Description

The production and transfer of heat originating from biological processes affecting the waste packages.

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

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.

Biologically-mediate processes within the waste package may generate heat. Once generated heat will be transferred within the waste package by a combination of conduction and convection. Heating will affect the physical, chemical, and biological properties of the heated materials. The rates of chemical and biological processes will depend upon the temperatures attained. Physical properties of the waste form and packaging, such as volumes and mechanical strength will also be influenced by the temperature evolution. Should the integrity of a waste package fail, the rate at which radionuclides and other contaminants are released from the package, and the forms in which they are released, will depend on variations in these physical, chemical, and biological properties due to biological processes that produce heat. The heating of the waste package due to biological processes within it, could potentially influence the chemical, physical and biological characteristics and properties of the surrounding barriers, whether engineered or natural.

2000 List

A reference to the related FEP(s) within the 2000 NEA IFEP List.

2.1.11

Related References