.1016/B978-0-12-817129-5.00005-6
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Lindborg T, Thorne M, Andersson E, Becker J, Brandefelt J, et al. (), Climate change and landscape development in post-closure safety assessment of solid radioactive waste disposal: Results of an initiative of the IAEA, Journal of Environmental Radioactivity , Elsevier, 183, 41-53, https://doi.org/10.1016/j.jenvrad.2017.12.006
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Cook SJ, Swift DA, Kirkbride MP, Knight PG, Waller RI (), The empirical basis for modelling glacial erosion rates, Nature Communications, Nature, 11(1), 1-7, https://doi.org/10.1038/s41467-020-14583-8
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Deprez M, De Kock T, De Schutter G, Cnudde V (), A review on freeze–thaw action and weathering of rocks, Earth Science Reviews, Elsevier, 203, 103143, https://doi.org/10.1016/j.earscirev.2020.103143