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Tritium transport in non-saturated concrete under temperature fluctuations
M Carme Chaparro1, Maarten W Saaltink2
1Karlsruhe Institute of Technology (KIT), Institute of Nuclear Waste Disposal (INE), PO Box 3640, 76021, Karlsruhe, Germany.
Journal of Environmental Radioactivity
|August 9, 2022
Summary
Environmental conditions drive tritium transport in concrete radioactive waste storage cells. Thermo-hydraulic processes, including evaporation and condensation, influence tritium movement, but no groundwater release is predicted.
Area of Science:
- Environmental Science
- Nuclear Engineering
- Materials Science
Background:
- Radioactive waste storage in concrete cells presents challenges for containing hazardous materials.
- Observed leaks of tritiated water from drains indicate internal transport mechanisms.
- Understanding tritium behavior is crucial for long-term waste management safety.
Purpose of the Study:
- To investigate the impact of environmental conditions on tritium transport within concrete storage cells.
- To identify the key thermo-hydraulic processes governing tritiated water movement.
- To model and predict tritium migration patterns and potential release pathways.
Main Methods:
- Development and application of 2D numerical models simulating tritium transport.
- Integration of temperature and humidity measurements to validate models.
- Analysis of tritium fluxes considering both liquid and gas phase transport.
Main Results:
- Tritiated water leaks are attributed to thermo-hydraulic processes like capillary rise, evaporation, and condensation.
- Tritium concentration within the concrete is significantly influenced by internal evaporation and condensation cycles.
- Differential transport mechanisms in liquid and gas phases create complex tritium concentration gradients.
Conclusions:
- Seasonal temperature fluctuations drive internal moisture movement and tritium redistribution.
- Distinct tritium concentration profiles emerge in wet versus dry zones within the concrete.
- Numerical models indicate no tritiated water release to the surrounding groundwater.
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