a) Background b) What should be done? c) Methods and tool
a) Estimating the long term safety of a geological
nuclear waste repository is a complicated computational
problem. Numerous scenarios of system failure must be
taken into account. Released radionuclides can be
transported long distances along the groundwater of rock
fractures. Sorption into the bedrock may also take place.
In the case of a release of radionuclides to the
groundwater, transport properties in fractures must be
well known. A common approximation of rock fracture flow
is flow between parallel plates. The shape of natural
fractures, however, is uneven and irregular. Varying
shape and size causes dispersion that affects transport.
b) Study the effect of dispersion caused by variable
aperture fractures to the transport and flow properties.
Build models of a single rock fracture in different
credible geometries. Calculate the flow field and
transport of a pulse of radionuclides trough the
fractures. Also, calculate the retention of nuclides
caused by matrix diffusion. Compare the results to the
c) Numerical methods: FEM with time integration. COMSOL
Multiphysics 4.2a, CAD Import Module, Subsurface Flow
Module, Chemical Reaction Engineering Module.
|Place of Publication||Espoo|
|Publisher||VTT Technical Research Centre of Finland|
|Number of pages||34|
|Publication status||Published - 2013|
|MoE publication type||Not Eligible|
- radionuclide transport
- bedrock fracture
- matrix diffusion
- parallel plate approximation