Description
The chemical speciation and solubility of any repository-derived contaminants in the biosphere under prevailing environmental conditions.
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
Comments
The “Comments” field, when present, contains any additional explanation of the IFEP, beyond that implicit in the FEP's description and provided in the “Relevance to Performance and Safety” field. This additional explanation may include, where appropriate, the IFEPs characteristics, the circumstances under which it might be relevant and its relationship to other (especially similar) IFEPs.
The concentration of an element in aqueous solution (at equilibrium) reflects the solubility of the solid compounds which contain the element. Factors such as temperature, gas partial pressure, ionic strength, the presence of complexing agents and pH and Eh conditions affect solubility. These factors also affect the chemical form and speciation of the element. Thus different solids of the same element may have different solubilities in a particular solution.
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.
Speciation of any repository-derived contaminants in the biosphere can be particularly important because of the relatively large concentrations of oxygen and carbon dioxide dissolved in rain water and the soil pore water and the presence of organic complexes and compounds. Bacteria, microbes and plants may chemically transform contaminants and thereby change their sorption and solubility properties.
2000 List
A reference to the related FEP(s) within the 2000 NEA IFEP List.
Related References
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Wheater HS, Bell JNB, Butler AP, Jackson BM, Ciciani L, Ashworth DJ and Shaw GG (), Biosphere Implications of Deep Disposal of Nuclear Waste: The Upwards Migration of Radionuclides in Vegetated Soils, Series on Environmental Science and Management: Volume 5, Imperial College Press, ISBN: 978-1-86094-743-8, http://www.worldscientific.com/worldscibooks/10.1142/P482#t=toc, 30 June 2007
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Von Gunten HR and Benes R (), Speciation of Radionuclides in the Environment, Paul Scherrer Institut Bericht Nr. 94-03, IAEA, ISSN 1019-0643, http://www.iaea.org/inis/collection/NCLCollectionStore/_Public/25/025/25025064.pdf?r=1, 31 January 1994
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Bakirdere S (), Speciation Studies in Soil, Sediment and Environmental Samples, CRC Press, ISBN 978-1-46659-485-2, 612, https://www.crcpress.com/Speciation-Studies-in-Soil-Sediment-and-Environmental-Samples/Bakirdere/p/book/9781466594852, 25 September 2013