Description
The possibility of a large meteorite or human space debris impact occurring at or close to the repository site and related consequences.
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.
- Event
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.
A large meteorite or human space debris impacting at or close to a repository site could impact on repository and safety by: 1) impairing the performance of the engineered and/or natural barriers; 2) transporting radionuclides and other contaminants from the repository to the biosphere and dispersing them there; 3) dispersing radionuclides and other contaminants that have already been released by the repository owing to other processes; 4) changing the topography, with consequent impacts on drainage; 5) affecting the nature of ecosystems that could be impacted by radionuclides and / or other contaminants that might reach the biosphere from the repository. Very large meteor impacts could cause faults and fractures to form and / or existing faults and fractures to be reactivated and to dilate and/or seal. There could be related influences on groundwater fluxes and chemistry. Large impacts may result in metamorphism of the rocks and dispersion of ejecta, which may be contaminated by radionuclides and/or other contaminants. Effects on surface topography could include cratering, damming of rivers or breaching of topographical barriers such as ranges of hills. These processes could alter the surface drainage and the spatial distributions of water bodies. For example lakes could form in impact craters. These changes could be accompanied by local changes in ecosystems and hence the natures of organisms that could be impacted by any radionuclides or other contaminants originating in a repository. In very extreme meteor impact events there could be a global effect on organisms, possibly including mass extinctions, which could be followed by evolutionary radiation. Some effects of impacts of meteorites or human space debris would occur immediately, such as the breaching of a repository. Other effects could be very long-lasting, such as the topographical changes and related effects that could be caused by the impact of a large meteorite.
2000 List
A reference to the related FEP(s) within the 2000 NEA IFEP List.
Related References
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Secure World Foundation (), Near-Earth Objects: Responding to the International Challenge, April 2014, https://swfound.org/media/170684/swf_neos-responding_to_the_international_challenge_2014.pdf
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Rumpf C, Lewis H G and Atkinson P M (), On the influence of impact effect modelling for global asteroid impact risk distribution, Acta Astronautica, 123, pp165–170, http://www.sciencedirect.com/science/article/pii/S0094576515302988
Special Section: Selected Papers from the International Workshop on Satellite Constellations and Formation Flying 2015