Description
The biological processes affecting the waste package such as degradation of organics, nitrate ions and sulphate ions, biofilm growth and volatilisation.
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
- 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.
Microbially/biologically mediated processes may affect the release of radionuclides and other contaminants from the waste and the potential mobility of these contaminants within the waste package. Microbially/biologically mediated processes may also impact upon the safety functions of waste package components. For example, microbial processes can lead to the formation of acidic and oxidising species that can participate in corrosion of the metals and generation of reducing conditions. Such microbially influenced corrosion may affect the ability of a steel container to contain the waste and / or its ability to resist mechanical deformation. Microbially/biologically mediated processes may generate or consume fluids (gas, non-aqueous phase liquids and water) and may change the specific volume of solid materials. These processes may thus change the pressures within a waste package and thereby the forces that could drive radionuclides or other contaminants from the waste package, should it be vented or become breached. Pressure changes may also lead to mechanical deformation, and potentially affect the integrity of, waste package components. Biofilms may form on or around the waste package and may act to concentrate radionuclides or other contaminants. Biofilms may also decrease the permeability of materials within the waste package.
2000 List
A reference to the related FEP(s) within the 2000 NEA IFEP List.
Related References
-
Wolfram J H, Rogers R D and Gazsó L G (Eds) (), Microbial Degradation Processes in Radioactive Waste Repository and in Nuclear Fuel Storage Areas, Volume 11, Microbial Degradation Processes in Radioactive Waste Repository and in Nuclear Fuel Storage Areas, Springer, ISBN 978-0-7923-4488-9, http://www.springer.com/gb/book/9780792344889
-
Mijnendonckx K, Small J, Abrahamsen-Mills L, Pedersen K, Leys N (), Microbiology in Nuclear Waste Disposal (MIND) – Deliverable 3.7 Final integration and evaluation report, Euratom research and training programme 2014-2018 under Grant Agreement no. 661880, https://mind15.eu/wp-content/uploads/2019/09/MIND-Deliverable-3.7-Final-integration-and-evaluation-report.pdf