RepoTREND: Repository Safety Analysis

For a long-term assessment of the safety of final repositories for radioactive waste, the program package RepoTREND (Transport and REtention of Non-decaying and Decaying contaminants in a final REPOsitory) is being developed and applied by GRS. In this program package, all relevant processes which contribute to the mobilisation and release of contaminants from the repository, transport through the host rock and adjacent rock formations as well as exposure in the biosphere have been implemented.

A final repository for radioactive waste could be considered as consisting of three compartments: the near-field, the far-field, and the biosphere. RepoTREND is modularly designed corresponding to this subdivision and provides computational modules for the simulation of the processes in each compartment.

Illustration of different exposure pathways with external exposure (exposure from the outside to the body) and internal exposure (intake of radioactive substances into the human body e.g. via airway or food)

Components of version 4.5 of RepoTREND

Near-field computational modules:

LOPOS – radionuclide mobilisation and one-phase transport in a repository in salt rock,
CLAYPOS – one-phase diffusive transport through a fully saturated clay barrier,

Farfield computational modules (GeoTREND-Family) for simulating the contaminant transport in fully saturated media:

POSA – porous media,
FRAME – porous-fractured media,
COFRAME – porous-fractured media in the presence of colloids,
Biosphere computational module BioTREND for calculating of annual effective doses and certain safety indicators,
Flexible configurable graphical user interface XENIA for entering the model parameters,
Framework for statistical analyses RepoSTAR.

Currently, the new computational module NaTREND for simulating the release of contaminants and their two-phase transport through the near field is being developed.

Computational modules of RepoTREND for different repository compartments