Description
An explosion resulting from the ignition of a flammable gas mixture in the repository. Gases could be produced from the corrosion and degradation of waste packages and/or engineered repository features and/or could enter the repository from the surrounding geosphere. Some gases might be flammable or might form an explosive mixture. For instance, hydrogen and methane could mix with oxygen and explode. However, a gas explosion can only occur if a flammable gas mixture forms and there is a source of ignition or the gas mixture has the capability to auto-ignite.
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.
Were a gas explosion to occur it might damage the EBS and surrounding geological barrier. Such an explosion may also provide a force driving the movement of fluids (water, non-aqueous liquids and gas), which may carry radionuclides and other contaminants, should they be released from the waste packages. A gas explosion may also modify the chemical environment within the repository, which may then impact upon the subsequent evolution of the EBS and potentially upon the release and migration of radionuclides and other contaminants, should they be released from the waste packages.
2000 List
A reference to the related FEP(s) within the 2000 NEA IFEP List.