Simulation of concrete deterioration in Finnish rock cavern conditions for final disposal of nuclear waste

• Concrete deterioration in Finnish rock cavern disposal conditions was simulated.
• Simulation requires advanced models instead of traditional linear diffusion models.
• Concrete analysed performed moderately during the period of 500 years.
• Corrosion of steel reinforcement cannot be excluded during the period analysed.

A simulation of concrete ageing in Finnish rock cavern disposal conditions showed that the concrete undergoes complex deterioration processes during the period required for lowering the level of radiation. In respect of the concrete ageing, the life time of the disposal facilities shall be divided into the periods before and after the closing of the caverns. Generally, the sulphate-resistant type of concrete analysed performed moderately during the analysed period of 500 years contrary to the corrosion of steel reinforcement, which cannot be excluded. Simulation of ageing clearly requires thermodynamical methods instead of linear diffusion models based on Fick’s law, which are traditionally used in construction industry. The study proves that the thermodynamical simulation method developed with adequate experimental data also makes it possible to observe latent factors of concrete deterioration.